cifs: multichannel: move channel selection above transport layer

Move the channel (TCP_Server_Info*) selection from the tranport
layer to higher in the call stack so that:

- credit handling is done with the server that will actually be used
  to send.
  * ->wait_mtu_credit
  * ->set_credits / set_credits
  * ->add_credits / add_credits
  * add_credits_and_wake_if

- potential reconnection (smb2_reconnect) done when initializing a
  request is checked and done with the server that will actually be
  used to send.

To do this:

- remove the cifs_pick_channel() call out of compound_send_recv()

- select channel and pass it down by adding a cifs_pick_channel(ses)
  call in:
  - smb311_posix_mkdir
  - SMB2_open
  - SMB2_ioctl
  - __SMB2_close
  - query_info
  - SMB2_change_notify
  - SMB2_flush
  - smb2_async_readv  (if none provided in context param)
  - SMB2_read         (if none provided in context param)
  - smb2_async_writev (if none provided in context param)
  - SMB2_write        (if none provided in context param)
  - SMB2_query_directory
  - send_set_info
  - SMB2_oplock_break
  - SMB311_posix_qfs_info
  - SMB2_QFS_info
  - SMB2_QFS_attr
  - smb2_lockv
  - SMB2_lease_break
    - smb2_compound_op
  - smb2_set_ea
  - smb2_ioctl_query_info
  - smb2_query_dir_first
  - smb2_query_info_comound
  - smb2_query_symlink
  - cifs_writepages
  - cifs_write_from_iter
  - cifs_send_async_read
  - cifs_read
  - cifs_readpages

- add TCP_Server_Info *server param argument to:
  - cifs_send_recv
  - compound_send_recv
  - SMB2_open_init
  - SMB2_query_info_init
  - SMB2_set_info_init
  - SMB2_close_init
  - SMB2_ioctl_init
  - smb2_iotcl_req_init
  - SMB2_query_directory_init
  - SMB2_notify_init
  - SMB2_flush_init
  - build_qfs_info_req
  - smb2_hdr_assemble
  - smb2_reconnect
  - fill_small_buf
  - smb2_plain_req_init
  - __smb2_plain_req_init

The read/write codepath is different than the rest as it is using
pages, io iterators and async calls. To deal with those we add a
server pointer in the cifs_writedata/cifs_readdata/cifs_io_parms
context struct and set it in:

- cifs_writepages      (wdata)
- cifs_write_from_iter (wdata)
- cifs_readpages       (rdata)
- cifs_send_async_read (rdata)

The [rw]data->server pointer is eventually copied to
cifs_io_parms->server to pass it down to SMB2_read/SMB2_write.
If SMB2_read/SMB2_write is called from a different place that doesn't
set the server field it will pick a channel.

Some places do not pick a channel and just use ses->server or
cifs_ses_server(ses). All cifs_ses_server(ses) calls are in codepaths
involving negprot/sess.setup.

- SMB2_negotiate         (binding channel)
- SMB2_sess_alloc_buffer (binding channel)
- SMB2_echo              (uses provided one)
- SMB2_logoff            (uses master)
- SMB2_tdis              (uses master)

(list not exhaustive)
Signed-off-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/cifsglob.h

@@ -1335,6 +1335,7 @@ struct cifs_io_parms {
 	__u64 offset;
 	unsigned int length;
 	struct cifs_tcon *tcon;
+	struct TCP_Server_Info *server;
 };
 
 struct cifs_aio_ctx {
@@ -1382,6 +1383,7 @@ struct cifs_readdata {
 				struct cifs_readdata *rdata,
 				struct iov_iter *iter);
 	struct kvec			iov[2];
+	struct TCP_Server_Info		*server;
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	struct smbd_mr			*mr;
 #endif
@@ -1408,6 +1410,7 @@ struct cifs_writedata {
 	pid_t				pid;
 	unsigned int			bytes;
 	int				result;
+	struct TCP_Server_Info		*server;
 #ifdef CONFIG_CIFS_SMB_DIRECT
 	struct smbd_mr			*mr;
 #endif

fs/cifs/cifsproto.h

@@ -98,9 +98,11 @@ extern int cifs_call_async(struct TCP_Server_Info *server,
 			const struct cifs_credits *exist_credits);
 extern struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses);
 extern int cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
+			  struct TCP_Server_Info *server,
 			  struct smb_rqst *rqst, int *resp_buf_type,
 			  const int flags, struct kvec *resp_iov);
 extern int compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
+			      struct TCP_Server_Info *server,
 			      const int flags, const int num_rqst,
 			      struct smb_rqst *rqst, int *resp_buf_type,
 			      struct kvec *resp_iov);

fs/cifs/file.c

@@ -2292,8 +2292,6 @@ wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
 		 struct address_space *mapping, struct writeback_control *wbc)
 {
 	int rc;
-	struct TCP_Server_Info *server =
-				tlink_tcon(wdata->cfile->tlink)->ses->server;
 
 	wdata->sync_mode = wbc->sync_mode;
 	wdata->nr_pages = nr_pages;
@@ -2305,14 +2303,15 @@ wdata_send_pages(struct cifs_writedata *wdata, unsigned int nr_pages,
 	wdata->bytes = ((nr_pages - 1) * PAGE_SIZE) + wdata->tailsz;
 	wdata->pid = wdata->cfile->pid;
 
-	rc = adjust_credits(server, &wdata->credits, wdata->bytes);
+	rc = adjust_credits(wdata->server, &wdata->credits, wdata->bytes);
 	if (rc)
 		return rc;
 
 	if (wdata->cfile->invalidHandle)
 		rc = -EAGAIN;
 	else
-		rc = server->ops->async_writev(wdata, cifs_writedata_release);
+		rc = wdata->server->ops->async_writev(wdata,
+						      cifs_writedata_release);
 
 	return rc;
 }
@@ -2349,7 +2348,8 @@ static int cifs_writepages(struct address_space *mapping,
 			range_whole = true;
 		scanned = true;
 	}
-	server = cifs_sb_master_tcon(cifs_sb)->ses->server;
+	server = cifs_pick_channel(cifs_sb_master_tcon(cifs_sb)->ses);
+
 retry:
 	while (!done && index <= end) {
 		unsigned int i, nr_pages, found_pages, wsize;
@@ -2403,6 +2403,7 @@ static int cifs_writepages(struct address_space *mapping,
 
 		wdata->credits = credits_on_stack;
 		wdata->cfile = cfile;
+		wdata->server = server;
 		cfile = NULL;
 
 		if (!wdata->cfile) {
@@ -2806,8 +2807,7 @@ cifs_resend_wdata(struct cifs_writedata *wdata, struct list_head *wdata_list,
 	unsigned int wsize;
 	struct cifs_credits credits;
 	int rc;
-	struct TCP_Server_Info *server =
-		tlink_tcon(wdata->cfile->tlink)->ses->server;
+	struct TCP_Server_Info *server = wdata->server;
 
 	do {
 		if (wdata->cfile->invalidHandle) {
@@ -2893,7 +2893,7 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
 	else
 		pid = current->tgid;
 
-	server = tlink_tcon(open_file->tlink)->ses->server;
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
 	xid = get_xid();
 
 	do {
@@ -2997,6 +2997,7 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
 		wdata->nr_pages = nr_pages;
 		wdata->offset = (__u64)offset;
 		wdata->cfile = cifsFileInfo_get(open_file);
+		wdata->server = server;
 		wdata->pid = pid;
 		wdata->bytes = cur_len;
 		wdata->pagesz = PAGE_SIZE;
@@ -3538,8 +3539,10 @@ static int cifs_resend_rdata(struct cifs_readdata *rdata,
 	unsigned int rsize;
 	struct cifs_credits credits;
 	int rc;
-	struct TCP_Server_Info *server =
-		tlink_tcon(rdata->cfile->tlink)->ses->server;
+	struct TCP_Server_Info *server;
+
+	/* XXX: should we pick a new channel here? */
+	server = rdata->server;
 
 	do {
 		if (rdata->cfile->invalidHandle) {
@@ -3618,7 +3621,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
 	size_t start;
 	struct iov_iter direct_iov = ctx->iter;
 
-	server = tlink_tcon(open_file->tlink)->ses->server;
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
 
 	if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
 		pid = open_file->pid;
@@ -3702,6 +3705,7 @@ cifs_send_async_read(loff_t offset, size_t len, struct cifsFileInfo *open_file,
 			rdata->tailsz = PAGE_SIZE;
 		}
 
+		rdata->server = server;
 		rdata->cfile = cifsFileInfo_get(open_file);
 		rdata->nr_pages = npages;
 		rdata->offset = offset;
@@ -4031,7 +4035,7 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
 	}
 	open_file = file->private_data;
 	tcon = tlink_tcon(open_file->tlink);
-	server = tcon->ses->server;
+	server = cifs_pick_channel(tcon->ses);
 
 	if (!server->ops->sync_read) {
 		free_xid(xid);
@@ -4070,6 +4074,7 @@ cifs_read(struct file *file, char *read_data, size_t read_size, loff_t *offset)
 			io_parms.tcon = tcon;
 			io_parms.offset = *offset;
 			io_parms.length = current_read_size;
+			io_parms.server = server;
 			rc = server->ops->sync_read(xid, &open_file->fid, &io_parms,
 						    &bytes_read, &cur_offset,
 						    &buf_type);
@@ -4372,7 +4377,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 		pid = current->tgid;
 
 	rc = 0;
-	server = tlink_tcon(open_file->tlink)->ses->server;
+	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
 
 	cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
 		 __func__, file, mapping, num_pages);
@@ -4443,6 +4448,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
 		}
 
 		rdata->cfile = cifsFileInfo_get(open_file);
+		rdata->server = server;
 		rdata->mapping = mapping;
 		rdata->offset = offset;
 		rdata->bytes = bytes;

fs/cifs/link.c

@@ -450,7 +450,7 @@ smb3_create_mf_symlink(unsigned int xid, struct cifs_tcon *tcon,
 	int rc;
 	struct cifs_fid fid;
 	struct cifs_open_parms oparms;
-	struct cifs_io_parms io_parms;
+	struct cifs_io_parms io_parms = {0};
 	__le16 *utf16_path;
 	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct kvec iov[2];

fs/cifs/smb2inode.c

@@ -74,6 +74,7 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	__u8 oplock = SMB2_OPLOCK_LEVEL_NONE;
 	struct cifs_fid fid;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server;
 	int num_rqst = 0;
 	int resp_buftype[3];
 	struct smb2_query_info_rsp *qi_rsp = NULL;
@@ -89,6 +90,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst = &vars->rqst[0];
 	rsp_iov = &vars->rsp_iov[0];
 
+	server = cifs_pick_channel(ses);
+
 	if (smb3_encryption_required(tcon))
 		flags |= CIFS_TRANSFORM_REQ;
 
@@ -115,7 +118,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 
 	rqst[num_rqst].rq_iov = &vars->open_iov[0];
 	rqst[num_rqst].rq_nvec = SMB2_CREATE_IOV_SIZE;
-	rc = SMB2_open_init(tcon, &rqst[num_rqst], &oplock, &vars->oparms,
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[num_rqst], &oplock, &vars->oparms,
 			    utf16_path);
 	kfree(utf16_path);
 	if (rc)
@@ -133,7 +137,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		rqst[num_rqst].rq_nvec = 1;
 
 		if (cfile)
-			rc = SMB2_query_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_query_info_init(tcon, server,
+				&rqst[num_rqst],
 				cfile->fid.persistent_fid,
 				cfile->fid.volatile_fid,
 				FILE_ALL_INFORMATION,
@@ -141,10 +146,11 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 				sizeof(struct smb2_file_all_info) +
 					  PATH_MAX * 2, 0, NULL);
 		else {
-			rc = SMB2_query_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_query_info_init(tcon, server,
+				&rqst[num_rqst],
 				COMPOUND_FID,
 				COMPOUND_FID,
-				 FILE_ALL_INFORMATION,
+				FILE_ALL_INFORMATION,
 				SMB2_O_INFO_FILE, 0,
 				sizeof(struct smb2_file_all_info) +
 					  PATH_MAX * 2, 0, NULL);
@@ -177,7 +183,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		size[0] = 1; /* sizeof __u8 See MS-FSCC section 2.4.11 */
 		data[0] = &delete_pending[0];
 
-		rc = SMB2_set_info_init(tcon, &rqst[num_rqst], COMPOUND_FID,
+		rc = SMB2_set_info_init(tcon, server,
+					&rqst[num_rqst], COMPOUND_FID,
 					COMPOUND_FID, current->tgid,
 					FILE_DISPOSITION_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
@@ -194,7 +201,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		size[0] = 8; /* sizeof __le64 */
 		data[0] = ptr;
 
-		rc = SMB2_set_info_init(tcon, &rqst[num_rqst], COMPOUND_FID,
+		rc = SMB2_set_info_init(tcon, server,
+					&rqst[num_rqst], COMPOUND_FID,
 					COMPOUND_FID, current->tgid,
 					FILE_END_OF_FILE_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
@@ -213,13 +221,15 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		data[0] = ptr;
 
 		if (cfile)
-			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_set_info_init(tcon, server,
+				&rqst[num_rqst],
 				cfile->fid.persistent_fid,
 				cfile->fid.volatile_fid, current->tgid,
 				FILE_BASIC_INFORMATION,
 				SMB2_O_INFO_FILE, 0, data, size);
 		else {
-			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_set_info_init(tcon, server,
+				&rqst[num_rqst],
 				COMPOUND_FID,
 				COMPOUND_FID, current->tgid,
 				FILE_BASIC_INFORMATION,
@@ -253,13 +263,15 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		data[1] = (__le16 *)ptr;
 
 		if (cfile)
-			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_set_info_init(tcon, server,
+						&rqst[num_rqst],
 						cfile->fid.persistent_fid,
 						cfile->fid.volatile_fid,
 					current->tgid, FILE_RENAME_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
 		else {
-			rc = SMB2_set_info_init(tcon, &rqst[num_rqst],
+			rc = SMB2_set_info_init(tcon, server,
+					&rqst[num_rqst],
 					COMPOUND_FID, COMPOUND_FID,
 					current->tgid, FILE_RENAME_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
@@ -289,7 +301,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 		size[1] = len + 2 /* null */;
 		data[1] = (__le16 *)ptr;
 
-		rc = SMB2_set_info_init(tcon, &rqst[num_rqst], COMPOUND_FID,
+		rc = SMB2_set_info_init(tcon, server,
+					&rqst[num_rqst], COMPOUND_FID,
 					COMPOUND_FID, current->tgid,
 					FILE_LINK_INFORMATION,
 					SMB2_O_INFO_FILE, 0, data, size);
@@ -312,7 +325,8 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	/* Close */
 	rqst[num_rqst].rq_iov = &vars->close_iov[0];
 	rqst[num_rqst].rq_nvec = 1;
-	rc = SMB2_close_init(tcon, &rqst[num_rqst], COMPOUND_FID,
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[num_rqst], COMPOUND_FID,
 			     COMPOUND_FID, false);
 	smb2_set_related(&rqst[num_rqst]);
 	if (rc)
@@ -323,11 +337,13 @@ smb2_compound_op(const unsigned int xid, struct cifs_tcon *tcon,
 	if (cfile) {
 		cifsFileInfo_put(cfile);
 		cfile = NULL;
-		rc = compound_send_recv(xid, ses, flags, num_rqst - 2,
+		rc = compound_send_recv(xid, ses, server,
+					flags, num_rqst - 2,
 					&rqst[1], &resp_buftype[1],
 					&rsp_iov[1]);
 	} else
-		rc = compound_send_recv(xid, ses, flags, num_rqst,
+		rc = compound_send_recv(xid, ses, server,
+					flags, num_rqst,
 					rqst, resp_buftype,
 					rsp_iov);
 

fs/cifs/smb2ops.c

@@ -708,7 +708,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = pfid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, &utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, &utf16_path);
 	if (rc)
 		goto oshr_free;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -717,7 +718,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID,
+	rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID,
 				  COMPOUND_FID, FILE_ALL_INFORMATION,
 				  SMB2_O_INFO_FILE, 0,
 				  sizeof(struct smb2_file_all_info) +
@@ -727,7 +729,8 @@ int open_shroot(unsigned int xid, struct cifs_tcon *tcon,
 
 	smb2_set_related(&rqst[1]);
 
-	rc = compound_send_recv(xid, ses, flags, 2, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 2, rqst,
 				resp_buftype, rsp_iov);
 	mutex_lock(&tcon->crfid.fid_mutex);
 
@@ -1102,6 +1105,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	    struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	__le16 *utf16_path = NULL;
 	int ea_name_len = strlen(ea_name);
 	int flags = 0;
@@ -1190,7 +1194,8 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto sea_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -1216,7 +1221,8 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	size[0] = len;
 	data[0] = ea;
 
-	rc = SMB2_set_info_init(tcon, &rqst[1], COMPOUND_FID,
+	rc = SMB2_set_info_init(tcon, server,
+				&rqst[1], COMPOUND_FID,
 				COMPOUND_FID, current->tgid,
 				FILE_FULL_EA_INFORMATION,
 				SMB2_O_INFO_FILE, 0, data, size);
@@ -1228,10 +1234,12 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	memset(&close_iov, 0, sizeof(close_iov));
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	/* no need to bump num_remote_opens because handle immediately closed */
 
@@ -1473,6 +1481,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 	struct smb_rqst *rqst;
 	struct kvec *rsp_iov;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	char __user *arg = (char __user *)p;
 	struct smb_query_info qi;
 	struct smb_query_info __user *pqi;
@@ -1505,7 +1514,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 		return -EINVAL;
 	}
 
-	if (!ses || !(ses->server)) {
+	if (!ses || !server) {
 		kfree(vars);
 		return -EIO;
 	}
@@ -1552,7 +1561,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 		oparms.desired_access = FILE_READ_ATTRIBUTES | READ_CONTROL;
 	}
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, path);
 	if (rc)
 		goto iqinf_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -1566,7 +1576,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 			rqst[1].rq_iov = &vars->io_iov[0];
 			rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
 
-			rc = SMB2_ioctl_init(tcon, &rqst[1],
+			rc = SMB2_ioctl_init(tcon, server,
+					     &rqst[1],
 					     COMPOUND_FID, COMPOUND_FID,
 					     qi.info_type, true, buffer,
 					     qi.output_buffer_length,
@@ -1585,7 +1596,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 			size[0] = 8;
 			data[0] = buffer;
 
-			rc = SMB2_set_info_init(tcon, &rqst[1],
+			rc = SMB2_set_info_init(tcon, server,
+					&rqst[1],
 					COMPOUND_FID, COMPOUND_FID,
 					current->tgid,
 					FILE_END_OF_FILE_INFORMATION,
@@ -1595,7 +1607,8 @@ smb2_ioctl_query_info(const unsigned int xid,
 		rqst[1].rq_iov = &vars->qi_iov[0];
 		rqst[1].rq_nvec = 1;
 
-		rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID,
+		rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID,
 				  COMPOUND_FID, qi.file_info_class,
 				  qi.info_type, qi.additional_information,
 				  qi.input_buffer_length,
@@ -1615,12 +1628,14 @@ smb2_ioctl_query_info(const unsigned int xid,
 	rqst[2].rq_iov = &vars->close_iov[0];
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto iqinf_exit;
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	if (rc)
 		goto iqinf_exit;
@@ -2172,6 +2187,7 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	struct cifs_open_parms oparms;
 	struct smb2_query_directory_rsp *qd_rsp = NULL;
 	struct smb2_create_rsp *op_rsp = NULL;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 
 	utf16_path = cifs_convert_path_to_utf16(path, cifs_sb);
 	if (!utf16_path)
@@ -2196,7 +2212,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto qdf_free;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2209,7 +2226,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qd_iov;
 	rqst[1].rq_nvec = SMB2_QUERY_DIRECTORY_IOV_SIZE;
 
-	rc = SMB2_query_directory_init(xid, tcon, &rqst[1],
+	rc = SMB2_query_directory_init(xid, tcon, server,
+				       &rqst[1],
 				       COMPOUND_FID, COMPOUND_FID,
 				       0, srch_inf->info_level);
 	if (rc)
@@ -2217,7 +2235,8 @@ smb2_query_dir_first(const unsigned int xid, struct cifs_tcon *tcon,
 
 	smb2_set_related(&rqst[1]);
 
-	rc = compound_send_recv(xid, tcon->ses, flags, 2, rqst,
+	rc = compound_send_recv(xid, tcon->ses, server,
+				flags, 2, rqst,
 				resp_buftype, rsp_iov);
 
 	/* If the open failed there is nothing to do */
@@ -2422,6 +2441,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 			 struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int flags = 0;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
@@ -2452,7 +2472,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto qic_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2461,7 +2482,8 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = qi_iov;
 	rqst[1].rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, &rqst[1], COMPOUND_FID, COMPOUND_FID,
+	rc = SMB2_query_info_init(tcon, server,
+				  &rqst[1], COMPOUND_FID, COMPOUND_FID,
 				  class, type, 0,
 				  output_len, 0,
 				  NULL);
@@ -2474,12 +2496,14 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto qic_exit;
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 	if (rc) {
 		free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
@@ -2811,6 +2835,7 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	struct kvec err_iov = {NULL, 0};
 	struct smb2_err_rsp *err_buf = NULL;
 	struct smb2_symlink_err_rsp *symlink;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 	unsigned int sub_len;
 	unsigned int sub_offset;
 	unsigned int print_len;
@@ -2856,7 +2881,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	oparms.fid = &fid;
 	oparms.reconnect = false;
 
-	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto querty_exit;
 	smb2_set_next_command(tcon, &rqst[0]);
@@ -2867,7 +2893,8 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[1].rq_iov = io_iov;
 	rqst[1].rq_nvec = SMB2_IOCTL_IOV_SIZE;
 
-	rc = SMB2_ioctl_init(tcon, &rqst[1], fid.persistent_fid,
+	rc = SMB2_ioctl_init(tcon, server,
+			     &rqst[1], fid.persistent_fid,
 			     fid.volatile_fid, FSCTL_GET_REPARSE_POINT,
 			     true /* is_fctl */, NULL, 0,
 			     CIFSMaxBufSize -
@@ -2885,13 +2912,15 @@ smb2_query_symlink(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst[2].rq_iov = close_iov;
 	rqst[2].rq_nvec = 1;
 
-	rc = SMB2_close_init(tcon, &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
+	rc = SMB2_close_init(tcon, server,
+			     &rqst[2], COMPOUND_FID, COMPOUND_FID, false);
 	if (rc)
 		goto querty_exit;
 
 	smb2_set_related(&rqst[2]);
 
-	rc = compound_send_recv(xid, tcon->ses, flags, 3, rqst,
+	rc = compound_send_recv(xid, tcon->ses, server,
+				flags, 3, rqst,
 				resp_buftype, rsp_iov);
 
 	create_rsp = rsp_iov[0].iov_base;

fs/cifs/smb2pdu.c

@@ -98,14 +98,13 @@ int smb3_encryption_required(const struct cifs_tcon *tcon)
 
 static void
 smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
-		  const struct cifs_tcon *tcon)
+		  const struct cifs_tcon *tcon,
+		  struct TCP_Server_Info *server)
 {
 	shdr->ProtocolId = SMB2_PROTO_NUMBER;
 	shdr->StructureSize = cpu_to_le16(64);
 	shdr->Command = smb2_cmd;
-	if (tcon && tcon->ses && tcon->ses->server) {
-		struct TCP_Server_Info *server = tcon->ses->server;
-
+	if (server) {
 		spin_lock(&server->req_lock);
 		/* Request up to 10 credits but don't go over the limit. */
 		if (server->credits >= server->max_credits)
@@ -125,8 +124,7 @@ smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
 
 	/* GLOBAL_CAP_LARGE_MTU will only be set if dialect > SMB2.02 */
 	/* See sections 2.2.4 and 3.2.4.1.5 of MS-SMB2 */
-	if ((tcon->ses) && (tcon->ses->server) &&
-	    (tcon->ses->server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
+	if (server && (server->capabilities & SMB2_GLOBAL_CAP_LARGE_MTU))
 		shdr->CreditCharge = cpu_to_le16(1);
 	/* else CreditCharge MBZ */
 
@@ -148,8 +146,7 @@ smb2_hdr_assemble(struct smb2_sync_hdr *shdr, __le16 smb2_cmd,
 /*	if (tcon->share_flags & SHI1005_FLAGS_DFS)
 		shdr->Flags |= SMB2_FLAGS_DFS_OPERATIONS; */
 
-	if (tcon->ses && tcon->ses->server && tcon->ses->server->sign &&
-	    !smb3_encryption_required(tcon))
+	if (server && server->sign && !smb3_encryption_required(tcon))
 		shdr->Flags |= SMB2_FLAGS_SIGNED;
 out:
 	return;
@@ -267,12 +264,12 @@ static inline int __smb2_reconnect(const struct nls_table *nlsc,
 #endif
 
 static int
-smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
+smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon,
+	       struct TCP_Server_Info *server)
 {
 	int rc;
 	struct nls_table *nls_codepage;
 	struct cifs_ses *ses;
-	struct TCP_Server_Info *server;
 	int retries;
 
 	/*
@@ -301,12 +298,10 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
 		}
 	}
 	if ((!tcon->ses) || (tcon->ses->status == CifsExiting) ||
-	    (!tcon->ses->server))
+	    (!tcon->ses->server) || !server)
 		return -EIO;
 
 	ses = tcon->ses;
-	server = ses->server;
-
 	retries = server->nr_targets;
 
 	/*
@@ -439,7 +434,9 @@ smb2_reconnect(__le16 smb2_command, struct cifs_tcon *tcon)
 }
 
 static void
-fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
+fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon,
+	       struct TCP_Server_Info *server,
+	       void *buf,
 	       unsigned int *total_len)
 {
 	struct smb2_sync_pdu *spdu = (struct smb2_sync_pdu *)buf;
@@ -452,7 +449,7 @@ fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
 	 */
 	memset(buf, 0, 256);
 
-	smb2_hdr_assemble(&spdu->sync_hdr, smb2_command, tcon);
+	smb2_hdr_assemble(&spdu->sync_hdr, smb2_command, tcon, server);
 	spdu->StructureSize2 = cpu_to_le16(parmsize);
 
 	*total_len = parmsize + sizeof(struct smb2_sync_hdr);
@@ -464,7 +461,8 @@ fill_small_buf(__le16 smb2_command, struct cifs_tcon *tcon, void *buf,
  * function must have filled in request_buf pointer.
  */
 static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
-				  void **request_buf, unsigned int *total_len)
+				 struct TCP_Server_Info *server,
+				 void **request_buf, unsigned int *total_len)
 {
 	/* BB eventually switch this to SMB2 specific small buf size */
 	if (smb2_command == SMB2_SET_INFO)
@@ -476,7 +474,7 @@ static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
 		return -ENOMEM;
 	}
 
-	fill_small_buf(smb2_command, tcon,
+	fill_small_buf(smb2_command, tcon, server,
 		       (struct smb2_sync_hdr *)(*request_buf),
 		       total_len);
 
@@ -490,27 +488,30 @@ static int __smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
 }
 
 static int smb2_plain_req_init(__le16 smb2_command, struct cifs_tcon *tcon,
+			       struct TCP_Server_Info *server,
 			       void **request_buf, unsigned int *total_len)
 {
 	int rc;
 
-	rc = smb2_reconnect(smb2_command, tcon);
+	rc = smb2_reconnect(smb2_command, tcon, server);
 	if (rc)
 		return rc;
 
-	return __smb2_plain_req_init(smb2_command, tcon, request_buf,
+	return __smb2_plain_req_init(smb2_command, tcon, server, request_buf,
 				     total_len);
 }
 
 static int smb2_ioctl_req_init(u32 opcode, struct cifs_tcon *tcon,
+			       struct TCP_Server_Info *server,
 			       void **request_buf, unsigned int *total_len)
 {
 	/* Skip reconnect only for FSCTL_VALIDATE_NEGOTIATE_INFO IOCTLs */
 	if (opcode == FSCTL_VALIDATE_NEGOTIATE_INFO) {
-		return __smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf,
-					     total_len);
+		return __smb2_plain_req_init(SMB2_IOCTL, tcon, server,
+					     request_buf, total_len);
 	}
-	return smb2_plain_req_init(SMB2_IOCTL, tcon, request_buf, total_len);
+	return smb2_plain_req_init(SMB2_IOCTL, tcon, server,
+				   request_buf, total_len);
 }
 
 /* For explanation of negotiate contexts see MS-SMB2 section 2.2.3.1 */
@@ -858,7 +859,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 		return -EIO;
 	}
 
-	rc = smb2_plain_req_init(SMB2_NEGOTIATE, NULL, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_NEGOTIATE, NULL, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -916,7 +918,8 @@ SMB2_negotiate(const unsigned int xid, struct cifs_ses *ses)
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 	rsp = (struct smb2_negotiate_rsp *)rsp_iov.iov_base;
 	/*
@@ -1227,8 +1230,9 @@ SMB2_sess_alloc_buffer(struct SMB2_sess_data *sess_data)
 	struct TCP_Server_Info *server = cifs_ses_server(ses);
 	unsigned int total_len;
 
-	rc = smb2_plain_req_init(SMB2_SESSION_SETUP, NULL, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_SESSION_SETUP, NULL, server,
+				 (void **) &req,
+				 &total_len);
 	if (rc)
 		return rc;
 
@@ -1305,6 +1309,7 @@ SMB2_sess_sendreceive(struct SMB2_sess_data *sess_data)
 
 	/* BB add code to build os and lm fields */
 	rc = cifs_send_recv(sess_data->xid, sess_data->ses,
+			    cifs_ses_server(sess_data->ses),
 			    &rqst,
 			    &sess_data->buf0_type,
 			    CIFS_LOG_ERROR | CIFS_NEG_OP, &rsp_iov);
@@ -1689,7 +1694,8 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 	if (ses->need_reconnect)
 		goto smb2_session_already_dead;
 
-	rc = smb2_plain_req_init(SMB2_LOGOFF, NULL, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_LOGOFF, NULL, ses->server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -1710,7 +1716,8 @@ SMB2_logoff(const unsigned int xid, struct cifs_ses *ses)
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, ses->server,
+			    &rqst, &resp_buf_type, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 	/*
 	 * No tcon so can't do
@@ -1751,7 +1758,10 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	__le16 *unc_path = NULL;
 	int flags = 0;
 	unsigned int total_len;
-	struct TCP_Server_Info *server = ses->server;
+	struct TCP_Server_Info *server;
+
+	/* always use master channel */
+	server = ses->server;
 
 	cifs_dbg(FYI, "TCON\n");
 
@@ -1772,8 +1782,8 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	/* SMB2 TREE_CONNECT request must be called with TreeId == 0 */
 	tcon->tid = 0;
 	atomic_set(&tcon->num_remote_opens, 0);
-	rc = smb2_plain_req_init(SMB2_TREE_CONNECT, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_TREE_CONNECT, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc) {
 		kfree(unc_path);
 		return rc;
@@ -1812,7 +1822,8 @@ SMB2_tcon(const unsigned int xid, struct cifs_ses *ses, const char *tree,
 	/* Need 64 for max size write so ask for more in case not there yet */
 	req->sync_hdr.CreditRequest = cpu_to_le16(64);
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 	rsp = (struct smb2_tree_connect_rsp *)rsp_iov.iov_base;
 	trace_smb3_tcon(xid, tcon->tid, ses->Suid, tree, rc);
@@ -1897,8 +1908,9 @@ SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
 
 	close_shroot_lease(&tcon->crfid);
 
-	rc = smb2_plain_req_init(SMB2_TREE_DISCONNECT, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_TREE_DISCONNECT, tcon, ses->server,
+				 (void **) &req,
+				 &total_len);
 	if (rc)
 		return rc;
 
@@ -1914,7 +1926,8 @@ SMB2_tdis(const unsigned int xid, struct cifs_tcon *tcon)
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, ses->server,
+			    &rqst, &resp_buf_type, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 	if (rc)
 		cifs_stats_fail_inc(tcon, SMB2_TREE_DISCONNECT_HE);
@@ -2468,6 +2481,7 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
 	int flags = 0;
 	unsigned int total_len;
 	__le16 *utf16_path = NULL;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 
 	cifs_dbg(FYI, "mkdir\n");
 
@@ -2476,13 +2490,14 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
 	if (!utf16_path)
 		return -ENOMEM;
 
-	if (!ses || !(ses->server)) {
+	if (!ses || !server) {
 		rc = -EIO;
 		goto err_free_path;
 	}
 
 	/* resource #2: request */
-	rc = smb2_plain_req_init(SMB2_CREATE, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_CREATE, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		goto err_free_path;
 
@@ -2568,7 +2583,8 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
 	trace_smb3_posix_mkdir_enter(xid, tcon->tid, ses->Suid, CREATE_NOT_FILE,
 				    FILE_WRITE_ATTRIBUTES);
 	/* resource #4: response buffer */
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_CREATE_HE);
 		trace_smb3_posix_mkdir_err(xid, tcon->tid, ses->Suid,
@@ -2597,10 +2613,10 @@ int smb311_posix_mkdir(const unsigned int xid, struct inode *inode,
 }
 
 int
-SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, __u8 *oplock,
+SMB2_open_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+	       struct smb_rqst *rqst, __u8 *oplock,
 	       struct cifs_open_parms *oparms, __le16 *path)
 {
-	struct TCP_Server_Info *server = tcon->ses->server;
 	struct smb2_create_req *req;
 	unsigned int n_iov = 2;
 	__u32 file_attributes = 0;
@@ -2611,7 +2627,8 @@ SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst, __u8 *oplock,
 	__le16 *copy_path;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_CREATE, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_CREATE, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -2783,9 +2800,9 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 {
 	struct smb_rqst rqst;
 	struct smb2_create_rsp *rsp = NULL;
-	struct TCP_Server_Info *server;
 	struct cifs_tcon *tcon = oparms->tcon;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	struct kvec iov[SMB2_CREATE_IOV_SIZE];
 	struct kvec rsp_iov = {NULL, 0};
 	int resp_buftype = CIFS_NO_BUFFER;
@@ -2793,9 +2810,7 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 	int flags = 0;
 
 	cifs_dbg(FYI, "create/open\n");
-	if (ses && (ses->server))
-		server = ses->server;
-	else
+	if (!ses || !server)
 		return -EIO;
 
 	if (smb3_encryption_required(tcon))
@@ -2806,14 +2821,16 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = SMB2_CREATE_IOV_SIZE;
 
-	rc = SMB2_open_init(tcon, &rqst, oplock, oparms, path);
+	rc = SMB2_open_init(tcon, server,
+			    &rqst, oplock, oparms, path);
 	if (rc)
 		goto creat_exit;
 
 	trace_smb3_open_enter(xid, tcon->tid, tcon->ses->Suid,
 		oparms->create_options, oparms->desired_access);
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags,
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags,
 			    &rsp_iov);
 	rsp = (struct smb2_create_rsp *)rsp_iov.iov_base;
 
@@ -2865,7 +2882,8 @@ SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms, __le16 *path,
 }
 
 int
-SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+SMB2_ioctl_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		struct smb_rqst *rqst,
 		u64 persistent_fid, u64 volatile_fid, u32 opcode,
 		bool is_fsctl, char *in_data, u32 indatalen,
 		__u32 max_response_size)
@@ -2876,7 +2894,8 @@ SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 	int rc;
 	char *in_data_buf;
 
-	rc = smb2_ioctl_req_init(opcode, tcon, (void **) &req, &total_len);
+	rc = smb2_ioctl_req_init(opcode, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -2976,12 +2995,12 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	struct smb_rqst rqst;
 	struct smb2_ioctl_rsp *rsp = NULL;
 	struct cifs_ses *ses;
+	struct TCP_Server_Info *server;
 	struct kvec iov[SMB2_IOCTL_IOV_SIZE];
 	struct kvec rsp_iov = {NULL, 0};
 	int resp_buftype = CIFS_NO_BUFFER;
 	int rc = 0;
 	int flags = 0;
-	struct TCP_Server_Info *server;
 
 	cifs_dbg(FYI, "SMB2 IOCTL\n");
 
@@ -2992,14 +3011,14 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	if (plen)
 		*plen = 0;
 
-	if (tcon)
-		ses = tcon->ses;
-	else
+	if (!tcon)
 		return -EIO;
 
+	ses = tcon->ses;
 	if (!ses)
 		return -EIO;
-	server = ses->server;
+
+	server = cifs_pick_channel(ses);
 	if (!server)
 		return -EIO;
 
@@ -3011,12 +3030,14 @@ SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = SMB2_IOCTL_IOV_SIZE;
 
-	rc = SMB2_ioctl_init(tcon, &rqst, persistent_fid, volatile_fid, opcode,
+	rc = SMB2_ioctl_init(tcon, server,
+			     &rqst, persistent_fid, volatile_fid, opcode,
 			     is_fsctl, in_data, indatalen, max_out_data_len);
 	if (rc)
 		goto ioctl_exit;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags,
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags,
 			    &rsp_iov);
 	rsp = (struct smb2_ioctl_rsp *)rsp_iov.iov_base;
 
@@ -3104,7 +3125,8 @@ SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 int
-SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+SMB2_close_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		struct smb_rqst *rqst,
 		u64 persistent_fid, u64 volatile_fid, bool query_attrs)
 {
 	struct smb2_close_req *req;
@@ -3112,7 +3134,8 @@ SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 	unsigned int total_len;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_CLOSE, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_CLOSE, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -3143,6 +3166,7 @@ __SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 	struct smb_rqst rqst;
 	struct smb2_close_rsp *rsp = NULL;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	struct kvec iov[1];
 	struct kvec rsp_iov;
 	int resp_buftype = CIFS_NO_BUFFER;
@@ -3152,7 +3176,7 @@ __SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 
 	cifs_dbg(FYI, "Close\n");
 
-	if (!ses || !(ses->server))
+	if (!ses || !server)
 		return -EIO;
 
 	if (smb3_encryption_required(tcon))
@@ -3168,12 +3192,14 @@ __SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 		query_attrs = true;
 
 	trace_smb3_close_enter(xid, persistent_fid, tcon->tid, ses->Suid);
-	rc = SMB2_close_init(tcon, &rqst, persistent_fid, volatile_fid,
+	rc = SMB2_close_init(tcon, server,
+			     &rqst, persistent_fid, volatile_fid,
 			     query_attrs);
 	if (rc)
 		goto close_exit;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	rsp = (struct smb2_close_rsp *)rsp_iov.iov_base;
 
 	if (rc != 0) {
@@ -3273,7 +3299,8 @@ smb2_validate_and_copy_iov(unsigned int offset, unsigned int buffer_length,
 }
 
 int
-SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+SMB2_query_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		     struct smb_rqst *rqst,
 		     u64 persistent_fid, u64 volatile_fid,
 		     u8 info_class, u8 info_type, u32 additional_info,
 		     size_t output_len, size_t input_len, void *input)
@@ -3283,8 +3310,8 @@ SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
 	unsigned int total_len;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -3336,7 +3363,7 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
 
 	if (!ses)
 		return -EIO;
-	server = ses->server;
+	server = cifs_pick_channel(ses);
 	if (!server)
 		return -EIO;
 
@@ -3348,7 +3375,8 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = SMB2_query_info_init(tcon, &rqst, persistent_fid, volatile_fid,
+	rc = SMB2_query_info_init(tcon, server,
+				  &rqst, persistent_fid, volatile_fid,
 				  info_class, info_type, additional_info,
 				  output_len, 0, NULL);
 	if (rc)
@@ -3357,7 +3385,8 @@ query_info(const unsigned int xid, struct cifs_tcon *tcon,
 	trace_smb3_query_info_enter(xid, persistent_fid, tcon->tid,
 				    ses->Suid, info_class, (__u32)info_type);
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	rsp = (struct smb2_query_info_rsp *)rsp_iov.iov_base;
 
 	if (rc) {
@@ -3442,15 +3471,17 @@ SMB2_get_srv_num(const unsigned int xid, struct cifs_tcon *tcon,
 
 static int
 SMB2_notify_init(const unsigned int xid, struct smb_rqst *rqst,
-		struct cifs_tcon *tcon, u64 persistent_fid, u64 volatile_fid,
-		u32 completion_filter, bool watch_tree)
+		 struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		 u64 persistent_fid, u64 volatile_fid,
+		 u32 completion_filter, bool watch_tree)
 {
 	struct smb2_change_notify_req *req;
 	struct kvec *iov = rqst->rq_iov;
 	unsigned int total_len;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_CHANGE_NOTIFY, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_CHANGE_NOTIFY, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -3477,6 +3508,7 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
 		u32 completion_filter)
 {
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	struct smb_rqst rqst;
 	struct kvec iov[1];
 	struct kvec rsp_iov = {NULL, 0};
@@ -3485,7 +3517,7 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc = 0;
 
 	cifs_dbg(FYI, "change notify\n");
-	if (!ses || !(ses->server))
+	if (!ses || !server)
 		return -EIO;
 
 	if (smb3_encryption_required(tcon))
@@ -3496,14 +3528,16 @@ SMB2_change_notify(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = SMB2_notify_init(xid, &rqst, tcon, persistent_fid, volatile_fid,
+	rc = SMB2_notify_init(xid, &rqst, tcon, server,
+			      persistent_fid, volatile_fid,
 			      completion_filter, watch_tree);
 	if (rc)
 		goto cnotify_exit;
 
 	trace_smb3_notify_enter(xid, persistent_fid, tcon->tid, ses->Suid,
 				(u8)watch_tree, completion_filter);
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 
 	if (rc != 0) {
 		cifs_stats_fail_inc(tcon, SMB2_CHANGE_NOTIFY_HE);
@@ -3593,7 +3627,7 @@ void smb2_reconnect_server(struct work_struct *work)
 	spin_unlock(&cifs_tcp_ses_lock);
 
 	list_for_each_entry_safe(tcon, tcon2, &tmp_list, rlist) {
-		rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon);
+		rc = smb2_reconnect(SMB2_INTERNAL_CMD, tcon, server);
 		if (!rc)
 			cifs_reopen_persistent_handles(tcon);
 		else
@@ -3633,7 +3667,8 @@ SMB2_echo(struct TCP_Server_Info *server)
 		return rc;
 	}
 
-	rc = smb2_plain_req_init(SMB2_ECHO, NULL, (void **)&req, &total_len);
+	rc = smb2_plain_req_init(SMB2_ECHO, NULL, server,
+				 (void **)&req, &total_len);
 	if (rc)
 		return rc;
 
@@ -3660,14 +3695,16 @@ SMB2_flush_free(struct smb_rqst *rqst)
 
 int
 SMB2_flush_init(const unsigned int xid, struct smb_rqst *rqst,
-		struct cifs_tcon *tcon, u64 persistent_fid, u64 volatile_fid)
+		struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		u64 persistent_fid, u64 volatile_fid)
 {
 	struct smb2_flush_req *req;
 	struct kvec *iov = rqst->rq_iov;
 	unsigned int total_len;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_FLUSH, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_FLUSH, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -3688,6 +3725,7 @@ SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	struct smb_rqst rqst;
 	struct kvec iov[1];
 	struct kvec rsp_iov = {NULL, 0};
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int resp_buftype = CIFS_NO_BUFFER;
 	int flags = 0;
 	int rc = 0;
@@ -3704,12 +3742,14 @@ SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon, u64 persistent_fid,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = SMB2_flush_init(xid, &rqst, tcon, persistent_fid, volatile_fid);
+	rc = SMB2_flush_init(xid, &rqst, tcon, server,
+			     persistent_fid, volatile_fid);
 	if (rc)
 		goto flush_exit;
 
 	trace_smb3_flush_enter(xid, persistent_fid, tcon->tid, ses->Suid);
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 
 	if (rc != 0) {
 		cifs_stats_fail_inc(tcon, SMB2_FLUSH_HE);
@@ -3737,14 +3777,13 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 	int rc = -EACCES;
 	struct smb2_read_plain_req *req = NULL;
 	struct smb2_sync_hdr *shdr;
-	struct TCP_Server_Info *server;
+	struct TCP_Server_Info *server = io_parms->server;
 
-	rc = smb2_plain_req_init(SMB2_READ, io_parms->tcon, (void **) &req,
-				 total_len);
+	rc = smb2_plain_req_init(SMB2_READ, io_parms->tcon, server,
+				 (void **) &req, total_len);
 	if (rc)
 		return rc;
 
-	server = io_parms->tcon->ses->server;
 	if (server == NULL)
 		return -ECONNABORTED;
 
@@ -3773,8 +3812,7 @@ smb2_new_read_req(void **buf, unsigned int *total_len,
 		rdata->bytes >= server->smbd_conn->rdma_readwrite_threshold) {
 
 		struct smbd_buffer_descriptor_v1 *v1;
-		bool need_invalidate =
-			io_parms->tcon->ses->server->dialect == SMB30_PROT_ID;
+		bool need_invalidate = server->dialect == SMB30_PROT_ID;
 
 		rdata->mr = smbd_register_mr(
 				server->smbd_conn, rdata->pages,
@@ -3831,7 +3869,7 @@ smb2_readv_callback(struct mid_q_entry *mid)
 {
 	struct cifs_readdata *rdata = mid->callback_data;
 	struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
-	struct TCP_Server_Info *server = tcon->ses->server;
+	struct TCP_Server_Info *server = rdata->server;
 	struct smb2_sync_hdr *shdr =
 				(struct smb2_sync_hdr *)rdata->iov[0].iov_base;
 	struct cifs_credits credits = { .value = 0, .instance = 0 };
@@ -3843,6 +3881,10 @@ smb2_readv_callback(struct mid_q_entry *mid)
 				 .rq_pagesz = rdata->pagesz,
 				 .rq_tailsz = rdata->tailsz };
 
+	WARN_ONCE(rdata->server != mid->server,
+		  "rdata server %p != mid server %p",
+		  rdata->server, mid->server);
+
 	cifs_dbg(FYI, "%s: mid=%llu state=%d result=%d bytes=%u\n",
 		 __func__, mid->mid, mid->mid_state, rdata->result,
 		 rdata->bytes);
@@ -3920,20 +3962,23 @@ smb2_async_readv(struct cifs_readdata *rdata)
 	struct smb_rqst rqst = { .rq_iov = rdata->iov,
 				 .rq_nvec = 1 };
 	struct TCP_Server_Info *server;
+	struct cifs_tcon *tcon = tlink_tcon(rdata->cfile->tlink);
 	unsigned int total_len;
 
 	cifs_dbg(FYI, "%s: offset=%llu bytes=%u\n",
 		 __func__, rdata->offset, rdata->bytes);
 
+	if (!rdata->server)
+		rdata->server = cifs_pick_channel(tcon->ses);
+
 	io_parms.tcon = tlink_tcon(rdata->cfile->tlink);
+	io_parms.server = server = rdata->server;
 	io_parms.offset = rdata->offset;
 	io_parms.length = rdata->bytes;
 	io_parms.persistent_fid = rdata->cfile->fid.persistent_fid;
 	io_parms.volatile_fid = rdata->cfile->fid.volatile_fid;
 	io_parms.pid = rdata->pid;
 
-	server = io_parms.tcon->ses->server;
-
 	rc = smb2_new_read_req(
 		(void **) &buf, &total_len, &io_parms, rdata, 0, 0);
 	if (rc)
@@ -3961,7 +4006,7 @@ smb2_async_readv(struct cifs_readdata *rdata)
 	}
 
 	kref_get(&rdata->refcount);
-	rc = cifs_call_async(io_parms.tcon->ses->server, &rqst,
+	rc = cifs_call_async(server, &rqst,
 			     cifs_readv_receive, smb2_readv_callback,
 			     smb3_handle_read_data, rdata, flags,
 			     &rdata->credits);
@@ -3993,6 +4038,9 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 	int flags = CIFS_LOG_ERROR;
 	struct cifs_ses *ses = io_parms->tcon->ses;
 
+	if (!io_parms->server)
+		io_parms->server = cifs_pick_channel(io_parms->tcon->ses);
+
 	*nbytes = 0;
 	rc = smb2_new_read_req((void **)&req, &total_len, io_parms, NULL, 0, 0);
 	if (rc)
@@ -4008,7 +4056,8 @@ SMB2_read(const unsigned int xid, struct cifs_io_parms *io_parms,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, io_parms->server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	rsp = (struct smb2_read_rsp *)rsp_iov.iov_base;
 
 	if (rc) {
@@ -4064,11 +4113,15 @@ smb2_writev_callback(struct mid_q_entry *mid)
 {
 	struct cifs_writedata *wdata = mid->callback_data;
 	struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
-	struct TCP_Server_Info *server = tcon->ses->server;
+	struct TCP_Server_Info *server = wdata->server;
 	unsigned int written;
 	struct smb2_write_rsp *rsp = (struct smb2_write_rsp *)mid->resp_buf;
 	struct cifs_credits credits = { .value = 0, .instance = 0 };
 
+	WARN_ONCE(wdata->server != mid->server,
+		  "wdata server %p != mid server %p",
+		  wdata->server, mid->server);
+
 	switch (mid->mid_state) {
 	case MID_RESPONSE_RECEIVED:
 		credits.value = le16_to_cpu(rsp->sync_hdr.CreditRequest);
@@ -4146,12 +4199,16 @@ smb2_async_writev(struct cifs_writedata *wdata,
 	struct smb2_write_req *req = NULL;
 	struct smb2_sync_hdr *shdr;
 	struct cifs_tcon *tcon = tlink_tcon(wdata->cfile->tlink);
-	struct TCP_Server_Info *server = tcon->ses->server;
+	struct TCP_Server_Info *server = wdata->server;
 	struct kvec iov[1];
 	struct smb_rqst rqst = { };
 	unsigned int total_len;
 
-	rc = smb2_plain_req_init(SMB2_WRITE, tcon, (void **) &req, &total_len);
+	if (!wdata->server)
+		server = wdata->server = cifs_pick_channel(tcon->ses);
+
+	rc = smb2_plain_req_init(SMB2_WRITE, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -4290,20 +4347,24 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
 	struct kvec rsp_iov;
 	int flags = 0;
 	unsigned int total_len;
+	struct TCP_Server_Info *server;
 
 	*nbytes = 0;
 
 	if (n_vec < 1)
 		return rc;
 
-	rc = smb2_plain_req_init(SMB2_WRITE, io_parms->tcon, (void **) &req,
-			     &total_len);
+	if (!io_parms->server)
+		io_parms->server = cifs_pick_channel(io_parms->tcon->ses);
+	server = io_parms->server;
+	if (server == NULL)
+		return -ECONNABORTED;
+
+	rc = smb2_plain_req_init(SMB2_WRITE, io_parms->tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
-	if (io_parms->tcon->ses->server == NULL)
-		return -ECONNABORTED;
-
 	if (smb3_encryption_required(io_parms->tcon))
 		flags |= CIFS_TRANSFORM_REQ;
 
@@ -4332,7 +4393,8 @@ SMB2_write(const unsigned int xid, struct cifs_io_parms *io_parms,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = n_vec + 1;
 
-	rc = cifs_send_recv(xid, io_parms->tcon->ses, &rqst,
+	rc = cifs_send_recv(xid, io_parms->tcon->ses, server,
+			    &rqst,
 			    &resp_buftype, flags, &rsp_iov);
 	rsp = (struct smb2_write_rsp *)rsp_iov.iov_base;
 
@@ -4506,11 +4568,12 @@ num_entries(int infotype, char *bufstart, char *end_of_buf, char **lastentry,
  * Readdir/FindFirst
  */
 int SMB2_query_directory_init(const unsigned int xid,
-			      struct cifs_tcon *tcon, struct smb_rqst *rqst,
+			      struct cifs_tcon *tcon,
+			      struct TCP_Server_Info *server,
+			      struct smb_rqst *rqst,
 			      u64 persistent_fid, u64 volatile_fid,
 			      int index, int info_level)
 {
-	struct TCP_Server_Info *server = tcon->ses->server;
 	struct smb2_query_directory_req *req;
 	unsigned char *bufptr;
 	__le16 asteriks = cpu_to_le16('*');
@@ -4521,8 +4584,8 @@ int SMB2_query_directory_init(const unsigned int xid,
 	struct kvec *iov = rqst->rq_iov;
 	int len, rc;
 
-	rc = smb2_plain_req_init(SMB2_QUERY_DIRECTORY, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_QUERY_DIRECTORY, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -4665,6 +4728,7 @@ SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 	struct kvec rsp_iov;
 	int rc = 0;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int flags = 0;
 
 	if (!ses || !(ses->server))
@@ -4678,13 +4742,15 @@ SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = SMB2_QUERY_DIRECTORY_IOV_SIZE;
 
-	rc = SMB2_query_directory_init(xid, tcon, &rqst, persistent_fid,
+	rc = SMB2_query_directory_init(xid, tcon, server,
+				       &rqst, persistent_fid,
 				       volatile_fid, index,
 				       srch_inf->info_level);
 	if (rc)
 		goto qdir_exit;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	rsp = (struct smb2_query_directory_rsp *)rsp_iov.iov_base;
 
 	if (rc) {
@@ -4721,17 +4787,19 @@ SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 }
 
 int
-SMB2_set_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
-	       u64 persistent_fid, u64 volatile_fid, u32 pid, u8 info_class,
-	       u8 info_type, u32 additional_info,
-		void **data, unsigned int *size)
+SMB2_set_info_init(struct cifs_tcon *tcon, struct TCP_Server_Info *server,
+		   struct smb_rqst *rqst,
+		   u64 persistent_fid, u64 volatile_fid, u32 pid,
+		   u8 info_class, u8 info_type, u32 additional_info,
+		   void **data, unsigned int *size)
 {
 	struct smb2_set_info_req *req;
 	struct kvec *iov = rqst->rq_iov;
 	unsigned int i, total_len;
 	int rc;
 
-	rc = smb2_plain_req_init(SMB2_SET_INFO, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_SET_INFO, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -4782,9 +4850,10 @@ send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc = 0;
 	int resp_buftype;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int flags = 0;
 
-	if (!ses || !(ses->server))
+	if (!ses || !server)
 		return -EIO;
 
 	if (!num)
@@ -4801,7 +4870,8 @@ send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = num;
 
-	rc = SMB2_set_info_init(tcon, &rqst, persistent_fid, volatile_fid, pid,
+	rc = SMB2_set_info_init(tcon, server,
+				&rqst, persistent_fid, volatile_fid, pid,
 				info_class, info_type, additional_info,
 				data, size);
 	if (rc) {
@@ -4810,7 +4880,8 @@ send_set_info(const unsigned int xid, struct cifs_tcon *tcon,
 	}
 
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags,
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags,
 			    &rsp_iov);
 	SMB2_set_info_free(&rqst);
 	rsp = (struct smb2_set_info_rsp *)rsp_iov.iov_base;
@@ -4873,6 +4944,7 @@ SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc;
 	struct smb2_oplock_break *req = NULL;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	int flags = CIFS_OBREAK_OP;
 	unsigned int total_len;
 	struct kvec iov[1];
@@ -4880,8 +4952,8 @@ SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
 	int resp_buf_type;
 
 	cifs_dbg(FYI, "SMB2_oplock_break\n");
-	rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -4902,7 +4974,8 @@ SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buf_type, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 
 	if (rc) {
@@ -4945,8 +5018,10 @@ copy_posix_fs_info_to_kstatfs(FILE_SYSTEM_POSIX_INFO *response_data,
 }
 
 static int
-build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
-		   int outbuf_len, u64 persistent_fid, u64 volatile_fid)
+build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon,
+		   struct TCP_Server_Info *server,
+		   int level, int outbuf_len, u64 persistent_fid,
+		   u64 volatile_fid)
 {
 	int rc;
 	struct smb2_query_info_req *req;
@@ -4954,11 +5029,11 @@ build_qfs_info_req(struct kvec *iov, struct cifs_tcon *tcon, int level,
 
 	cifs_dbg(FYI, "Query FSInfo level %d\n", level);
 
-	if ((tcon->ses == NULL) || (tcon->ses->server == NULL))
+	if ((tcon->ses == NULL) || server == NULL)
 		return -EIO;
 
-	rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_QUERY_INFO, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -4988,10 +5063,12 @@ SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc = 0;
 	int resp_buftype;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	FILE_SYSTEM_POSIX_INFO *info = NULL;
 	int flags = 0;
 
-	rc = build_qfs_info_req(&iov, tcon, FS_POSIX_INFORMATION,
+	rc = build_qfs_info_req(&iov, tcon, server,
+				FS_POSIX_INFORMATION,
 				sizeof(FILE_SYSTEM_POSIX_INFO),
 				persistent_fid, volatile_fid);
 	if (rc)
@@ -5004,7 +5081,8 @@ SMB311_posix_qfs_info(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = &iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(iov.iov_base);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
@@ -5036,10 +5114,12 @@ SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc = 0;
 	int resp_buftype;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	struct smb2_fs_full_size_info *info = NULL;
 	int flags = 0;
 
-	rc = build_qfs_info_req(&iov, tcon, FS_FULL_SIZE_INFORMATION,
+	rc = build_qfs_info_req(&iov, tcon, server,
+				FS_FULL_SIZE_INFORMATION,
 				sizeof(struct smb2_fs_full_size_info),
 				persistent_fid, volatile_fid);
 	if (rc)
@@ -5052,7 +5132,8 @@ SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = &iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(iov.iov_base);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
@@ -5084,6 +5165,7 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon,
 	int rc = 0;
 	int resp_buftype, max_len, min_len;
 	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = cifs_pick_channel(ses);
 	unsigned int rsp_len, offset;
 	int flags = 0;
 
@@ -5104,7 +5186,8 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon,
 		return -EINVAL;
 	}
 
-	rc = build_qfs_info_req(&iov, tcon, level, max_len,
+	rc = build_qfs_info_req(&iov, tcon, server,
+				level, max_len,
 				persistent_fid, volatile_fid);
 	if (rc)
 		return rc;
@@ -5116,7 +5199,8 @@ SMB2_QFS_attr(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = &iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buftype, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buftype, flags, &rsp_iov);
 	cifs_small_buf_release(iov.iov_base);
 	if (rc) {
 		cifs_stats_fail_inc(tcon, SMB2_QUERY_INFO_HE);
@@ -5169,10 +5253,12 @@ smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon,
 	unsigned int count;
 	int flags = CIFS_NO_RSP_BUF;
 	unsigned int total_len;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 
 	cifs_dbg(FYI, "smb2_lockv num lock %d\n", num_lock);
 
-	rc = smb2_plain_req_init(SMB2_LOCK, tcon, (void **) &req, &total_len);
+	rc = smb2_plain_req_init(SMB2_LOCK, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -5198,7 +5284,8 @@ smb2_lockv(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 2;
 
-	rc = cifs_send_recv(xid, tcon->ses, &rqst, &resp_buf_type, flags,
+	rc = cifs_send_recv(xid, tcon->ses, server,
+			    &rqst, &resp_buf_type, flags,
 			    &rsp_iov);
 	cifs_small_buf_release(req);
 	if (rc) {
@@ -5243,10 +5330,11 @@ SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon,
 	int resp_buf_type;
 	__u64 *please_key_high;
 	__u64 *please_key_low;
+	struct TCP_Server_Info *server = cifs_pick_channel(tcon->ses);
 
 	cifs_dbg(FYI, "SMB2_lease_break\n");
-	rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, (void **) &req,
-			     &total_len);
+	rc = smb2_plain_req_init(SMB2_OPLOCK_BREAK, tcon, server,
+				 (void **) &req, &total_len);
 	if (rc)
 		return rc;
 
@@ -5269,7 +5357,8 @@ SMB2_lease_break(const unsigned int xid, struct cifs_tcon *tcon,
 	rqst.rq_iov = iov;
 	rqst.rq_nvec = 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, &resp_buf_type, flags, &rsp_iov);
+	rc = cifs_send_recv(xid, ses, server,
+			    &rqst, &resp_buf_type, flags, &rsp_iov);
 	cifs_small_buf_release(req);
 
 	please_key_low = (__u64 *)lease_key;

fs/cifs/smb2proto.h

@@ -143,7 +143,9 @@ extern int SMB2_open(const unsigned int xid, struct cifs_open_parms *oparms,
 		     struct smb2_file_all_info *buf,
 		     struct create_posix_rsp *posix,
 		     struct kvec *err_iov, int *resp_buftype);
-extern int SMB2_open_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_open_init(struct cifs_tcon *tcon,
+			  struct TCP_Server_Info *server,
+			  struct smb_rqst *rqst,
 			  __u8 *oplock, struct cifs_open_parms *oparms,
 			  __le16 *path);
 extern void SMB2_open_free(struct smb_rqst *rqst);
@@ -151,7 +153,9 @@ extern int SMB2_ioctl(const unsigned int xid, struct cifs_tcon *tcon,
 		     u64 persistent_fid, u64 volatile_fid, u32 opcode,
 		     bool is_fsctl, char *in_data, u32 indatalen, u32 maxoutlen,
 		     char **out_data, u32 *plen /* returned data len */);
-extern int SMB2_ioctl_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_ioctl_init(struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
+			   struct smb_rqst *rqst,
 			   u64 persistent_fid, u64 volatile_fid, u32 opcode,
 			   bool is_fsctl, char *in_data, u32 indatalen,
 			   __u32 max_response_size);
@@ -165,19 +169,25 @@ extern int __SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 			struct smb2_file_network_open_info *pbuf);
 extern int SMB2_close(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
-extern int SMB2_close_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
-		      u64 persistent_fid, u64 volatile_fid, bool query_attrs);
+extern int SMB2_close_init(struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
+			   struct smb_rqst *rqst,
+			   u64 persistent_fid, u64 volatile_fid,
+			   bool query_attrs);
 extern void SMB2_close_free(struct smb_rqst *rqst);
 extern int SMB2_flush(const unsigned int xid, struct cifs_tcon *tcon,
 		      u64 persistent_file_id, u64 volatile_file_id);
 extern int SMB2_flush_init(const unsigned int xid, struct smb_rqst *rqst,
 			   struct cifs_tcon *tcon,
+			   struct TCP_Server_Info *server,
 			   u64 persistent_file_id, u64 volatile_file_id);
 extern void SMB2_flush_free(struct smb_rqst *rqst);
 extern int SMB2_query_info(const unsigned int xid, struct cifs_tcon *tcon,
 			   u64 persistent_file_id, u64 volatile_file_id,
 			   struct smb2_file_all_info *data);
-extern int SMB2_query_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_query_info_init(struct cifs_tcon *tcon,
+				struct TCP_Server_Info *server,
+				struct smb_rqst *rqst,
 				u64 persistent_fid, u64 volatile_fid,
 				u8 info_class, u8 info_type,
 				u32 additional_info, size_t output_len,
@@ -201,6 +211,7 @@ extern int SMB2_query_directory(const unsigned int xid, struct cifs_tcon *tcon,
 				u64 persistent_fid, u64 volatile_fid, int index,
 				struct cifs_search_info *srch_inf);
 extern int SMB2_query_directory_init(unsigned int xid, struct cifs_tcon *tcon,
+				     struct TCP_Server_Info *server,
 				     struct smb_rqst *rqst,
 				     u64 persistent_fid, u64 volatile_fid,
 				     int index, int info_level);
@@ -208,7 +219,9 @@ extern void SMB2_query_directory_free(struct smb_rqst *rqst);
 extern int SMB2_set_eof(const unsigned int xid, struct cifs_tcon *tcon,
 			u64 persistent_fid, u64 volatile_fid, u32 pid,
 			__le64 *eof);
-extern int SMB2_set_info_init(struct cifs_tcon *tcon, struct smb_rqst *rqst,
+extern int SMB2_set_info_init(struct cifs_tcon *tcon,
+			      struct TCP_Server_Info *server,
+			      struct smb_rqst *rqst,
 			      u64 persistent_fid, u64 volatile_fid, u32 pid,
 			      u8 info_class, u8 info_type, u32 additional_info,
 			      void **data, unsigned int *size);

fs/cifs/transport.c

@@ -1020,6 +1020,7 @@ struct TCP_Server_Info *cifs_pick_channel(struct cifs_ses *ses)
 
 int
 compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
+		   struct TCP_Server_Info *server,
 		   const int flags, const int num_rqst, struct smb_rqst *rqst,
 		   int *resp_buf_type, struct kvec *resp_iov)
 {
@@ -1031,20 +1032,17 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 	};
 	unsigned int instance;
 	char *buf;
-	struct TCP_Server_Info *server;
 
 	optype = flags & CIFS_OP_MASK;
 
 	for (i = 0; i < num_rqst; i++)
 		resp_buf_type[i] = CIFS_NO_BUFFER;  /* no response buf yet */
 
-	if ((ses == NULL) || (ses->server == NULL)) {
+	if (!ses || !ses->server || !server) {
 		cifs_dbg(VFS, "Null session\n");
 		return -EIO;
 	}
 
-	server = cifs_pick_channel(ses);
-
 	if (server->tcpStatus == CifsExiting)
 		return -ENOENT;
 
@@ -1239,11 +1237,12 @@ compound_send_recv(const unsigned int xid, struct cifs_ses *ses,
 
 int
 cifs_send_recv(const unsigned int xid, struct cifs_ses *ses,
+	       struct TCP_Server_Info *server,
 	       struct smb_rqst *rqst, int *resp_buf_type, const int flags,
 	       struct kvec *resp_iov)
 {
-	return compound_send_recv(xid, ses, flags, 1, rqst, resp_buf_type,
-				  resp_iov);
+	return compound_send_recv(xid, ses, server, flags, 1,
+				  rqst, resp_buf_type, resp_iov);
 }
 
 int
@@ -1278,7 +1277,8 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 	rqst.rq_iov = new_iov;
 	rqst.rq_nvec = n_vec + 1;
 
-	rc = cifs_send_recv(xid, ses, &rqst, resp_buf_type, flags, resp_iov);
+	rc = cifs_send_recv(xid, ses, ses->server,
+			    &rqst, resp_buf_type, flags, resp_iov);
 	if (n_vec + 1 > CIFS_MAX_IOV_SIZE)
 		kfree(new_iov);
 	return rc;