Merge tag 'nfs-for-5.0-4' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull more NFS client fixes from Anna Schumaker:
 "Three fixes this time.

  Nicolas's is for xprtrdma completion vector allocation on single-core
  systems. Greg's adds an error check when allocating a debugfs dentry.
  And Ben's is an additional fix for nfs_page_async_flush() to prevent
  pages from accidentally getting truncated.

  Summary:

   - Make sure Send CQ is allocated on an existing compvec

   - Properly check debugfs dentry before using it

   - Don't use page_file_mapping() after removing a page"

* tag 'nfs-for-5.0-4' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFS: Don't use page_file_mapping after removing the page
  rpc: properly check debugfs dentry before using it
  xprtrdma: Make sure Send CQ is allocated on an existing compvec

fs/nfs/write.c

@@ -238,9 +238,9 @@ static void nfs_grow_file(struct page *page, unsigned int offset, unsigned int c
 }
 
 /* A writeback failed: mark the page as bad, and invalidate the page cache */
-static void nfs_set_pageerror(struct page *page)
+static void nfs_set_pageerror(struct address_space *mapping)
 {
-	nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page));
+	nfs_zap_mapping(mapping->host, mapping);
 }
 
 /*
@@ -994,7 +994,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr)
 		nfs_list_remove_request(req);
 		if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) &&
 		    (hdr->good_bytes < bytes)) {
-			nfs_set_pageerror(req->wb_page);
+			nfs_set_pageerror(page_file_mapping(req->wb_page));
 			nfs_context_set_write_error(req->wb_context, hdr->error);
 			goto remove_req;
 		}
@@ -1348,7 +1348,8 @@ int nfs_updatepage(struct file *file, struct page *page,
 		unsigned int offset, unsigned int count)
 {
 	struct nfs_open_context *ctx = nfs_file_open_context(file);
-	struct inode	*inode = page_file_mapping(page)->host;
+	struct address_space *mapping = page_file_mapping(page);
+	struct inode	*inode = mapping->host;
 	int		status = 0;
 
 	nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE);
@@ -1366,7 +1367,7 @@ int nfs_updatepage(struct file *file, struct page *page,
 
 	status = nfs_writepage_setup(ctx, page, offset, count);
 	if (status < 0)
-		nfs_set_pageerror(page);
+		nfs_set_pageerror(mapping);
 	else
 		__set_page_dirty_nobuffers(page);
 out:

net/sunrpc/debugfs.c

@@ -146,7 +146,7 @@ rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
 	rcu_read_lock();
 	xprt = rcu_dereference(clnt->cl_xprt);
 	/* no "debugfs" dentry? Don't bother with the symlink. */
-	if (!xprt->debugfs) {
+	if (IS_ERR_OR_NULL(xprt->debugfs)) {
 		rcu_read_unlock();
 		return;
 	}

net/sunrpc/xprtrdma/verbs.c

@@ -527,7 +527,8 @@ rpcrdma_ep_create(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia,
 
 	sendcq = ib_alloc_cq(ia->ri_device, NULL,
 			     ep->rep_attr.cap.max_send_wr + 1,
-			     1, IB_POLL_WORKQUEUE);
+			     ia->ri_device->num_comp_vectors > 1 ? 1 : 0,
+			     IB_POLL_WORKQUEUE);
 	if (IS_ERR(sendcq)) {
 		rc = PTR_ERR(sendcq);
 		goto out1;