[SCSI] Prevent scsi_execute_async from guessing cdb length

When the scsi_execute_async interface was added it ended up reducing
the flexibility of userspace to send arbitrary scsi commands through
sg using SG_IO. The SG_IO interface allows userspace to specify the
CDB length. This is now ignored in scsi_execute_async and it is
guessed using the COMMAND_SIZE macro, which is not always correct,
particularly for vendor specific commands. This patch adds a cmd_len
parameter to the scsi_execute_async interface to allow the caller
to specify the length of the CDB.
Signed-off-by: Brian King <brking@us.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

drivers/scsi/scsi_error.c

@@ -1350,7 +1350,7 @@ static void scsi_eh_lock_door(struct scsi_device *sdev)
 	cmnd[4] = SCSI_REMOVAL_PREVENT;
 	cmnd[5] = 0;
 
-	scsi_execute_async(sdev, cmnd, DMA_NONE, NULL, 0, 0, 10 * HZ,
+	scsi_execute_async(sdev, cmnd, 6, DMA_NONE, NULL, 0, 0, 10 * HZ,
 			   5, NULL, NULL, GFP_KERNEL);
 }
 

drivers/scsi/scsi_lib.c

@@ -436,6 +436,7 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
  * scsi_execute_async - insert request
  * @sdev:	scsi device
  * @cmd:	scsi command
+ * @cmd_len:	length of scsi cdb
  * @data_direction: data direction
  * @buffer:	data buffer (this can be a kernel buffer or scatterlist)
  * @bufflen:	len of buffer
@@ -445,7 +446,7 @@ static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl,
  * @flags:	or into request flags
  **/
 int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
-		       int data_direction, void *buffer, unsigned bufflen,
+		       int cmd_len, int data_direction, void *buffer, unsigned bufflen,
 		       int use_sg, int timeout, int retries, void *privdata,
 		       void (*done)(void *, char *, int, int), gfp_t gfp)
 {
@@ -472,7 +473,7 @@ int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
 	if (err)
 		goto free_req;
 
-	req->cmd_len = COMMAND_SIZE(cmd[0]);
+	req->cmd_len = cmd_len;
 	memcpy(req->cmd, cmd, req->cmd_len);
 	req->sense = sioc->sense;
 	req->sense_len = 0;

drivers/scsi/sg.c

@@ -741,7 +741,7 @@ sg_common_write(Sg_fd * sfp, Sg_request * srp,
 	hp->duration = jiffies_to_msecs(jiffies);
 /* Now send everything of to mid-level. The next time we hear about this
    packet is when sg_cmd_done() is called (i.e. a callback). */
-	if (scsi_execute_async(sdp->device, cmnd, data_dir, srp->data.buffer,
+	if (scsi_execute_async(sdp->device, cmnd, hp->cmd_len, data_dir, srp->data.buffer,
 				hp->dxfer_len, srp->data.k_use_sg, timeout,
 				SG_DEFAULT_RETRIES, srp, sg_cmd_done,
 				GFP_ATOMIC)) {

drivers/scsi/st.c

@@ -508,7 +508,7 @@ st_do_scsi(struct st_request * SRpnt, struct scsi_tape * STp, unsigned char *cmd
 	STp->buffer->cmdstat.have_sense = 0;
 	STp->buffer->syscall_result = 0;
 
-	if (scsi_execute_async(STp->device, cmd, direction,
+	if (scsi_execute_async(STp->device, cmd, COMMAND_SIZE(cmd[0]), direction,
 			&((STp->buffer)->sg[0]), bytes, (STp->buffer)->sg_segs,
 			       timeout, retries, SRpnt, st_sleep_done, GFP_KERNEL)) {
 		/* could not allocate the buffer or request was too large */

include/scsi/scsi_device.h

@@ -275,7 +275,7 @@ extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
 			    int data_direction, void *buffer, unsigned bufflen,
 			    struct scsi_sense_hdr *, int timeout, int retries);
 extern int scsi_execute_async(struct scsi_device *sdev,
-			      const unsigned char *cmd, int data_direction,
+			      const unsigned char *cmd, int cmd_len, int data_direction,
 			      void *buffer, unsigned bufflen, int use_sg,
 			      int timeout, int retries, void *privdata,
 			      void (*done)(void *, char *, int, int),