diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 148d3af92aefad04fa42c48780ba4138e8033e59..ecfbbd30dce530ac24830f56f293a13c85cdeef3 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -875,16 +875,24 @@ static void scsi_end_bidi_request(struct scsi_cmnd *cmd)
* (the normal case for most drivers), we don't need
* the logic to deal with cleaning up afterwards.
*
- * We must do one of several things here:
- *
- * a) Call scsi_end_request. This will finish off the
- * specified number of sectors. If we are done, the
- * command block will be released, and the queue
- * function will be goosed. If we are not done, then
- * scsi_end_request will directly goose the queue.
- *
- * b) We can just use scsi_requeue_command() here. This would
- * be used if we just wanted to retry, for example.
+ * We must call scsi_end_request(). This will finish off
+ * the specified number of sectors. If we are done, the
+ * command block will be released and the queue function
+ * will be goosed. If we are not done then we have to
+ * figure out what to do next:
+ *
+ * a) We can call scsi_requeue_command(). The request
+ * will be unprepared and put back on the queue. Then
+ * a new command will be created for it. This should
+ * be used if we made forward progress, or if we want
+ * to switch from READ(10) to READ(6) for example.
+ *
+ * b) We can call scsi_queue_insert(). The request will
+ * be put back on the queue and retried using the same
+ * command as before, possibly after a delay.
+ *
+ * c) We can call blk_end_request() with -EIO to fail
+ * the remainder of the request.
*/
void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
{
@@ -896,6 +904,9 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
struct scsi_sense_hdr sshdr;
int sense_valid = 0;
int sense_deferred = 0;
+ enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
+ ACTION_DELAYED_RETRY} action;
+ char *description = NULL;
if (result) {
sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
@@ -947,10 +958,13 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
return;
this_count = blk_rq_bytes(req);
- /* good_bytes = 0, or (inclusive) there were leftovers and
- * result = 0, so scsi_end_request couldn't retry.
- */
- if (sense_valid && !sense_deferred) {
+ if (host_byte(result) == DID_RESET) {
+ /* Third party bus reset or reset for error recovery
+ * reasons. Just retry the command and see what
+ * happens.
+ */
+ action = ACTION_RETRY;
+ } else if (sense_valid && !sense_deferred) {
switch (sshdr.sense_key) {
case UNIT_ATTENTION:
if (cmd->device->removable) {
@@ -958,16 +972,15 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
* and quietly refuse further access.
*/
cmd->device->changed = 1;
- scsi_end_request(cmd, -EIO, this_count, 1);
- return;
+ description = "Media Changed";
+ action = ACTION_FAIL;
} else {
/* Must have been a power glitch, or a
* bus reset. Could not have been a
* media change, so we just retry the
- * request and see what happens.
+ * command and see what happens.
*/
- scsi_requeue_command(q, cmd);
- return;
+ action = ACTION_RETRY;
}
break;
case ILLEGAL_REQUEST:
@@ -983,21 +996,18 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
(cmd->cmnd[0] == READ_10 ||
cmd->cmnd[0] == WRITE_10)) {
+ /* This will issue a new 6-byte command. */
cmd->device->use_10_for_rw = 0;
- /* This will cause a retry with a
- * 6-byte command.
- */
- scsi_requeue_command(q, cmd);
- } else if (sshdr.asc == 0x10) /* DIX */
- scsi_end_request(cmd, -EIO, this_count, 0);
- else
- scsi_end_request(cmd, -EIO, this_count, 1);
- return;
+ action = ACTION_REPREP;
+ } else
+ action = ACTION_FAIL;
+ break;
case ABORTED_COMMAND:
if (sshdr.asc == 0x10) { /* DIF */
- scsi_end_request(cmd, -EIO, this_count, 0);
- return;
- }
+ action = ACTION_FAIL;
+ description = "Data Integrity Failure";
+ } else
+ action = ACTION_RETRY;
break;
case NOT_READY:
/* If the device is in the process of becoming
@@ -1012,49 +1022,57 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
case 0x07: /* operation in progress */
case 0x08: /* Long write in progress */
case 0x09: /* self test in progress */
- scsi_requeue_command(q, cmd);
- return;
- default:
+ action = ACTION_DELAYED_RETRY;
break;
}
+ } else {
+ description = "Device not ready";
+ action = ACTION_FAIL;
}
- if (!(req->cmd_flags & REQ_QUIET))
- scsi_cmd_print_sense_hdr(cmd,
- "Device not ready",
- &sshdr);
-
- scsi_end_request(cmd, -EIO, this_count, 1);
- return;
+ break;
case VOLUME_OVERFLOW:
- if (!(req->cmd_flags & REQ_QUIET)) {
- scmd_printk(KERN_INFO, cmd,
- "Volume overflow, CDB: ");
- __scsi_print_command(cmd->cmnd);
- scsi_print_sense("", cmd);
- }
/* See SSC3rXX or current. */
- scsi_end_request(cmd, -EIO, this_count, 1);
- return;
+ action = ACTION_FAIL;
+ break;
default:
+ description = "Unhandled sense code";
+ action = ACTION_FAIL;
break;
}
+ } else {
+ description = "Unhandled error code";
+ action = ACTION_FAIL;
}
- if (host_byte(result) == DID_RESET) {
- /* Third party bus reset or reset for error recovery
- * reasons. Just retry the request and see what
- * happens.
- */
- scsi_requeue_command(q, cmd);
- return;
- }
- if (result) {
+
+ switch (action) {
+ case ACTION_FAIL:
+ /* Give up and fail the remainder of the request */
if (!(req->cmd_flags & REQ_QUIET)) {
+ if (description)
+ scmd_printk(KERN_INFO, cmd, "%s",
+ description);
scsi_print_result(cmd);
if (driver_byte(result) & DRIVER_SENSE)
scsi_print_sense("", cmd);
}
+ blk_end_request(req, -EIO, blk_rq_bytes(req));
+ scsi_next_command(cmd);
+ break;
+ case ACTION_REPREP:
+ /* Unprep the request and put it back at the head of the queue.
+ * A new command will be prepared and issued.
+ */
+ scsi_requeue_command(q, cmd);
+ break;
+ case ACTION_RETRY:
+ /* Retry the same command immediately */
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
+ break;
+ case ACTION_DELAYED_RETRY:
+ /* Retry the same command after a delay */
+ scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
+ break;
}
- scsi_end_request(cmd, -EIO, this_count, !result);
}
static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,