Hi Jens and James,
As you know a side effect of SCSI using REQ_BLOCK_PC is that commands
that used to originate from SCSI do not obey the retries value, and we
now add extra processing of failures in scsi_io_completion.
The patch below adds a retry count on the request which is used like the
timeout value. And it changes scsi_generic_done to always complete the
entire command which emulates the old behavior we had with
scsi_wait_req/scsi_do_req where scsi_io_completeion does not process the
error and request additional retries.
Patch was made against scsi-rc-fixes.
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
diff --git a/drivers/block/scsi_ioctl.c b/drivers/block/scsi_ioctl.c
--- a/drivers/block/scsi_ioctl.c
+++ b/drivers/block/scsi_ioctl.c
@@ -302,6 +302,7 @@ static int sg_io(struct file *file, requ
rq->timeout = q->sg_timeout;
if (!rq->timeout)
rq->timeout = BLK_DEFAULT_TIMEOUT;
+ rq->retries = 1;
start_time = jiffies;
@@ -412,6 +413,7 @@ static int sg_scsi_ioctl(struct file *fi
rq->timeout = BLK_DEFAULT_TIMEOUT;
break;
}
+ rq->retries = 1;
memset(sense, 0, sizeof(sense));
rq->sense = sense;
@@ -570,6 +572,7 @@ int scsi_cmd_ioctl(struct file *file, st
rq->data = NULL;
rq->data_len = 0;
rq->timeout = BLK_DEFAULT_TIMEOUT;
+ rq->retries = 1;
memset(rq->cmd, 0, sizeof(rq->cmd));
rq->cmd[0] = GPCMD_START_STOP_UNIT;
rq->cmd[4] = 0x02 + (close != 0);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -337,6 +337,7 @@ int scsi_execute(struct scsi_device *sde
memcpy(req->cmd, cmd, req->cmd_len);
req->sense = sense;
req->sense_len = 0;
+ req->retries = retries;
req->timeout = timeout;
req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET;
@@ -1125,7 +1126,13 @@ static int scsi_issue_flush_fn(request_q
static void scsi_generic_done(struct scsi_cmnd *cmd)
{
BUG_ON(!blk_pc_request(cmd->request));
- scsi_io_completion(cmd, cmd->result == 0 ? cmd->bufflen : 0, 0);
+ /*
+ * This will complete the whole command with uptodate=1 so
+ * as far as the block layer is concerned the command completed
+ * successfully. Since his is a REQ_BLOCK_PC command though the
+ * caller should check the request errors value
+ */
+ scsi_io_completion(cmd, cmd->bufflen, 0);
}
static int scsi_prep_fn(struct request_queue *q, struct request *req)
@@ -1273,7 +1280,7 @@ static int scsi_prep_fn(struct request_q
cmd->sc_data_direction = DMA_NONE;
cmd->transfersize = req->data_len;
- cmd->allowed = 3;
+ cmd->allowed = req->retries;
cmd->timeout_per_command = req->timeout;
cmd->done = scsi_generic_done;
}
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -86,7 +86,6 @@
* Number of allowed retries
*/
#define SD_MAX_RETRIES 5
-#define SD_PASSTHROUGH_RETRIES 1
static void scsi_disk_release(struct kref *kref);
@@ -248,7 +247,7 @@ static int sd_init_command(struct scsi_c
timeout = rq->timeout;
SCpnt->transfersize = rq->data_len;
- SCpnt->allowed = SD_PASSTHROUGH_RETRIES;
+ SCpnt->allowed = rq->retries;
goto queue;
}
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4215,6 +4215,7 @@ static int st_init_command(struct scsi_c
else
SCpnt->sc_data_direction = DMA_NONE;
+ SCpnt->allowed = rq->retries;
SCpnt->timeout_per_command = rq->timeout;
SCpnt->transfersize = rq->data_len;
SCpnt->done = st_intr;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -184,6 +184,7 @@ struct request {
void *sense;
unsigned int timeout;
+ int retries;
/*
* For Power Management requests
-
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