Embedding scsi_end_request() into scsi_io_completion actually simplifies
the code and makes it clearer what's going on.
There is absolutely no functional and/or side effects changes after this
patch.
Patch was inspired by Alan Stern.
CC: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
CC: Matthew Wilcox <matthew@xxxxxx>
Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
---
drivers/scsi/scsi_lib.c | 92 ++++++++++-------------------------------------
1 files changed, 19 insertions(+), 73 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index db3bb7f..d76a69b 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -512,66 +512,6 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
scsi_run_queue(sdev->request_queue);
}
-/*
- * Function: scsi_end_request()
- *
- * Purpose: Post-processing of completed commands (usually invoked at end
- * of upper level post-processing and scsi_io_completion).
- *
- * Arguments: cmd - command that is complete.
- * error - 0 if I/O indicates success, < 0 for I/O error.
- * bytes - number of bytes of completed I/O
- * requeue - indicates whether we should requeue leftovers.
- *
- * Lock status: Assumed that lock is not held upon entry.
- *
- * Returns: cmd if requeue required, NULL otherwise.
- *
- * Notes: This is called for block device requests in order to
- * mark some number of sectors as complete.
- *
- * We are guaranteeing that the request queue will be goosed
- * at some point during this call.
- * Notes: If cmd was requeued, upon return it will be a stale pointer.
- */
-static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
- int bytes, int requeue)
-{
- struct request *req = cmd->request;
-
- /*
- * If there are blocks left over at the end, set up the command
- * to queue the remainder of them.
- */
- if (blk_end_request(req, error, bytes)) {
- /* kill remainder if no retrys */
- if (error && scsi_noretry_cmd(cmd))
- blk_end_request_all(req, error);
- else {
- if (requeue) {
- /*
- * Bleah. Leftovers again. Stick the
- * leftovers in the front of the
- * queue, and goose the queue again.
- */
- scsi_release_buffers(cmd);
- scsi_requeue_command(cmd);
- cmd = NULL;
- }
- return cmd;
- }
- }
-
- cmd->request = NULL;
- /*
- * This will goose the queue request function at the end, so we don't
- * need to worry about launching another command.
- */
- scsi_release_buffers(cmd);
- scsi_next_command(cmd);
- return NULL;
-}
-
static inline unsigned int scsi_sgtable_index(unsigned short nents)
{
unsigned int index;
@@ -704,7 +644,7 @@ 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,
+ enum {ACTION_NEXT_CMND, ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
ACTION_DELAYED_RETRY} action;
char *description = NULL;
@@ -780,17 +720,19 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
error = 0;
}
- /*
- * A number of bytes were successfully read. If there
- * are leftovers and there is some kind of error
- * (result != 0), retry the rest.
- */
- if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL)
- return;
-
- error = -EIO;
-
- if (host_byte(result) == DID_RESET) {
+ if (likely(0 == blk_end_request(req, error, good_bytes))) {
+ /* All is done and good move to next command */
+ cmd->request = NULL;
+ action = ACTION_NEXT_CMND;
+ } else if (result == 0) {
+ /* Wrote some bytes but request was split */
+ action = ACTION_REPREP;
+ } else if (error && scsi_noretry_cmd(cmd)) {
+ /* kill remainder if no retries */
+ blk_end_request_all(req, error);
+ cmd->request = NULL;
+ action = ACTION_NEXT_CMND;
+ } else if (host_byte(result) == DID_RESET) {
/* Third party bus reset or reset for error recovery
* reasons. Just retry the command and see what
* happens.
@@ -886,6 +828,10 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
}
switch (action) {
+ case ACTION_NEXT_CMND:
+ scsi_release_buffers(cmd);
+ scsi_next_command(cmd);
+ break;
case ACTION_FAIL:
/* Give up and fail the remainder of the request */
scsi_release_buffers(cmd);
@@ -898,7 +844,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
scsi_print_sense("", cmd);
scsi_print_command(cmd);
}
- if (blk_end_request_err(req, error))
+ if (blk_end_request_err(req, error ? error : -EIO))
scsi_requeue_command(cmd);
else
scsi_next_command(cmd);
--
1.7.2.3
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