From: Hannes Reinecke <h...@suse.de>
Add a new blkprep return code BLKPREP_DONE to signal completion
without I/O error.
Signed-off-by: Hannes Reinecke <h...@suse.de>
Changelog (Damien):
Rewrite adding blk_prep_end_request as suggested by Christoph Hellwig
Suggested-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Damien Le Moal <damien.lem...@hgst.com>
---
block/blk-core.c | 42 ++++++++++++++++++++++++++----------------
drivers/scsi/scsi_lib.c | 1 +
include/linux/blkdev.h | 1 +
3 files changed, 28 insertions(+), 16 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 2c5d069d..8dbbb1a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -2341,6 +2341,17 @@ void blk_account_io_start(struct request *rq, bool
new_io)
part_stat_unlock();
}
+static void blk_prep_end_request(struct request *rq, int error)
+{
+ /*
+ * Mark this request as started so we don't trigger
+ * any debug logic in the end I/O path.
+ */
+ rq->cmd_flags |= REQ_QUIET;
+ blk_start_request(rq);
+ __blk_end_request_all(rq, error);
+}
+
/**
* blk_peek_request - peek at the top of a request queue
* @q: request queue to peek at
@@ -2408,9 +2419,10 @@ struct request *blk_peek_request(struct request_queue *q)
break;
ret = q->prep_rq_fn(q, rq);
- if (ret == BLKPREP_OK) {
- break;
- } else if (ret == BLKPREP_DEFER) {
+ switch(ret) {
+ case BLKPREP_OK:
+ goto out;
+ case BLKPREP_DEFER:
/*
* the request may have been (partially) prepped.
* we need to keep this request in the front to
@@ -2425,25 +2437,23 @@ struct request *blk_peek_request(struct request_queue
*q)
*/
--rq->nr_phys_segments;
}
-
rq = NULL;
+ goto out;
+ case BLKPREP_KILL:
+ blk_prep_end_request(rq, -EIO);
break;
- } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) {
- int err = (ret == BLKPREP_INVALID) ? -EREMOTEIO : -EIO;
-
- rq->cmd_flags |= REQ_QUIET;
- /*
- * Mark this request as started so we don't trigger
- * any debug logic in the end I/O path.
- */
- blk_start_request(rq);
- __blk_end_request_all(rq, err);
- } else {
+ case BLKPREP_INVALID:
+ blk_prep_end_request(rq, -EREMOTEIO);
+ break;
+ case BLKPREP_DONE:
+ blk_prep_end_request(rq, 0);
+ break;
+ default:
printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
break;
}
}
-
+out:
return rq;
}
EXPORT_SYMBOL(blk_peek_request);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c71344a..f99504d 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1260,6 +1260,7 @@ scsi_prep_return(struct request_queue *q, struct request
*req, int ret)
case BLKPREP_KILL:
case BLKPREP_INVALID:
req->errors = DID_NO_CONNECT << 16;
+ case BLKPREP_DONE:
/* release the command and kill it */
if (req->special) {
struct scsi_cmnd *cmd = req->special;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 1165594..a85f95b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -819,6 +819,7 @@ enum {
BLKPREP_KILL, /* fatal error, kill, return -EIO */
BLKPREP_DEFER, /* leave on queue */
BLKPREP_INVALID, /* invalid command, kill, return -EREMOTEIO */
+ BLKPREP_DONE, /* complete w/o error */
};
extern unsigned long blk_max_low_pfn, blk_max_pfn;
--
2.7.4
--
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