This patch is for the incoming refcnt on scsi_cmnd. It can help the
scsi_done handler to run against the abort handler in parallel.
In the following patch, if a thread takes the REQ_ATOM_COMPLETE,
then it can drop the ref when end of this request. But if it fails
to take REQ_ATOM_COMPLETE, it should drop the ref immediately.
Here, using the return of blk_complete_request() to notice its caller.
Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com>
---
block/blk-softirq.c | 13 ++++++++++---
include/linux/blkdev.h | 2 +-
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/block/blk-softirq.c b/block/blk-softirq.c
index 467c8de..6a841ae 100644
--- a/block/blk-softirq.c
+++ b/block/blk-softirq.c
@@ -156,6 +156,9 @@ do_local:
* blk_complete_request - end I/O on a request
* @req: the request being processed
*
+ * return -1 if fail to call __blk_complete_request which implies another
+ * routine is handling this req
+ *
* Description:
* Ends all I/O on a request. It does not handle partial completions,
* unless the driver actually implements this in its completion callback
@@ -163,12 +166,16 @@ do_local:
* through a softirq handler. The user must have registered a completion
* callback through blk_queue_softirq_done().
**/
-void blk_complete_request(struct request *req)
+int blk_complete_request(struct request *req)
{
+ int ret = -1;
if (unlikely(blk_should_fake_timeout(req->q)))
- return;
- if (!blk_mark_rq_complete(req))
+ return ret;
+ if (!blk_mark_rq_complete(req)) {
__blk_complete_request(req);
+ ret = 0;
+ }
+ return ret;
}
EXPORT_SYMBOL(blk_complete_request);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ee7ddcd..23deadb 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -945,7 +945,7 @@ extern void __blk_end_request_all(struct request *rq, int
error);
extern bool __blk_end_request_cur(struct request *rq, int error);
extern bool __blk_end_request_err(struct request *rq, int error);
-extern void blk_complete_request(struct request *);
+extern int blk_complete_request(struct request *);
extern void __blk_complete_request(struct request *);
extern void blk_abort_request(struct request *);
extern void blk_unprep_request(struct request *);
--
1.8.1.4
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