[PATCH 1/2] libosd: BUG: blk_put_request called from within request_end_io

Boaz Harrosh
2009-03-31T17:08:03Z

A fix for a very serious and stupid bug in osd_initiator. It
used to call blk_put_request() regardless of if it was from
the end_io callback or if called after a sync execution.
It should call the unlocked version __blk_put_request() instead.

Also fixed is the remove of _abort_unexecuted_bios hack, and use of
blk_end_request(,-ERROR,) to deallocate half baked requests. I've
audited the code and it should be safe.

Reported and
Tested-by: Xu Yang <onlyxuyang@qq.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
drivers/scsi/osd/osd_initiator.c | 42 +++++++++++++++++++++----------------
1 files changed, 24 insertions(+), 18 deletions(-)

diff --git a/drivers/scsi/osd/osd_initiator.c b/drivers/scsi/osd/osd_initiator.c
index 552f58b..2a5f077 100644
--- a/drivers/scsi/osd/osd_initiator.c
+++ b/drivers/scsi/osd/osd_initiator.c
@@ -338,20 +338,6 @@ struct osd_request *osd_start_request(struct osd_dev *dev, gfp_t gfp)
}
EXPORT_SYMBOL(osd_start_request);

-/*
- * If osd_finalize_request() was called but the request was not executed through
- * the block layer, then we must release BIOs.
- */
-static void _abort_unexecuted_bios(struct request *rq)
-{
- struct bio *bio;
-
- while ((bio = rq->bio) != NULL) {
- rq->bio = bio->bi_next;
- bio_endio(bio, 0);
- }
-}
-
static void _osd_free_seg(struct osd_request *or __unused,
struct _osd_req_data_segment *seg)
{
@@ -363,9 +349,30 @@ static void _osd_free_seg(struct osd_request *or __unused,
seg->alloc_size = 0;
}

+static void _put_request(struct request *rq , bool is_async)
+{
+ if (is_async) {
+ WARN_ON(rq->bio);
+ __blk_put_request(rq->q, rq);
+ } else {
+ /*
+ * If osd_finalize_request() was called but the request was not
+ * executed through the block layer, then we must release BIOs.
+ * TODO: Keep error code in or->async_error. Need to audit all
+ * code paths.
+ */
+ if (unlikely(rq->bio))
+ blk_end_request(rq, -ENOMEM, blk_rq_bytes(rq));
+ else
+ blk_put_request(rq);
+ }
+}
+
void osd_end_request(struct osd_request *or)
{
struct request *rq = or->request;
+ /* IMPORTANT: make sure this agrees with osd_execute_request_async */
+ bool is_async = (or->request->end_io_data == or);

_osd_free_seg(or, &or->set_attr);
_osd_free_seg(or, &or->enc_get_attr);
@@ -373,12 +380,11 @@ void osd_end_request(struct osd_request *or)

if (rq) {
if (rq->next_rq) {
- _abort_unexecuted_bios(rq->next_rq);
- blk_put_request(rq->next_rq);
+ _put_request(rq->next_rq, is_async);
+ rq->next_rq = NULL;
}

- _abort_unexecuted_bios(rq);
- blk_put_request(rq);
+ _put_request(rq, is_async);
}
_osd_request_free(or);
}
--
1.6.2.1