We can't initalize the elevator fields for flushes as flush share space
in struct request with the elevator data. But currently we can't
commnicate that a request is a flush through blk_get_request as we
can only pass READ or WRITE, and the low-level code looks at the
possible NULL bio to check for a flush.
Fix this by allowing to pass any block op and flags, and by checking for
the flush flags in __get_request.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-core.c | 26 ++++----------------------
1 file changed, 4 insertions(+), 22 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index a61f140..732b719 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1022,25 +1022,6 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr)
return 0;
}
-/*
- * Determine if elevator data should be initialized when allocating the
- * request associated with @bio.
- */
-static bool blk_rq_should_init_elevator(struct bio *bio)
-{
- if (!bio)
- return true;
-
- /*
- * Flush requests do not use the elevator so skip initialization.
- * This allows a request to share the flush and elevator data.
- */
- if (bio->bi_opf & (REQ_PREFLUSH | REQ_FUA))
- return false;
-
- return true;
-}
-
/**
* __get_request - get a free request
* @rl: request list to allocate from
@@ -1119,10 +1100,13 @@ static struct request *__get_request(struct request_list *rl, unsigned int op,
* request is freed. This guarantees icq's won't be destroyed and
* makes creating new ones safe.
*
+ * Flush requests do not use the elevator so skip initialization.
+ * This allows a request to share the flush and elevator data.
+ *
* Also, lookup icq while holding queue_lock. If it doesn't exist,
* it will be created after releasing queue_lock.
*/
- if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
+ if (!(op & (REQ_PREFLUSH | REQ_FUA)) && !blk_queue_bypass(q)) {
rq_flags |= RQF_ELVPRIV;
q->nr_rqs_elvpriv++;
if (et->icq_cache && ioc)
@@ -1276,8 +1260,6 @@ static struct request *blk_old_get_request(struct request_queue *q, int rw,
{
struct request *rq;
- BUG_ON(rw != READ && rw != WRITE);
-
/* create ioc upfront */
create_io_context(gfp_mask, q->node);
--
2.1.4
--
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