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| author | Christoph Hellwig <hch@lst.de> | 2020-04-25 09:53:36 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-04-25 09:45:44 -0600 |
| commit | 8cf7961dab42c9177a556b719c15f5b9449c24d1 (patch) | |
| tree | cf0e7e5d0b7f6f0ee665629b61fc91cc56ed77c7 /drivers/md/dm.c | |
| parent | ae3cc8d8ff061d3ffca96665685550e70a86472a (diff) | |
| download | linux-8cf7961dab42c9177a556b719c15f5b9449c24d1.tar.bz2 | |
block: bypass ->make_request_fn for blk-mq drivers
Call blk_mq_make_request when no ->make_request_fn is set. This is
safe now that blk_alloc_queue always sets up the pointer for make_request
based drivers. This avoids an indirect call in the blk-mq driver I/O
fast path, which is rather expensive due to spectre mitigations.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index db9e46114653..0eb93da44ea2 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1788,6 +1788,9 @@ static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio) int srcu_idx; struct dm_table *map; + if (dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) + return blk_mq_make_request(q, bio); + map = dm_get_live_table(md, &srcu_idx); /* if we're suspended, we have to queue this io for later */ |