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author | Damien Le Moal <damien.lemoal@wdc.com> | 2018-11-20 10:52:38 +0900 |
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committer | Jens Axboe <axboe@kernel.dk> | 2018-11-19 19:03:50 -0700 |
commit | 20578bdfd0418efb11ec316229e670d085cd574a (patch) | |
tree | da06d71830298114eafa0e4d68473a709f1770c7 /block | |
parent | 668ffc03418bc779f699797c72ecf968cd6525a9 (diff) | |
download | linux-stable-20578bdfd0418efb11ec316229e670d085cd574a.tar.gz linux-stable-20578bdfd0418efb11ec316229e670d085cd574a.tar.bz2 linux-stable-20578bdfd0418efb11ec316229e670d085cd574a.zip |
block: Initialize BIO I/O priority early
For the synchronous I/O path case (read(), write() etc system calls), a
BIO I/O priority is not initialized until the execution of
blk_init_request_from_bio() when the BIO is submitted and a request
initialized for the BIO execution. This is due to the ki_ioprio field of
the struct kiocb defined on stack being always initialized to
IOPRIO_CLASS_NONE, regardless of the calling process I/O context ioprio
value set with ioprio_set(). This late initialization can result in the
BIO being merged to pending requests even when the I/O priorities
differ.
Fix this by initializing the ki_iopriority field of on stack struct
kiocb using the get_current_ioprio() helper, ensuring that all BIOs
allocated and submitted for the system call execution see the correct
intended I/O priority early. With this, since a BIO I/O priority is
always set to the intended effective value for both the sync and async
path, blk_init_request_from_bio() can be simplified.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Adam Manzanares <adam.manzanares@wdc.com>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
-rw-r--r-- | block/blk-core.c | 5 |
1 files changed, 1 insertions, 4 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index dde30b08aa14..04f5be473638 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -814,10 +814,7 @@ void blk_init_request_from_bio(struct request *req, struct bio *bio) req->cmd_flags |= REQ_FAILFAST_MASK; req->__sector = bio->bi_iter.bi_sector; - if (ioprio_valid(bio_prio(bio))) - req->ioprio = bio_prio(bio); - else - req->ioprio = get_current_ioprio(); + req->ioprio = bio_prio(bio); req->write_hint = bio->bi_write_hint; blk_rq_bio_prep(req->q, req, bio); } |