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block: avoid polling configuration errors

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This patch adds a poll queue check, aiming to help users use polled IO
accurately.

If users do polled IO but the device doesn't have poll queues, they will
get suboptimal performance data and waste CPU resources. Add a poll queue
check batching this. If users don't have the device properly configured,
or if it simply doesn't support polled IO, it will error the IO with
-EOPNOTSUPP. This is similar to what we used to do for sync polled IO,
which is no longer supported.

Signed-off-by: hexue <xue01.he@samsung.com>
Link: https://lore.kernel.org/r/20240718070817.1031494-1-xue01.he@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
hexue 2024-07-18 15:08:17 +08:00 committed by Jens Axboe
parent 8a47e33f50
commit 73e59d3eec
1 changed files with 4 additions and 1 deletions
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5
block/blk-core.c
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@ -791,8 +791,11 @@ void submit_bio_noacct(struct bio *bio)
}
}
if (!(q->limits.features & BLK_FEAT_POLL))
if (!(q->limits.features & BLK_FEAT_POLL) &&
(bio->bi_opf & REQ_POLLED)) {
bio_clear_polled(bio);
goto not_supported;
}
switch (bio_op(bio)) {
case REQ_OP_READ: