| From 1688299983f40f69dd60f433e6be882a87ec68dd Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 13 Feb 2025 08:18:46 -0700 |
| Subject: block: cleanup and fix batch completion adding conditions |
| |
| From: Jens Axboe <axboe@kernel.dk> |
| |
| [ Upstream commit 1f47ed294a2bd577d5ae43e6e28e1c9a3be4a833 ] |
| |
| The conditions for whether or not a request is allowed adding to a |
| completion batch are a bit hard to read, and they also have a few |
| issues. One is that ioerror may indeed be a random value on passthrough, |
| and it's being checked unconditionally of whether or not the given |
| request is a passthrough request or not. |
| |
| Rewrite the conditions to be separate for easier reading, and only check |
| ioerror for non-passthrough requests. This fixes an issue with bio |
| unmapping on passthrough, where it fails getting added to a batch. This |
| both leads to suboptimal performance, and may trigger a potential |
| schedule-under-atomic condition for polled passthrough IO. |
| |
| Fixes: f794f3351f26 ("block: add support for blk_mq_end_request_batch()") |
| Link: https://lore.kernel.org/r/20575f0a-656e-4bb3-9d82-dec6c7e3a35c@kernel.dk |
| Signed-off-by: Jens Axboe <axboe@kernel.dk> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| include/linux/blk-mq.h | 18 ++++++++++++++---- |
| 1 file changed, 14 insertions(+), 4 deletions(-) |
| |
| diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h |
| index 958ed7e89b301..1d482c2aabbdf 100644 |
| --- a/include/linux/blk-mq.h |
| +++ b/include/linux/blk-mq.h |
| @@ -849,12 +849,22 @@ static inline bool blk_mq_add_to_batch(struct request *req, |
| void (*complete)(struct io_comp_batch *)) |
| { |
| /* |
| - * blk_mq_end_request_batch() can't end request allocated from |
| - * sched tags |
| + * Check various conditions that exclude batch processing: |
| + * 1) No batch container |
| + * 2) Has scheduler data attached |
| + * 3) Not a passthrough request and end_io set |
| + * 4) Not a passthrough request and an ioerror |
| */ |
| - if (!iob || (req->rq_flags & RQF_SCHED_TAGS) || ioerror || |
| - (req->end_io && !blk_rq_is_passthrough(req))) |
| + if (!iob) |
| return false; |
| + if (req->rq_flags & RQF_SCHED_TAGS) |
| + return false; |
| + if (!blk_rq_is_passthrough(req)) { |
| + if (req->end_io) |
| + return false; |
| + if (ioerror < 0) |
| + return false; |
| + } |
| |
| if (!iob->complete) |
| iob->complete = complete; |
| -- |
| 2.39.5 |
| |
