block: provide bio_clear_hipri() helper

Any case that turns off REQ_HIPRI must also clear BIO_PERCPU_CACHE, as non-polled IO may complete through hard/soft IRQ and hence isn't safe for our polled bio alloc cache. Provide a helper that does just that, and use it in the merging code as well if we split a bio and turn off polling. Fixes: be863b9 ("block: clear BIO_PERCPU_CACHE flag if polling isn't supported") Reported-by: Keith Busch <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
tobetter · Aug 23, 2021 · 270a1c9 · 270a1c9
1 parent 01cfa28
commit 270a1c9
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Showing 3 changed files with 10 additions and 6 deletions.
diff --git a/block/blk-core.c b/block/blk-core.c
@@ -832,11 +832,8 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
 		}
 	}
 
-	if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) {
-		/* can't support alloc cache if we turn off polling */
-		bio_clear_flag(bio, BIO_PERCPU_CACHE);
-		bio->bi_opf &= ~REQ_HIPRI;
-	}
+	if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+		bio_clear_hipri(bio);
 
 	switch (bio_op(bio)) {
 	case REQ_OP_DISCARD:

diff --git a/block/blk-merge.c b/block/blk-merge.c
@@ -285,7 +285,7 @@ static struct bio *blk_bio_segment_split(struct request_queue *q,
 	 * iopoll in direct IO routine. Given performance gain of iopoll for
 	 * big IO can be trival, disable iopoll when split needed.
 	 */
-	bio->bi_opf &= ~REQ_HIPRI;
+	bio_clear_hipri(bio);
 
 	return bio_split(bio, sectors, GFP_NOIO, bs);
 }

diff --git a/block/blk.h b/block/blk.h
@@ -364,4 +364,11 @@ extern struct device_attribute dev_attr_events;
 extern struct device_attribute dev_attr_events_async;
 extern struct device_attribute dev_attr_events_poll_msecs;
 
+static inline void bio_clear_hipri(struct bio *bio)
+{
+	/* can't support alloc cache if we turn off polling */
+	bio_clear_flag(bio, BIO_PERCPU_CACHE);
+	bio->bi_opf &= ~REQ_HIPRI;
+}
+
 #endif /* BLK_INTERNAL_H */