From c0e5631df893c6fda7752b9796c49c08375c5260 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Tue, 5 Sep 2023 09:42:05 +0000 Subject: [PATCH] Revert "blk-mq: fix potential io hang by wrong 'wake_batch'" This reverts commit 931bd6758bcc0f3d27d0492456798afae028e52f which is commit 4f1731df60f9033669f024d06ae26a6301260b55 upstream. It breaks the Android ABI and can be brought back in an abi-safe way in the future if it is still needed. Bug: 161946584 Change-Id: I131cbca13e9472d8d8157b64700e1a3db8006ae5 Signed-off-by: Greg Kroah-Hartman --- block/blk-mq-debugfs.c | 2 +- block/blk-mq-tag.c | 15 +++++---------- include/linux/blk-mq.h | 3 ++- 3 files changed, 8 insertions(+), 12 deletions(-) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 7675e663df36..bd942341b638 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -427,7 +427,7 @@ static void blk_mq_debugfs_tags_show(struct seq_file *m, seq_printf(m, "nr_tags=%u\n", tags->nr_tags); seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags); seq_printf(m, "active_queues=%d\n", - READ_ONCE(tags->active_queues)); + atomic_read(&tags->active_queues)); seq_puts(m, "\nbitmap_tags:\n"); sbitmap_queue_show(&tags->bitmap_tags, m); diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c index bba0adf1229a..6d53948dd181 100644 --- a/block/blk-mq-tag.c +++ b/block/blk-mq-tag.c @@ -40,7 +40,6 @@ static void blk_mq_update_wake_batch(struct blk_mq_tags *tags, void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) { unsigned int users; - struct blk_mq_tags *tags = hctx->tags; /* * calling test_bit() prior to test_and_set_bit() is intentional, @@ -58,11 +57,9 @@ void __blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx) return; } - spin_lock_irq(&tags->lock); - users = tags->active_queues + 1; - WRITE_ONCE(tags->active_queues, users); - blk_mq_update_wake_batch(tags, users); - spin_unlock_irq(&tags->lock); + users = atomic_inc_return(&hctx->tags->active_queues); + + blk_mq_update_wake_batch(hctx->tags, users); } /* @@ -95,11 +92,9 @@ void __blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx) return; } - spin_lock_irq(&tags->lock); - users = tags->active_queues - 1; - WRITE_ONCE(tags->active_queues, users); + users = atomic_dec_return(&tags->active_queues); + blk_mq_update_wake_batch(tags, users); - spin_unlock_irq(&tags->lock); blk_mq_tag_wakeup_all(tags, false); } diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 1272683fa05c..151578ea4b31 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -750,7 +750,8 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q, struct blk_mq_tags { unsigned int nr_tags; unsigned int nr_reserved_tags; - unsigned int active_queues; + + atomic_t active_queues; struct sbitmap_queue bitmap_tags; struct sbitmap_queue breserved_tags;