From: Christoph Hellwig <hch@lst.de>
Date: Thu, 9 Dec 2021 07:31:25 +0100
Subject: [PATCH] block: refactor put_io_context
Git-commit: edf70ff5a1ed9769da35178454d743828061a6a3
Patch-mainline: v5.17-rc1
References: jsc#PED-1183
Move the code to delay freeing the icqs into a separate helper.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211209063131.18537-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-ioc.c | 38 +++++++++++++++++++-------------------
1 file changed, 19 insertions(+), 19 deletions(-)
diff --git a/block/blk-ioc.c b/block/blk-ioc.c
index 04f3d2b0ca7d..ca996214c10a 100644
--- a/block/blk-ioc.c
+++ b/block/blk-ioc.c
@@ -143,6 +143,24 @@ static void ioc_release_fn(struct work_struct *work)
kmem_cache_free(iocontext_cachep, ioc);
}
+/*
+ * Releasing icqs requires reverse order double locking and we may already be
+ * holding a queue_lock. Do it asynchronously from a workqueue.
+ */
+static bool ioc_delay_free(struct io_context *ioc)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ioc->lock, flags);
+ if (!hlist_empty(&ioc->icq_list)) {
+ queue_work(system_power_efficient_wq, &ioc->release_work);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+ return true;
+ }
+ spin_unlock_irqrestore(&ioc->lock, flags);
+ return false;
+}
+
/**
* put_io_context - put a reference of io_context
* @ioc: io_context to put
@@ -152,26 +170,8 @@ static void ioc_release_fn(struct work_struct *work)
*/
void put_io_context(struct io_context *ioc)
{
- unsigned long flags;
- bool free_ioc = false;
-
BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
-
- /*
- * Releasing ioc requires reverse order double locking and we may
- * already be holding a queue_lock. Do it asynchronously from wq.
- */
- if (atomic_long_dec_and_test(&ioc->refcount)) {
- spin_lock_irqsave(&ioc->lock, flags);
- if (!hlist_empty(&ioc->icq_list))
- queue_work(system_power_efficient_wq,
- &ioc->release_work);
- else
- free_ioc = true;
- spin_unlock_irqrestore(&ioc->lock, flags);
- }
-
- if (free_ioc)
+ if (atomic_long_dec_and_test(&ioc->refcount) && !ioc_delay_free(ioc))
kmem_cache_free(iocontext_cachep, ioc);
}
EXPORT_SYMBOL_GPL(put_io_context);
--
2.35.3