dm: refactor deferred bio_list processing (6d6f10df) · Commits · 戴 / test

drivers/md/dm.c

+29 −38

Original line number	Diff line number	Diff line
		@@ -1262,19 +1262,27 @@ EXPORT_SYMBOL_GPL(dm_put);
		/*
		* Process the deferred bios
		*/
		static void __flush_deferred_io(struct mapped_device md, struct bio c)
		static void __flush_deferred_io(struct mapped_device *md)
		{
		struct bio *n;
		struct bio *c;

		while (c) {
		n = c->bi_next;
		c->bi_next = NULL;
		while ((c = bio_list_pop(&md->deferred))) {
		if (__split_bio(md, c))
		bio_io_error(c);
		c = n;
		}
		}

		static void __merge_pushback_list(struct mapped_device *md)
		{
		unsigned long flags;

		spin_lock_irqsave(&md->pushback_lock, flags);
		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
		bio_list_merge_head(&md->deferred, &md->pushback);
		bio_list_init(&md->pushback);
		spin_unlock_irqrestore(&md->pushback_lock, flags);
		}

		/*
		* Swap in a new table (destroying old one).
		*/
		@@ -1346,9 +1354,7 @@ static void unlock_fs(struct mapped_device *md)
		int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
		{
		struct dm_table *map = NULL;
		unsigned long flags;
		DECLARE_WAITQUEUE(wait, current);
		struct bio *def;
		int r = -EINVAL;
		int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
		int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
		@@ -1378,17 +1384,17 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
		r = -ENOMEM;
		goto flush_and_out;
		}
		}

		/*
		* Flush I/O to the device.
		* noflush supersedes do_lockfs, because lock_fs() needs to flush I/Os.
		* Flush I/O to the device. noflush supersedes do_lockfs,
		* because lock_fs() needs to flush I/Os.
		*/
		if (do_lockfs && !noflush) {
		if (do_lockfs) {
		r = lock_fs(md);
		if (r)
		goto out;
		}
		}

		/*
		* First we set the BLOCK_IO flag so no more ios will be mapped.
		@@ -1421,20 +1427,14 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
		down_write(&md->io_lock);
		remove_wait_queue(&md->wait, &wait);

		if (noflush) {
		spin_lock_irqsave(&md->pushback_lock, flags);
		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
		bio_list_merge_head(&md->deferred, &md->pushback);
		bio_list_init(&md->pushback);
		spin_unlock_irqrestore(&md->pushback_lock, flags);
		}
		if (noflush)
		__merge_pushback_list(md);

		/* were we interrupted ? */
		r = -EINTR;
		if (atomic_read(&md->pending)) {
		clear_bit(DMF_BLOCK_IO, &md->flags);
		def = bio_list_get(&md->deferred);
		__flush_deferred_io(md, def);
		__flush_deferred_io(md);
		up_write(&md->io_lock);
		unlock_fs(md);
		goto out; /* pushback list is already flushed, so skip flush */
		@@ -1454,15 +1454,8 @@ flush_and_out:
		* flush them before return.
		*/
		down_write(&md->io_lock);

		spin_lock_irqsave(&md->pushback_lock, flags);
		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
		bio_list_merge_head(&md->deferred, &md->pushback);
		bio_list_init(&md->pushback);
		spin_unlock_irqrestore(&md->pushback_lock, flags);

		def = bio_list_get(&md->deferred);
		__flush_deferred_io(md, def);
		__merge_pushback_list(md);
		__flush_deferred_io(md);
		up_write(&md->io_lock);
		}

		@@ -1482,7 +1475,6 @@ out_unlock:
		int dm_resume(struct mapped_device *md)
		{
		int r = -EINVAL;
		struct bio *def;
		struct dm_table *map = NULL;

		mutex_lock(&md->suspend_lock);
		@@ -1500,8 +1492,7 @@ int dm_resume(struct mapped_device *md)
		down_write(&md->io_lock);
		clear_bit(DMF_BLOCK_IO, &md->flags);

		def = bio_list_get(&md->deferred);
		__flush_deferred_io(md, def);
		__flush_deferred_io(md);
		up_write(&md->io_lock);

		unlock_fs(md);

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