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Commit 6143e2ce authored by Christoph Hellwig's avatar Christoph Hellwig Committed by NeilBrown
Browse files

raid5-cache: use bio chaining 



Simplify the bio completion handler by using bio chaining and submitting
bios as soon as they are full.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarShaohua Li <shli@fb.com>
Signed-off-by: default avatarNeilBrown <neilb@suse.com>
parent 2b8ef16e

drivers/md/raid5-cache.c

+16 −22
Original line number Diff line number Diff line
@@ -100,8 +100,6 @@ struct r5l_io_unit { 
	struct page *meta_page;	/* store meta block */

	int meta_offset;	/* current offset in meta_page */



	struct bio_list bios;

	atomic_t pending_io;	/* pending bios not written to log yet */

	struct bio *current_bio;/* current_bio accepting new data */



	atomic_t pending_stripe;/* how many stripes not flushed to raid */
@@ -112,6 +110,7 @@ struct r5l_io_unit { 
	struct list_head stripe_list; /* stripes added to the io_unit */



	int state;

	bool need_split_bio;

};



/* r5l_io_unit state */
@@ -215,9 +214,6 @@ static void r5l_log_endio(struct bio *bio) 


	bio_put(bio);



	if (!atomic_dec_and_test(&io->pending_io))

		return;



	spin_lock_irqsave(&log->io_list_lock, flags);

	__r5l_set_io_unit_state(io, IO_UNIT_IO_END);

	if (log->need_cache_flush)
@@ -235,7 +231,6 @@ static void r5l_submit_current_io(struct r5l_log *log) 
{

	struct r5l_io_unit *io = log->current_io;

	struct r5l_meta_block *block;

	struct bio *bio;

	unsigned long flags;

	u32 crc;
@@ -252,22 +247,17 @@ static void r5l_submit_current_io(struct r5l_log *log) 
	__r5l_set_io_unit_state(io, IO_UNIT_IO_START);

	spin_unlock_irqrestore(&log->io_list_lock, flags);



	while ((bio = bio_list_pop(&io->bios)))

		submit_bio(WRITE, bio);

	submit_bio(WRITE, io->current_bio);

}



static struct bio *r5l_bio_alloc(struct r5l_log *log, struct r5l_io_unit *io)

static struct bio *r5l_bio_alloc(struct r5l_log *log)

{

	struct bio *bio = bio_kmalloc(GFP_NOIO | __GFP_NOFAIL, BIO_MAX_PAGES);



	bio->bi_rw = WRITE;

	bio->bi_bdev = log->rdev->bdev;

	bio->bi_iter.bi_sector = log->rdev->data_offset + log->log_start;

	bio->bi_end_io = r5l_log_endio;

	bio->bi_private = io;



	bio_list_add(&io->bios, bio);

	atomic_inc(&io->pending_io);

	return bio;

}
@@ -283,7 +273,7 @@ static void r5_reserve_log_entry(struct r5l_log *log, struct r5l_io_unit *io) 
	 * of BLOCK_SECTORS.

	 */

	if (log->log_start == 0)

		io->current_bio = NULL;

		io->need_split_bio = true;



	io->log_end = log->log_start;

}
@@ -296,7 +286,6 @@ static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log) 
	/* We can't handle memory allocate failure so far */

	io = kmem_cache_zalloc(log->io_kc, GFP_NOIO | __GFP_NOFAIL);

	io->log = log;

	bio_list_init(&io->bios);

	INIT_LIST_HEAD(&io->log_sibling);

	INIT_LIST_HEAD(&io->stripe_list);

	io->state = IO_UNIT_RUNNING;
@@ -312,7 +301,9 @@ static struct r5l_io_unit *r5l_new_meta(struct r5l_log *log) 
	io->meta_offset = sizeof(struct r5l_meta_block);

	io->seq = log->seq++;



	io->current_bio = r5l_bio_alloc(log, io);

	io->current_bio = r5l_bio_alloc(log);

	io->current_bio->bi_end_io = r5l_log_endio;

	io->current_bio->bi_private = io;

	bio_add_page(io->current_bio, io->meta_page, PAGE_SIZE, 0);



	r5_reserve_log_entry(log, io);
@@ -361,15 +352,18 @@ static void r5l_append_payload_page(struct r5l_log *log, struct page *page) 
{

	struct r5l_io_unit *io = log->current_io;



alloc_bio:

	if (!io->current_bio)

		io->current_bio = r5l_bio_alloc(log, io);

	if (io->need_split_bio) {

		struct bio *prev = io->current_bio;



	if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0)) {

		io->current_bio = NULL;

		goto alloc_bio;

		io->current_bio = r5l_bio_alloc(log);

		bio_chain(io->current_bio, prev);



		submit_bio(WRITE, prev);

	}



	if (!bio_add_page(io->current_bio, page, PAGE_SIZE, 0))

		BUG();



	r5_reserve_log_entry(log, io);

}