From 6143e2cecb9ef9c7d3392c9c2583f231705413a5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 5 Oct 2015 09:31:16 +0200 Subject: [PATCH] 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: Christoph Hellwig Reviewed-by: Shaohua Li Signed-off-by: NeilBrown --- drivers/md/raid5-cache.c | 38 ++++++++++++++++---------------------- 1 file changed, 16 insertions(+), 22 deletions(-) diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index 4e6046f1b0aa..d3b5441b4c11 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -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); } -- 2.20.1