Simplify the bio completion handler by using bio chaining and submitting
bios as soon as they are full.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
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 af274e9..50ec1aa 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -91,8 +91,6 @@ 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 */
@@ -103,6 +101,7 @@ 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 */
@@ -191,9 +190,6 @@ 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);
r5l_log_run_stripes(log);
@@ -204,7 +200,6 @@ 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;
@@ -221,22 +216,17 @@ 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 | REQ_FUA, bio);
+ submit_bio(WRITE | REQ_FUA, 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;
}
@@ -252,7 +242,7 @@ 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;
}
@@ -265,7 +255,6 @@ 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;
@@ -281,7 +270,9 @@ 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);
@@ -329,15 +320,18 @@ 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);
}
--
1.9.1
--
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