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lightnvm: pblk: simplify path on REQ_PREFLUSH

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On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in
the write to cache path, instead of finding the correct entry context
and imposing a memory barrier. This simplifies the code and might
potentially prevent race conditions when adding functionality to the
write path.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Javier González 2017-10-13 14:46:17 +02:00 committed by Jens Axboe
parent 55e836d401
commit 6ca2f71f3e
2 changed files with 4 additions and 8 deletions
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4
drivers/lightnvm/pblk-cache.c
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@ -43,8 +43,10 @@ int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
if (unlikely(!bio_has_data(bio)))
goto out;
w_ctx.flags = flags;
pblk_ppa_set_empty(&w_ctx.ppa);
w_ctx.flags = flags;
if (bio->bi_opf & REQ_PREFLUSH)
w_ctx.flags |= PBLK_FLUSH_ENTRY;
for (i = 0; i < nr_entries; i++) {
void *data = bio_data(bio);

8
drivers/lightnvm/pblk-rb.c
View File

@ -355,7 +355,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
{
struct pblk_rb_entry *entry;
unsigned int subm, sync_point;
int flags;
subm = READ_ONCE(rb->subm);
@ -369,12 +368,6 @@ static int pblk_rb_sync_point_set(struct pblk_rb *rb, struct bio *bio,
sync_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1);
entry = &rb->entries[sync_point];
flags = READ_ONCE(entry->w_ctx.flags);
flags |= PBLK_FLUSH_ENTRY;
/* Release flags on context. Protect from writes */
smp_store_release(&entry->w_ctx.flags, flags);
/* Protect syncs */
smp_store_release(&rb->sync_point, sync_point);
@ -454,6 +447,7 @@ static int pblk_rb_may_write_flush(struct pblk_rb *rb, unsigned int nr_entries,
/* Protect from read count */
smp_store_release(&rb->mem, mem);
return 1;
}