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Commit 6ca2f71f authored by Javier González's avatar Javier González Committed by Jens Axboe
Browse files

lightnvm: pblk: simplify path on REQ_PREFLUSH 



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: default avatarJavier González <javier@cnexlabs.com>
Signed-off-by: default avatarMatias Bjørling <m@bjorling.me>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 55e836d4

drivers/lightnvm/pblk-cache.c

+3 −1
Original line number Diff line number Diff line
@@ -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);

drivers/lightnvm/pblk-rb.c

+1 −7
Original line number Diff line number Diff line
@@ -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;

}