From 3c05ef115c696392d9703be3fe014100ec77864d Mon Sep 17 00:00:00 2001 From: Hans Holmberg Date: Fri, 30 Mar 2018 00:04:58 +0200 Subject: [PATCH] lightnvm: pblk: prevent race in pblk_rb_flush_point_set MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Make sure that we are not advancing the sync pointer while we're adding bios to the write buffer entry completion list. This race condition results in bios not completing and was identified by a hang when running xfstest generic/113. Signed-off-by: Hans Holmberg Reviewed-by: Javier González Signed-off-by: Matias Bjørling Signed-off-by: Jens Axboe --- drivers/lightnvm/pblk-rb.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/lightnvm/pblk-rb.c b/drivers/lightnvm/pblk-rb.c index 8b14340..52fdd85 100644 --- a/drivers/lightnvm/pblk-rb.c +++ b/drivers/lightnvm/pblk-rb.c @@ -355,10 +355,13 @@ static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio, struct pblk_rb_entry *entry; unsigned int sync, flush_point; + pblk_rb_sync_init(rb, NULL); sync = READ_ONCE(rb->sync); - if (pos == sync) + if (pos == sync) { + pblk_rb_sync_end(rb, NULL); return 0; + } #ifdef CONFIG_NVM_DEBUG atomic_inc(&rb->inflight_flush_point); @@ -367,8 +370,6 @@ static int pblk_rb_flush_point_set(struct pblk_rb *rb, struct bio *bio, flush_point = (pos == 0) ? (rb->nr_entries - 1) : (pos - 1); entry = &rb->entries[flush_point]; - pblk_rb_sync_init(rb, NULL); - /* Protect flush points */ smp_store_release(&rb->flush_point, flush_point); -- 2.7.4