[GIT PULL 11/37] lightnvm: pblk: prevent race in pblk_rb_flush_point_set
From: Matias Bjørling <hidden>
Date: 2018-03-29 22:13:39
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Hans Holmberg <redacted> 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 <redacted> Reviewed-by: Javier González <redacted> Signed-off-by: Matias Bjørling <redacted> --- 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 8b1434060fb3..52fdd85dbc97 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);
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2.11.0