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authorHans Holmberg <hans.holmberg@cnexlabs.com>2018-03-30 00:04:58 +0200
committerJens Axboe <axboe@kernel.dk>2018-03-29 17:29:09 -0600
commit3c05ef115c696392d9703be3fe014100ec77864d (patch)
tree7ef312bb9ac423359ee54ea7b7dd420981edd412 /drivers/lightnvm
parentb966c50b14de56cd73d40d3fa87b48bbab6e5c8a (diff)
downloadlinux-3c05ef115c696392d9703be3fe014100ec77864d.tar.bz2
lightnvm: pblk: prevent race in pblk_rb_flush_point_set
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 <hans.holmberg@cnexlabs.com> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/lightnvm')
-rw-r--r--drivers/lightnvm/pblk-rb.c7
1 files 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);