diff options
| author | Logan Gunthorpe | 2022-04-07 10:57:10 -0600 |
|---|---|---|
| committer | Song Liu | 2022-04-25 14:00:36 -0700 |
| commit | e38b0432550507a78d63c8da094e5f50820bdf92 (patch) | |
| tree | cea047480fc45df5002b43964e3418727ae5dcd8 /drivers/md | |
| parent | b0920ede081b3f1659872f80ce552305610675a6 (diff) | |
md/raid5: Annotate rdev/replacement accesses when nr_pending is elevated
There are a number of accesses to __rcu variables that should be safe
because nr_pending in the disk is known to be elevated.
Create a wrapper around rcu_dereference_protected() to annotate these
accesses and verify that nr_pending is non-zero.
This fixes a number of sparse warnings.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/raid5.c | 28 |
1 files changed, 19 insertions, 9 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index c4051625d293..6dc9d7cfa095 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2648,6 +2648,16 @@ static void shrink_stripes(struct r5conf *conf) conf->slab_cache = NULL; } +/* + * This helper wraps rcu_dereference_protected() and can be used when + * it is known that the nr_pending of the rdev is elevated. + */ +static struct md_rdev *rdev_pend_deref(struct md_rdev __rcu *rdev) +{ + return rcu_dereference_protected(rdev, + atomic_read(&rcu_access_pointer(rdev)->nr_pending)); +} + static void raid5_end_read_request(struct bio * bi) { struct stripe_head *sh = bi->bi_private; @@ -2674,9 +2684,9 @@ static void raid5_end_read_request(struct bio * bi) * In that case it moved down to 'rdev'. * rdev is not removed until all requests are finished. */ - rdev = conf->disks[i].replacement; + rdev = rdev_pend_deref(conf->disks[i].replacement); if (!rdev) - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); if (use_new_offset(conf, sh)) s = sh->sector + rdev->new_data_offset; @@ -2790,11 +2800,11 @@ static void raid5_end_write_request(struct bio *bi) for (i = 0 ; i < disks; i++) { if (bi == &sh->dev[i].req) { - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); break; } if (bi == &sh->dev[i].rreq) { - rdev = conf->disks[i].replacement; + rdev = rdev_pend_deref(conf->disks[i].replacement); if (rdev) replacement = 1; else @@ -2802,7 +2812,7 @@ static void raid5_end_write_request(struct bio *bi) * replaced it. rdev is not removed * until all requests are finished. */ - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); break; } } @@ -5210,23 +5220,23 @@ finish: struct r5dev *dev = &sh->dev[i]; if (test_and_clear_bit(R5_WriteError, &dev->flags)) { /* We own a safe reference to the rdev */ - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); if (!rdev_set_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0)) md_error(conf->mddev, rdev); rdev_dec_pending(rdev, conf->mddev); } if (test_and_clear_bit(R5_MadeGood, &dev->flags)) { - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); rdev_clear_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0); rdev_dec_pending(rdev, conf->mddev); } if (test_and_clear_bit(R5_MadeGoodRepl, &dev->flags)) { - rdev = conf->disks[i].replacement; + rdev = rdev_pend_deref(conf->disks[i].replacement); if (!rdev) /* rdev have been moved down */ - rdev = conf->disks[i].rdev; + rdev = rdev_pend_deref(conf->disks[i].rdev); rdev_clear_badblocks(rdev, sh->sector, RAID5_STRIPE_SECTORS(conf), 0); rdev_dec_pending(rdev, conf->mddev); |