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md/raid5-ppl: Annotate with rcu_dereference_protected()

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To suppress the last remaining sparse warnings about accessing
rdev, add rcu_dereference_protected calls to a couple places
in raid5-ppl. All of these places are called under raid5_run and
therefore are occurring before the array has started and is thus
safe.

There's no sensible check to do for the second argument of
rcu_dereference_protected() so a comment is added instead.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
This commit is contained in:
Logan Gunthorpe 2022-04-07 10:57:12 -06:00 committed by Song Liu
parent 9aeb7f99a1
commit 4f4ee2bf32
1 changed files with 10 additions and 3 deletions
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13
drivers/md/raid5-ppl.c
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@ -883,7 +883,9 @@ static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
(unsigned long long)r_sector, dd_idx,
(unsigned long long)sector);
rdev = conf->disks[dd_idx].rdev;
/* Array has not started so rcu dereference is safe */
rdev = rcu_dereference_protected(
conf->disks[dd_idx].rdev, 1);
if (!rdev || (!test_bit(In_sync, &rdev->flags) &&
sector >= rdev->recovery_offset)) {
pr_debug("%s:%*s data member disk %d missing\n",
@ -934,7 +936,10 @@ static int ppl_recover_entry(struct ppl_log *log, struct ppl_header_entry *e,
parity_sector = raid5_compute_sector(conf, r_sector_first + i,
0, &disk, &sh);
BUG_ON(sh.pd_idx != le32_to_cpu(e->parity_disk));
parity_rdev = conf->disks[sh.pd_idx].rdev;
/* Array has not started so rcu dereference is safe */
parity_rdev = rcu_dereference_protected(
conf->disks[sh.pd_idx].rdev, 1);
BUG_ON(parity_rdev->bdev->bd_dev != log->rdev->bdev->bd_dev);
pr_debug("%s:%*s write parity at sector %llu, disk %s\n",
@ -1404,7 +1409,9 @@ int ppl_init_log(struct r5conf *conf)
for (i = 0; i < ppl_conf->count; i++) {
struct ppl_log *log = &ppl_conf->child_logs[i];
struct md_rdev *rdev = conf->disks[i].rdev;
/* Array has not started so rcu dereference is safe */
struct md_rdev *rdev =
rcu_dereference_protected(conf->disks[i].rdev, 1);
mutex_init(&log->io_mutex);
spin_lock_init(&log->io_list_lock);