6.6-stable review patch. If anyone has any objections, please let me know.
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From: Yu Kuai yukuai3@huawei.com
commit f9cfe7e7f96a9414a17d596e288693c4f2325d49 upstream.
Commit cf1b6d4441ff ("md: simplify md_seq_ops") introduce following regressions:
1) If list all_mddevs is emptly, personalities and unused devices won't be showed to user anymore. 2) If seq_file buffer overflowed from md_seq_show(), then md_seq_start() will be called again, hence personalities will be showed to user again. 3) If seq_file buffer overflowed from md_seq_stop(), seq_read_iter() doesn't handle this, hence unused devices won't be showed to user.
Fix above problems by printing personalities and unused devices in md_seq_show().
Fixes: cf1b6d4441ff ("md: simplify md_seq_ops") Cc: stable@vger.kernel.org # v6.7+ Signed-off-by: Yu Kuai yukuai3@huawei.com Signed-off-by: Song Liu song@kernel.org Link: https://lore.kernel.org/r/20240109133957.2975272-1-yukuai1@huaweicloud.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/md/md.c | 40 +++++++++++++++++++++++++++------------- 1 file changed, 27 insertions(+), 13 deletions(-)
--- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8121,6 +8121,19 @@ static void status_unused(struct seq_fil seq_printf(seq, "\n"); }
+static void status_personalities(struct seq_file *seq) +{ + struct md_personality *pers; + + seq_puts(seq, "Personalities : "); + spin_lock(&pers_lock); + list_for_each_entry(pers, &pers_list, list) + seq_printf(seq, "[%s] ", pers->name); + + spin_unlock(&pers_lock); + seq_puts(seq, "\n"); +} + static int status_resync(struct seq_file *seq, struct mddev *mddev) { sector_t max_sectors, resync, res; @@ -8262,20 +8275,10 @@ static int status_resync(struct seq_file static void *md_seq_start(struct seq_file *seq, loff_t *pos) __acquires(&all_mddevs_lock) { - struct md_personality *pers; - - seq_puts(seq, "Personalities : "); - spin_lock(&pers_lock); - list_for_each_entry(pers, &pers_list, list) - seq_printf(seq, "[%s] ", pers->name); - - spin_unlock(&pers_lock); - seq_puts(seq, "\n"); seq->poll_event = atomic_read(&md_event_count); - spin_lock(&all_mddevs_lock);
- return seq_list_start(&all_mddevs, *pos); + return seq_list_start_head(&all_mddevs, *pos); }
static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos) @@ -8286,7 +8289,6 @@ static void *md_seq_next(struct seq_file static void md_seq_stop(struct seq_file *seq, void *v) __releases(&all_mddevs_lock) { - status_unused(seq); spin_unlock(&all_mddevs_lock); }
@@ -8319,10 +8321,18 @@ static void md_bitmap_status(struct seq_
static int md_seq_show(struct seq_file *seq, void *v) { - struct mddev *mddev = list_entry(v, struct mddev, all_mddevs); + struct mddev *mddev; sector_t sectors; struct md_rdev *rdev;
+ if (v == &all_mddevs) { + status_personalities(seq); + if (list_empty(&all_mddevs)) + status_unused(seq); + return 0; + } + + mddev = list_entry(v, struct mddev, all_mddevs); if (!mddev_get(mddev)) return 0;
@@ -8403,6 +8413,10 @@ static int md_seq_show(struct seq_file * spin_unlock(&mddev->lock); mutex_unlock(&mddev->bitmap_info.mutex); spin_lock(&all_mddevs_lock); + + if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs)) + status_unused(seq); + if (atomic_dec_and_test(&mddev->active)) __mddev_put(mddev);