[dm-devel] [PATCH] dm stats: Add missing check for alloc_percpu

[Jiasheng Jiang]

Add the check for the return value of alloc_precpu and return the error
if it fails.
Moreover, Add the check for the return value of dm_stats_init casadely.

Fixes: fd2ed4d25270 ("dm: add statistics support")
Signed-off-by: Jiasheng Jiang <jiash...@iscas.ac.cn>
---
 drivers/md/dm-stats.c | 7 ++++++-
 drivers/md/dm-stats.h | 2 +-
 drivers/md/dm.c       | 4 +++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index c21a19ab73f7..db2d997a6c18 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -188,7 +188,7 @@ static int dm_stat_in_flight(struct dm_stat_shared *shared)
               atomic_read(&shared->in_flight[WRITE]);
 }
 
-void dm_stats_init(struct dm_stats *stats)
+int dm_stats_init(struct dm_stats *stats)
 {
        int cpu;
        struct dm_stats_last_position *last;
@@ -197,11 +197,16 @@ void dm_stats_init(struct dm_stats *stats)
        INIT_LIST_HEAD(&stats->list);
        stats->precise_timestamps = false;
        stats->last = alloc_percpu(struct dm_stats_last_position);
+       if (!stats->last)
+               return -ENOMEM;
+
        for_each_possible_cpu(cpu) {
                last = per_cpu_ptr(stats->last, cpu);
                last->last_sector = (sector_t)ULLONG_MAX;
                last->last_rw = UINT_MAX;
        }
+
+       return 0;
 }
 
 void dm_stats_cleanup(struct dm_stats *stats)
diff --git a/drivers/md/dm-stats.h b/drivers/md/dm-stats.h
index 0bc152c8e4f3..c6728c8b4159 100644
--- a/drivers/md/dm-stats.h
+++ b/drivers/md/dm-stats.h
@@ -21,7 +21,7 @@ struct dm_stats_aux {
        unsigned long long duration_ns;
 };
 
-void dm_stats_init(struct dm_stats *st);
+int dm_stats_init(struct dm_stats *st);
 void dm_stats_cleanup(struct dm_stats *st);
 
 struct mapped_device;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index eace45a18d45..b6ace995b9ca 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -2097,7 +2097,9 @@ static struct mapped_device *alloc_dev(int minor)
        if (!md->pending_io)
                goto bad;
 
-       dm_stats_init(&md->stats);
+       r = dm_stats_init(&md->stats);
+       if (r < 0)
+               goto bad;
 
        /* Populate the mapping, nobody knows we exist yet */
        spin_lock(&_minor_lock);
-- 
2.25.1

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