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| author | NeilBrown <neilb@suse.de> | 2014-12-15 12:56:59 +1100 |
|---|---|---|
| committer | NeilBrown <neilb@suse.de> | 2015-02-06 09:32:55 +1100 |
| commit | 7b1485bab9c49b0d3811d72beb0de60c7b8b337d (patch) | |
| tree | 7cb275a901ca30331d6c53be02be58bd578cb2b8 /drivers/md/raid5.c | |
| parent | f97fcad38f2ecf2e34b6f0ab93f74f2978dbe008 (diff) | |
| download | lwn-7b1485bab9c49b0d3811d72beb0de60c7b8b337d.tar.gz lwn-7b1485bab9c49b0d3811d72beb0de60c7b8b337d.zip | |
md/raid5: use ->lock to protect accessing raid5 sysfs attributes.
It is important that mddev->private isn't freed while
a sysfs attribute function is accessing it.
So use mddev->lock to protect the setting of ->private to NULL, and
take that lock when checking ->private for NULL and de-referencing it
in the sysfs access functions.
This only applies to the read ('show') side of access. Write
access will be handled separately.
Signed-off-by: NeilBrown <neilb@suse.de>
Diffstat (limited to 'drivers/md/raid5.c')
| -rw-r--r-- | drivers/md/raid5.c | 44 |
1 files changed, 28 insertions, 16 deletions
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index dab908b2aa9a..d5b80174b3b3 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5354,11 +5354,14 @@ static void raid5d(struct md_thread *thread) static ssize_t raid5_show_stripe_cache_size(struct mddev *mddev, char *page) { - struct r5conf *conf = mddev->private; + struct r5conf *conf; + int ret = 0; + spin_lock(&mddev->lock); + conf = mddev->private; if (conf) - return sprintf(page, "%d\n", conf->max_nr_stripes); - else - return 0; + ret = sprintf(page, "%d\n", conf->max_nr_stripes); + spin_unlock(&mddev->lock); + return ret; } int @@ -5422,11 +5425,14 @@ raid5_stripecache_size = __ATTR(stripe_cache_size, S_IRUGO | S_IWUSR, static ssize_t raid5_show_preread_threshold(struct mddev *mddev, char *page) { - struct r5conf *conf = mddev->private; + struct r5conf *conf; + int ret = 0; + spin_lock(&mddev->lock); + conf = mddev->private; if (conf) - return sprintf(page, "%d\n", conf->bypass_threshold); - else - return 0; + ret = sprintf(page, "%d\n", conf->bypass_threshold); + spin_unlock(&mddev->lock); + return ret; } static ssize_t @@ -5456,11 +5462,14 @@ raid5_preread_bypass_threshold = __ATTR(preread_bypass_threshold, static ssize_t raid5_show_skip_copy(struct mddev *mddev, char *page) { - struct r5conf *conf = mddev->private; + struct r5conf *conf; + int ret = 0; + spin_lock(&mddev->lock); + conf = mddev->private; if (conf) - return sprintf(page, "%d\n", conf->skip_copy); - else - return 0; + ret = sprintf(page, "%d\n", conf->skip_copy); + spin_unlock(&mddev->lock); + return ret; } static ssize_t @@ -5512,11 +5521,14 @@ raid5_stripecache_active = __ATTR_RO(stripe_cache_active); static ssize_t raid5_show_group_thread_cnt(struct mddev *mddev, char *page) { - struct r5conf *conf = mddev->private; + struct r5conf *conf; + int ret = 0; + spin_lock(&mddev->lock); + conf = mddev->private; if (conf) - return sprintf(page, "%d\n", conf->worker_cnt_per_group); - else - return 0; + ret = sprintf(page, "%d\n", conf->worker_cnt_per_group); + spin_unlock(&mddev->lock); + return ret; } static int alloc_thread_groups(struct r5conf *conf, int cnt, |