dm snapshot: fix a possible invalid memory access on unload

[firefly-linux-kernel-4.4.55.git] / drivers / md / md.h

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 03cec5bdcaae751378f8ac2ad5a470c60219d2c7..318ca8fd430f1f9cd422d84cde77ac6a1fff435a 100644 (file)
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -386,7 +386,18 @@ struct mddev {
 
        struct work_struct del_work;    /* used for delayed sysfs removal */
 
-       spinlock_t                      write_lock;
+       /* "lock" protects:
+        *   flush_bio transition from NULL to !NULL
+        *   rdev superblocks, events
+        *   clearing MD_CHANGE_*
+        *   in_sync - and related safemode and MD_CHANGE changes
+        *   pers (also protected by reconfig_mutex and pending IO).
+        *   clearing ->bitmap
+        *   clearing ->bitmap_info.file
+        *   changing ->resync_{min,max}
+        *   setting MD_RECOVERY_RUNNING (which interacts with resync_{min,max})
+        */
+       spinlock_t                      lock;
        wait_queue_head_t               sb_wait;        /* for waiting on superblock updates */
        atomic_t                        pending_writes; /* number of active superblock writes */
 
@@ -439,13 +450,30 @@ struct mddev {
        void (*sync_super)(struct mddev *mddev, struct md_rdev *rdev);
 };
 
-static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
+static inline int __must_check mddev_lock(struct mddev *mddev)
 {
-       int faulty = test_bit(Faulty, &rdev->flags);
-       if (atomic_dec_and_test(&rdev->nr_pending) && faulty)
-               set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+       return mutex_lock_interruptible(&mddev->reconfig_mutex);
+}
+
+/* Sometimes we need to take the lock in a situation where
+ * failure due to interrupts is not acceptable.
+ */
+static inline void mddev_lock_nointr(struct mddev *mddev)
+{
+       mutex_lock(&mddev->reconfig_mutex);
+}
+
+static inline int mddev_is_locked(struct mddev *mddev)
+{
+       return mutex_is_locked(&mddev->reconfig_mutex);
 }
 
+static inline int mddev_trylock(struct mddev *mddev)
+{
+       return mutex_trylock(&mddev->reconfig_mutex);
+}
+extern void mddev_unlock(struct mddev *mddev);
+
 static inline void md_sync_acct(struct block_device *bdev, unsigned long nr_sectors)
 {
        atomic_add(nr_sectors, &bdev->bd_contains->bd_disk->sync_io);
@@ -459,7 +487,7 @@ struct md_personality
        struct module *owner;
        void (*make_request)(struct mddev *mddev, struct bio *bio);
        int (*run)(struct mddev *mddev);
-       int (*stop)(struct mddev *mddev);
+       void (*free)(struct mddev *mddev, void *priv);
        void (*status)(struct seq_file *seq, struct mddev *mddev);
        /* error_handler must set ->faulty and clear ->in_sync
         * if appropriate, and should abort recovery if needed
@@ -490,6 +518,13 @@ struct md_personality
         * array.
         */
        void *(*takeover) (struct mddev *mddev);
+       /* congested implements bdi.congested_fn().
+        * Will not be called while array is 'suspended' */
+       int (*congested)(struct mddev *mddev, int bits);
+       /* mergeable_bvec is use to implement ->merge_bvec_fn */
+       int (*mergeable_bvec)(struct mddev *mddev,
+                             struct bvec_merge_data *bvm,
+                             struct bio_vec *biovec);
 };
 
 struct md_sysfs_entry {
@@ -624,4 +659,14 @@ static inline int mddev_check_plugged(struct mddev *mddev)
        return !!blk_check_plugged(md_unplug, mddev,
                                   sizeof(struct blk_plug_cb));
 }
+
+static inline void rdev_dec_pending(struct md_rdev *rdev, struct mddev *mddev)
+{
+       int faulty = test_bit(Faulty, &rdev->flags);
+       if (atomic_dec_and_test(&rdev->nr_pending) && faulty) {
+               set_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
+               md_wakeup_thread(mddev->thread);
+       }
+}
+
 #endif /* _MD_MD_H */