Merge tag 'v4.19.50-rt22' into toradex_4.19.y-rt

Linux 4.19.50-rt22

15 files changed, 378 insertions, 249 deletions

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index c18586fccb6f..17defbf4f332 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -96,13 +96,8 @@ static struct page *brd_insert_page(struct brd_device *brd, sector_t sector)
 	/*
 	 * Must use NOIO because we don't want to recurse back into the
 	 * block or filesystem layers from page reclaim.
-	 *
-	 * Cannot support DAX and highmem, because our ->direct_access
-	 * routine for DAX must return memory that is always addressable.
-	 * If DAX was reworked to use pfns and kmap throughout, this
-	 * restriction might be able to be lifted.
 	 */
-	gfp_flags = GFP_NOIO | __GFP_ZERO;
+	gfp_flags = GFP_NOIO | __GFP_ZERO | __GFP_HIGHMEM;
 	page = alloc_page(gfp_flags);
 	if (!page)
 		return NULL;
diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index b4f02768ba47..319fabdd63a3 100644
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -668,14 +668,15 @@ drbd_set_role(struct drbd_device *const device, enum drbd_role new_role, int for
 		if (rv == SS_TWO_PRIMARIES) {
 			/* Maybe the peer is detected as dead very soon...
 			   retry at most once more in this case. */
-			int timeo;
-			rcu_read_lock();
-			nc = rcu_dereference(connection->net_conf);
-			timeo = nc ? (nc->ping_timeo + 1) * HZ / 10 : 1;
-			rcu_read_unlock();
-			schedule_timeout_interruptible(timeo);
-			if (try < max_tries)
+			if (try < max_tries) {
+				int timeo;
 				try = max_tries - 1;
+				rcu_read_lock();
+				nc = rcu_dereference(connection->net_conf);
+				timeo = nc ? (nc->ping_timeo + 1) * HZ / 10 : 1;
+				rcu_read_unlock();
+				schedule_timeout_interruptible(timeo);
+			}
 			continue;
 		}
 		if (rv < SS_SUCCESS) {
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 75f6b47169e6..cb919b964066 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -3364,7 +3364,7 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
 	enum drbd_conns rv = C_MASK;
 	enum drbd_disk_state mydisk;
 	struct net_conf *nc;
-	int hg, rule_nr, rr_conflict, tentative;
+	int hg, rule_nr, rr_conflict, tentative, always_asbp;
 
 	mydisk = device->state.disk;
 	if (mydisk == D_NEGOTIATING)
@@ -3415,8 +3415,12 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
 
 	rcu_read_lock();
 	nc = rcu_dereference(peer_device->connection->net_conf);
+	always_asbp = nc->always_asbp;
+	rr_conflict = nc->rr_conflict;
+	tentative = nc->tentative;
+	rcu_read_unlock();
 
-	if (hg == 100 || (hg == -100 && nc->always_asbp)) {
+	if (hg == 100 || (hg == -100 && always_asbp)) {
 		int pcount = (device->state.role == R_PRIMARY)
 			   + (peer_role == R_PRIMARY);
 		int forced = (hg == -100);
@@ -3455,9 +3459,6 @@ static enum drbd_conns drbd_sync_handshake(struct drbd_peer_device *peer_device,
 			     "Sync from %s node\n",
 			     (hg < 0) ? "peer" : "this");
 	}
-	rr_conflict = nc->rr_conflict;
-	tentative = nc->tentative;
-	rcu_read_unlock();
 
 	if (hg == -100) {
 		/* FIXME this log message is not correct if we end up here
@@ -4141,7 +4142,7 @@ static int receive_uuids(struct drbd_connection *connection, struct packet_info
 	kfree(device->p_uuid);
 	device->p_uuid = p_uuid;
 
-	if (device->state.conn < C_CONNECTED &&
+	if ((device->state.conn < C_CONNECTED || device->state.pdsk == D_DISKLESS) &&
 	    device->state.disk < D_INCONSISTENT &&
 	    device->state.role == R_PRIMARY &&
 	    (device->ed_uuid & ~((u64)1)) != (p_uuid[UI_CURRENT] & ~((u64)1))) {
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index fdabd0b74492..a8de56f1936d 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -4084,7 +4084,7 @@ static unsigned int floppy_check_events(struct gendisk *disk,
 
 	if (time_after(jiffies, UDRS->last_checked + UDP->checkfreq)) {
 		if (lock_fdc(drive))
-			return -EINTR;
+			return 0;
 		poll_drive(false, 0);
 		process_fd_request();
 	}
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index ea9debf59b22..f1e63eb7cbca 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -83,7 +83,7 @@
 #include <linux/uaccess.h>
 
 static DEFINE_IDR(loop_index_idr);
-static DEFINE_MUTEX(loop_index_mutex);
+static DEFINE_MUTEX(loop_ctl_mutex);
 
 static int max_part;
 static int part_shift;
@@ -631,18 +631,7 @@ static void loop_reread_partitions(struct loop_device *lo,
 {
 	int rc;
 
-	/*
-	 * bd_mutex has been held already in release path, so don't
-	 * acquire it if this function is called in such case.
-	 *
-	 * If the reread partition isn't from release path, lo_refcnt
-	 * must be at least one and it can only become zero when the
-	 * current holder is released.
-	 */
-	if (!atomic_read(&lo->lo_refcnt))
-		rc = __blkdev_reread_part(bdev);
-	else
-		rc = blkdev_reread_part(bdev);
+	rc = blkdev_reread_part(bdev);
 	if (rc)
 		pr_warn("%s: partition scan of loop%d (%s) failed (rc=%d)\n",
 			__func__, lo->lo_number, lo->lo_file_name, rc);
@@ -668,7 +657,7 @@ static int loop_validate_file(struct file *file, struct block_device *bdev)
 			return -EBADF;
 
 		l = f->f_mapping->host->i_bdev->bd_disk->private_data;
-		if (l->lo_state == Lo_unbound) {
+		if (l->lo_state != Lo_bound) {
 			return -EINVAL;
 		}
 		f = l->lo_backing_file;
@@ -689,26 +678,30 @@ static int loop_validate_file(struct file *file, struct block_device *bdev)
 static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 			  unsigned int arg)
 {
-	struct file	*file, *old_file;
+	struct file	*file = NULL, *old_file;
 	int		error;
+	bool		partscan;
 
+	error = mutex_lock_killable(&loop_ctl_mutex);
+	if (error)
+		return error;
 	error = -ENXIO;
 	if (lo->lo_state != Lo_bound)
-		goto out;
+		goto out_err;
 
 	/* the loop device has to be read-only */
 	error = -EINVAL;
 	if (!(lo->lo_flags & LO_FLAGS_READ_ONLY))
-		goto out;
+		goto out_err;
 
 	error = -EBADF;
 	file = fget(arg);
 	if (!file)
-		goto out;
+		goto out_err;
 
 	error = loop_validate_file(file, bdev);
 	if (error)
-		goto out_putf;
+		goto out_err;
 
 	old_file = lo->lo_backing_file;
 
@@ -716,7 +709,7 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 
 	/* size of the new backing store needs to be the same */
 	if (get_loop_size(lo, file) != get_loop_size(lo, old_file))
-		goto out_putf;
+		goto out_err;
 
 	/* and ... switch */
 	blk_mq_freeze_queue(lo->lo_queue);
@@ -727,15 +720,22 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 			     lo->old_gfp_mask & ~(__GFP_IO|__GFP_FS));
 	loop_update_dio(lo);
 	blk_mq_unfreeze_queue(lo->lo_queue);
-
+	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
+	mutex_unlock(&loop_ctl_mutex);
+	/*
+	 * We must drop file reference outside of loop_ctl_mutex as dropping
+	 * the file ref can take bd_mutex which creates circular locking
+	 * dependency.
+	 */
 	fput(old_file);
-	if (lo->lo_flags & LO_FLAGS_PARTSCAN)
+	if (partscan)
 		loop_reread_partitions(lo, bdev);
 	return 0;
 
- out_putf:
-	fput(file);
- out:
+out_err:
+	mutex_unlock(&loop_ctl_mutex);
+	if (file)
+		fput(file);
 	return error;
 }
 
@@ -910,6 +910,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	int		lo_flags = 0;
 	int		error;
 	loff_t		size;
+	bool		partscan;
 
 	/* This is safe, since we have a reference from open(). */
 	__module_get(THIS_MODULE);
@@ -919,13 +920,17 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	if (!file)
 		goto out;
 
+	error = mutex_lock_killable(&loop_ctl_mutex);
+	if (error)
+		goto out_putf;
+
 	error = -EBUSY;
 	if (lo->lo_state != Lo_unbound)
-		goto out_putf;
+		goto out_unlock;
 
 	error = loop_validate_file(file, bdev);
 	if (error)
-		goto out_putf;
+		goto out_unlock;
 
 	mapping = file->f_mapping;
 	inode = mapping->host;
@@ -937,10 +942,10 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	error = -EFBIG;
 	size = get_loop_size(lo, file);
 	if ((loff_t)(sector_t)size != size)
-		goto out_putf;
+		goto out_unlock;
 	error = loop_prepare_queue(lo);
 	if (error)
-		goto out_putf;
+		goto out_unlock;
 
 	error = 0;
 
@@ -972,18 +977,22 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
 	lo->lo_state = Lo_bound;
 	if (part_shift)
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
-	if (lo->lo_flags & LO_FLAGS_PARTSCAN)
-		loop_reread_partitions(lo, bdev);
+	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN;
 
 	/* Grab the block_device to prevent its destruction after we
-	 * put /dev/loopXX inode. Later in loop_clr_fd() we bdput(bdev).
+	 * put /dev/loopXX inode. Later in __loop_clr_fd() we bdput(bdev).
 	 */
 	bdgrab(bdev);
+	mutex_unlock(&loop_ctl_mutex);
+	if (partscan)
+		loop_reread_partitions(lo, bdev);
 	return 0;
 
- out_putf:
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
+out_putf:
 	fput(file);
- out:
+out:
 	/* This is safe: open() is still holding a reference. */
 	module_put(THIS_MODULE);
 	return error;
@@ -1026,39 +1035,31 @@ loop_init_xfer(struct loop_device *lo, struct loop_func_table *xfer,
 	return err;
 }
 
-static int loop_clr_fd(struct loop_device *lo)
+static int __loop_clr_fd(struct loop_device *lo, bool release)
 {
-	struct file *filp = lo->lo_backing_file;
+	struct file *filp = NULL;
 	gfp_t gfp = lo->old_gfp_mask;
 	struct block_device *bdev = lo->lo_device;
+	int err = 0;
+	bool partscan = false;
+	int lo_number;
 
-	if (lo->lo_state != Lo_bound)
-		return -ENXIO;
-
-	/*
-	 * If we've explicitly asked to tear down the loop device,
-	 * and it has an elevated reference count, set it for auto-teardown when
-	 * the last reference goes away. This stops $!~#$@ udev from
-	 * preventing teardown because it decided that it needs to run blkid on
-	 * the loopback device whenever they appear. xfstests is notorious for
-	 * failing tests because blkid via udev races with a losetup
-	 * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
-	 * command to fail with EBUSY.
-	 */
-	if (atomic_read(&lo->lo_refcnt) > 1) {
-		lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
-		mutex_unlock(&lo->lo_ctl_mutex);
-		return 0;
+	mutex_lock(&loop_ctl_mutex);
+	if (WARN_ON_ONCE(lo->lo_state != Lo_rundown)) {
+		err = -ENXIO;
+		goto out_unlock;
 	}
 
-	if (filp == NULL)
-		return -EINVAL;
+	filp = lo->lo_backing_file;
+	if (filp == NULL) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
 
 	/* freeze request queue during the transition */
 	blk_mq_freeze_queue(lo->lo_queue);
 
 	spin_lock_irq(&lo->lo_lock);
-	lo->lo_state = Lo_rundown;
 	lo->lo_backing_file = NULL;
 	spin_unlock_irq(&lo->lo_lock);
 
@@ -1089,26 +1090,92 @@ static int loop_clr_fd(struct loop_device *lo)
 		kobject_uevent(&disk_to_dev(bdev->bd_disk)->kobj, KOBJ_CHANGE);
 	}
 	mapping_set_gfp_mask(filp->f_mapping, gfp);
-	lo->lo_state = Lo_unbound;
 	/* This is safe: open() is still holding a reference. */
 	module_put(THIS_MODULE);
 	blk_mq_unfreeze_queue(lo->lo_queue);
 
-	if (lo->lo_flags & LO_FLAGS_PARTSCAN && bdev)
-		loop_reread_partitions(lo, bdev);
+	partscan = lo->lo_flags & LO_FLAGS_PARTSCAN && bdev;
+	lo_number = lo->lo_number;
+	loop_unprepare_queue(lo);
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
+	if (partscan) {
+		/*
+		 * bd_mutex has been held already in release path, so don't
+		 * acquire it if this function is called in such case.
+		 *
+		 * If the reread partition isn't from release path, lo_refcnt
+		 * must be at least one and it can only become zero when the
+		 * current holder is released.
+		 */
+		if (release)
+			err = __blkdev_reread_part(bdev);
+		else
+			err = blkdev_reread_part(bdev);
+		if (err)
+			pr_warn("%s: partition scan of loop%d failed (rc=%d)\n",
+				__func__, lo_number, err);
+		/* Device is gone, no point in returning error */
+		err = 0;
+	}
+
+	/*
+	 * lo->lo_state is set to Lo_unbound here after above partscan has
+	 * finished.
+	 *
+	 * There cannot be anybody else entering __loop_clr_fd() as
+	 * lo->lo_backing_file is already cleared and Lo_rundown state
+	 * protects us from all the other places trying to change the 'lo'
+	 * device.
+	 */
+	mutex_lock(&loop_ctl_mutex);
 	lo->lo_flags = 0;
 	if (!part_shift)
 		lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
-	loop_unprepare_queue(lo);
-	mutex_unlock(&lo->lo_ctl_mutex);
+	lo->lo_state = Lo_unbound;
+	mutex_unlock(&loop_ctl_mutex);
+
 	/*
-	 * Need not hold lo_ctl_mutex to fput backing file.
-	 * Calling fput holding lo_ctl_mutex triggers a circular
+	 * Need not hold loop_ctl_mutex to fput backing file.
+	 * Calling fput holding loop_ctl_mutex triggers a circular
 	 * lock dependency possibility warning as fput can take
-	 * bd_mutex which is usually taken before lo_ctl_mutex.
+	 * bd_mutex which is usually taken before loop_ctl_mutex.
 	 */
-	fput(filp);
-	return 0;
+	if (filp)
+		fput(filp);
+	return err;
+}
+
+static int loop_clr_fd(struct loop_device *lo)
+{
+	int err;
+
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		return err;
+	if (lo->lo_state != Lo_bound) {
+		mutex_unlock(&loop_ctl_mutex);
+		return -ENXIO;
+	}
+	/*
+	 * If we've explicitly asked to tear down the loop device,
+	 * and it has an elevated reference count, set it for auto-teardown when
+	 * the last reference goes away. This stops $!~#$@ udev from
+	 * preventing teardown because it decided that it needs to run blkid on
+	 * the loopback device whenever they appear. xfstests is notorious for
+	 * failing tests because blkid via udev races with a losetup
+	 * <dev>/do something like mkfs/losetup -d <dev> causing the losetup -d
+	 * command to fail with EBUSY.
+	 */
+	if (atomic_read(&lo->lo_refcnt) > 1) {
+		lo->lo_flags |= LO_FLAGS_AUTOCLEAR;
+		mutex_unlock(&loop_ctl_mutex);
+		return 0;
+	}
+	lo->lo_state = Lo_rundown;
+	mutex_unlock(&loop_ctl_mutex);
+
+	return __loop_clr_fd(lo, false);
 }
 
 static int
@@ -1117,47 +1184,72 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	int err;
 	struct loop_func_table *xfer;
 	kuid_t uid = current_uid();
+	struct block_device *bdev;
+	bool partscan = false;
 
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		return err;
 	if (lo->lo_encrypt_key_size &&
 	    !uid_eq(lo->lo_key_owner, uid) &&
-	    !capable(CAP_SYS_ADMIN))
-		return -EPERM;
-	if (lo->lo_state != Lo_bound)
-		return -ENXIO;
-	if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE)
-		return -EINVAL;
+	    !capable(CAP_SYS_ADMIN)) {
+		err = -EPERM;
+		goto out_unlock;
+	}
+	if (lo->lo_state != Lo_bound) {
+		err = -ENXIO;
+		goto out_unlock;
+	}
+	if ((unsigned int) info->lo_encrypt_key_size > LO_KEY_SIZE) {
+		err = -EINVAL;
+		goto out_unlock;
+	}
+
+	if (lo->lo_offset != info->lo_offset ||
+	    lo->lo_sizelimit != info->lo_sizelimit) {
+		sync_blockdev(lo->lo_device);
+		kill_bdev(lo->lo_device);
+	}
 
 	/* I/O need to be drained during transfer transition */
 	blk_mq_freeze_queue(lo->lo_queue);
 
 	err = loop_release_xfer(lo);
 	if (err)
-		goto exit;
+		goto out_unfreeze;
 
 	if (info->lo_encrypt_type) {
 		unsigned int type = info->lo_encrypt_type;
 
 		if (type >= MAX_LO_CRYPT) {
 			err = -EINVAL;
-			goto exit;
+			goto out_unfreeze;
 		}
 		xfer = xfer_funcs[type];
 		if (xfer == NULL) {
 			err = -EINVAL;
-			goto exit;
+			goto out_unfreeze;
 		}
 	} else
 		xfer = NULL;
 
 	err = loop_init_xfer(lo, xfer, info);
 	if (err)
-		goto exit;
+		goto out_unfreeze;
 
 	if (lo->lo_offset != info->lo_offset ||
 	    lo->lo_sizelimit != info->lo_sizelimit) {
+		/* kill_bdev should have truncated all the pages */
+		if (lo->lo_device->bd_inode->i_mapping->nrpages) {
+			err = -EAGAIN;
+			pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
+				__func__, lo->lo_number, lo->lo_file_name,
+				lo->lo_device->bd_inode->i_mapping->nrpages);
+			goto out_unfreeze;
+		}
 		if (figure_loop_size(lo, info->lo_offset, info->lo_sizelimit)) {
 			err = -EFBIG;
-			goto exit;
+			goto out_unfreeze;
 		}
 	}
 
@@ -1189,15 +1281,20 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 	/* update dio if lo_offset or transfer is changed */
 	__loop_update_dio(lo, lo->use_dio);
 
- exit:
+out_unfreeze:
 	blk_mq_unfreeze_queue(lo->lo_queue);
 
 	if (!err && (info->lo_flags & LO_FLAGS_PARTSCAN) &&
 	     !(lo->lo_flags & LO_FLAGS_PARTSCAN)) {
 		lo->lo_flags |= LO_FLAGS_PARTSCAN;
 		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
-		loop_reread_partitions(lo, lo->lo_device);
+		bdev = lo->lo_device;
+		partscan = true;
 	}
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
+	if (partscan)
+		loop_reread_partitions(lo, bdev);
 
 	return err;
 }
@@ -1205,12 +1302,15 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 static int
 loop_get_status(struct loop_device *lo, struct loop_info64 *info)
 {
-	struct file *file;
+	struct path path;
 	struct kstat stat;
 	int ret;
 
+	ret = mutex_lock_killable(&loop_ctl_mutex);
+	if (ret)
+		return ret;
 	if (lo->lo_state != Lo_bound) {
-		mutex_unlock(&lo->lo_ctl_mutex);
+		mutex_unlock(&loop_ctl_mutex);
 		return -ENXIO;
 	}
 
@@ -1229,17 +1329,17 @@ loop_get_status(struct loop_device *lo, struct loop_info64 *info)
 		       lo->lo_encrypt_key_size);
 	}
 
-	/* Drop lo_ctl_mutex while we call into the filesystem. */
-	file = get_file(lo->lo_backing_file);
-	mutex_unlock(&lo->lo_ctl_mutex);
-	ret = vfs_getattr(&file->f_path, &stat, STATX_INO,
-			  AT_STATX_SYNC_AS_STAT);
+	/* Drop loop_ctl_mutex while we call into the filesystem. */
+	path = lo->lo_backing_file->f_path;
+	path_get(&path);
+	mutex_unlock(&loop_ctl_mutex);
+	ret = vfs_getattr(&path, &stat, STATX_INO, AT_STATX_SYNC_AS_STAT);
 	if (!ret) {
 		info->lo_device = huge_encode_dev(stat.dev);
 		info->lo_inode = stat.ino;
 		info->lo_rdevice = huge_encode_dev(stat.rdev);
 	}
-	fput(file);
+	path_put(&path);
 	return ret;
 }
 
@@ -1323,10 +1423,8 @@ loop_get_status_old(struct loop_device *lo, struct loop_info __user *arg) {
 	struct loop_info64 info64;
 	int err;
 
-	if (!arg) {
-		mutex_unlock(&lo->lo_ctl_mutex);
+	if (!arg)
 		return -EINVAL;
-	}
 	err = loop_get_status(lo, &info64);
 	if (!err)
 		err = loop_info64_to_old(&info64, &info);
@@ -1341,10 +1439,8 @@ loop_get_status64(struct loop_device *lo, struct loop_info64 __user *arg) {
 	struct loop_info64 info64;
 	int err;
 
-	if (!arg) {
-		mutex_unlock(&lo->lo_ctl_mutex);
+	if (!arg)
 		return -EINVAL;
-	}
 	err = loop_get_status(lo, &info64);
 	if (!err && copy_to_user(arg, &info64, sizeof(info64)))
 		err = -EFAULT;
@@ -1376,22 +1472,64 @@ static int loop_set_dio(struct loop_device *lo, unsigned long arg)
 
 static int loop_set_block_size(struct loop_device *lo, unsigned long arg)
 {
+	int err = 0;
+
 	if (lo->lo_state != Lo_bound)
 		return -ENXIO;
 
 	if (arg < 512 || arg > PAGE_SIZE || !is_power_of_2(arg))
 		return -EINVAL;
 
+	if (lo->lo_queue->limits.logical_block_size != arg) {
+		sync_blockdev(lo->lo_device);
+		kill_bdev(lo->lo_device);
+	}
+
 	blk_mq_freeze_queue(lo->lo_queue);
 
+	/* kill_bdev should have truncated all the pages */
+	if (lo->lo_queue->limits.logical_block_size != arg &&
+			lo->lo_device->bd_inode->i_mapping->nrpages) {
+		err = -EAGAIN;
+		pr_warn("%s: loop%d (%s) has still dirty pages (nrpages=%lu)\n",
+			__func__, lo->lo_number, lo->lo_file_name,
+			lo->lo_device->bd_inode->i_mapping->nrpages);
+		goto out_unfreeze;
+	}
+
 	blk_queue_logical_block_size(lo->lo_queue, arg);
 	blk_queue_physical_block_size(lo->lo_queue, arg);
 	blk_queue_io_min(lo->lo_queue, arg);
 	loop_update_dio(lo);
-
+out_unfreeze:
 	blk_mq_unfreeze_queue(lo->lo_queue);
 
-	return 0;
+	return err;
+}
+
+static int lo_simple_ioctl(struct loop_device *lo, unsigned int cmd,
+			   unsigned long arg)
+{
+	int err;
+
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		return err;
+	switch (cmd) {
+	case LOOP_SET_CAPACITY:
+		err = loop_set_capacity(lo);
+		break;
+	case LOOP_SET_DIRECT_IO:
+		err = loop_set_dio(lo, arg);
+		break;
+	case LOOP_SET_BLOCK_SIZE:
+		err = loop_set_block_size(lo, arg);
+		break;
+	default:
+		err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
+	}
+	mutex_unlock(&loop_ctl_mutex);
+	return err;
 }
 
 static int lo_ioctl(struct block_device *bdev, fmode_t mode,
@@ -1400,64 +1538,42 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
 	struct loop_device *lo = bdev->bd_disk->private_data;
 	int err;
 
-	err = mutex_lock_killable_nested(&lo->lo_ctl_mutex, 1);
-	if (err)
-		goto out_unlocked;
-
 	switch (cmd) {
 	case LOOP_SET_FD:
-		err = loop_set_fd(lo, mode, bdev, arg);
-		break;
+		return loop_set_fd(lo, mode, bdev, arg);
 	case LOOP_CHANGE_FD:
-		err = loop_change_fd(lo, bdev, arg);
-		break;
+		return loop_change_fd(lo, bdev, arg);
 	case LOOP_CLR_FD:
-		/* loop_clr_fd would have unlocked lo_ctl_mutex on success */
-		err = loop_clr_fd(lo);
-		if (!err)
-			goto out_unlocked;
-		break;
+		return loop_clr_fd(lo);
 	case LOOP_SET_STATUS:
 		err = -EPERM;
-		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
+		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
 			err = loop_set_status_old(lo,
 					(struct loop_info __user *)arg);
+		}
 		break;
 	case LOOP_GET_STATUS:
-		err = loop_get_status_old(lo, (struct loop_info __user *) arg);
-		/* loop_get_status() unlocks lo_ctl_mutex */
-		goto out_unlocked;
+		return loop_get_status_old(lo, (struct loop_info __user *) arg);
 	case LOOP_SET_STATUS64:
 		err = -EPERM;
-		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
+		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN)) {
 			err = loop_set_status64(lo,
 					(struct loop_info64 __user *) arg);
+		}
 		break;
 	case LOOP_GET_STATUS64:
-		err = loop_get_status64(lo, (struct loop_info64 __user *) arg);
-		/* loop_get_status() unlocks lo_ctl_mutex */
-		goto out_unlocked;
+		return loop_get_status64(lo, (struct loop_info64 __user *) arg);
 	case LOOP_SET_CAPACITY:
-		err = -EPERM;
-		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
-			err = loop_set_capacity(lo);
-		break;
 	case LOOP_SET_DIRECT_IO:
-		err = -EPERM;
-		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
-			err = loop_set_dio(lo, arg);
-		break;
 	case LOOP_SET_BLOCK_SIZE:
-		err = -EPERM;
-		if ((mode & FMODE_WRITE) || capable(CAP_SYS_ADMIN))
-			err = loop_set_block_size(lo, arg);
-		break;
+		if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN))
+			return -EPERM;
+		/* Fall through */
 	default:
-		err = lo->ioctl ? lo->ioctl(lo, cmd, arg) : -EINVAL;
+		err = lo_simple_ioctl(lo, cmd, arg);
+		break;
 	}
-	mutex_unlock(&lo->lo_ctl_mutex);
 
-out_unlocked:
 	return err;
 }
 
@@ -1571,10 +1687,8 @@ loop_get_status_compat(struct loop_device *lo,
 	struct loop_info64 info64;
 	int err;
 
-	if (!arg) {
-		mutex_unlock(&lo->lo_ctl_mutex);
+	if (!arg)
 		return -EINVAL;
-	}
 	err = loop_get_status(lo, &info64);
 	if (!err)
 		err = loop_info64_to_compat(&info64, arg);
@@ -1589,20 +1703,12 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
 
 	switch(cmd) {
 	case LOOP_SET_STATUS:
-		err = mutex_lock_killable(&lo->lo_ctl_mutex);
-		if (!err) {
-			err = loop_set_status_compat(lo,
-						     (const struct compat_loop_info __user *)arg);
-			mutex_unlock(&lo->lo_ctl_mutex);
-		}
+		err = loop_set_status_compat(lo,
+			     (const struct compat_loop_info __user *)arg);
 		break;
 	case LOOP_GET_STATUS:
-		err = mutex_lock_killable(&lo->lo_ctl_mutex);
-		if (!err) {
-			err = loop_get_status_compat(lo,
-						     (struct compat_loop_info __user *)arg);
-			/* loop_get_status() unlocks lo_ctl_mutex */
-		}
+		err = loop_get_status_compat(lo,
+				     (struct compat_loop_info __user *)arg);
 		break;
 	case LOOP_SET_CAPACITY:
 	case LOOP_CLR_FD:
@@ -1626,9 +1732,11 @@ static int lo_compat_ioctl(struct block_device *bdev, fmode_t mode,
 static int lo_open(struct block_device *bdev, fmode_t mode)
 {
 	struct loop_device *lo;
-	int err = 0;
+	int err;
 
-	mutex_lock(&loop_index_mutex);
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		return err;
 	lo = bdev->bd_disk->private_data;
 	if (!lo) {
 		err = -ENXIO;
@@ -1637,26 +1745,30 @@ static int lo_open(struct block_device *bdev, fmode_t mode)
 
 	atomic_inc(&lo->lo_refcnt);
 out:
-	mutex_unlock(&loop_index_mutex);
+	mutex_unlock(&loop_ctl_mutex);
 	return err;
 }
 
-static void __lo_release(struct loop_device *lo)
+static void lo_release(struct gendisk *disk, fmode_t mode)
 {
-	int err;
+	struct loop_device *lo;
 
+	mutex_lock(&loop_ctl_mutex);
+	lo = disk->private_data;
 	if (atomic_dec_return(&lo->lo_refcnt))
-		return;
+		goto out_unlock;
 
-	mutex_lock(&lo->lo_ctl_mutex);
 	if (lo->lo_flags & LO_FLAGS_AUTOCLEAR) {
+		if (lo->lo_state != Lo_bound)
+			goto out_unlock;
+		lo->lo_state = Lo_rundown;
+		mutex_unlock(&loop_ctl_mutex);
 		/*
 		 * In autoclear mode, stop the loop thread
 		 * and remove configuration after last close.
 		 */
-		err = loop_clr_fd(lo);
-		if (!err)
-			return;
+		__loop_clr_fd(lo, true);
+		return;
 	} else if (lo->lo_state == Lo_bound) {
 		/*
 		 * Otherwise keep thread (if running) and config,
@@ -1666,14 +1778,8 @@ static void __lo_release(struct loop_device *lo)
 		blk_mq_unfreeze_queue(lo->lo_queue);
 	}
 
-	mutex_unlock(&lo->lo_ctl_mutex);
-}
-
-static void lo_release(struct gendisk *disk, fmode_t mode)
-{
-	mutex_lock(&loop_index_mutex);
-	__lo_release(disk->private_data);
-	mutex_unlock(&loop_index_mutex);
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
 }
 
 static const struct block_device_operations lo_fops = {
@@ -1712,10 +1818,10 @@ static int unregister_transfer_cb(int id, void *ptr, void *data)
 	struct loop_device *lo = ptr;
 	struct loop_func_table *xfer = data;
 
-	mutex_lock(&lo->lo_ctl_mutex);
+	mutex_lock(&loop_ctl_mutex);
 	if (lo->lo_encryption == xfer)
 		loop_release_xfer(lo);
-	mutex_unlock(&lo->lo_ctl_mutex);
+	mutex_unlock(&loop_ctl_mutex);
 	return 0;
 }
 
@@ -1896,7 +2002,6 @@ static int loop_add(struct loop_device **l, int i)
 	if (!part_shift)
 		disk->flags |= GENHD_FL_NO_PART_SCAN;
 	disk->flags |= GENHD_FL_EXT_DEVT;
-	mutex_init(&lo->lo_ctl_mutex);
 	atomic_set(&lo->lo_refcnt, 0);
 	lo->lo_number		= i;
 	spin_lock_init(&lo->lo_lock);
@@ -1975,7 +2080,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data)
 	struct kobject *kobj;
 	int err;
 
-	mutex_lock(&loop_index_mutex);
+	mutex_lock(&loop_ctl_mutex);
 	err = loop_lookup(&lo, MINOR(dev) >> part_shift);
 	if (err < 0)
 		err = loop_add(&lo, MINOR(dev) >> part_shift);
@@ -1983,7 +2088,7 @@ static struct kobject *loop_probe(dev_t dev, int *part, void *data)
 		kobj = NULL;
 	else
 		kobj = get_disk_and_module(lo->lo_disk);
-	mutex_unlock(&loop_index_mutex);
+	mutex_unlock(&loop_ctl_mutex);
 
 	*part = 0;
 	return kobj;
@@ -1993,9 +2098,13 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
 			       unsigned long parm)
 {
 	struct loop_device *lo;
-	int ret = -ENOSYS;
+	int ret;
+
+	ret = mutex_lock_killable(&loop_ctl_mutex);
+	if (ret)
+		return ret;
 
-	mutex_lock(&loop_index_mutex);
+	ret = -ENOSYS;
 	switch (cmd) {
 	case LOOP_CTL_ADD:
 		ret = loop_lookup(&lo, parm);
@@ -2009,21 +2118,15 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
 		ret = loop_lookup(&lo, parm);
 		if (ret < 0)
 			break;
-		ret = mutex_lock_killable(&lo->lo_ctl_mutex);
-		if (ret)
-			break;
 		if (lo->lo_state != Lo_unbound) {
 			ret = -EBUSY;
-			mutex_unlock(&lo->lo_ctl_mutex);
 			break;
 		}
 		if (atomic_read(&lo->lo_refcnt) > 0) {
 			ret = -EBUSY;
-			mutex_unlock(&lo->lo_ctl_mutex);
 			break;
 		}
 		lo->lo_disk->private_data = NULL;
-		mutex_unlock(&lo->lo_ctl_mutex);
 		idr_remove(&loop_index_idr, lo->lo_number);
 		loop_remove(lo);
 		break;
@@ -2033,7 +2136,7 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd,
 			break;
 		ret = loop_add(&lo, -1);
 	}
-	mutex_unlock(&loop_index_mutex);
+	mutex_unlock(&loop_ctl_mutex);
 
 	return ret;
 }
@@ -2117,10 +2220,10 @@ static int __init loop_init(void)
 				  THIS_MODULE, loop_probe, NULL, NULL);
 
 	/* pre-create number of devices given by config or max_loop */
-	mutex_lock(&loop_index_mutex);
+	mutex_lock(&loop_ctl_mutex);
 	for (i = 0; i < nr; i++)
 		loop_add(&lo, i);
-	mutex_unlock(&loop_index_mutex);
+	mutex_unlock(&loop_ctl_mutex);
 
 	printk(KERN_INFO "loop: module loaded\n");
 	return 0;
diff --git a/drivers/block/loop.h b/drivers/block/loop.h
index 4d42c7af7de7..af75a5ee4094 100644
--- a/drivers/block/loop.h
+++ b/drivers/block/loop.h
@@ -54,7 +54,6 @@ struct loop_device {
 
 	spinlock_t		lo_lock;
 	int			lo_state;
-	struct mutex		lo_ctl_mutex;
 	struct kthread_worker	worker;
 	struct task_struct	*worker_task;
 	bool			use_dio;
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 14a51254c3db..c13a6d1796a7 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -288,9 +288,10 @@ static void nbd_size_update(struct nbd_device *nbd)
 	blk_queue_physical_block_size(nbd->disk->queue, config->blksize);
 	set_capacity(nbd->disk, config->bytesize >> 9);
 	if (bdev) {
-		if (bdev->bd_disk)
+		if (bdev->bd_disk) {
 			bd_set_size(bdev, config->bytesize);
-		else
+			set_blocksize(bdev, config->blksize);
+		} else
 			bdev->bd_invalidated = 1;
 		bdput(bdev);
 	}
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 73ed5f3a862d..585378bc988c 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -5982,7 +5982,6 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
 	struct list_head *tmp;
 	int dev_id;
 	char opt_buf[6];
-	bool already = false;
 	bool force = false;
 	int ret;
 
@@ -6015,13 +6014,13 @@ static ssize_t do_rbd_remove(struct bus_type *bus,
 		spin_lock_irq(&rbd_dev->lock);
 		if (rbd_dev->open_count && !force)
 			ret = -EBUSY;
-		else
-			already = test_and_set_bit(RBD_DEV_FLAG_REMOVING,
-							&rbd_dev->flags);
+		else if (test_and_set_bit(RBD_DEV_FLAG_REMOVING,
+					  &rbd_dev->flags))
+			ret = -EINPROGRESS;
 		spin_unlock_irq(&rbd_dev->lock);
 	}
 	spin_unlock(&rbd_dev_list_lock);
-	if (ret < 0 || already)
+	if (ret)
 		return ret;
 
 	if (force) {
diff --git a/drivers/block/sunvdc.c b/drivers/block/sunvdc.c
index f68e9baffad7..5d7024057540 100644
--- a/drivers/block/sunvdc.c
+++ b/drivers/block/sunvdc.c
@@ -45,6 +45,8 @@ MODULE_VERSION(DRV_MODULE_VERSION);
 #define WAITING_FOR_GEN_CMD	0x04
 #define WAITING_FOR_ANY		-1
 
+#define	VDC_MAX_RETRIES	10
+
 static struct workqueue_struct *sunvdc_wq;
 
 struct vdc_req_entry {
@@ -431,6 +433,7 @@ static int __vdc_tx_trigger(struct vdc_port *port)
 		.end_idx		= dr->prod,
 	};
 	int err, delay;
+	int retries = 0;
 
 	hdr.seq = dr->snd_nxt;
 	delay = 1;
@@ -443,6 +446,8 @@ static int __vdc_tx_trigger(struct vdc_port *port)
 		udelay(delay);
 		if ((delay <<= 1) > 128)
 			delay = 128;
+		if (retries++ > VDC_MAX_RETRIES)
+			break;
 	} while (err == -EAGAIN);
 
 	if (err == -ENOTCONN)
diff --git a/drivers/block/swim3.c b/drivers/block/swim3.c
index 469541c1e51e..20907a0a043b 100644
--- a/drivers/block/swim3.c
+++ b/drivers/block/swim3.c
@@ -1026,7 +1026,11 @@ static void floppy_release(struct gendisk *disk, fmode_t mode)
 	struct swim3 __iomem *sw = fs->swim3;
 
 	mutex_lock(&swim3_mutex);
-	if (fs->ref_count > 0 && --fs->ref_count == 0) {
+	if (fs->ref_count > 0)
+		--fs->ref_count;
+	else if (fs->ref_count == -1)
+		fs->ref_count = 0;
+	if (fs->ref_count == 0) {
 		swim3_action(fs, MOTOR_OFF);
 		out_8(&sw->control_bic, 0xff);
 		swim3_select(fs, RELAX);
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 23752dc99b00..dd64f586679e 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -446,6 +446,8 @@ static int init_vq(struct virtio_blk *vblk)
 	if (err)
 		num_vqs = 1;
 
+	num_vqs = min_t(unsigned int, nr_cpu_ids, num_vqs);
+
 	vblk->vqs = kmalloc_array(num_vqs, sizeof(*vblk->vqs), GFP_KERNEL);
 	if (!vblk->vqs)
 		return -ENOMEM;
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 3e905da33bcb..5830d9417886 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1310,11 +1310,11 @@ static void blkif_free_ring(struct blkfront_ring_info *rinfo)
 		}
 
 free_shadow:
-		kfree(rinfo->shadow[i].grants_used);
+		kvfree(rinfo->shadow[i].grants_used);
 		rinfo->shadow[i].grants_used = NULL;
-		kfree(rinfo->shadow[i].indirect_grants);
+		kvfree(rinfo->shadow[i].indirect_grants);
 		rinfo->shadow[i].indirect_grants = NULL;
-		kfree(rinfo->shadow[i].sg);
+		kvfree(rinfo->shadow[i].sg);
 		rinfo->shadow[i].sg = NULL;
 	}
 
@@ -1353,7 +1353,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
 	for (i = 0; i < info->nr_rings; i++)
 		blkif_free_ring(&info->rinfo[i]);
 
-	kfree(info->rinfo);
+	kvfree(info->rinfo);
 	info->rinfo = NULL;
 	info->nr_rings = 0;
 }
@@ -1914,9 +1914,9 @@ static int negotiate_mq(struct blkfront_info *info)
 	if (!info->nr_rings)
 		info->nr_rings = 1;
 
-	info->rinfo = kcalloc(info->nr_rings,
-			      sizeof(struct blkfront_ring_info),
-			      GFP_KERNEL);
+	info->rinfo = kvcalloc(info->nr_rings,
+			       sizeof(struct blkfront_ring_info),
+			       GFP_KERNEL);
 	if (!info->rinfo) {
 		xenbus_dev_fatal(info->xbdev, -ENOMEM, "allocating ring_info structure");
 		info->nr_rings = 0;
@@ -2232,17 +2232,17 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
 
 	for (i = 0; i < BLK_RING_SIZE(info); i++) {
 		rinfo->shadow[i].grants_used =
-			kcalloc(grants,
-				sizeof(rinfo->shadow[i].grants_used[0]),
-				GFP_NOIO);
-		rinfo->shadow[i].sg = kcalloc(psegs,
-					      sizeof(rinfo->shadow[i].sg[0]),
-					      GFP_NOIO);
+			kvcalloc(grants,
+				 sizeof(rinfo->shadow[i].grants_used[0]),
+				 GFP_NOIO);
+		rinfo->shadow[i].sg = kvcalloc(psegs,
+					       sizeof(rinfo->shadow[i].sg[0]),
+					       GFP_NOIO);
 		if (info->max_indirect_segments)
 			rinfo->shadow[i].indirect_grants =
-				kcalloc(INDIRECT_GREFS(grants),
-					sizeof(rinfo->shadow[i].indirect_grants[0]),
-					GFP_NOIO);
+				kvcalloc(INDIRECT_GREFS(grants),
+					 sizeof(rinfo->shadow[i].indirect_grants[0]),
+					 GFP_NOIO);
 		if ((rinfo->shadow[i].grants_used == NULL) ||
 			(rinfo->shadow[i].sg == NULL) ||
 		     (info->max_indirect_segments &&
@@ -2256,11 +2256,11 @@ static int blkfront_setup_indirect(struct blkfront_ring_info *rinfo)
 
 out_of_memory:
 	for (i = 0; i < BLK_RING_SIZE(info); i++) {
-		kfree(rinfo->shadow[i].grants_used);
+		kvfree(rinfo->shadow[i].grants_used);
 		rinfo->shadow[i].grants_used = NULL;
-		kfree(rinfo->shadow[i].sg);
+		kvfree(rinfo->shadow[i].sg);
 		rinfo->shadow[i].sg = NULL;
-		kfree(rinfo->shadow[i].indirect_grants);
+		kvfree(rinfo->shadow[i].indirect_grants);
 		rinfo->shadow[i].indirect_grants = NULL;
 	}
 	if (!list_empty(&rinfo->indirect_pages)) {
diff --git a/drivers/block/xsysace.c b/drivers/block/xsysace.c
index c24589414c75..0f36db0cf74a 100644
--- a/drivers/block/xsysace.c
+++ b/drivers/block/xsysace.c
@@ -1063,6 +1063,8 @@ static int ace_setup(struct ace_device *ace)
 	return 0;
 
 err_read:
+	/* prevent double queue cleanup */
+	ace->gd->queue = NULL;
 	put_disk(ace->gd);
 err_alloc_disk:
 	blk_cleanup_queue(ace->queue);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 7bc9240be628..ffa3e9d67571 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -62,6 +62,16 @@ static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
 		spin_lock_init(&zram->table[index].lock);
 }
 
+static int zram_slot_trylock(struct zram *zram, u32 index)
+{
+	int ret;
+
+	ret = spin_trylock(&zram->table[index].lock);
+	if (ret)
+		__set_bit(ZRAM_LOCK, &zram->table[index].value);
+	return ret;
+}
+
 static void zram_slot_lock(struct zram *zram, u32 index)
 {
 	spin_lock(&zram->table[index].lock);
@@ -77,6 +87,11 @@ static void zram_slot_unlock(struct zram *zram, u32 index)
 #else
 static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
 
+static int zram_slot_trylock(struct zram *zram, u32 index)
+{
+	return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].value);
+}
+
 static void zram_slot_lock(struct zram *zram, u32 index)
 {
 	bit_spin_lock(ZRAM_LOCK, &zram->table[index].value);
@@ -407,8 +422,10 @@ static ssize_t backing_dev_store(struct device *dev,
 
 	bdev = bdgrab(I_BDEV(inode));
 	err = blkdev_get(bdev, FMODE_READ | FMODE_WRITE | FMODE_EXCL, zram);
-	if (err < 0)
+	if (err < 0) {
+		bdev = NULL;
 		goto out;
+	}
 
 	nr_pages = i_size_read(inode) >> PAGE_SHIFT;
 	bitmap_sz = BITS_TO_LONGS(nr_pages) * sizeof(long);
@@ -424,7 +441,6 @@ static ssize_t backing_dev_store(struct device *dev,
 		goto out;
 
 	reset_bdev(zram);
-	spin_lock_init(&zram->bitmap_lock);
 
 	zram->old_block_size = old_block_size;
 	zram->bdev = bdev;
@@ -468,29 +484,24 @@ out:
 
 static unsigned long get_entry_bdev(struct zram *zram)
 {
-	unsigned long entry;
-
-	spin_lock(&zram->bitmap_lock);
+	unsigned long blk_idx = 1;
+retry:
 	/* skip 0 bit to confuse zram.handle = 0 */
-	entry = find_next_zero_bit(zram->bitmap, zram->nr_pages, 1);
-	if (entry == zram->nr_pages) {
-		spin_unlock(&zram->bitmap_lock);
+	blk_idx = find_next_zero_bit(zram->bitmap, zram->nr_pages, blk_idx);
+	if (blk_idx == zram->nr_pages)
 		return 0;
-	}
 
-	set_bit(entry, zram->bitmap);
-	spin_unlock(&zram->bitmap_lock);
+	if (test_and_set_bit(blk_idx, zram->bitmap))
+		goto retry;
 
-	return entry;
+	return blk_idx;
 }
 
 static void put_entry_bdev(struct zram *zram, unsigned long entry)
 {
 	int was_set;
 
-	spin_lock(&zram->bitmap_lock);
 	was_set = test_and_clear_bit(entry, zram->bitmap);
-	spin_unlock(&zram->bitmap_lock);
 	WARN_ON_ONCE(!was_set);
 }
 
@@ -539,18 +550,18 @@ struct zram_work {
 	struct zram *zram;
 	unsigned long entry;
 	struct bio *bio;
+	struct bio_vec bvec;
 };
 
 #if PAGE_SIZE != 4096
 static void zram_sync_read(struct work_struct *work)
 {
-	struct bio_vec bvec;
 	struct zram_work *zw = container_of(work, struct zram_work, work);
 	struct zram *zram = zw->zram;
 	unsigned long entry = zw->entry;
 	struct bio *bio = zw->bio;
 
-	read_from_bdev_async(zram, &bvec, entry, bio);
+	read_from_bdev_async(zram, &zw->bvec, entry, bio);
 }
 
 /*
@@ -563,6 +574,7 @@ static int read_from_bdev_sync(struct zram *zram, struct bio_vec *bvec,
 {
 	struct zram_work work;
 
+	work.bvec = *bvec;
 	work.zram = zram;
 	work.entry = entry;
 	work.bio = bio;
@@ -911,9 +923,10 @@ static ssize_t debug_stat_show(struct device *dev,
 
 	down_read(&zram->init_lock);
 	ret = scnprintf(buf, PAGE_SIZE,
-			"version: %d\n%8llu\n",
+			"version: %d\n%8llu %8llu\n",
 			version,
-			(u64)atomic64_read(&zram->stats.writestall));
+			(u64)atomic64_read(&zram->stats.writestall),
+			(u64)atomic64_read(&zram->stats.miss_free));
 	up_read(&zram->init_lock);
 
 	return ret;
@@ -1429,10 +1442,14 @@ static void zram_slot_free_notify(struct block_device *bdev,
 
 	zram = bdev->bd_disk->private_data;
 
-	zram_slot_lock(zram, index);
+	atomic64_inc(&zram->stats.notify_free);
+	if (!zram_slot_trylock(zram, index)) {
+		atomic64_inc(&zram->stats.miss_free);
+		return;
+	}
+
 	zram_free_page(zram, index);
 	zram_slot_unlock(zram, index);
-	atomic64_inc(&zram->stats.notify_free);
 }
 
 static int zram_rw_page(struct block_device *bdev, sector_t sector,
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 1015c7574d54..144e91061df8 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -82,6 +82,7 @@ struct zram_stats {
 	atomic64_t pages_stored;	/* no. of pages currently stored */
 	atomic_long_t max_used_pages;	/* no. of maximum pages stored */
 	atomic64_t writestall;		/* no. of write slow paths */
+	atomic64_t miss_free;		/* no. of missed free */
 };
 
 struct zram {
@@ -113,7 +114,6 @@ struct zram {
 	unsigned int old_block_size;
 	unsigned long *bitmap;
 	unsigned long nr_pages;
-	spinlock_t bitmap_lock;
 #endif
 #ifdef CONFIG_ZRAM_MEMORY_TRACKING
 	struct dentry *debugfs_dir;