Merge tag 'block-5.14-2021-07-08' of git://git.kernel.dk/linux-block

Pull more block updates from Jens Axboe:
 "A combination of changes that ended up depending on both the driver
  and core branch (and/or the IDE removal), and a few late arriving
  fixes. In detail:

   - Fix io ticks wrap-around issue (Chunguang)

   - nvme-tcp sock locking fix (Maurizio)

   - s390-dasd fixes (Kees, Christoph)

   - blk_execute_rq polling support (Keith)

   - blk-cgroup RCU iteration fix (Yu)

   - nbd backend ID addition (Prasanna)

   - Partition deletion fix (Yufen)

   - Use blk_mq_alloc_disk for mmc, mtip32xx, ubd (Christoph)

   - Removal of now dead block request types due to IDE removal
     (Christoph)

   - Loop probing and control device cleanups (Christoph)

   - Device uevent fix (Christoph)

   - Misc cleanups/fixes (Tetsuo, Christoph)"

* tag 'block-5.14-2021-07-08' of git://git.kernel.dk/linux-block: (34 commits)
  blk-cgroup: prevent rcu_sched detected stalls warnings while iterating blkgs
  block: fix the problem of io_ticks becoming smaller
  nvme-tcp: can't set sk_user_data without write_lock
  loop: remove unused variable in loop_set_status()
  block: remove the bdgrab in blk_drop_partitions
  block: grab a device refcount in disk_uevent
  s390/dasd: Avoid field over-reading memcpy()
  dasd: unexport dasd_set_target_state
  block: check disk exist before trying to add partition
  ubd: remove dead code in ubd_setup_common
  nvme: use return value from blk_execute_rq()
  block: return errors from blk_execute_rq()
  nvme: use blk_execute_rq() for passthrough commands
  block: support polling through blk_execute_rq
  block: remove REQ_OP_SCSI_{IN,OUT}
  block: mark blk_mq_init_queue_data static
  loop: rewrite loop_exit using idr_for_each_entry
  loop: split loop_lookup
  loop: don't allow deleting an unspecified loop device
  loop: move loop_ctl_mutex locking into loop_add
  ...

1 files changed, 70 insertions, 99 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cc0e8c39a48b..f37b9e3d833c 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1434,7 +1434,6 @@ static int
 loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 {
 	int err;
-	struct block_device *bdev;
 	kuid_t uid = current_uid();
 	int prev_lo_flags;
 	bool partscan = false;
@@ -1503,7 +1502,6 @@ out_unfreeze:
 	if (!err && (lo->lo_flags & LO_FLAGS_PARTSCAN) &&
 	     !(prev_lo_flags & LO_FLAGS_PARTSCAN)) {
 		lo->lo_disk->flags &= ~GENHD_FL_NO_PART_SCAN;
-		bdev = lo->lo_device;
 		partscan = true;
 	}
 out_unlock:
@@ -2237,7 +2235,7 @@ static const struct blk_mq_ops loop_mq_ops = {
 	.complete	= lo_complete_rq,
 };
 
-static int loop_add(struct loop_device **l, int i)
+static int loop_add(int i)
 {
 	struct loop_device *lo;
 	struct gendisk *disk;
@@ -2247,9 +2245,12 @@ static int loop_add(struct loop_device **l, int i)
 	lo = kzalloc(sizeof(*lo), GFP_KERNEL);
 	if (!lo)
 		goto out;
-
 	lo->lo_state = Lo_unbound;
 
+	err = mutex_lock_killable(&loop_ctl_mutex);
+	if (err)
+		goto out_free_dev;
+
 	/* allocate id, if @id >= 0, we're requesting that specific id */
 	if (i >= 0) {
 		err = idr_alloc(&loop_index_idr, lo, i, i + 1, GFP_KERNEL);
@@ -2259,7 +2260,7 @@ static int loop_add(struct loop_device **l, int i)
 		err = idr_alloc(&loop_index_idr, lo, 0, 0, GFP_KERNEL);
 	}
 	if (err < 0)
-		goto out_free_dev;
+		goto out_unlock;
 	i = err;
 
 	err = -ENOMEM;
@@ -2326,13 +2327,15 @@ static int loop_add(struct loop_device **l, int i)
 	disk->queue		= lo->lo_queue;
 	sprintf(disk->disk_name, "loop%d", i);
 	add_disk(disk);
-	*l = lo;
-	return lo->lo_number;
+	mutex_unlock(&loop_ctl_mutex);
+	return i;
 
 out_cleanup_tags:
 	blk_mq_free_tag_set(&lo->tag_set);
 out_free_idr:
 	idr_remove(&loop_index_idr, i);
+out_unlock:
+	mutex_unlock(&loop_ctl_mutex);
 out_free_dev:
 	kfree(lo);
 out:
@@ -2348,109 +2351,86 @@ static void loop_remove(struct loop_device *lo)
 	kfree(lo);
 }
 
-static int find_free_cb(int id, void *ptr, void *data)
+static void loop_probe(dev_t dev)
 {
-	struct loop_device *lo = ptr;
-	struct loop_device **l = data;
+	int idx = MINOR(dev) >> part_shift;
 
-	if (lo->lo_state == Lo_unbound) {
-		*l = lo;
-		return 1;
-	}
-	return 0;
+	if (max_loop && idx >= max_loop)
+		return;
+	loop_add(idx);
 }
 
-static int loop_lookup(struct loop_device **l, int i)
+static int loop_control_remove(int idx)
 {
 	struct loop_device *lo;
-	int ret = -ENODEV;
+	int ret;
 
-	if (i < 0) {
-		int err;
+	if (idx < 0) {
+		pr_warn("deleting an unspecified loop device is not supported.\n");
+		return -EINVAL;
+	}
+		
+	ret = mutex_lock_killable(&loop_ctl_mutex);
+	if (ret)
+		return ret;
 
-		err = idr_for_each(&loop_index_idr, &find_free_cb, &lo);
-		if (err == 1) {
-			*l = lo;
-			ret = lo->lo_number;
-		}
-		goto out;
+	lo = idr_find(&loop_index_idr, idx);
+	if (!lo) {
+		ret = -ENODEV;
+		goto out_unlock_ctrl;
 	}
 
-	/* lookup and return a specific i */
-	lo = idr_find(&loop_index_idr, i);
-	if (lo) {
-		*l = lo;
-		ret = lo->lo_number;
+	ret = mutex_lock_killable(&lo->lo_mutex);
+	if (ret)
+		goto out_unlock_ctrl;
+	if (lo->lo_state != Lo_unbound ||
+	    atomic_read(&lo->lo_refcnt) > 0) {
+		mutex_unlock(&lo->lo_mutex);
+		ret = -EBUSY;
+		goto out_unlock_ctrl;
 	}
-out:
+	lo->lo_state = Lo_deleting;
+	mutex_unlock(&lo->lo_mutex);
+
+	idr_remove(&loop_index_idr, lo->lo_number);
+	loop_remove(lo);
+out_unlock_ctrl:
+	mutex_unlock(&loop_ctl_mutex);
 	return ret;
 }
 
-static void loop_probe(dev_t dev)
+static int loop_control_get_free(int idx)
 {
-	int idx = MINOR(dev) >> part_shift;
 	struct loop_device *lo;
+	int id, ret;
 
-	if (max_loop && idx >= max_loop)
-		return;
-
-	mutex_lock(&loop_ctl_mutex);
-	if (loop_lookup(&lo, idx) < 0)
-		loop_add(&lo, idx);
+	ret = mutex_lock_killable(&loop_ctl_mutex);
+	if (ret)
+		return ret;
+	idr_for_each_entry(&loop_index_idr, lo, id) {
+		if (lo->lo_state == Lo_unbound)
+			goto found;
+	}
 	mutex_unlock(&loop_ctl_mutex);
+	return loop_add(-1);
+found:
+	mutex_unlock(&loop_ctl_mutex);
+	return id;
 }
 
 static long loop_control_ioctl(struct file *file, unsigned int cmd,
 			       unsigned long parm)
 {
-	struct loop_device *lo;
-	int ret;
-
-	ret = mutex_lock_killable(&loop_ctl_mutex);
-	if (ret)
-		return ret;
-
-	ret = -ENOSYS;
 	switch (cmd) {
 	case LOOP_CTL_ADD:
-		ret = loop_lookup(&lo, parm);
-		if (ret >= 0) {
-			ret = -EEXIST;
-			break;
-		}
-		ret = loop_add(&lo, parm);
-		break;
+		return loop_add(parm);
 	case LOOP_CTL_REMOVE:
-		ret = loop_lookup(&lo, parm);
-		if (ret < 0)
-			break;
-		ret = mutex_lock_killable(&lo->lo_mutex);
-		if (ret)
-			break;
-		if (lo->lo_state != Lo_unbound) {
-			ret = -EBUSY;
-			mutex_unlock(&lo->lo_mutex);
-			break;
-		}
-		if (atomic_read(&lo->lo_refcnt) > 0) {
-			ret = -EBUSY;
-			mutex_unlock(&lo->lo_mutex);
-			break;
-		}
-		lo->lo_state = Lo_deleting;
-		mutex_unlock(&lo->lo_mutex);
-		idr_remove(&loop_index_idr, lo->lo_number);
-		loop_remove(lo);
-		break;
+		return loop_control_remove(parm);
 	case LOOP_CTL_GET_FREE:
-		ret = loop_lookup(&lo, -1);
-		if (ret >= 0)
-			break;
-		ret = loop_add(&lo, -1);
+		return loop_control_get_free(parm);
+	default:
+		return -ENOSYS;
 	}
-	mutex_unlock(&loop_ctl_mutex);
-
-	return ret;
 }
 
 static const struct file_operations loop_ctl_fops = {
@@ -2473,7 +2453,6 @@ MODULE_ALIAS("devname:loop-control");
 static int __init loop_init(void)
 {
 	int i, nr;
-	struct loop_device *lo;
 	int err;
 
 	part_shift = 0;
@@ -2525,10 +2504,8 @@ static int __init loop_init(void)
 	}
 
 	/* pre-create number of devices given by config or max_loop */
-	mutex_lock(&loop_ctl_mutex);
 	for (i = 0; i < nr; i++)
-		loop_add(&lo, i);
-	mutex_unlock(&loop_ctl_mutex);
+		loop_add(i);
 
 	printk(KERN_INFO "loop: module loaded\n");
 	return 0;
@@ -2539,26 +2516,20 @@ err_out:
 	return err;
 }
 
-static int loop_exit_cb(int id, void *ptr, void *data)
-{
-	struct loop_device *lo = ptr;
-
-	loop_remove(lo);
-	return 0;
-}
-
 static void __exit loop_exit(void)
 {
-	mutex_lock(&loop_ctl_mutex);
-
-	idr_for_each(&loop_index_idr, &loop_exit_cb, NULL);
-	idr_destroy(&loop_index_idr);
+	struct loop_device *lo;
+	int id;
 
 	unregister_blkdev(LOOP_MAJOR, "loop");
-
 	misc_deregister(&loop_misc);
 
+	mutex_lock(&loop_ctl_mutex);
+	idr_for_each_entry(&loop_index_idr, lo, id)
+		loop_remove(lo);
 	mutex_unlock(&loop_ctl_mutex);
+
+	idr_destroy(&loop_index_idr);
 }
 
 module_init(loop_init);