Merge tag 'block-6.15-20250509' of git://git.kernel.dk/linux

Pull block fixes from Jens Axboe:

 - Fix for a regression in this series for loop and read/write iterator
   handling

 - zone append block update tweak

 - remove a broken IO priority test

 - NVMe pull request via Christoph:
      - unblock ctrl state transition for firmware update (Daniel
        Wagner)

* tag 'block-6.15-20250509' of git://git.kernel.dk/linux:
  block: remove test of incorrect io priority level
  nvme: unblock ctrl state transition for firmware update
  block: only update request sector if needed
  loop: Add sanity check for read/write_iter

1 files changed, 23 insertions, 0 deletions

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 46cba261075f..b8ba7de08753 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -505,6 +505,17 @@ static void loop_assign_backing_file(struct loop_device *lo, struct file *file)
 	lo->lo_min_dio_size = loop_query_min_dio_size(lo);
 }
 
+static int loop_check_backing_file(struct file *file)
+{
+	if (!file->f_op->read_iter)
+		return -EINVAL;
+
+	if ((file->f_mode & FMODE_WRITE) && !file->f_op->write_iter)
+		return -EINVAL;
+
+	return 0;
+}
+
 /*
  * loop_change_fd switched the backing store of a loopback device to
  * a new file. This is useful for operating system installers to free up
@@ -526,6 +537,10 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	if (!file)
 		return -EBADF;
 
+	error = loop_check_backing_file(file);
+	if (error)
+		return error;
+
 	/* suppress uevents while reconfiguring the device */
 	dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1);
 
@@ -963,6 +978,14 @@ static int loop_configure(struct loop_device *lo, blk_mode_t mode,
 
 	if (!file)
 		return -EBADF;
+
+	if ((mode & BLK_OPEN_WRITE) && !file->f_op->write_iter)
+		return -EINVAL;
+
+	error = loop_check_backing_file(file);
+	if (error)
+		return error;
+
 	is_loop = is_loop_device(file);
 
 	/* This is safe, since we have a reference from open(). */