loop: LOOP_SET_FD: send uevents for partitions

Remove the suppression of the uevents before scanning for partitions.
The partitions inherit their suppression settings from their parent device,
which lead to the uevents being dropped.

This is similar to the same changes for LOOP_CONFIGURE done in
commit bb430b6 ("loop: LOOP_CONFIGURE: send uevents for partitions").

Fixes: 498ef5c ("loop: suppress uevents while reconfiguring the device")
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20250415-loop-uevent-changed-v3-1-60ff69ac6088@linutronix.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: t-8ch

drivers/block/loop.c

@@ -662,19 +662,20 @@ static int loop_change_fd(struct loop_device *lo, struct block_device *bdev,
 	 * dependency.
 	 */
 	fput(old_file);
+	dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0);
 	if (partscan)
 		loop_reread_partitions(lo);
 
 	error = 0;
 done:
-	dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0);
 	kobject_uevent(&disk_to_dev(lo->lo_disk)->kobj, KOBJ_CHANGE);
 	return error;
 
 out_err:
 	loop_global_unlock(lo, is_loop);
 out_putf:
 	fput(file);
+	dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0);
 	goto done;
 }