On Sun, Mar 12, 2023 at 07:10:31PM +0000, Alyssa Ross wrote: > + * Now that we are done, reread the partitions with uevent > + * re-enabled if appropriate to let userspace know about the > + * changes. > + */ > + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), !partscan_uevent); > + if (partscan) > + loop_reread_partitions(lo); > + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); What worries me here is that you move the partition re-read out of the exclusive claim, which is another potentially user visible change (and user visible behavior changes are a field of landmines in loop as you have noticed). But in the end we only need to suppress the events until Lo_Bound is set. So something like the patch below that reduces the no even critical section might do the job? diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 839373451c2b7d..9d61c027185141 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1010,9 +1010,6 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, /* This is safe, since we have a reference from open(). */ __module_get(THIS_MODULE); - /* suppress uevents while reconfiguring the device */ - dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); - /* * If we don't hold exclusive handle for the device, upgrade to it * here to avoid changing device under exclusive owner. @@ -1067,6 +1064,9 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, } } + /* suppress uevents while reconfiguring the device */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 1); + disk_force_media_change(lo->lo_disk, DISK_EVENT_MEDIA_CHANGE); set_disk_ro(lo->lo_disk, (lo->lo_flags & LO_FLAGS_READ_ONLY) != 0); @@ -1109,17 +1109,17 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, if (partscan) clear_bit(GD_SUPPRESS_PART_SCAN, &lo->lo_disk->state); + /* enable and uncork uevent now that we are done */ + dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); + loop_global_unlock(lo, is_loop); if (partscan) loop_reread_partitions(lo); + if (!(mode & FMODE_EXCL)) bd_abort_claiming(bdev, loop_configure); - error = 0; -done: - /* enable and uncork uevent now that we are done */ - dev_set_uevent_suppress(disk_to_dev(lo->lo_disk), 0); - return error; + return 0; out_unlock: loop_global_unlock(lo, is_loop); @@ -1130,7 +1130,7 @@ static int loop_configure(struct loop_device *lo, fmode_t mode, fput(file); /* This is safe: open() is still holding a reference. */ module_put(THIS_MODULE); - goto done; + return error; } static void __loop_clr_fd(struct loop_device *lo, bool release)
