scsi: target: Put lun_ref at end of tmr processing

Testing with Loopback I found that, after a Loopback LUN has executed a
TMR, I can no longer unlink the LUN.  The rm command hangs in
transport_clear_lun_ref() at wait_for_completion(&lun->lun_shutdown_comp)
The reason is, that transport_lun_remove_cmd() is not called at the end of
target_tmr_work().

It seems, that in other fabrics this call happens implicitly when the
fabric drivers call transport_generic_free_cmd() during their
->queue_tm_rsp().

Unfortunately Loopback seems to not comply to the common way
of calling transport_generic_free_cmd() from ->queue_*().
Instead it calls transport_generic_free_cmd() from its
  ->check_stop_free() only.

But the ->check_stop_free() is called by
transport_cmd_check_stop_to_fabric() after it has reset the se_cmd->se_lun
pointer.  Therefore the following transport_generic_free_cmd() skips the
transport_lun_remove_cmd().

So this patch re-adds the transport_lun_remove_cmd() at the end of
target_tmr_work(), which was removed during commit 2c9fa49e100f ("scsi:
target/core: Make ABORT and LUN RESET handling synchronous").

For fabrics using transport_generic_free_cmd() in the usual way the double
call to transport_lun_remove_cmd() doesn't harm, as
transport_lun_remove_cmd() checks for this situation and does not release
lun_ref twice.

Link: https://lore.kernel.org/r/[email protected]
Fixes: 2c9fa49e100f ("scsi: target/core: Make ABORT and LUN RESET handling synchronous")
Cc: [email protected]
Tested-by: Bryant G. Ly <[email protected]>
Reviewed-by: Bart van Assche <[email protected]>
Signed-off-by: Bodo Stroesser <[email protected]>
Signed-off-by: Martin K. Petersen <[email protected]>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 594b724bbf7976fce43c3f380a5b63a6d9969cd8..264a822c0bfac681c3e0b3da281f8b561204a36d 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -3350,6 +3350,7 @@ static void target_tmr_work(struct work_struct *work)
 
        cmd->se_tfo->queue_tm_rsp(cmd);
 
+       transport_lun_remove_cmd(cmd);
        transport_cmd_check_stop_to_fabric(cmd);
        return;