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target: Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce

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commit 1d6ef27659 upstream.

This patch addresses a COMPARE_AND_WRITE se_device->caw_sem leak,
that would be triggered during normal se_cmd shutdown or abort
via __transport_wait_for_tasks().

This would occur because target_complete_cmd() would catch this
early and do complete_all(&cmd->t_transport_stop_comp), but since
target_complete_ok_work() or target_complete_failure_work() are
never called to invoke se_cmd->transport_complete_callback(),
the COMPARE_AND_WRITE specific callbacks never release caw_sem.

To address this special case, go ahead and release caw_sem
directly from target_complete_cmd().

(Remove '&& success' from check, to release caw_sem regardless
 of scsi_status - nab)

Signed-off-by: Jiang Yi <jiangyilism@gmail.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jiang Yi 2017-06-25 12:28:50 -07:00 • committed by Greg Kroah-Hartman
commit 8d83251372
1 changed files with 9 additions and 0 deletions
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9
drivers/target/target_core_transport.c
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@ -728,6 +728,15 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
if (cmd->transport_state & CMD_T_ABORTED ||
cmd->transport_state & CMD_T_STOP) {
spin_unlock_irqrestore(&cmd->t_state_lock, flags);
/*
* If COMPARE_AND_WRITE was stopped by __transport_wait_for_tasks(),
* release se_device->caw_sem obtained by sbc_compare_and_write()
* since target_complete_ok_work() or target_complete_failure_work()
* won't be called to invoke the normal CAW completion callbacks.
*/
if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
up(&dev->caw_sem);
}
complete_all(&cmd->t_transport_stop_comp);
return;
} else if (!success) {