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Commit 9ff9d15e authored by Bart Van Assche's avatar Bart Van Assche Committed by Nicholas Bellinger
Browse files

target: Invoke release_cmd() callback without holding a spinlock 



This patch fixes the following kernel warning because it avoids that
IRQs are disabled while ft_release_cmd() is invoked (fc_seq_set_resp()
invokes spin_unlock_bh()):

WARNING: CPU: 3 PID: 117 at kernel/softirq.c:150 __local_bh_enable_ip+0xaa/0x110()
Call Trace:
 [<ffffffff814f71eb>] dump_stack+0x4f/0x7b
 [<ffffffff8105e56a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff8105e65a>] warn_slowpath_null+0x1a/0x20
 [<ffffffff81062b2a>] __local_bh_enable_ip+0xaa/0x110
 [<ffffffff814ff229>] _raw_spin_unlock_bh+0x39/0x40
 [<ffffffffa03a7f94>] fc_seq_set_resp+0xe4/0x100 [libfc]
 [<ffffffffa02e604a>] ft_free_cmd+0x4a/0x90 [tcm_fc]
 [<ffffffffa02e6972>] ft_release_cmd+0x12/0x20 [tcm_fc]
 [<ffffffffa042bd66>] target_release_cmd_kref+0x56/0x90 [target_core_mod]
 [<ffffffffa042caf0>] target_put_sess_cmd+0xc0/0x110 [target_core_mod]
 [<ffffffffa042cb81>] transport_release_cmd+0x41/0x70 [target_core_mod]
 [<ffffffffa042d975>] transport_generic_free_cmd+0x35/0x420 [target_core_mod]

Signed-off-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Acked-by: default avatarJoern Engel <joern@logfs.org>
Reviewed-by: default avatarAndy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 057085e5

drivers/target/target_core_tmr.c

+6 −1
Original line number Diff line number Diff line
@@ -130,6 +130,9 @@ void core_tmr_abort_task( 
		if (tmr->ref_task_tag != ref_tag)

			continue;



		if (!kref_get_unless_zero(&se_cmd->cmd_kref))

			continue;



		printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",

			se_cmd->se_tfo->get_fabric_name(), ref_tag);
@@ -139,13 +142,15 @@ void core_tmr_abort_task( 
			       " skipping\n", ref_tag);

			spin_unlock(&se_cmd->t_state_lock);

			spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);



			target_put_sess_cmd(se_cmd);



			goto out;

		}

		se_cmd->transport_state |= CMD_T_ABORTED;

		spin_unlock(&se_cmd->t_state_lock);



		list_del_init(&se_cmd->se_cmd_list);

		kref_get(&se_cmd->cmd_kref);

		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);



		cancel_work_sync(&se_cmd->work);

drivers/target/target_core_transport.c

+6 −6
Original line number Diff line number Diff line
@@ -2509,23 +2509,24 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref) 
EXPORT_SYMBOL(target_get_sess_cmd);



static void target_release_cmd_kref(struct kref *kref)

		__releases(&se_cmd->se_sess->sess_cmd_lock)

{

	struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);

	struct se_session *se_sess = se_cmd->se_sess;

	unsigned long flags;



	spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);

	if (list_empty(&se_cmd->se_cmd_list)) {

		spin_unlock(&se_sess->sess_cmd_lock);

		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);

		se_cmd->se_tfo->release_cmd(se_cmd);

		return;

	}

	if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {

		spin_unlock(&se_sess->sess_cmd_lock);

		spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);

		complete(&se_cmd->cmd_wait_comp);

		return;

	}

	list_del(&se_cmd->se_cmd_list);

	spin_unlock(&se_sess->sess_cmd_lock);

	spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);



	se_cmd->se_tfo->release_cmd(se_cmd);

}
@@ -2541,8 +2542,7 @@ int target_put_sess_cmd(struct se_cmd *se_cmd) 
		se_cmd->se_tfo->release_cmd(se_cmd);

		return 1;

	}

	return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref,

			&se_sess->sess_cmd_lock);

	return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);

}

EXPORT_SYMBOL(target_put_sess_cmd);