iscsi-target: Fix iscsit_free_cmd() se_cmd->cmd_kref shutdown handling
With the introduction of target_get_sess_cmd() referencing counting for
ISCSI_OP_SCSI_CMD processing with iser-target, iscsit_free_cmd() usage
in traditional iscsi-target driver code now needs to be aware of the
active I/O shutdown case when a remaining se_cmd->cmd_kref reference may
exist after transport_generic_free_cmd() completes, requiring a final
target_put_sess_cmd() to release iscsi_cmd descriptor memory.
This patch changes iscsit_free_cmd() to invoke __iscsit_free_cmd() before
transport_generic_free_cmd() -> target_put_sess_cmd(), and also avoids
aquiring the per-connection queue locks for typical fast-path calls
during normal ISTATE_REMOVE operation.
Also update iscsit_free_cmd() usage throughout iscsi-target to
use the new 'bool shutdown' parameter.
This patch fixes a regression bug introduced during v3.10-rc1 in
commit 3e1c81a95, that was causing the following WARNING to appear:
[ 257.235153] ------------[ cut here]------------
[ 257.240314] WARNING: at kernel/softirq.c:160 local_bh_enable_ip+0x3c/0x86()
[ 257.248089] Modules linked in: vhost_scsi ib_srpt ib_cm ib_sa ib_mad ib_core tcm_qla2xxx tcm_loop
tcm_fc libfc iscsi_target_mod target_core_pscsi target_core_file
target_core_iblock target_core_mod configfs ipv6 iscsi_tcp libiscsi_tcp
libiscsi scsi_transport_iscsi loop acpi_cpufreq freq_table mperf
kvm_intel kvm crc32c_intel button ehci_pci pcspkr joydev i2c_i801
microcode ext3 jbd raid10 raid456 async_pq async_xor xor async_memcpy
async_raid6_recov raid6_pq async_tx raid1 raid0 linear igb hwmon
i2c_algo_bit i2c_core ptp ata_piix libata qla2xxx uhci_hcd ehci_hcd
mlx4_core scsi_transport_fc scsi_tgt pps_core
[ 257.308748] CPU: 1 PID: 3295 Comm: iscsi_ttx Not tainted 3.10.0-rc2+ #103
[ 257.316329] Hardware name: Intel Corporation S5520HC/S5520HC, BIOS S5500.86B.01.00.0057.031020111721 03/10/2011
[ 257.327597] ffffffff814c24b7 ffff880458331b58 ffffffff8138eef2 ffff880458331b98
[ 257.335892] ffffffff8102c052 ffff880400000008 0000000000000000 ffff88085bdf0000
[ 257.344191] ffff88085bdf00d8 ffff88085bdf00e0 ffff88085bdf00f8 ffff880458331ba8
[ 257.352488] Call Trace:
[ 257.355223] [<ffffffff8138eef2>] dump_stack+0x19/0x1f
[ 257.360963] [<ffffffff8102c052>] warn_slowpath_common+0x62/0x7b
[ 257.367669] [<ffffffff8102c080>] warn_slowpath_null+0x15/0x17
[ 257.374181] [<ffffffff81032345>] local_bh_enable_ip+0x3c/0x86
[ 257.380697] [<ffffffff813917fd>] _raw_spin_unlock_bh+0x10/0x12
[ 257.387311] [<ffffffffa029069c>] iscsit_free_r2ts_from_list+0x5e/0x67 [iscsi_target_mod]
[ 257.396438] [<ffffffffa02906c5>] iscsit_release_cmd+0x20/0x223 [iscsi_target_mod]
[ 257.404893] [<ffffffffa02977a4>] lio_release_cmd+0x3a/0x3e [iscsi_target_mod]
[ 257.412964] [<ffffffffa01d59a1>] target_release_cmd_kref+0x7a/0x7c [target_core_mod]
[ 257.421712] [<ffffffffa01d69bc>] target_put_sess_cmd+0x5f/0x7f [target_core_mod]
[ 257.430071] [<ffffffffa01d6d6d>] transport_release_cmd+0x59/0x6f [target_core_mod]
[ 257.438625] [<ffffffffa01d6eb4>] transport_put_cmd+0x131/0x140 [target_core_mod]
[ 257.446985] [<ffffffffa01d6192>] ? transport_wait_for_tasks+0xfa/0x1d5 [target_core_mod]
[ 257.456121] [<ffffffffa01d6f11>] transport_generic_free_cmd+0x4e/0x52 [target_core_mod]
[ 257.465159] [<ffffffff81050537>] ? __migrate_task+0x110/0x110
[ 257.471674] [<ffffffffa02904ba>] iscsit_free_cmd+0x46/0x55 [iscsi_target_mod]
[ 257.479741] [<ffffffffa0291edb>] iscsit_immediate_queue+0x301/0x353 [iscsi_target_mod]
[ 257.488683] [<ffffffffa0292f7e>] iscsi_target_tx_thread+0x1c6/0x2a8 [iscsi_target_mod]
[ 257.497623] [<ffffffff81047486>] ? wake_up_bit+0x25/0x25
[ 257.503652] [<ffffffffa0292db8>] ? iscsit_ack_from_expstatsn+0xd5/0xd5 [iscsi_target_mod]
[ 257.512882] [<ffffffff81046f89>] kthread+0xb0/0xb8
[ 257.518329] [<ffffffff81046ed9>] ? kthread_freezable_should_stop+0x60/0x60
[ 257.526105] [<ffffffff81396fec>] ret_from_fork+0x7c/0xb0
[ 257.532133] [<ffffffff81046ed9>] ? kthread_freezable_should_stop+0x60/0x60
[ 257.539906] ---[ end trace 5520397d0f2e0800 ]---
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 2cc6c9a..08a3bac 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -676,40 +676,56 @@
void iscsit_release_cmd(struct iscsi_cmd *cmd)
{
- struct iscsi_conn *conn = cmd->conn;
-
- iscsit_free_r2ts_from_list(cmd);
- iscsit_free_all_datain_reqs(cmd);
-
kfree(cmd->buf_ptr);
kfree(cmd->pdu_list);
kfree(cmd->seq_list);
kfree(cmd->tmr_req);
kfree(cmd->iov_data);
- if (conn) {
- iscsit_remove_cmd_from_immediate_queue(cmd, conn);
- iscsit_remove_cmd_from_response_queue(cmd, conn);
- }
-
kmem_cache_free(lio_cmd_cache, cmd);
}
-void iscsit_free_cmd(struct iscsi_cmd *cmd)
+static void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
+ bool check_queues)
{
+ struct iscsi_conn *conn = cmd->conn;
+
+ if (scsi_cmd) {
+ if (cmd->data_direction == DMA_TO_DEVICE) {
+ iscsit_stop_dataout_timer(cmd);
+ iscsit_free_r2ts_from_list(cmd);
+ }
+ if (cmd->data_direction == DMA_FROM_DEVICE)
+ iscsit_free_all_datain_reqs(cmd);
+ }
+
+ if (conn && check_queues) {
+ iscsit_remove_cmd_from_immediate_queue(cmd, conn);
+ iscsit_remove_cmd_from_response_queue(cmd, conn);
+ }
+}
+
+void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
+{
+ struct se_cmd *se_cmd = NULL;
+ int rc;
/*
* Determine if a struct se_cmd is associated with
* this struct iscsi_cmd.
*/
switch (cmd->iscsi_opcode) {
case ISCSI_OP_SCSI_CMD:
- if (cmd->data_direction == DMA_TO_DEVICE)
- iscsit_stop_dataout_timer(cmd);
+ se_cmd = &cmd->se_cmd;
+ __iscsit_free_cmd(cmd, true, shutdown);
/*
* Fallthrough
*/
case ISCSI_OP_SCSI_TMFUNC:
- transport_generic_free_cmd(&cmd->se_cmd, 1);
+ rc = transport_generic_free_cmd(&cmd->se_cmd, 1);
+ if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
+ __iscsit_free_cmd(cmd, true, shutdown);
+ target_put_sess_cmd(se_cmd->se_sess, se_cmd);
+ }
break;
case ISCSI_OP_REJECT:
/*
@@ -718,11 +734,19 @@
* associated cmd->se_cmd needs to be released.
*/
if (cmd->se_cmd.se_tfo != NULL) {
- transport_generic_free_cmd(&cmd->se_cmd, 1);
+ se_cmd = &cmd->se_cmd;
+ __iscsit_free_cmd(cmd, true, shutdown);
+
+ rc = transport_generic_free_cmd(&cmd->se_cmd, 1);
+ if (!rc && shutdown && se_cmd->se_sess) {
+ __iscsit_free_cmd(cmd, true, shutdown);
+ target_put_sess_cmd(se_cmd->se_sess, se_cmd);
+ }
break;
}
/* Fall-through */
default:
+ __iscsit_free_cmd(cmd, false, shutdown);
cmd->release_cmd(cmd);
break;
}