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Message-ID: <e7089b22f1e74855e76b64e5a0923771a108b770.camel@HansenPartnership.com>
Date: Fri, 20 Nov 2020 12:30:34 -0800
From: James Bottomley <James.Bottomley@...senPartnership.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-scsi <linux-scsi@...r.kernel.org>,
linux-kernel <linux-kernel@...r.kernel.org>
Subject: [GIT PULL] SCSI fixes for 5.10-rc4
Fixes for two fairly obscure but annoying when triggered races in
iSCSI.
The patch is available here:
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git scsi-fixes
The short changelog is:
Lee Duncan (1):
scsi: libiscsi: Fix NOP race condition
Mike Christie (1):
scsi: target: iscsi: Fix cmd abort fabric stop race
and the diffstat:
drivers/scsi/libiscsi.c | 23 +++++++++++++++--------
drivers/target/iscsi/iscsi_target.c | 17 +++++++++++++----
include/scsi/libiscsi.h | 3 +++
3 files changed, 31 insertions(+), 12 deletions(-)
With full diff below.
James
---
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 1e9c3171fa9f..f9314f1393fb 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -533,8 +533,8 @@ static void iscsi_complete_task(struct iscsi_task *task, int state)
if (conn->task == task)
conn->task = NULL;
- if (conn->ping_task == task)
- conn->ping_task = NULL;
+ if (READ_ONCE(conn->ping_task) == task)
+ WRITE_ONCE(conn->ping_task, NULL);
/* release get from queueing */
__iscsi_put_task(task);
@@ -738,6 +738,9 @@ __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
task->conn->session->age);
}
+ if (unlikely(READ_ONCE(conn->ping_task) == INVALID_SCSI_TASK))
+ WRITE_ONCE(conn->ping_task, task);
+
if (!ihost->workq) {
if (iscsi_prep_mgmt_task(conn, task))
goto free_task;
@@ -941,8 +944,11 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
struct iscsi_nopout hdr;
struct iscsi_task *task;
- if (!rhdr && conn->ping_task)
- return -EINVAL;
+ if (!rhdr) {
+ if (READ_ONCE(conn->ping_task))
+ return -EINVAL;
+ WRITE_ONCE(conn->ping_task, INVALID_SCSI_TASK);
+ }
memset(&hdr, 0, sizeof(struct iscsi_nopout));
hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
@@ -957,11 +963,12 @@ static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
if (!task) {
+ if (!rhdr)
+ WRITE_ONCE(conn->ping_task, NULL);
iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
return -EIO;
} else if (!rhdr) {
/* only track our nops */
- conn->ping_task = task;
conn->last_ping = jiffies;
}
@@ -984,7 +991,7 @@ static int iscsi_nop_out_rsp(struct iscsi_task *task,
struct iscsi_conn *conn = task->conn;
int rc = 0;
- if (conn->ping_task != task) {
+ if (READ_ONCE(conn->ping_task) != task) {
/*
* If this is not in response to one of our
* nops then it must be from userspace.
@@ -1923,7 +1930,7 @@ static void iscsi_start_tx(struct iscsi_conn *conn)
*/
static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
{
- if (conn->ping_task &&
+ if (READ_ONCE(conn->ping_task) &&
time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
(conn->ping_timeout * HZ), jiffies))
return 1;
@@ -2058,7 +2065,7 @@ enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
* Checking the transport already or nop from a cmd timeout still
* running
*/
- if (conn->ping_task) {
+ if (READ_ONCE(conn->ping_task)) {
task->have_checked_conn = true;
rc = BLK_EH_RESET_TIMER;
goto done;
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index f77e5eee6b80..518fac4864cf 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -483,8 +483,7 @@ EXPORT_SYMBOL(iscsit_queue_rsp);
void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
spin_lock_bh(&conn->cmd_lock);
- if (!list_empty(&cmd->i_conn_node) &&
- !(cmd->se_cmd.transport_state & CMD_T_FABRIC_STOP))
+ if (!list_empty(&cmd->i_conn_node))
list_del_init(&cmd->i_conn_node);
spin_unlock_bh(&conn->cmd_lock);
@@ -4083,12 +4082,22 @@ static void iscsit_release_commands_from_conn(struct iscsi_conn *conn)
spin_lock_bh(&conn->cmd_lock);
list_splice_init(&conn->conn_cmd_list, &tmp_list);
- list_for_each_entry(cmd, &tmp_list, i_conn_node) {
+ list_for_each_entry_safe(cmd, cmd_tmp, &tmp_list, i_conn_node) {
struct se_cmd *se_cmd = &cmd->se_cmd;
if (se_cmd->se_tfo != NULL) {
spin_lock_irq(&se_cmd->t_state_lock);
- se_cmd->transport_state |= CMD_T_FABRIC_STOP;
+ if (se_cmd->transport_state & CMD_T_ABORTED) {
+ /*
+ * LIO's abort path owns the cleanup for this,
+ * so put it back on the list and let
+ * aborted_task handle it.
+ */
+ list_move_tail(&cmd->i_conn_node,
+ &conn->conn_cmd_list);
+ } else {
+ se_cmd->transport_state |= CMD_T_FABRIC_STOP;
+ }
spin_unlock_irq(&se_cmd->t_state_lock);
}
}
diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h
index c25fb86ffae9..b3bbd10eb3f0 100644
--- a/include/scsi/libiscsi.h
+++ b/include/scsi/libiscsi.h
@@ -132,6 +132,9 @@ struct iscsi_task {
void *dd_data; /* driver/transport data */
};
+/* invalid scsi_task pointer */
+#define INVALID_SCSI_TASK (struct iscsi_task *)-1l
+
static inline int iscsi_task_has_unsol_data(struct iscsi_task *task)
{
return task->unsol_r2t.data_length > task->unsol_r2t.sent;
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