3.11.10.7 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
commit f56cbbb4b5871e5bc2838ddeeba5b29debc2a734 upstream.
This patch converts iscsit_ack_from_expstatsn() to populate a local
ack_list of commands, and call iscsit_free_cmd() directly from RX
thread context, instead of using iscsit_add_cmd_to_immediate_queue()
to queue the acknowledged commands to be released from TX thread
context.
It is helpful to release the acknowledge commands as quickly as
possible, along with the associated percpu_ida tags, in order to
prevent percpu_ida_alloc() from having to steal tags from other
CPUs while waiting for iscsit_free_cmd() to happen from TX thread
context.
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 9c6136e..f6de529 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -774,7 +774,8 @@ static void iscsit_unmap_iovec(struct iscsi_cmd *cmd)
static void iscsit_ack_from_expstatsn(struct iscsi_conn *conn, u32 exp_statsn)
{
- struct iscsi_cmd *cmd;
+ LIST_HEAD(ack_list);
+ struct iscsi_cmd *cmd, *cmd_p;
conn->exp_statsn = exp_statsn;
@@ -782,19 +783,23 @@ static void iscsit_ack_from_expstatsn(struct iscsi_conn *conn, u32 exp_statsn)
return;
spin_lock_bh(&conn->cmd_lock);
- list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
+ list_for_each_entry_safe(cmd, cmd_p, &conn->conn_cmd_list, i_conn_node) {
spin_lock(&cmd->istate_lock);
if ((cmd->i_state == ISTATE_SENT_STATUS) &&
iscsi_sna_lt(cmd->stat_sn, exp_statsn)) {
cmd->i_state = ISTATE_REMOVE;
spin_unlock(&cmd->istate_lock);
- iscsit_add_cmd_to_immediate_queue(cmd, conn,
- cmd->i_state);
+ list_move_tail(&cmd->i_conn_node, &ack_list);
continue;
}
spin_unlock(&cmd->istate_lock);
}
spin_unlock_bh(&conn->cmd_lock);
+
+ list_for_each_entry_safe(cmd, cmd_p, &ack_list, i_conn_node) {
+ list_del(&cmd->i_conn_node);
+ iscsit_free_cmd(cmd, false);
+ }
}
static int iscsit_allocate_iovecs(struct iscsi_cmd *cmd)
--
1.9.1
--
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