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authorNicholas Bellinger <nab@linux-iscsi.org>2013-02-27 17:53:52 -0800
committerNicholas Bellinger <nab@linux-iscsi.org>2013-02-27 19:03:22 -0800
commitfd3a9025c0349bc9b01d627529f54e6e1e389015 (patch)
tree2b76a08283890e902756307e6e2c004c10a24099 /drivers/target
parent972b29c8f86093f44e1d781588bd5c5faae3d8e3 (diff)
downloadlinux-fd3a9025c0349bc9b01d627529f54e6e1e389015.tar.gz
iscsi-target: Fix immediate queue starvation regression with DATAIN
This patch addresses a v3.5+ regression in iscsi-target where TX thread process context -> handle_response_queue() execution is allowed to run unbounded while servicing constant outgoing flow of ISTATE_SEND_DATAIN response state. This ends up preventing memory release of StatSN acknowledged commands in a timely manner when under heavy large block streaming DATAIN workloads. The regression bug was initially introduced with: commit 6f3c0e69a9c20441bdc6d3b2d18b83b244384ec6 Author: Andy Grover <agrover@redhat.com> Date: Tue Apr 3 15:51:09 2012 -0700 target/iscsi: Refactor target_tx_thread immediate+response queue loops Go ahead and follow original iscsi_target_tx_thread() logic and check to break for immediate queue processing after each DataIN Sequence and/or Response PDU has been sent. Reported-by: Benjamin ESTRABAUD <be@mpstor.com> Cc: Andy Grover <agrover@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/iscsi/iscsi_target.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 23a98e65830..af77396234a 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -3583,6 +3583,10 @@ check_rsp_state:
spin_lock_bh(&cmd->istate_lock);
cmd->i_state = ISTATE_SENT_STATUS;
spin_unlock_bh(&cmd->istate_lock);
+
+ if (atomic_read(&conn->check_immediate_queue))
+ return 1;
+
continue;
} else if (ret == 2) {
/* Still must send status,
@@ -3672,7 +3676,7 @@ check_rsp_state:
}
if (atomic_read(&conn->check_immediate_queue))
- break;
+ return 1;
}
return 0;
@@ -3716,12 +3720,15 @@ restart:
signal_pending(current))
goto transport_err;
+get_immediate:
ret = handle_immediate_queue(conn);
if (ret < 0)
goto transport_err;
ret = handle_response_queue(conn);
- if (ret == -EAGAIN)
+ if (ret == 1)
+ goto get_immediate;
+ else if (ret == -EAGAIN)
goto restart;
else if (ret < 0)
goto transport_err;