The talitos driver can cause starvation of other softirqs and as such
it can also cause rcu stalls like:
INFO: rcu_sched self-detected stall on CPU { 1} (t=15001 jiffies g=6799 c=6798
q=728)
INFO: rcu_sched detected stalls on CPUs/tasks: { 1} (detected by 0, t=15002
jiffies, g=6799, c=6798, q=728)
Task dump for CPU 1:
ovs-vswitchd R running 0 3225 1 0x00000004
Call Trace:
[c68879a0] [00000002] 0x2 (unreliable)
[c6887a60] [00000000] (null)
CPU: 1 PID: 3225 Comm: ovs-vswitchd Tainted: G W 3.10.36 #2
Call Trace:
[effe9900] [c0006b08] show_stack+0x44/0x15c (unreliable)
[effe9940] [c0072eb0] rcu_check_callbacks+0x21c/0x668
[effe99a0] [c0030f48] update_process_times+0x44/0x70
[effe99c0] [c005fdac] tick_sched_timer+0x2d4/0x314
[effe9a00] [c00466f4] __run_hrtimer.isra.29+0x54/0xf8
[effe9a20] [c0047110] hrtimer_interrupt+0x1a4/0x3bc
[effe9aa0] [c000827c] timer_interrupt+0x15c/0x1a4
[effe9ad0] [c000d470] ret_from_except+0x0/0x18
--- Exception: 901 at memcpy+0x1c/0x9c
LR = pskb_expand_head+0x94/0x298
[effe9b90] [c02260c0] pskb_expand_head+0x68/0x298 (unreliable)
[effe9bc0] [f159d20c] 0xf159d20c
[effe9bd0] [c02344f4] dev_hard_start_xmit+0x2b8/0x454
[effe9c00] [c024d330] sch_direct_xmit+0x70/0x1e8
[effe9c20] [c0234914] dev_queue_xmit+0x284/0x4fc
[effe9c50] [c02cf3b0] vlan_dev_hard_start_xmit+0xa8/0x178
[effe9c60] [c02344f4] dev_hard_start_xmit+0x2b8/0x454
[effe9c90] [c0234a64] dev_queue_xmit+0x3d4/0x4fc
[effe9cc0] [f14cb2c4] ovs_netdev_get_name+0xac/0x404 [openvswitch]
[effe9ce0] [f14c9698] ovs_vport_send+0x28/0xe8 [openvswitch]
[effe9d00] [f14c0000] 0xf14c0000
[effe9d10] [f14c0b84] 0xf14c0b84
[effe9d90] [f14c0c74] ovs_execute_actions+0xa4/0x1270 [openvswitch]
[effe9dc0] [f14c3a30] ovs_dp_process_received_packet+0xd0/0x11c [openvswitch]
[effe9e70] [f14ca3f0] ovs_vport_deferred_free+0xc98/0xd78 [openvswitch]
[effe9e80] [c02344f4] dev_hard_start_xmit+0x2b8/0x454
[effe9eb0] [c0234a64] dev_queue_xmit+0x3d4/0x4fc
[effe9ee0] [c0266924] ip_finish_output+0x450/0x4b4
[effe9f10] [f13a8920] talitos_submit+0x2d8/0x3f1c [talitos]
[effe9f60] [f13a8aa4] talitos_submit+0x45c/0x3f1c [talitos]
[effe9f70] [c002aa9c] tasklet_action+0xe4/0x178
[effe9fa0] [c002ac18] __do_softirq+0xe8/0x1ac
[effe9ff0] [c000b974] call_do_softirq+0x14/0x24
[c6887ee0] [c0004498] do_softirq+0x84/0xc4
[c6887f00] [c002ae2c] irq_exit+0x64/0x7c
[c6887f10] [c0004268] do_IRQ+0x12c/0x154
[c6887f40] [c000d470] ret_from_except+0x0/0x18
Work around this by processing a maximum amount of 16 finished requests
and rescheduling the done-tasklet if any work is left.
This allows other softirqs to run.
Signed-off-by: Helmut Schaa <helmut.sc...@googlemail.com>
---
drivers/crypto/talitos.c | 35 +++++++++++++++++++++++------------
1 file changed, 23 insertions(+), 12 deletions(-)
diff --git a/drivers/crypto/talitos.c b/drivers/crypto/talitos.c
index 624b8be..e0f03da 100644
--- a/drivers/crypto/talitos.c
+++ b/drivers/crypto/talitos.c
@@ -244,17 +244,18 @@ EXPORT_SYMBOL(talitos_submit);
/*
* process what was done, notify callback of error if not
*/
-static void flush_channel(struct device *dev, int ch, int error, int reset_ch)
+static int flush_channel(struct device *dev, int ch, int error, int reset_ch)
{
struct talitos_private *priv = dev_get_drvdata(dev);
struct talitos_request *request, saved_req;
unsigned long flags;
int tail, status;
+ int cnt = 16;
spin_lock_irqsave(&priv->chan[ch].tail_lock, flags);
tail = priv->chan[ch].tail;
- while (priv->chan[ch].fifo[tail].desc) {
+ while (priv->chan[ch].fifo[tail].desc && (--cnt > 0)) {
request = &priv->chan[ch].fifo[tail];
/* descriptors with their done bits set don't get the error */
@@ -291,36 +292,46 @@ static void flush_channel(struct device *dev, int ch, int
error, int reset_ch)
status);
/* channel may resume processing in single desc error case */
if (error && !reset_ch && status == error)
- return;
+ return 0;
spin_lock_irqsave(&priv->chan[ch].tail_lock, flags);
tail = priv->chan[ch].tail;
}
spin_unlock_irqrestore(&priv->chan[ch].tail_lock, flags);
+
+ if (cnt == 0)
+ return 1; /* Need to reschedule */
+ return 0;
}
/*
* process completed requests for channels that have done status
*/
-#define DEF_TALITOS_DONE(name, ch_done_mask) \
+#define DEF_TALITOS_DONE(name, ch_done_mask, tlet)
\
static void talitos_done_##name(unsigned long data) \
{ \
struct device *dev = (struct device *)data; \
struct talitos_private *priv = dev_get_drvdata(dev); \
unsigned long flags; \
+ int resched = 0; \
\
if (ch_done_mask & 1) \
- flush_channel(dev, 0, 0, 0); \
+ resched += flush_channel(dev, 0, 0, 0); \
if (priv->num_channels == 1) \
goto out; \
if (ch_done_mask & (1 << 2)) \
- flush_channel(dev, 1, 0, 0); \
+ resched += flush_channel(dev, 1, 0, 0); \
if (ch_done_mask & (1 << 4)) \
- flush_channel(dev, 2, 0, 0); \
+ resched += flush_channel(dev, 2, 0, 0); \
if (ch_done_mask & (1 << 6)) \
- flush_channel(dev, 3, 0, 0); \
+ resched += flush_channel(dev, 3, 0, 0); \
\
out: \
+ if (resched) { \
+ tasklet_schedule(&priv->done_task[tlet]); \
+ return; \
+ } \
+ \
/* At this point, all completed channels have been processed */ \
/* Unmask done interrupts for channels completed later on. */ \
spin_lock_irqsave(&priv->reg_lock, flags); \
@@ -328,9 +339,9 @@ out:
\
setbits32(priv->reg + TALITOS_IMR_LO, TALITOS_IMR_LO_INIT); \
spin_unlock_irqrestore(&priv->reg_lock, flags); \
}
-DEF_TALITOS_DONE(4ch, TALITOS_ISR_4CHDONE)
-DEF_TALITOS_DONE(ch0_2, TALITOS_ISR_CH_0_2_DONE)
-DEF_TALITOS_DONE(ch1_3, TALITOS_ISR_CH_1_3_DONE)
+DEF_TALITOS_DONE(4ch, TALITOS_ISR_4CHDONE, 0)
+DEF_TALITOS_DONE(ch0_2, TALITOS_ISR_CH_0_2_DONE, 0)
+DEF_TALITOS_DONE(ch1_3, TALITOS_ISR_CH_1_3_DONE, 1)
/*
* locate current (offending) descriptor
@@ -489,7 +500,7 @@ static void talitos_error(struct device *dev, u32 isr, u32
isr_lo)
if (v_lo & TALITOS_CCPSR_LO_SRL)
dev_err(dev, "scatter return/length error\n");
- flush_channel(dev, ch, error, reset_ch);
+ while (flush_channel(dev, ch, error, reset_ch));
if (reset_ch) {
reset_channel(dev, ch);
--
1.8.4.5
--
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