system/linux
system/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux synced 2024-09-19 18:46:35 +00:00
Code Issues Packages Projects Releases Wiki Activity

can: fix slowpath issue in hrtimer callback function

Browse source 
Due to the loopback functionality in can_send() we can not invoke it
from hardirq context which was done inside the
bcm_tx_timeout_handler() hrtimer callback:

[  700.361154]  [<c012228c>] warn_slowpath+0x80/0xb6
[  700.361163]  [<c013d559>] valid_state+0x125/0x136
[  700.361171]  [<c013d858>] mark_lock+0x18e/0x332
[  700.361180]  [<c013e300>] __lock_acquire+0x12e/0xb1e
[  700.361189]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361198]  [<c031e20a>] dev_queue_xmit+0x191/0x479
[  700.361206]  [<c01262a7>] __local_bh_disable+0x2b/0x64
[  700.361213]  [<c031e20a>] dev_queue_xmit+0x191/0x479
[  700.361225]  [<f8aa69a1>] can_send+0xd7/0x11a [can]
[  700.361235]  [<f8ab522b>] bcm_can_tx+0x9d/0xd9 [can_bcm]
[  700.361245]  [<f8ab597f>] bcm_tx_timeout_handler+0x6a/0xbc [can_bcm]
[  700.361255]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361263]  [<c0134143>] __run_hrtimer+0x5a/0x86
[  700.361273]  [<f8ab5915>] bcm_tx_timeout_handler+0x0/0xbc [can_bcm]
[  700.361282]  [<c0134a50>] hrtimer_interrupt+0xb9/0x110

This patch moves the rest of the functionality from the hrtimer
callback to the already existing tasklet to fix this slowpath problem.

Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Oliver Hartkopp 2009-01-14 21:06:55 -08:00 committed by David S. Miller
parent d57bc36e7a
commit c53a6ee88b
1 changed files with 37 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

71
net/can/bcm.c
View file

@ -347,16 +347,42 @@ static void bcm_tx_timeout_tsklet(unsigned long data)
struct bcm_op *op = (struct bcm_op *)data;
struct bcm_msg_head msg_head;
/* create notification to user */
msg_head.opcode = TX_EXPIRED;
msg_head.flags = op->flags;
msg_head.count = op->count;
msg_head.ival1 = op->ival1;
msg_head.ival2 = op->ival2;
msg_head.can_id = op->can_id;
msg_head.nframes = 0;
if (op->kt_ival1.tv64 && (op->count > 0)) {
bcm_send_to_user(op, &msg_head, NULL, 0);
op->count--;
if (!op->count && (op->flags & TX_COUNTEVT)) {
/* create notification to user */
msg_head.opcode = TX_EXPIRED;
msg_head.flags = op->flags;
msg_head.count = op->count;
msg_head.ival1 = op->ival1;
msg_head.ival2 = op->ival2;
msg_head.can_id = op->can_id;
msg_head.nframes = 0;
bcm_send_to_user(op, &msg_head, NULL, 0);
}
}
if (op->kt_ival1.tv64 && (op->count > 0)) {
/* send (next) frame */
bcm_can_tx(op);
hrtimer_start(&op->timer,
ktime_add(ktime_get(), op->kt_ival1),
HRTIMER_MODE_ABS);
} else {
if (op->kt_ival2.tv64) {
/* send (next) frame */
bcm_can_tx(op);
hrtimer_start(&op->timer,
ktime_add(ktime_get(), op->kt_ival2),
HRTIMER_MODE_ABS);
}
}
}
/*
@ -365,33 +391,10 @@ static void bcm_tx_timeout_tsklet(unsigned long data)
static enum hrtimer_restart bcm_tx_timeout_handler(struct hrtimer *hrtimer)
{
struct bcm_op *op = container_of(hrtimer, struct bcm_op, timer);
enum hrtimer_restart ret = HRTIMER_NORESTART;
if (op->kt_ival1.tv64 && (op->count > 0)) {
tasklet_schedule(&op->tsklet);
op->count--;
if (!op->count && (op->flags & TX_COUNTEVT))
tasklet_schedule(&op->tsklet);
}
if (op->kt_ival1.tv64 && (op->count > 0)) {
/* send (next) frame */
bcm_can_tx(op);
hrtimer_forward(hrtimer, ktime_get(), op->kt_ival1);
ret = HRTIMER_RESTART;
} else {
if (op->kt_ival2.tv64) {
/* send (next) frame */
bcm_can_tx(op);
hrtimer_forward(hrtimer, ktime_get(), op->kt_ival2);
ret = HRTIMER_RESTART;
}
}
return ret;
return HRTIMER_NORESTART;
}
/*