Re: Re: I2C: Fix i2c fail problem when a process is terminated by a signal on octeon in 3.8

Re: Re: I2C: Fix i2c fail problem when a process is terminated by a signal on octeon in 3.8

[송은봉]

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>If the wait is not interruptible, I think you will not be able to 'kill
>-9' a userspace process blocked here.

As your words. the process will not be killed immediately, but after timeout(2 jiffies) it will be killed.
I think that delay is acceptable. 


------- Original Message -------
Sender : David Daney<ddaney@caviumnetworks.com>
Date : 2013-02-27 08:07 (GMT+09:00)
Title : Re: I2C: Fix i2c fail problem when a process is terminated by a signal on octeon in 3.8

On 02/26/2013 12:54 PM, ¼ÛÀººÀ wrote:
> I've been debugging the abnormal operation of i2c on octeon.
> If a process is terminated by signal in the middle of i2c operation,
> next i2c read operation which is done by another process was failed.
> So i changed to ignore signal in the middle of i2c operation.
> After that the problem was not reproduced.
> 

This is a known issue.  However I don't think the solution you have is
correct...

> Signed-off-by: EunBong Song > >
> 
> diff -up drivers/i2c/busses/i2c-octeon.c{.orig,}
> --- drivers/i2c/busses/i2c-octeon.c.orig 2013-02-21 08:09:03.168018843 -0800
> +++ drivers/i2c/busses/i2c-octeon.c 2013-02-21 08:09:38.344018898 -0800
> @@ -183,7 +183,7 @@ static irqreturn_t octeon_i2c_isr(int ir
>    struct octeon_i2c *i2c = dev_id;
> 
>    octeon_i2c_int_disable(i2c);
> - wake_up_interruptible(&i2c->queue);
> + wake_up(&i2c->queue);
> 
>    return IRQ_HANDLED;
>   }
> @@ -206,7 +206,7 @@ static int octeon_i2c_wait(struct octeon
> 
>    octeon_i2c_int_enable(i2c);
> 
> - result = wait_event_interruptible_timeout(i2c->queue,
> + result = wait_event_timeout(i2c->queue,

If the wait is not interruptible, I think you will not be able to 'kill
-9' a userspace process blocked here.

>           octeon_i2c_test_iflg(i2c),
>           i2c->adap.timeout);
> 

The real solution is to move processing of the I2C protocol to a kernel
thread and communicate between the this thread and userspace via a
command queue mechanism, much like the way it is done in the mmc/host
driver infrastructure.

David Daneyÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥

Re: Re: I2C: Fix i2c fail problem when a process is terminated by a signal on octeon in 3.8

[EUNBONG SONG]

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>Basically OK, but you have lots of whitespace issues, so I can't apply
>your patch. Please resend and make sure it applies.

Sorry, I rewrite my patch here.

Signed-off-by: EunBong Song <eunb.song@samsung.com>
 ---
 drivers/i2c/busses/i2c-octeon.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 935585e..b2e3259 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -183,7 +183,7 @@ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
 	struct octeon_i2c *i2c = dev_id;
 
 	octeon_i2c_int_disable(i2c);
-	wake_up_interruptible(&i2c->queue);
+	wake_up(&i2c->queue);
 
 	return IRQ_HANDLED;
 }
@@ -206,9 +206,9 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
 
 	octeon_i2c_int_enable(i2c);
 
-	result = wait_event_interruptible_timeout(i2c->queue,
-						  octeon_i2c_test_iflg(i2c),
-						  i2c->adap.timeout);
+	result = wait_event_timeout(i2c->queue,
+					octeon_i2c_test_iflg(i2c),
+					i2c->adap.timeout);
 
 	octeon_i2c_int_disable(i2c);
 
-- 
1.7.0.1

Thanks.ÿôèº{.nÇ+‰·Ÿ®‰­†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a­¢f£¢·hšïêÿ‘êçz_è®\x03(­éšŽŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨è­Ú&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥