LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
* [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
@ 2018-04-10 13:04 Jia-Ju Bai
  2018-05-04 16:29 ` Lorenzo Pieralisi
                   ` (2 more replies)
  0 siblings, 3 replies; 5+ messages in thread
From: Jia-Ju Bai @ 2018-04-10 13:04 UTC (permalink / raw)
  To: kishon, bhelgaas, nsekhar, john, shawn.lin
  Cc: linux-pci, linux-kernel, Jia-Ju Bai

pci_epf_test_write() is never called in atomic context.

The call chain ending up at pci_epf_test_write() is:
[1] pci_epf_test_write() <- pci_epf_test_cmd_handler()

pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK() 
in pci_epf_test_probe().
This function is not called in atomic context.

Despite never getting called from atomic context, pci_epf_test_write()
calls mdelay() to busily wait.
This is not necessary and can be replaced with usleep_range() to
avoid busy waiting.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
---
 drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
index f9308c2..2f0642e 100644
--- a/drivers/pci/endpoint/functions/pci-epf-test.c
+++ b/drivers/pci/endpoint/functions/pci-epf-test.c
@@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
 	 * wait 1ms inorder for the write to complete. Without this delay L3
 	 * error in observed in the host system.
 	 */
-	mdelay(1);
+	usleep_range(1000, 2000);
 
 	kfree(buf);
 
-- 
1.9.1

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
  2018-04-10 13:04 [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write Jia-Ju Bai
@ 2018-05-04 16:29 ` Lorenzo Pieralisi
  2018-05-05 10:03   ` Kishon Vijay Abraham I
  2018-05-08 10:53 ` Lorenzo Pieralisi
  2018-05-11 14:18 ` Lorenzo Pieralisi
  2 siblings, 1 reply; 5+ messages in thread
From: Lorenzo Pieralisi @ 2018-05-04 16:29 UTC (permalink / raw)
  To: Jia-Ju Bai, kishon
  Cc: bhelgaas, nsekhar, john, shawn.lin, linux-pci, linux-kernel

On Tue, Apr 10, 2018 at 09:04:06PM +0800, Jia-Ju Bai wrote:
> pci_epf_test_write() is never called in atomic context.
> 
> The call chain ending up at pci_epf_test_write() is:
> [1] pci_epf_test_write() <- pci_epf_test_cmd_handler()
> 
> pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK() 
> in pci_epf_test_probe().
> This function is not called in atomic context.
> 
> Despite never getting called from atomic context, pci_epf_test_write()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() to
> avoid busy waiting.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I'd request Kishon's ACK on this.

Thanks,
Lorenzo

> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index f9308c2..2f0642e 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>  	 * wait 1ms inorder for the write to complete. Without this delay L3
>  	 * error in observed in the host system.
>  	 */
> -	mdelay(1);
> +	usleep_range(1000, 2000);
>  
>  	kfree(buf);
>  
> -- 
> 1.9.1
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
  2018-05-04 16:29 ` Lorenzo Pieralisi
@ 2018-05-05 10:03   ` Kishon Vijay Abraham I
  0 siblings, 0 replies; 5+ messages in thread
From: Kishon Vijay Abraham I @ 2018-05-05 10:03 UTC (permalink / raw)
  To: Lorenzo Pieralisi, Jia-Ju Bai
  Cc: bhelgaas, nsekhar, john, shawn.lin, linux-pci, linux-kernel



On Friday 04 May 2018 09:59 PM, Lorenzo Pieralisi wrote:
> On Tue, Apr 10, 2018 at 09:04:06PM +0800, Jia-Ju Bai wrote:
>> pci_epf_test_write() is never called in atomic context.
>>
>> The call chain ending up at pci_epf_test_write() is:
>> [1] pci_epf_test_write() <- pci_epf_test_cmd_handler()
>>
>> pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK() 
>> in pci_epf_test_probe().
>> This function is not called in atomic context.
>>
>> Despite never getting called from atomic context, pci_epf_test_write()
>> calls mdelay() to busily wait.
>> This is not necessary and can be replaced with usleep_range() to
>> avoid busy waiting.
>>
>> This is found by a static analysis tool named DCNS written by myself.
>> And I also manually check it.
>>
>> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
>> ---
>>  drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> I'd request Kishon's ACK on this.

sorry, missed this before.

Acked-by: Kishon Vijay Abraham I <kishon@ti.com>
> 
> Thanks,
> Lorenzo
> 
>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>> index f9308c2..2f0642e 100644
>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>> @@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>>  	 * wait 1ms inorder for the write to complete. Without this delay L3
>>  	 * error in observed in the host system.
>>  	 */
>> -	mdelay(1);
>> +	usleep_range(1000, 2000);
>>  
>>  	kfree(buf);
>>  
>> -- 
>> 1.9.1
>>

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
  2018-04-10 13:04 [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write Jia-Ju Bai
  2018-05-04 16:29 ` Lorenzo Pieralisi
@ 2018-05-08 10:53 ` Lorenzo Pieralisi
  2018-05-11 14:18 ` Lorenzo Pieralisi
  2 siblings, 0 replies; 5+ messages in thread
From: Lorenzo Pieralisi @ 2018-05-08 10:53 UTC (permalink / raw)
  To: Jia-Ju Bai
  Cc: kishon, bhelgaas, nsekhar, john, shawn.lin, linux-pci, linux-kernel

On Tue, Apr 10, 2018 at 09:04:06PM +0800, Jia-Ju Bai wrote:
> pci_epf_test_write() is never called in atomic context.
> 
> The call chain ending up at pci_epf_test_write() is:
> [1] pci_epf_test_write() <- pci_epf_test_cmd_handler()
> 
> pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK() 
> in pci_epf_test_probe().
> This function is not called in atomic context.
> 
> Despite never getting called from atomic context, pci_epf_test_write()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() to
> avoid busy waiting.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied to pci/endpoint for v4.18, thanks.

Lorenzo

> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index f9308c2..2f0642e 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>  	 * wait 1ms inorder for the write to complete. Without this delay L3
>  	 * error in observed in the host system.
>  	 */
> -	mdelay(1);
> +	usleep_range(1000, 2000);
>  
>  	kfree(buf);
>  
> -- 
> 1.9.1
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write
  2018-04-10 13:04 [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write Jia-Ju Bai
  2018-05-04 16:29 ` Lorenzo Pieralisi
  2018-05-08 10:53 ` Lorenzo Pieralisi
@ 2018-05-11 14:18 ` Lorenzo Pieralisi
  2 siblings, 0 replies; 5+ messages in thread
From: Lorenzo Pieralisi @ 2018-05-11 14:18 UTC (permalink / raw)
  To: Jia-Ju Bai
  Cc: kishon, bhelgaas, nsekhar, john, shawn.lin, linux-pci, linux-kernel

On Tue, Apr 10, 2018 at 09:04:06PM +0800, Jia-Ju Bai wrote:
> pci_epf_test_write() is never called in atomic context.
> 
> The call chain ending up at pci_epf_test_write() is:
> [1] pci_epf_test_write() <- pci_epf_test_cmd_handler()
> 
> pci_epf_test_cmd_handler() is set as a parameter of INIT_DELAYED_WORK() 
> in pci_epf_test_probe().
> This function is not called in atomic context.
> 
> Despite never getting called from atomic context, pci_epf_test_write()
> calls mdelay() to busily wait.
> This is not necessary and can be replaced with usleep_range() to
> avoid busy waiting.
> 
> This is found by a static analysis tool named DCNS written by myself.
> And I also manually check it.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
> ---
>  drivers/pci/endpoint/functions/pci-epf-test.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied to pci/endpoint for v4.18, thanks.

Lorenzo

> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index f9308c2..2f0642e 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -237,7 +237,7 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>  	 * wait 1ms inorder for the write to complete. Without this delay L3
>  	 * error in observed in the host system.
>  	 */
> -	mdelay(1);
> +	usleep_range(1000, 2000);
>  
>  	kfree(buf);
>  
> -- 
> 1.9.1
> 

^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2018-05-11 14:18 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-04-10 13:04 [PATCH] pci: endpoint: Replace mdelay with usleep_range in pci_epf_test_write Jia-Ju Bai
2018-05-04 16:29 ` Lorenzo Pieralisi
2018-05-05 10:03   ` Kishon Vijay Abraham I
2018-05-08 10:53 ` Lorenzo Pieralisi
2018-05-11 14:18 ` Lorenzo Pieralisi

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).