Re: [PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Dominik Brodowski]

On Sun, Mar 18, 2018 at 04:12:10PM +0100, Harald Welte wrote:
> Hi Jia-Ju Bai,
> 
> On Sun, Mar 18, 2018 at 10:49:57PM +0800, Jia-Ju Bai wrote:
> > This is found by a static analysis tool named DCNS written by myself.
> 
> nice catch!
> 
> > Signed-off-by: Jia-Ju Bai 
> 
> Acked-by: Harald Welte 

Applied to pcmcia-next.

Thanks,
Dominik

Re: [PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Dominik Brodowski]

On Sun, Mar 18, 2018 at 04:12:10PM +0100, Harald Welte wrote:
> Hi Jia-Ju Bai,
> 
> On Sun, Mar 18, 2018 at 10:49:57PM +0800, Jia-Ju Bai wrote:
> > This is found by a static analysis tool named DCNS written by myself.
> 
> nice catch!
> 
> > Signed-off-by: Jia-Ju Bai 
> 
> Acked-by: Harald Welte 

Applied to pcmcia-next.

Thanks,
Dominik

Re: [PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Harald Welte]

Hi Jia-Ju Bai,

On Sun, Mar 18, 2018 at 10:49:57PM +0800, Jia-Ju Bai wrote:
> This is found by a static analysis tool named DCNS written by myself.

nice catch!

> Signed-off-by: Jia-Ju Bai 

Acked-by: Harald Welte 

-- 
- Harald Welte    http://laforge.gnumonks.org/

"Privacy in residential applications is a desirable marketing option."
  (ETSI EN 300 175-7 Ch. A6)

Re: [PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Harald Welte]

Hi Jia-Ju Bai,

On Sun, Mar 18, 2018 at 10:49:57PM +0800, Jia-Ju Bai wrote:
> This is found by a static analysis tool named DCNS written by myself.

nice catch!

> Signed-off-by: Jia-Ju Bai 

Acked-by: Harald Welte 

-- 
- Harald Weltehttp://laforge.gnumonks.org/

"Privacy in residential applications is a desirable marketing option."
  (ETSI EN 300 175-7 Ch. A6)

[PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Jia-Ju Bai]

set_protocol() is never called in atomic context.

The call chains ending up at set_protocol() are:
[1] set_protocol() <- monitor_card()
[2] set_protocol() <- cmm_ioctl()
monitor_card() is only set in setup_timer(), and cmm_ioctl() is only 
set as ".unlocked_ioctl" in file_operations structure "cm4000_fops".

Despite never getting called from atomic context, set_protocol() calls
mdelay(10), i.e. busy wait for 10ms.
That 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.

Signed-off-by: Jia-Ju Bai 
---
 drivers/char/pcmcia/cm4000_cs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index cd53771..56fc671 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -530,7 +530,7 @@ static int set_protocol(struct cm4000_dev *dev, struct 
ptsreq *ptsreq)
DEBUGP(5, dev, "NumRecBytes is valid\n");
break;
}
-   mdelay(10);
+   usleep_range(1, 11000);
}
if (i == 100) {
DEBUGP(5, dev, "Timeout waiting for NumRecBytes getting "
@@ -546,7 +546,7 @@ static int set_protocol(struct cm4000_dev *dev, struct 
ptsreq *ptsreq)
DEBUGP(2, dev, "NumRecBytes = %i\n", num_bytes_read);
break;
}
-   mdelay(10);
+   usleep_range(1, 11000);
}
 
/* check whether it is a short PTS reply? */
-- 
1.9.1

[PATCH] char: pcmcia: cm4000_cs: Replace mdelay with usleep_range in set_protocol

[Jia-Ju Bai]

set_protocol() is never called in atomic context.

The call chains ending up at set_protocol() are:
[1] set_protocol() <- monitor_card()
[2] set_protocol() <- cmm_ioctl()
monitor_card() is only set in setup_timer(), and cmm_ioctl() is only 
set as ".unlocked_ioctl" in file_operations structure "cm4000_fops".

Despite never getting called from atomic context, set_protocol() calls
mdelay(10), i.e. busy wait for 10ms.
That 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.

Signed-off-by: Jia-Ju Bai 
---
 drivers/char/pcmcia/cm4000_cs.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index cd53771..56fc671 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -530,7 +530,7 @@ static int set_protocol(struct cm4000_dev *dev, struct 
ptsreq *ptsreq)
DEBUGP(5, dev, "NumRecBytes is valid\n");
break;
}
-   mdelay(10);
+   usleep_range(1, 11000);
}
if (i == 100) {
DEBUGP(5, dev, "Timeout waiting for NumRecBytes getting "
@@ -546,7 +546,7 @@ static int set_protocol(struct cm4000_dev *dev, struct 
ptsreq *ptsreq)
DEBUGP(2, dev, "NumRecBytes = %i\n", num_bytes_read);
break;
}
-   mdelay(10);
+   usleep_range(1, 11000);
}
 
/* check whether it is a short PTS reply? */
-- 
1.9.1