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* [PATCH] staging: sm750fb: always take the lock
@ 2017-06-26  5:45 AbdAllah-MEZITI
  2017-06-26  6:33 ` Frans Klaver
  2017-06-26  9:11 ` Geert Uytterhoeven
  0 siblings, 2 replies; 8+ messages in thread
From: AbdAllah-MEZITI @ 2017-06-26  5:45 UTC (permalink / raw)
  To: sudipm.mukherjee
  Cc: AbdAllah MEZITI, Teddy Wang, Greg Kroah-Hartman, linux-fbdev,
	devel, linux-kernel

This patch
- will always take the lock
- fix the sparse warning:
drivers/staging/sm750fb/sm750.c:159:13: warning: context imbalance in 'lynxfb_ops_fillrect' - different lock contexts for basic block
drivers/staging/sm750fb/sm750.c:231:9: warning: context imbalance in 'lynxfb_ops_copyarea' - different lock contexts for basic block
drivers/staging/sm750fb/sm750.c:235:13: warning: context imbalance in 'lynxfb_ops_imageblit' - different lock contexts for basic block

Signed-off-by: AbdAllah MEZITI <abdallah.meziti.pro@gmail.com>
---
 drivers/staging/sm750fb/sm750.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 386d4ad..4a22190 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -186,16 +186,14 @@ static void lynxfb_ops_fillrect(struct fb_info *info,
 	 * If not use spin_lock,system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_fillrect(&sm750_dev->accel,
 				     base, pitch, Bpp,
 				     region->dx, region->dy,
 				     region->width, region->height,
 				     color, rop);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static void lynxfb_ops_copyarea(struct fb_info *info,
@@ -220,16 +218,14 @@ static void lynxfb_ops_copyarea(struct fb_info *info,
 	 * If not use spin_lock, system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_copyarea(&sm750_dev->accel,
 				     base, pitch, region->sx, region->sy,
 				     base, pitch, Bpp, region->dx, region->dy,
 				     region->width, region->height,
 				     HW_ROP2_COPY);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static void lynxfb_ops_imageblit(struct fb_info *info,
@@ -269,8 +265,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
 	 * If not use spin_lock, system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_imageblit(&sm750_dev->accel,
 				      image->data, image->width >> 3, 0,
@@ -278,8 +273,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
 				      image->dx, image->dy,
 				      image->width, image->height,
 				      fgcol, bgcol, HW_ROP2_COPY);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static int lynxfb_ops_pan_display(struct fb_var_screeninfo *var,
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-26  5:45 [PATCH] staging: sm750fb: always take the lock AbdAllah-MEZITI
@ 2017-06-26  6:33 ` Frans Klaver
  2017-06-26  9:11 ` Geert Uytterhoeven
  1 sibling, 0 replies; 8+ messages in thread
From: Frans Klaver @ 2017-06-26  6:33 UTC (permalink / raw)
  To: AbdAllah-MEZITI
  Cc: Sudip Mukherjee, Teddy Wang, Greg Kroah-Hartman, linux-fbdev,
	devel, linux-kernel

There's no version number. Which one is the correct one?

On Mon, Jun 26, 2017 at 7:45 AM, AbdAllah-MEZITI
<abdallah.meziti.pro@gmail.com> wrote:
> This patch
> - will always take the lock
> - fix the sparse warning:
> drivers/staging/sm750fb/sm750.c:159:13: warning: context imbalance in 'lynxfb_ops_fillrect' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:231:9: warning: context imbalance in 'lynxfb_ops_copyarea' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:235:13: warning: context imbalance in 'lynxfb_ops_imageblit' - different lock contexts for basic block
>
> Signed-off-by: AbdAllah MEZITI <abdallah.meziti.pro@gmail.com>
> ---
>  drivers/staging/sm750fb/sm750.c | 18 ++++++------------
>  1 file changed, 6 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
> index 386d4ad..4a22190 100644
> --- a/drivers/staging/sm750fb/sm750.c
> +++ b/drivers/staging/sm750fb/sm750.c
> @@ -186,16 +186,14 @@ static void lynxfb_ops_fillrect(struct fb_info *info,
>          * If not use spin_lock,system will die if user load driver
>          * and immediately unload driver frequently (dual)
>          */
> -       if (sm750_dev->fb_count > 1)
> -               spin_lock(&sm750_dev->slock);
> +       spin_lock(&sm750_dev->slock);
>
>         sm750_dev->accel.de_fillrect(&sm750_dev->accel,
>                                      base, pitch, Bpp,
>                                      region->dx, region->dy,
>                                      region->width, region->height,
>                                      color, rop);
> -       if (sm750_dev->fb_count > 1)
> -               spin_unlock(&sm750_dev->slock);
> +       spin_unlock(&sm750_dev->slock);
>  }
>
>  static void lynxfb_ops_copyarea(struct fb_info *info,
> @@ -220,16 +218,14 @@ static void lynxfb_ops_copyarea(struct fb_info *info,
>          * If not use spin_lock, system will die if user load driver
>          * and immediately unload driver frequently (dual)
>          */
> -       if (sm750_dev->fb_count > 1)
> -               spin_lock(&sm750_dev->slock);
> +       spin_lock(&sm750_dev->slock);
>
>         sm750_dev->accel.de_copyarea(&sm750_dev->accel,
>                                      base, pitch, region->sx, region->sy,
>                                      base, pitch, Bpp, region->dx, region->dy,
>                                      region->width, region->height,
>                                      HW_ROP2_COPY);
> -       if (sm750_dev->fb_count > 1)
> -               spin_unlock(&sm750_dev->slock);
> +       spin_unlock(&sm750_dev->slock);
>  }
>
>  static void lynxfb_ops_imageblit(struct fb_info *info,
> @@ -269,8 +265,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
>          * If not use spin_lock, system will die if user load driver
>          * and immediately unload driver frequently (dual)
>          */
> -       if (sm750_dev->fb_count > 1)
> -               spin_lock(&sm750_dev->slock);
> +       spin_lock(&sm750_dev->slock);
>
>         sm750_dev->accel.de_imageblit(&sm750_dev->accel,
>                                       image->data, image->width >> 3, 0,
> @@ -278,8 +273,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
>                                       image->dx, image->dy,
>                                       image->width, image->height,
>                                       fgcol, bgcol, HW_ROP2_COPY);
> -       if (sm750_dev->fb_count > 1)
> -               spin_unlock(&sm750_dev->slock);
> +       spin_unlock(&sm750_dev->slock);
>  }
>
>  static int lynxfb_ops_pan_display(struct fb_var_screeninfo *var,
> --
> 2.7.4
>

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-26  5:45 [PATCH] staging: sm750fb: always take the lock AbdAllah-MEZITI
  2017-06-26  6:33 ` Frans Klaver
@ 2017-06-26  9:11 ` Geert Uytterhoeven
  2017-06-26  9:16   ` Frans Klaver
  1 sibling, 1 reply; 8+ messages in thread
From: Geert Uytterhoeven @ 2017-06-26  9:11 UTC (permalink / raw)
  To: AbdAllah-MEZITI
  Cc: Sudip Mukherjee, Teddy Wang, Greg Kroah-Hartman,
	Linux Fbdev development list, driverdevel, linux-kernel

On Mon, Jun 26, 2017 at 7:45 AM, AbdAllah-MEZITI
<abdallah.meziti.pro@gmail.com> wrote:
> This patch
> - will always take the lock

Why?

"The current code only takes the lock if multiple instances are in use.
 This is error-prone, and confuses static analyzers.
 As taking the lock in case of a single instance is harmful and cheap,
 change the code to always take the lock."

> - fix the sparse warning:
> drivers/staging/sm750fb/sm750.c:159:13: warning: context imbalance in 'lynxfb_ops_fillrect' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:231:9: warning: context imbalance in 'lynxfb_ops_copyarea' - different lock contexts for basic block
> drivers/staging/sm750fb/sm750.c:235:13: warning: context imbalance in 'lynxfb_ops_imageblit' - different lock contexts for basic block

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-26  9:11 ` Geert Uytterhoeven
@ 2017-06-26  9:16   ` Frans Klaver
  2017-06-26  9:19     ` Geert Uytterhoeven
  0 siblings, 1 reply; 8+ messages in thread
From: Frans Klaver @ 2017-06-26  9:16 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: AbdAllah-MEZITI, Sudip Mukherjee, Teddy Wang, Greg Kroah-Hartman,
	Linux Fbdev development list, driverdevel, linux-kernel

On Mon, Jun 26, 2017 at 11:11 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> On Mon, Jun 26, 2017 at 7:45 AM, AbdAllah-MEZITI
> <abdallah.meziti.pro@gmail.com> wrote:
>> This patch
>> - will always take the lock
>
> Why?
>
> "The current code only takes the lock if multiple instances are in use.
>  This is error-prone, and confuses static analyzers.
>  As taking the lock in case of a single instance is harmful and cheap,
>  change the code to always take the lock."

I would argue that it's not harmful, lest people get confused about
it. And I agree that this explanation is much more useful than just
mentioning the warnings that you saw.

Thanks,
Frans

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-26  9:16   ` Frans Klaver
@ 2017-06-26  9:19     ` Geert Uytterhoeven
  0 siblings, 0 replies; 8+ messages in thread
From: Geert Uytterhoeven @ 2017-06-26  9:19 UTC (permalink / raw)
  To: Frans Klaver
  Cc: AbdAllah-MEZITI, Sudip Mukherjee, Teddy Wang, Greg Kroah-Hartman,
	Linux Fbdev development list, driverdevel, linux-kernel

On Mon, Jun 26, 2017 at 11:16 AM, Frans Klaver <fransklaver@gmail.com> wrote:
> On Mon, Jun 26, 2017 at 11:11 AM, Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
>> On Mon, Jun 26, 2017 at 7:45 AM, AbdAllah-MEZITI
>> <abdallah.meziti.pro@gmail.com> wrote:
>>> This patch
>>> - will always take the lock
>>
>> Why?
>>
>> "The current code only takes the lock if multiple instances are in use.
>>  This is error-prone, and confuses static analyzers.
>>  As taking the lock in case of a single instance is harmful and cheap,
>>  change the code to always take the lock."
>
> I would argue that it's not harmful, lest people get confused about

Sorry, I meant "harmless". I should start caring as much for commit
messages I write for other people as for those I write for myself ;-)

> it. And I agree that this explanation is much more useful than just
> mentioning the warnings that you saw.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-25 21:39 AbdAllah-MEZITI
  2017-06-26  4:55 ` Greg Kroah-Hartman
@ 2017-06-26  6:25 ` Frans Klaver
  1 sibling, 0 replies; 8+ messages in thread
From: Frans Klaver @ 2017-06-26  6:25 UTC (permalink / raw)
  To: AbdAllah-MEZITI
  Cc: Sudip Mukherjee, Teddy Wang, Greg Kroah-Hartman, linux-fbdev,
	devel, linux-kernel

On Sun, Jun 25, 2017 at 11:39 PM, AbdAllah-MEZITI
<abdallah.meziti.pro@gmail.com> wrote:
> Subject: [PATCH] staging: sm750fb: always take the lock

When sending a new version of your patch, include a version number:

Subject: [PATCH V2] staging: ...

Frans

^ permalink raw reply	[flat|nested] 8+ messages in thread
* Re: [PATCH] staging: sm750fb: always take the lock
  2017-06-25 21:39 AbdAllah-MEZITI
@ 2017-06-26  4:55 ` Greg Kroah-Hartman
  2017-06-26  6:25 ` Frans Klaver
  1 sibling, 0 replies; 8+ messages in thread
From: Greg Kroah-Hartman @ 2017-06-26  4:55 UTC (permalink / raw)
  To: AbdAllah-MEZITI
  Cc: sudipm.mukherjee, devel, linux-fbdev, Teddy Wang, linux-kernel

On Sun, Jun 25, 2017 at 11:39:20PM +0200, AbdAllah-MEZITI wrote:
> Signed-off-by: AbdAllah MEZITI <abdallah.meziti.pro@gmail.com>

I can't take patches without any changelog text, sorry.

greg k-h

^ permalink raw reply	[flat|nested] 8+ messages in thread
* [PATCH] staging: sm750fb: always take the lock
@ 2017-06-25 21:39 AbdAllah-MEZITI
  2017-06-26  4:55 ` Greg Kroah-Hartman
  2017-06-26  6:25 ` Frans Klaver
  0 siblings, 2 replies; 8+ messages in thread
From: AbdAllah-MEZITI @ 2017-06-25 21:39 UTC (permalink / raw)
  To: sudipm.mukherjee
  Cc: AbdAllah MEZITI, Teddy Wang, Greg Kroah-Hartman, linux-fbdev,
	devel, linux-kernel

Signed-off-by: AbdAllah MEZITI <abdallah.meziti.pro@gmail.com>
---
 drivers/staging/sm750fb/sm750.c | 18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/sm750fb/sm750.c b/drivers/staging/sm750fb/sm750.c
index 386d4ad..4a22190 100644
--- a/drivers/staging/sm750fb/sm750.c
+++ b/drivers/staging/sm750fb/sm750.c
@@ -186,16 +186,14 @@ static void lynxfb_ops_fillrect(struct fb_info *info,
 	 * If not use spin_lock,system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_fillrect(&sm750_dev->accel,
 				     base, pitch, Bpp,
 				     region->dx, region->dy,
 				     region->width, region->height,
 				     color, rop);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static void lynxfb_ops_copyarea(struct fb_info *info,
@@ -220,16 +218,14 @@ static void lynxfb_ops_copyarea(struct fb_info *info,
 	 * If not use spin_lock, system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_copyarea(&sm750_dev->accel,
 				     base, pitch, region->sx, region->sy,
 				     base, pitch, Bpp, region->dx, region->dy,
 				     region->width, region->height,
 				     HW_ROP2_COPY);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static void lynxfb_ops_imageblit(struct fb_info *info,
@@ -269,8 +265,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
 	 * If not use spin_lock, system will die if user load driver
 	 * and immediately unload driver frequently (dual)
 	 */
-	if (sm750_dev->fb_count > 1)
-		spin_lock(&sm750_dev->slock);
+	spin_lock(&sm750_dev->slock);
 
 	sm750_dev->accel.de_imageblit(&sm750_dev->accel,
 				      image->data, image->width >> 3, 0,
@@ -278,8 +273,7 @@ static void lynxfb_ops_imageblit(struct fb_info *info,
 				      image->dx, image->dy,
 				      image->width, image->height,
 				      fgcol, bgcol, HW_ROP2_COPY);
-	if (sm750_dev->fb_count > 1)
-		spin_unlock(&sm750_dev->slock);
+	spin_unlock(&sm750_dev->slock);
 }
 
 static int lynxfb_ops_pan_display(struct fb_var_screeninfo *var,
-- 
2.7.4

^ permalink raw reply related	[flat|nested] 8+ messages in thread
end of thread, other threads:[~2017-06-26  9:19 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-06-26  5:45 [PATCH] staging: sm750fb: always take the lock AbdAllah-MEZITI
2017-06-26  6:33 ` Frans Klaver
2017-06-26  9:11 ` Geert Uytterhoeven
2017-06-26  9:16   ` Frans Klaver
2017-06-26  9:19     ` Geert Uytterhoeven
  -- strict thread matches above, loose matches on Subject: below --
2017-06-25 21:39 AbdAllah-MEZITI
2017-06-26  4:55 ` Greg Kroah-Hartman
2017-06-26  6:25 ` Frans Klaver

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