[PATCH] zram: include linux/err.h

[PATCH] zram: include linux/err.h

[Arnd Bergmann]

The zram driver uses the ERR_PTR macro defined in <linux/err.h>
and relies on this header to be included implicitly through
other headers, which is not (always) the case on the ARM architecture.

Adding an explicit #include allows us to build the driver in
all configurations.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
index 92a83df..3507bef 100644
--- a/drivers/block/zram/zcomp.c
+++ b/drivers/block/zram/zcomp.c
@@ -7,6 +7,7 @@
  * 2 of the License, or (at your option) any later version.
  */
 
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/slab.h>

Re: [PATCH] zram: include linux/err.h

[Sergey Senozhatsky]

Hello Arnd,

On (03/15/14 10:40), Arnd Bergmann wrote:
> The zram driver uses the ERR_PTR macro defined in <linux/err.h>
> and relies on this header to be included implicitly through
> other headers, which is not (always) the case on the ARM architecture.
> 

returned from zcomp ERR_PTR is checked and used in zram_drv.c, should
in this case there also be inclusion of err.h in zram_drv.h? if so, it
probably makes sense to move inclusion of err.h to zcomp.h, which is
included both in zcomp.c and zram_drv.c

> Adding an explicit #include allows us to build the driver in
> all configurations.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c
> index 92a83df..3507bef 100644
> --- a/drivers/block/zram/zcomp.c
> +++ b/drivers/block/zram/zcomp.c
> @@ -7,6 +7,7 @@
>   * 2 of the License, or (at your option) any later version.
>   */
>  
> +#include <linux/err.h>
>  #include <linux/kernel.h>
>  #include <linux/string.h>
>  #include <linux/slab.h>
> 

Re: [PATCH] zram: include linux/err.h

[Arnd Bergmann]

On Saturday 15 March 2014, Sergey Senozhatsky wrote:
> On (03/15/14 10:40), Arnd Bergmann wrote:
> > The zram driver uses the ERR_PTR macro defined in <linux/err.h>
> > and relies on this header to be included implicitly through
> > other headers, which is not (always) the case on the ARM architecture.
> > 
> 
> returned from zcomp ERR_PTR is checked and used in zram_drv.c, should
> in this case there also be inclusion of err.h in zram_drv.h? if so, it
> probably makes sense to move inclusion of err.h to zcomp.h, which is
> included both in zcomp.c and zram_drv.c
> 

The normal convention is to only include headers from other headers if
that is required by the contents of the header itself.

Following the common conventions, it's better to include linux/err.h
in both zram_drv.c and zcomp.c, but not in zram_drv.h.
I didn't do that in my patch, because I only got a build error in
one of the two files.

	Arnd

Re: [PATCH] zram: include linux/err.h

[Sergey Senozhatsky]

Hello Arnd,

On (03/15/14 21:26), Arnd Bergmann wrote:
> On Saturday 15 March 2014, Sergey Senozhatsky wrote:
> > On (03/15/14 10:40), Arnd Bergmann wrote:
> > > The zram driver uses the ERR_PTR macro defined in <linux/err.h>
> > > and relies on this header to be included implicitly through
> > > other headers, which is not (always) the case on the ARM architecture.
> > > 
> > 
> > returned from zcomp ERR_PTR is checked and used in zram_drv.c, should
> > in this case there also be inclusion of err.h in zram_drv.h? if so, it
> > probably makes sense to move inclusion of err.h to zcomp.h, which is
> > included both in zcomp.c and zram_drv.c
> > 
> 
> The normal convention is to only include headers from other headers if
> that is required by the contents of the header itself.
> 
> Following the common conventions, it's better to include linux/err.h
> in both zram_drv.c and zcomp.c, but not in zram_drv.h.

thanks.

may I ask you to resend the patch with linux/err.h included
in both zram_drv.c and zcomp.c?

	-ss

> I didn't do that in my patch, because I only got a build error in
> one of the two files.
> 
> 	Arnd
> 

Re: [PATCH] zram: include linux/err.h

[Sergey Senozhatsky]

On (03/19/14 10:39), Minchan Kim wrote:
> On Sat, Mar 15, 2014 at 10:40:08AM +0100, Arnd Bergmann wrote:
> > The zram driver uses the ERR_PTR macro defined in <linux/err.h>
> > and relies on this header to be included implicitly through
> > other headers, which is not (always) the case on the ARM architecture.
> > 
> > Adding an explicit #include allows us to build the driver in
> > all configurations.
> > 
> > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> Regardless of resend fixing another part Sergey asked,
> 
> Acked-by: Minchan Kim <minchan@kernel.org>
> 

Andrew, could you please apply this one? I'll send a patch
to also include err.h in zram_drv shortly.

	-ss

> Thanks!
> 
> 
> -- 
> Kind regards,
> Minchan Kim
>