[PATCH] Centralize the macro definition of "__packed".

[PATCH] Centralize the macro definition of "__packed".

[Robert P. J. Day]

  Centralize the attribute macro definition of "__packed" so no
subsystem has to do that explicitly.

Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>

---

  compile tested to make sure the HFS subsystem still builds.  now
there's just 50 gazillion usages of "__attribute__((packed))" that can
be tightened up.


 fs/hfs/hfs.h                 |    2 --
 fs/hfsplus/hfsplus_raw.h     |    2 --
 include/linux/compiler-gcc.h |    1 +
 3 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/fs/hfs/hfs.h b/fs/hfs/hfs.h
index 88099ab..1445e3a 100644
--- a/fs/hfs/hfs.h
+++ b/fs/hfs/hfs.h
@@ -83,8 +83,6 @@

 /*======== HFS structures as they appear on the disk ========*/

-#define __packed __attribute__ ((packed))
-
 /* Pascal-style string of up to 31 characters */
 struct hfs_name {
 	u8 len;
diff --git a/fs/hfsplus/hfsplus_raw.h b/fs/hfsplus/hfsplus_raw.h
index 4920553..fe99fe8 100644
--- a/fs/hfsplus/hfsplus_raw.h
+++ b/fs/hfsplus/hfsplus_raw.h
@@ -15,8 +15,6 @@

 #include <linux/types.h>

-#define __packed __attribute__ ((packed))
-
 /* Some constants */
 #define HFSPLUS_SECTOR_SIZE        512
 #define HFSPLUS_SECTOR_SHIFT         9
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index 6e1c44a..b6e39f5 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -27,6 +27,7 @@
 #define __inline__	__inline__	__attribute__((always_inline))
 #define __inline	__inline	__attribute__((always_inline))
 #define __deprecated			__attribute__((deprecated))
+#define __packed			__attribute__((packed))
 #define  noinline			__attribute__((noinline))
 #define __attribute_pure__		__attribute__((pure))
 #define __attribute_const__		__attribute__((__const__))

Re: [PATCH] Centralize the macro definition of "__packed".

[Robert P. J. Day]

On Thu, 18 Jan 2007, Robert P. J. Day wrote:

>   Centralize the attribute macro definition of "__packed" so no
> subsystem has to do that explicitly.

ummm ... might want to ignore this submission, i want to do some
tweaking first.  sorry.

rday

Re: [PATCH] Centralize the macro definition of "__packed".

[Tim Schmielau]

On Thu, 18 Jan 2007, Robert P. J. Day wrote:

>   Centralize the attribute macro definition of "__packed" so no
> subsystem has to do that explicitly.
> 
> Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
> 
> ---
> 
>   compile tested to make sure the HFS subsystem still builds.  now
> there's just 50 gazillion usages of "__attribute__((packed))" that can
> be tightened up.
> 
> 
>  fs/hfs/hfs.h                 |    2 --
>  fs/hfsplus/hfsplus_raw.h     |    2 --
>  include/linux/compiler-gcc.h |    1 +
>  3 files changed, 1 insertion(+), 4 deletions(-)

Moving definitions into compiler-gcc.h only will screw non-gcc compilers 
like icc.
They should probably go into the generic section of compiler.h instead.

Tim

Re: [PATCH] Centralize the macro definition of "__packed".

[Robert P. J. Day]

On Thu, 18 Jan 2007, Tim Schmielau wrote:

> On Thu, 18 Jan 2007, Robert P. J. Day wrote:
>
> >   Centralize the attribute macro definition of "__packed" so no
> > subsystem has to do that explicitly.
> >
> > Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
> >
> > ---
> >
> >   compile tested to make sure the HFS subsystem still builds.  now
> > there's just 50 gazillion usages of "__attribute__((packed))" that can
> > be tightened up.
> >
> >
> >  fs/hfs/hfs.h                 |    2 --
> >  fs/hfsplus/hfsplus_raw.h     |    2 --
> >  include/linux/compiler-gcc.h |    1 +
> >  3 files changed, 1 insertion(+), 4 deletions(-)
>
> Moving definitions into compiler-gcc.h only will screw non-gcc
> compilers like icc. They should probably go into the generic section
> of compiler.h instead.

actually, it *appears* that the standard works this way.  the macro
"__deprecated" is defined in compiler-gcc.h with:

    #define __deprecated __attribute__((deprecated))

while the more generic compiler.h handles whether or not it was
defined:

    #ifndef __deprecated
    # define __deprecated           /* unimplemented */
    #endif

so i'm guessing that's how any new attribute shortcut macros should be
handled, yes?

rday

Re: [PATCH] Centralize the macro definition of "__packed".

[Tim Schmielau]

On Thu, 18 Jan 2007, Robert P. J. Day wrote:

> actually, it *appears* that the standard works this way.  the macro
> "__deprecated" is defined in compiler-gcc.h with:
> 
>     #define __deprecated __attribute__((deprecated))
> 
> while the more generic compiler.h handles whether or not it was
> defined:
> 
>     #ifndef __deprecated
>     # define __deprecated           /* unimplemented */
>     #endif
> 
> so i'm guessing that's how any new attribute shortcut macros should be
> handled, yes?

Well, since the definitions lived well in compiler-generic land for quite 
some time, I'd guess it should be ok not to #ifndef - guard them. 
likely() and unlikely() are currently handled like that.
If the need ever arises to make them compiler specific, whoever does that 
can still add the #ifndef then.

Tim

Re: [PATCH] Centralize the macro definition of "__packed".

[Robert P. J. Day]

On Thu, 18 Jan 2007, Tim Schmielau wrote:

> On Thu, 18 Jan 2007, Robert P. J. Day wrote:
>
> > actually, it *appears* that the standard works this way.  the macro
> > "__deprecated" is defined in compiler-gcc.h with:
> >
> >     #define __deprecated __attribute__((deprecated))
> >
> > while the more generic compiler.h handles whether or not it was
> > defined:
> >
> >     #ifndef __deprecated
> >     # define __deprecated           /* unimplemented */
> >     #endif
> >
> > so i'm guessing that's how any new attribute shortcut macros should be
> > handled, yes?
>
> Well, since the definitions lived well in compiler-generic land for
> quite some time, I'd guess it should be ok not to #ifndef - guard
> them. likely() and unlikely() are currently handled like that. If
> the need ever arises to make them compiler specific, whoever does
> that can still add the #ifndef then.

as it is, i believe the only two compilers that are officially
supported for building the kernel are gcc and icc, and icc identifies
itself as a GNU compiler anyway, so adding to compiler-gcc.h should be
safe until the situation changes.

and, as you say, if the situation changes, fixing compiler.h would be
easy.

rday