The __SWAB_64_THRU_32__ case of a 64-bit byte swap was depending on the
no-longer-existant ___swab32() method (three underscores).  We got rid
of some of the worst indirection and complexity, and now it should just
use the 32-bit swab function that was defined right above it.
Reported-and-tested-by: NNicolas Pitre <nico@cam.org>
Reported-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The first step to make swab.h a regular header that will
include an asm/swab.h with arch overrides.

Avoid the gratuitous differences introduced in the new
linux/swab.h by naming the ___constant_swabXX bits and
__fswabXX bits exactly as found in the old implementation
in byteorder/swab[b].h

Use this new swab.h in byteorder/[big|little]_endian.h and
remove the two old swab headers.

Although the inclusion of asm/byteorder.h looks strange in
linux/swab.h, this will allow each arch to move the actual
arch overrides for the swab bits in an asm file and then
the includes can be cleaned up without requiring a flag day
for all arches at once.

Keep providing __fswabXX in case some userspace was using them
directly, but the revised __swabXX should be used instead in
any new code and will always do constant folding not dependent
on the optimization level, which means the __constant versions
can be phased out in-kernel.

Arches that use the old-style arch macros will lose their
optimized versions until they move to the new style, but at
least they will still compile.  Many arches have already moved
and the patches to move the remaining arches are trivial.
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This makes the new implementation of the byteorder helpers match the old
in how it degraded when an arch-defined version was not available:

1) swab()
	- look for arch defined
	- if not, use generic c version

2) swabp()
	- look for arch-defined
	- if not, deref pointer and use swab()

3) swabs()
	- look for arch defined
	- if not, use swabp
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Collect the implementations from include/linux/byteorder/swab.h, swabb.h
in swab.h

The functionality provided covers:
u16 swab16(u16 val) - return a byteswapped 16 bit value
u32 swab32(u32 val) - return a byteswapped 32 bit value
u64 swab64(u64 val) - return a byteswapped 64 bit value
u32 swahw32(u32 val) - return a wordswapped 32 bit value
u32 swahb32(u32 val) - return a high/low byteswapped 32 bit value

Similar to above, but return swapped value from a naturally-aligned pointer
u16 swab16p(u16 *p)
u32 swab32p(u32 *p)
u64 swab64p(u64 *p)
u32 swahw32p(u32 *p)
u32 swahb32p(u32 *p)

Similar to above, but swap the value in-place (in-situ)
void swab16s(u16 *p)
void swab32s(u32 *p)
void swab64s(u64 *p)
void swahw32s(u32 *p)
void swahb32s(u32 *p)

Arches can override any of these with an optimized version by defining an
inline in their asm/byteorder.h (example given for swab16()):

u16 __arch_swab16() {}
 #define __arch_swab16 __arch_swab16
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>