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asm-generic: fix -Wtype-limits compiler warnings 

Commit d66acc39c7 ("bitops: Optimise get_order()") introduced a
compilation warning because "rx_frag_size" is an "ushort" while
PAGE_SHIFT here is 16.

The commit changed the get_order() to be a multi-line macro where
compilers insist to check all statements in the macro even when
__builtin_constant_p(rx_frag_size) will return false as "rx_frag_size"
is a module parameter.

In file included from ./arch/powerpc/include/asm/page_64.h:107,
                 from ./arch/powerpc/include/asm/page.h:242,
                 from ./arch/powerpc/include/asm/mmu.h:132,
                 from ./arch/powerpc/include/asm/lppaca.h:47,
                 from ./arch/powerpc/include/asm/paca.h:17,
                 from ./arch/powerpc/include/asm/current.h:13,
                 from ./include/linux/thread_info.h:21,
                 from ./arch/powerpc/include/asm/processor.h:39,
                 from ./include/linux/prefetch.h:15,
                 from drivers/net/ethernet/emulex/benet/be_main.c:14:
drivers/net/ethernet/emulex/benet/be_main.c: In function 'be_rx_cqs_create':
./include/asm-generic/getorder.h:54:9: warning: comparison is always
true due to limited range of data type [-Wtype-limits]
   (((n) < (1UL << PAGE_SHIFT)) ? 0 :  \
         ^
drivers/net/ethernet/emulex/benet/be_main.c:3138:33: note: in expansion
of macro 'get_order'
  adapter->big_page_size = (1 << get_order(rx_frag_size)) * PAGE_SIZE;
                                 ^~~~~~~~~

Fix it by moving all of this multi-line macro into a proper function,
and killing __get_order() off.

[akpm@linux-foundation.org: remove __get_order() altogether]
[cai@lca.pw: v2]
  Link: http://lkml.kernel.org/r/1564000166-31428-1-git-send-email-cai@lca.pw
Link: http://lkml.kernel.org/r/1563914986-26502-1-git-send-email-cai@lca.pw
Fixes: d66acc39c7 ("bitops: Optimise get_order()")
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: James Y Knight <jyknight@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Qian Cai 2019-08-02 21:49:19 -07:00 committed by Linus Torvalds
parent b59b1baab7
commit cbedfe1134
1 changed files with 20 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
include/asm-generic/getorder.h
View File

@ -7,24 +7,6 @@
#include <linux/compiler.h>
#include <linux/log2.h>
/*
* Runtime evaluation of get_order()
*/
static inline __attribute_const__
int __get_order(unsigned long size)
{
int order;
size--;
size >>= PAGE_SHIFT;
#if BITS_PER_LONG == 32
order = fls(size);
#else
order = fls64(size);
#endif
return order;
}
/**
* get_order - Determine the allocation order of a memory size
* @size: The size for which to get the order
@ -43,19 +25,27 @@ int __get_order(unsigned long size)
* to hold an object of the specified size.
*
* The result is undefined if the size is 0.
*
* This function may be used to initialise variables with compile time
* evaluations of constants.
*/
#define get_order(n) \
( \
__builtin_constant_p(n) ? ( \
((n) == 0UL) ? BITS_PER_LONG - PAGE_SHIFT : \
(((n) < (1UL << PAGE_SHIFT)) ? 0 : \
ilog2((n) - 1) - PAGE_SHIFT + 1) \
) : \
__get_order(n) \
)
static inline __attribute_const__ int get_order(unsigned long size)
{
if (__builtin_constant_p(size)) {
if (!size)
return BITS_PER_LONG - PAGE_SHIFT;
if (size < (1UL << PAGE_SHIFT))
return 0;
return ilog2((size) - 1) - PAGE_SHIFT + 1;
}
size--;
size >>= PAGE_SHIFT;
#if BITS_PER_LONG == 32
return fls(size);
#else
return fls64(size);
#endif
}
#endif /* __ASSEMBLY__ */