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Commitd66acc39c7("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>
53 lines
1.2 KiB
C
53 lines
1.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __ASM_GENERIC_GETORDER_H
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#define __ASM_GENERIC_GETORDER_H
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#ifndef __ASSEMBLY__
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#include <linux/compiler.h>
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#include <linux/log2.h>
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/**
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* get_order - Determine the allocation order of a memory size
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* @size: The size for which to get the order
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*
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* Determine the allocation order of a particular sized block of memory. This
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* is on a logarithmic scale, where:
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*
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* 0 -> 2^0 * PAGE_SIZE and below
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* 1 -> 2^1 * PAGE_SIZE to 2^0 * PAGE_SIZE + 1
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* 2 -> 2^2 * PAGE_SIZE to 2^1 * PAGE_SIZE + 1
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* 3 -> 2^3 * PAGE_SIZE to 2^2 * PAGE_SIZE + 1
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* 4 -> 2^4 * PAGE_SIZE to 2^3 * PAGE_SIZE + 1
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* ...
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*
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* The order returned is used to find the smallest allocation granule required
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* to hold an object of the specified size.
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*
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* The result is undefined if the size is 0.
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*/
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static inline __attribute_const__ int get_order(unsigned long size)
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{
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if (__builtin_constant_p(size)) {
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if (!size)
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return BITS_PER_LONG - PAGE_SHIFT;
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if (size < (1UL << PAGE_SHIFT))
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return 0;
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return ilog2((size) - 1) - PAGE_SHIFT + 1;
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}
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size--;
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size >>= PAGE_SHIFT;
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#if BITS_PER_LONG == 32
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return fls(size);
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#else
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return fls64(size);
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#endif
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}
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#endif /* __ASSEMBLY__ */
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#endif /* __ASM_GENERIC_GETORDER_H */
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