Re: [PATCHv3] powerpc: mm: radix_tlb: rearrange the if-else block
From: Nathan Chancellor <nathan@kernel.org>
Date: 2022-01-28 15:03:08
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On Fri, Jan 28, 2022 at 02:17:13PM +0100, Anders Roxell wrote:
Clang warns:
arch/powerpc/mm/book3s64/radix_tlb.c:1191:23: error: variable 'hstart' is uninitialized when used here [-Werror,-Wuninitialized]
__tlbiel_va_range(hstart, hend, pid,
^~~~~~
arch/powerpc/mm/book3s64/radix_tlb.c:1175:23: note: initialize the variable 'hstart' to silence this warning
unsigned long hstart, hend;
^
= 0
arch/powerpc/mm/book3s64/radix_tlb.c:1191:31: error: variable 'hend' is uninitialized when used here [-Werror,-Wuninitialized]
__tlbiel_va_range(hstart, hend, pid,
^~~~
arch/powerpc/mm/book3s64/radix_tlb.c:1175:29: note: initialize the variable 'hend' to silence this warning
unsigned long hstart, hend;
^
= 0
2 errors generated.
Rework the 'if (IS_ENABLE(CONFIG_TRANSPARENT_HUGEPAGE))' so hstart/hend
always gets initialized, this will silence the warnings. That will also
simplify the 'else' path. Clang is getting confused with these warnings,
but the warnings is a false-positive.
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Christophe Leroy <redacted>
Signed-off-by: Anders Roxell <redacted>Reviewed-by: Nathan Chancellor <nathan@kernel.org>
quoted hunk ↗ jump to hunk
--- arch/powerpc/mm/book3s64/radix_tlb.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 7724af19ed7e..5172d5cec2c0 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c@@ -1171,15 +1171,12 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm, } } } else { - bool hflush = false; + bool hflush; unsigned long hstart, hend; - if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { - hstart = (start + PMD_SIZE - 1) & PMD_MASK; - hend = end & PMD_MASK; - if (hstart < hend) - hflush = true; - } + hstart = (start + PMD_SIZE - 1) & PMD_MASK; + hend = end & PMD_MASK; + hflush = IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && hstart < hend; if (type == FLUSH_TYPE_LOCAL) { asm volatile("ptesync": : :"memory");-- 2.34.1