Re: [PATCHv2] powerpc: mm: radix_tlb: rearrange the if-else block
From: Christophe Leroy <hidden>
Date: 2022-01-28 10:14:10
Also in:
lkml, llvm
Le 28/01/2022 à 11:08, Anders Roxell a écrit :
quoted hunk ↗ jump to hunk
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> Signed-off-by: Anders Roxell <redacted> --- arch/powerpc/mm/book3s64/radix_tlb.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-)diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 7724af19ed7e..7d65965a0688 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c@@ -1174,12 +1174,9 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm, bool hflush = false;
You should then remove the default initialisation of hflush to false which has become pointless. With that fixed, Reviewed-by: Christophe Leroy <redacted>
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");