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authorHugh Dickins <hugh@veritas.com>2005-10-29 21:16:28 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2005-10-30 00:40:40 -0400
commit663b97f7efd001b0c56bd5fce059c5272725b86f (patch)
treec80088db3514bf7f1749243e81fc3abaf7252ebd /arch/ia64
parent705e87c0c3c38424f7f30556c85bc20e808d2f59 (diff)
[PATCH] mm: flush_tlb_range outside ptlock
There was one small but very significant change in the previous patch: mprotect's flush_tlb_range fell outside the page_table_lock: as it is in 2.4, but that doesn't prove it safe in 2.6. On some architectures flush_tlb_range comes to the same as flush_tlb_mm, which has always been called from outside page_table_lock in dup_mmap, and is so proved safe. Others required a deeper audit: I could find no reliance on page_table_lock in any; but in ia64 and parisc found some code which looks a bit as if it might want preemption disabled. That won't do any actual harm, so pending a decision from the maintainers, disable preemption there. Remove comments on page_table_lock from flush_tlb_mm, flush_tlb_range and flush_tlb_page entries in cachetlb.txt: they were rather misleading (what generic code does is different from what usually happens), the rules are now changing, and it's not yet clear where we'll end up (will the generic tlb_flush_mmu happen always under lock? never under lock? or sometimes under and sometimes not?). Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/mm/tlb.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index c93e0f2b5fea..c79a9b96d02b 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -158,10 +158,12 @@ flush_tlb_range (struct vm_area_struct *vma, unsigned long start, unsigned long
158# ifdef CONFIG_SMP 158# ifdef CONFIG_SMP
159 platform_global_tlb_purge(mm, start, end, nbits); 159 platform_global_tlb_purge(mm, start, end, nbits);
160# else 160# else
161 preempt_disable();
161 do { 162 do {
162 ia64_ptcl(start, (nbits<<2)); 163 ia64_ptcl(start, (nbits<<2));
163 start += (1UL << nbits); 164 start += (1UL << nbits);
164 } while (start < end); 165 } while (start < end);
166 preempt_enable();
165# endif 167# endif
166 168
167 ia64_srlz_i(); /* srlz.i implies srlz.d */ 169 ia64_srlz_i(); /* srlz.i implies srlz.d */