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authorBenjamin Herrenschmidt <benh@kernel.crashing.org>2007-06-16 10:16:12 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-16 13:16:16 -0700
commit8dab5241d06bfc9ee141ea78c56cde5070d7460d (patch)
treedd9dc3c64c17862b169f4cbe5fd4a108d960c920 /mm
parent679ce0ace6b1a07043bc3b405a34ddccad808886 (diff)
downloadlinux-8dab5241d06bfc9ee141ea78c56cde5070d7460d.tar.bz2
Rework ptep_set_access_flags and fix sun4c
Some changes done a while ago to avoid pounding on ptep_set_access_flags and update_mmu_cache in some race situations break sun4c which requires update_mmu_cache() to always be called on minor faults. This patch reworks ptep_set_access_flags() semantics, implementations and callers so that it's now responsible for returning whether an update is necessary or not (basically whether the PTE actually changed). This allow fixing the sparc implementation to always return 1 on sun4c. [akpm@linux-foundation.org: fixes, cleanups] Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: David Miller <davem@davemloft.net> Cc: Mark Fortescue <mark@mtfhpc.demon.co.uk> Acked-by: William Lee Irwin III <wli@holomorphy.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c7
-rw-r--r--mm/memory.c13
2 files changed, 10 insertions, 10 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index eb7180db3033..a45d1f0691ce 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -326,9 +326,10 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma,
pte_t entry;
entry = pte_mkwrite(pte_mkdirty(*ptep));
- ptep_set_access_flags(vma, address, ptep, entry, 1);
- update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
+ if (ptep_set_access_flags(vma, address, ptep, entry, 1)) {
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+ }
}
diff --git a/mm/memory.c b/mm/memory.c
index cb94488ab96d..f64cbf9baa36 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1691,9 +1691,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
flush_cache_page(vma, address, pte_pfn(orig_pte));
entry = pte_mkyoung(orig_pte);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- ptep_set_access_flags(vma, address, page_table, entry, 1);
- update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
+ if (ptep_set_access_flags(vma, address, page_table, entry,1)) {
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+ }
ret |= VM_FAULT_WRITE;
goto unlock;
}
@@ -2525,10 +2526,9 @@ static inline int handle_pte_fault(struct mm_struct *mm,
pte_t *pte, pmd_t *pmd, int write_access)
{
pte_t entry;
- pte_t old_entry;
spinlock_t *ptl;
- old_entry = entry = *pte;
+ entry = *pte;
if (!pte_present(entry)) {
if (pte_none(entry)) {
if (vma->vm_ops) {
@@ -2561,8 +2561,7 @@ static inline int handle_pte_fault(struct mm_struct *mm,
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- if (!pte_same(old_entry, entry)) {
- ptep_set_access_flags(vma, address, pte, entry, write_access);
+ if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
update_mmu_cache(vma, address, entry);
lazy_mmu_prot_update(entry);
} else {