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Message-ID: <604427e00904131245r1125eadapc4f526ac42cf68a@mail.gmail.com>
Date: Mon, 13 Apr 2009 12:45:59 -0700
From: Ying Han <yinghan@...gle.com>
To: linux-mm@...ck.org, linux-kernel <linux-kernel@...r.kernel.org>,
akpm <akpm@...ux-foundation.org>, torvalds@...ux-foundation.org,
Ingo Molnar <mingo@...e.hu>, Mike Waychison <mikew@...gle.com>,
Rohit Seth <rohitseth@...gle.com>,
Hugh Dickins <hugh@...itas.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
"H. Peter Anvin" <hpa@...or.com>,
Török Edwin <edwintorok@...il.com>,
Lee Schermerhorn <lee.schermerhorn@...com>,
Nick Piggin <npiggin@...e.de>,
Wu Fengguang <fengguang.wu@...el.com>
Subject: [V4][PATCH 1/4]Remove internal use of 'write_access' in mm/memory.c
Remove internal use of 'write_access' in mm/memory.c
The fault handling routines really want more fine-grained flags than a
single "was it a write fault" boolean - the callers will want to set
flags like "you can return a retry error" etc.
And that's actually how the VM works internally, but right now the
top-level fault handling functions in mm/memory.c all pass just the
'write_access' boolean around.
This switches them over to pass around the FAULT_FLAG_xyzzy 'flags'
variable instead. The 'write_access' calling convention still exists
for the exported 'handle_mm_fault()' function, but that is next.
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Ying Han <yinghan@...gle.com>
---
include/linux/hugetlb.h | 2 +-
mm/hugetlb.c | 12 +++++++-----
mm/memory.c | 43 ++++++++++++++++++++++---------------------
3 files changed, 30 insertions(+), 27 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 03be7f2..ef873ef 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -31,7 +31,7 @@ void hugetlb_report_meminfo(struct seq_file *);
int hugetlb_report_node_meminfo(int, char *);
unsigned long hugetlb_total_pages(void);
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, int write_access);
+ unsigned long address, unsigned int flags);
int hugetlb_reserve_pages(struct inode *inode, long from, long to,
struct vm_area_struct *vma,
int acctflags);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 107da3d..12f6ca4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2063,7 +2063,7 @@ backout_unlocked:
}
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, int write_access)
+ unsigned long address, unsigned int flags)
{
pte_t *ptep;
pte_t entry;
@@ -2084,7 +2084,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_str
mutex_lock(&hugetlb_instantiation_mutex);
entry = huge_ptep_get(ptep);
if (huge_pte_none(entry)) {
- ret = hugetlb_no_page(mm, vma, address, ptep, write_access);
+ ret = hugetlb_no_page(mm, vma, address, ptep,
+ flags & FAULT_FLAG_WRITE);
goto out_mutex;
}
@@ -2098,7 +2099,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_str
* page now as it is used to determine if a reservation has been
* consumed.
*/
- if (write_access && !pte_write(entry)) {
+ if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
if (vma_needs_reservation(h, vma, address) < 0) {
ret = VM_FAULT_OOM;
goto out_mutex;
@@ -2115,7 +2116,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_str
goto out_page_table_lock;
- if (write_access) {
+ if (flags & FAULT_FLAG_WRITE) {
if (!pte_write(entry)) {
ret = hugetlb_cow(mm, vma, address, ptep, entry,
pagecache_page);
@@ -2124,7 +2125,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_str
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- if (huge_ptep_set_access_flags(vma, address, ptep, entry, write_access))
+ if (huge_ptep_set_access_flags(vma, address, ptep, entry,
+ flags & FAULT_FLAG_WRITE))
update_mmu_cache(vma, address, entry);
out_page_table_lock:
diff --git a/mm/memory.c b/mm/memory.c
index baa999e..bfecdfb 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2393,7 +2393,7 @@ int vmtruncate_range(struct inode *inode, loff_t offset, l
*/
static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
spinlock_t *ptl;
struct page *page;
@@ -2472,9 +2472,9 @@ static int do_swap_page(struct mm_struct *mm, struct vm_ar
inc_mm_counter(mm, anon_rss);
pte = mk_pte(page, vma->vm_page_prot);
- if (write_access && reuse_swap_page(page)) {
+ if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
pte = maybe_mkwrite(pte_mkdirty(pte), vma);
- write_access = 0;
+ flags &= ~FAULT_FLAG_WRITE;
}
flush_icache_page(vma, page);
set_pte_at(mm, address, page_table, pte);
@@ -2487,7 +2487,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_ar
try_to_free_swap(page);
unlock_page(page);
- if (write_access) {
+ if (flags & FAULT_FLAG_WRITE) {
ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
if (ret & VM_FAULT_ERROR)
ret &= VM_FAULT_ERROR;
@@ -2515,7 +2515,7 @@ out_nomap:
*/
static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access)
+ unsigned int flags)
{
struct page *page;
spinlock_t *ptl;
@@ -2675,7 +2675,7 @@ static int __do_fault(struct mm_struct *mm, struct vm_area
* due to the bad i386 page protection. But it's valid
* for other architectures too.
*
- * Note that if write_access is true, we either now have
+ * Note that if FAULT_FLAG_WRITE is set, we either now have
* an exclusive copy of the page, or this is a shared mapping,
* so we can make it writable and dirty to avoid having to
* handle that later.
@@ -2730,11 +2730,10 @@ out_unlocked:
static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
pgoff_t pgoff = (((address & PAGE_MASK)
- vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
- unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
pte_unmap(page_table);
return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
@@ -2751,12 +2750,12 @@ static int do_linear_fault(struct mm_struct *mm, struct
*/
static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
- int write_access, pte_t orig_pte)
+ unsigned int flags, pte_t orig_pte)
{
- unsigned int flags = FAULT_FLAG_NONLINEAR |
- (write_access ? FAULT_FLAG_WRITE : 0);
pgoff_t pgoff;
+ flags |= FAULT_FLAG_NONLINEAR;
+
if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
return 0;
@@ -2787,7 +2786,7 @@ static int do_nonlinear_fault(struct mm_struct *mm, struct
*/
static inline int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
- pte_t *pte, pmd_t *pmd, int write_access)
+ pte_t *pte, pmd_t *pmd, unsigned int flags)
{
pte_t entry;
spinlock_t *ptl;
@@ -2798,30 +2797,31 @@ static inline int handle_pte_fault(struct mm_struct *mm,
if (vma->vm_ops) {
if (likely(vma->vm_ops->fault))
return do_linear_fault(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
}
return do_anonymous_page(mm, vma, address,
- pte, pmd, write_access);
+ pte, pmd, flags);
}
if (pte_file(entry))
return do_nonlinear_fault(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
return do_swap_page(mm, vma, address,
- pte, pmd, write_access, entry);
+ pte, pmd, flags, entry);
}
ptl = pte_lockptr(mm, pmd);
spin_lock(ptl);
if (unlikely(!pte_same(*pte, entry)))
goto unlock;
- if (write_access) {
+ if (flags & FAULT_FLAG_WRITE) {
if (!pte_write(entry))
return do_wp_page(mm, vma, address,
pte, pmd, ptl, entry);
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
+ if (ptep_set_access_flags(vma, address, pte, entry,
+ flags & FAULT_FLAG_WRITE)) {
update_mmu_cache(vma, address, entry);
} else {
/*
@@ -2830,7 +2830,7 @@ static inline int handle_pte_fault(struct mm_struct *mm,
* This still avoids useless tlb flushes for .text page faults
* with threads.
*/
- if (write_access)
+ if (flags & FAULT_FLAG_WRITE)
flush_tlb_page(vma, address);
}
unlock:
@@ -2848,13 +2848,14 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ unsigned int flags = write_access ? FAULT_FLAG_WRITE : 0;
__set_current_state(TASK_RUNNING);
count_vm_event(PGFAULT);
if (unlikely(is_vm_hugetlb_page(vma)))
- return hugetlb_fault(mm, vma, address, write_access);
+ return hugetlb_fault(mm, vma, address, flags);
pgd = pgd_offset(mm, address);
pud = pud_alloc(mm, pgd, address);
@@ -2867,7 +2868,7 @@ int handle_mm_fault(struct mm_struct *mm, struct vm_area_s
if (!pte)
return VM_FAULT_OOM;
- return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
+ return handle_pte_fault(mm, vma, address, pte, pmd, flags);
}
#ifndef __PAGETABLE_PUD_FOLDED
--
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