From: Hugh Dickins <hugh@veritas.com>
Convert filemap_sync pagetable walkers to loops using p?d_addr_end; use
similar loop to split filemap_sync into chunks. Merge filemap_sync_pte
into sync_pte_range, cut filemap_ off the longer names, vma arg first.
There is no error from filemap_sync, nor is any use made of the flags:
if it should do something else for MS_INVALIDATE, reinstate it when that
is implemented. Remove the redundant flush_tlb_range from afterwards:
as its comment noted, each dirty pte has already been flushed.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/msync.c | 180 +++++++++++++++++++----------------------------------
1 files changed, 67 insertions(+), 113 deletions(-)
diff -puN mm/msync.c~ptwalk-sync_page_range mm/msync.c
--- 25/mm/msync.c~ptwalk-sync_page_range 2005-03-09 16:34:08.000000000 -0800
+++ 25-akpm/mm/msync.c 2005-03-09 16:34:08.000000000 -0800
@@ -21,155 +21,109 @@
* Called with mm->page_table_lock held to protect against other
* threads/the swapper from ripping pte's out from under us.
*/
-static int filemap_sync_pte(pte_t *ptep, struct vm_area_struct *vma,
- unsigned long address, unsigned int flags)
-{
- pte_t pte = *ptep;
- unsigned long pfn = pte_pfn(pte);
- struct page *page;
- if (pte_present(pte) && pfn_valid(pfn)) {
- page = pfn_to_page(pfn);
- if (!PageReserved(page) &&
- (ptep_clear_flush_dirty(vma, address, ptep) ||
- page_test_and_clear_dirty(page)))
- set_page_dirty(page);
- }
- return 0;
-}
-
-static int filemap_sync_pte_range(pmd_t * pmd,
- unsigned long address, unsigned long end,
- struct vm_area_struct *vma, unsigned int flags)
+static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
+ unsigned long addr, unsigned long end)
{
pte_t *pte;
- int error;
if (pmd_none_or_clear_bad(pmd))
- return 0;
- pte = pte_offset_map(pmd, address);
- if ((address & PMD_MASK) != (end & PMD_MASK))
- end = (address & PMD_MASK) + PMD_SIZE;
- error = 0;
+ return;
+ pte = pte_offset_map(pmd, addr);
do {
- error |= filemap_sync_pte(pte, vma, address, flags);
- address += PAGE_SIZE;
- pte++;
- } while (address && (address < end));
+ unsigned long pfn;
+ struct page *page;
- pte_unmap(pte - 1);
+ if (!pte_present(*pte))
+ continue;
+ pfn = pte_pfn(*pte);
+ if (!pfn_valid(pfn))
+ continue;
+ page = pfn_to_page(pfn);
+ if (PageReserved(page))
+ continue;
- return error;
+ if (ptep_clear_flush_dirty(vma, addr, pte) ||
+ page_test_and_clear_dirty(page))
+ set_page_dirty(page);
+ } while (pte++, addr += PAGE_SIZE, addr != end);
+ pte_unmap(pte - 1);
}
-static inline int filemap_sync_pmd_range(pud_t * pud,
- unsigned long address, unsigned long end,
- struct vm_area_struct *vma, unsigned int flags)
+static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
+ unsigned long addr, unsigned long end)
{
- pmd_t * pmd;
- int error;
+ pmd_t *pmd;
+ unsigned long next;
if (pud_none_or_clear_bad(pud))
- return 0;
- pmd = pmd_offset(pud, address);
- if ((address & PUD_MASK) != (end & PUD_MASK))
- end = (address & PUD_MASK) + PUD_SIZE;
- error = 0;
+ return;
+ pmd = pmd_offset(pud, addr);
do {
- error |= filemap_sync_pte_range(pmd, address, end, vma, flags);
- address = (address + PMD_SIZE) & PMD_MASK;
- pmd++;
- } while (address && (address < end));
- return error;
+ next = pmd_addr_end(addr, end);
+ sync_pte_range(vma, pmd, addr, next);
+ } while (pmd++, addr = next, addr != end);
}
-static inline int filemap_sync_pud_range(pgd_t *pgd,
- unsigned long address, unsigned long end,
- struct vm_area_struct *vma, unsigned int flags)
+static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+ unsigned long addr, unsigned long end)
{
pud_t *pud;
- int error;
+ unsigned long next;
if (pgd_none_or_clear_bad(pgd))
- return 0;
- pud = pud_offset(pgd, address);
- if ((address & PGDIR_MASK) != (end & PGDIR_MASK))
- end = (address & PGDIR_MASK) + PGDIR_SIZE;
- error = 0;
+ return;
+ pud = pud_offset(pgd, addr);
do {
- error |= filemap_sync_pmd_range(pud, address, end, vma, flags);
- address = (address + PUD_SIZE) & PUD_MASK;
- pud++;
- } while (address && (address < end));
- return error;
+ next = pud_addr_end(addr, end);
+ sync_pmd_range(vma, pud, addr, next);
+ } while (pud++, addr = next, addr != end);
}
-static int __filemap_sync(struct vm_area_struct *vma, unsigned long address,
- size_t size, unsigned int flags)
+static void sync_page_range(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
{
+ struct mm_struct *mm = vma->vm_mm;
pgd_t *pgd;
- unsigned long end = address + size;
unsigned long next;
- int i;
- int error = 0;
-
- /* Aquire the lock early; it may be possible to avoid dropping
- * and reaquiring it repeatedly.
- */
- spin_lock(&vma->vm_mm->page_table_lock);
-
- pgd = pgd_offset(vma->vm_mm, address);
- flush_cache_range(vma, address, end);
/* For hugepages we can't go walking the page table normally,
* but that's ok, hugetlbfs is memory based, so we don't need
* to do anything more on an msync() */
if (is_vm_hugetlb_page(vma))
- goto out;
-
- if (address >= end)
- BUG();
- for (i = pgd_index(address); i <= pgd_index(end-1); i++) {
- next = (address + PGDIR_SIZE) & PGDIR_MASK;
- if (next <= address || next > end)
- next = end;
- error |= filemap_sync_pud_range(pgd, address, next, vma, flags);
- address = next;
- pgd++;
- }
- /*
- * Why flush ? filemap_sync_pte already flushed the tlbs with the
- * dirty bits.
- */
- flush_tlb_range(vma, end - size, end);
- out:
- spin_unlock(&vma->vm_mm->page_table_lock);
+ return;
- return error;
+ BUG_ON(addr >= end);
+ pgd = pgd_offset(mm, addr);
+ flush_cache_range(vma, addr, end);
+ spin_lock(&mm->page_table_lock);
+ do {
+ next = pgd_addr_end(addr, end);
+ sync_pud_range(vma, pgd, addr, next);
+ } while (pgd++, addr = next, addr != end);
+ spin_unlock(&mm->page_table_lock);
}
#ifdef CONFIG_PREEMPT
-static int filemap_sync(struct vm_area_struct *vma, unsigned long address,
- size_t size, unsigned int flags)
+static void filemap_sync(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
{
const size_t chunk = 64 * 1024; /* bytes */
- int error = 0;
-
- while (size) {
- size_t sz = min(size, chunk);
+ unsigned long next;
- error |= __filemap_sync(vma, address, sz, flags);
+ do {
+ next = addr + chunk;
+ if (next > end || next < addr)
+ next = end;
+ sync_page_range(vma, addr, next);
cond_resched();
- address += sz;
- size -= sz;
- }
- return error;
+ } while (addr = next, addr != end);
}
#else
-static int filemap_sync(struct vm_area_struct *vma, unsigned long address,
- size_t size, unsigned int flags)
+static void filemap_sync(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
{
- return __filemap_sync(vma, address, size, flags);
+ sync_page_range(vma, addr, end);
}
#endif
@@ -184,19 +138,19 @@ static int filemap_sync(struct vm_area_s
* So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to
* applications.
*/
-static int msync_interval(struct vm_area_struct * vma,
- unsigned long start, unsigned long end, int flags)
+static int msync_interval(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end, int flags)
{
int ret = 0;
- struct file * file = vma->vm_file;
+ struct file *file = vma->vm_file;
if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
return -EBUSY;
if (file && (vma->vm_flags & VM_SHARED)) {
- ret = filemap_sync(vma, start, end-start, flags);
+ filemap_sync(vma, addr, end);
- if (!ret && (flags & MS_SYNC)) {
+ if (flags & MS_SYNC) {
struct address_space *mapping = file->f_mapping;
int err;
@@ -221,7 +175,7 @@ static int msync_interval(struct vm_area
asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
{
unsigned long end;
- struct vm_area_struct * vma;
+ struct vm_area_struct *vma;
int unmapped_error, error = -EINVAL;
if (flags & MS_SYNC)
_