Since its birth, get_user_pages has been calling a misguided get_page_map
function. follow_page has already returned NULL if the pfn is invalid,
we cannot reach an invalid pfn from a validated struct page.
Remove get_page_map, and the messy rewind in get_user_pages to cope with
its failure. Oh, and could we please call that "struct page *page" like
everywhere else, instead of "struct page *map"?
Signed-off-by: Hugh Dickins <[email protected]>
---
mm/memory.c | 45 ++++++++++-----------------------------------
1 files changed, 10 insertions(+), 35 deletions(-)
--- 2.6.12-rc6/mm/memory.c 2005-05-25 18:09:21.000000000 +0100
+++ linux/mm/memory.c 2005-06-04 20:41:55.000000000 +0100
@@ -840,23 +840,8 @@ check_user_page_readable(struct mm_struc
{
return __follow_page(mm, address, /*read*/1, /*write*/0) != NULL;
}
-
EXPORT_SYMBOL(check_user_page_readable);
-/*
- * Given a physical address, is there a useful struct page pointing to
- * it? This may become more complex in the future if we start dealing
- * with IO-aperture pages for direct-IO.
- */
-
-static inline struct page *get_page_map(struct page *page)
-{
- if (!pfn_valid(page_to_pfn(page)))
- return NULL;
- return page;
-}
-
-
static inline int
untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
unsigned long address)
@@ -887,7 +872,6 @@ untouched_anonymous_page(struct mm_struc
return 0;
}
-
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int len, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
@@ -951,21 +935,21 @@ int get_user_pages(struct task_struct *t
}
spin_lock(&mm->page_table_lock);
do {
- struct page *map;
+ struct page *page;
int lookup_write = write;
cond_resched_lock(&mm->page_table_lock);
- while (!(map = follow_page(mm, start, lookup_write))) {
+ while (!(page = follow_page(mm, start, lookup_write))) {
/*
* Shortcut for anonymous pages. We don't want
* to force the creation of pages tables for
- * insanly big anonymously mapped areas that
+ * insanely big anonymously mapped areas that
* nobody touched so far. This is important
* for doing a core dump for these mappings.
*/
if (!lookup_write &&
untouched_anonymous_page(mm,vma,start)) {
- map = ZERO_PAGE(start);
+ page = ZERO_PAGE(start);
break;
}
spin_unlock(&mm->page_table_lock);
@@ -994,30 +978,21 @@ int get_user_pages(struct task_struct *t
spin_lock(&mm->page_table_lock);
}
if (pages) {
- pages[i] = get_page_map(map);
- if (!pages[i]) {
- spin_unlock(&mm->page_table_lock);
- while (i--)
- page_cache_release(pages[i]);
- i = -EFAULT;
- goto out;
- }
- flush_dcache_page(pages[i]);
- if (!PageReserved(pages[i]))
- page_cache_get(pages[i]);
+ pages[i] = page;
+ flush_dcache_page(page);
+ if (!PageReserved(page))
+ page_cache_get(page);
}
if (vmas)
vmas[i] = vma;
i++;
start += PAGE_SIZE;
len--;
- } while(len && start < vma->vm_end);
+ } while (len && start < vma->vm_end);
spin_unlock(&mm->page_table_lock);
- } while(len);
-out:
+ } while (len);
return i;
}
-
EXPORT_SYMBOL(get_user_pages);
static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
-
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