mm: FOLL flags for GUP flags
__get_user_pages() has been taking its own GUP flags, then processing
them into FOLL flags for follow_page(). Though oddly named, the FOLL
flags are more widely used, so pass them to __get_user_pages() now.
Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct.
(The patch to __get_user_pages() looks peculiar, with both gup_flags
and foll_flags: the gup_flags remain constant; but as before there's
an exceptional case, out of scope of the patch, in which foll_flags
per page have FOLL_WRITE masked off.)
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 45ee5b5..5409ece 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1232,6 +1232,7 @@
#define FOLL_TOUCH 0x02 /* mark page accessed */
#define FOLL_GET 0x04 /* do get_page on page */
#define FOLL_DUMP 0x08 /* give error on hole if it would be zero */
+#define FOLL_FORCE 0x10 /* get_user_pages read/write w/o permission */
typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
void *data);
diff --git a/mm/internal.h b/mm/internal.h
index d414750..7559657 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -250,12 +250,8 @@
}
#endif /* CONFIG_SPARSEMEM */
-#define GUP_FLAGS_WRITE 0x01
-#define GUP_FLAGS_FORCE 0x02
-#define GUP_FLAGS_DUMP 0x04
-
int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int len, int flags,
+ unsigned long start, int len, unsigned int foll_flags,
struct page **pages, struct vm_area_struct **vmas);
#define ZONE_RECLAIM_NOSCAN -2
diff --git a/mm/memory.c b/mm/memory.c
index c8b5b94..5c694f2 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1209,27 +1209,29 @@
}
int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int nr_pages, int flags,
+ unsigned long start, int nr_pages, unsigned int gup_flags,
struct page **pages, struct vm_area_struct **vmas)
{
int i;
- unsigned int vm_flags = 0;
- int write = !!(flags & GUP_FLAGS_WRITE);
- int force = !!(flags & GUP_FLAGS_FORCE);
+ unsigned long vm_flags;
if (nr_pages <= 0)
return 0;
+
+ VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
+
/*
* Require read or write permissions.
- * If 'force' is set, we only require the "MAY" flags.
+ * If FOLL_FORCE is set, we only require the "MAY" flags.
*/
- vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+ vm_flags = (gup_flags & FOLL_WRITE) ?
+ (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= (gup_flags & FOLL_FORCE) ?
+ (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
i = 0;
do {
struct vm_area_struct *vma;
- unsigned int foll_flags;
vma = find_extend_vma(mm, start);
if (!vma && in_gate_area(tsk, start)) {
@@ -1241,7 +1243,7 @@
pte_t *pte;
/* user gate pages are read-only */
- if (write)
+ if (gup_flags & FOLL_WRITE)
return i ? : -EFAULT;
if (pg > TASK_SIZE)
pgd = pgd_offset_k(pg);
@@ -1278,22 +1280,15 @@
!(vm_flags & vma->vm_flags))
return i ? : -EFAULT;
- foll_flags = FOLL_TOUCH;
- if (pages)
- foll_flags |= FOLL_GET;
- if (flags & GUP_FLAGS_DUMP)
- foll_flags |= FOLL_DUMP;
- if (write)
- foll_flags |= FOLL_WRITE;
-
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &nr_pages, i, foll_flags);
+ &start, &nr_pages, i, gup_flags);
continue;
}
do {
struct page *page;
+ unsigned int foll_flags = gup_flags;
/*
* If we have a pending SIGKILL, don't keep faulting
@@ -1302,9 +1297,6 @@
if (unlikely(fatal_signal_pending(current)))
return i ? i : -ERESTARTSYS;
- if (write)
- foll_flags |= FOLL_WRITE;
-
cond_resched();
while (!(page = follow_page(vma, start, foll_flags))) {
int ret;
@@ -1415,12 +1407,14 @@
unsigned long start, int nr_pages, int write, int force,
struct page **pages, struct vm_area_struct **vmas)
{
- int flags = 0;
+ int flags = FOLL_TOUCH;
+ if (pages)
+ flags |= FOLL_GET;
if (write)
- flags |= GUP_FLAGS_WRITE;
+ flags |= FOLL_WRITE;
if (force)
- flags |= GUP_FLAGS_FORCE;
+ flags |= FOLL_FORCE;
return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
}
@@ -1447,7 +1441,7 @@
struct page *page;
if (__get_user_pages(current, current->mm, addr, 1,
- GUP_FLAGS_FORCE | GUP_FLAGS_DUMP, &page, &vma) < 1)
+ FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
return NULL;
if (page == ZERO_PAGE(0)) {
page_cache_release(page);
diff --git a/mm/mlock.c b/mm/mlock.c
index e13918d..22041aa 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -166,9 +166,9 @@
VM_BUG_ON(end > vma->vm_end);
VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
- gup_flags = 0;
+ gup_flags = FOLL_TOUCH | FOLL_GET;
if (vma->vm_flags & VM_WRITE)
- gup_flags = GUP_FLAGS_WRITE;
+ gup_flags |= FOLL_WRITE;
while (nr_pages > 0) {
int i;
diff --git a/mm/nommu.c b/mm/nommu.c
index 386443e..2d02ca1 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -168,20 +168,20 @@
}
int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long start, int nr_pages, int flags,
+ unsigned long start, int nr_pages, int foll_flags,
struct page **pages, struct vm_area_struct **vmas)
{
struct vm_area_struct *vma;
unsigned long vm_flags;
int i;
- int write = !!(flags & GUP_FLAGS_WRITE);
- int force = !!(flags & GUP_FLAGS_FORCE);
/* calculate required read or write permissions.
- * - if 'force' is set, we only require the "MAY" flags.
+ * If FOLL_FORCE is set, we only require the "MAY" flags.
*/
- vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
- vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
+ vm_flags = (foll_flags & FOLL_WRITE) ?
+ (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
+ vm_flags &= (foll_flags & FOLL_FORCE) ?
+ (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
for (i = 0; i < nr_pages; i++) {
vma = find_vma(mm, start);
@@ -223,9 +223,9 @@
int flags = 0;
if (write)
- flags |= GUP_FLAGS_WRITE;
+ flags |= FOLL_WRITE;
if (force)
- flags |= GUP_FLAGS_FORCE;
+ flags |= FOLL_FORCE;
return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
}