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mm: replace get_user_pages_unlocked() write/force parameters with gup_flags

Browse source 
This removes the 'write' and 'force' use from get_user_pages_unlocked()
and replaces them with 'gup_flags' to make the use of FOLL_FORCE
explicit in callers as use of this flag can result in surprising
behaviour (and hence bugs) within the mm subsystem.

Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Lorenzo Stoakes 2016-10-13 01:20:13 +01:00 committed by Linus Torvalds
parent d4944b0ece
commit c164154f66
14 changed files with 27 additions and 36 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/mips/mm/gup.c
View file

@ -287,7 +287,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
pages += nr;
ret = get_user_pages_unlocked(start, (end - start) >> PAGE_SHIFT,
write, 0, pages);
pages, write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

3
arch/s390/mm/gup.c
View file

@ -266,7 +266,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
/* Try to get the remaining pages with get_user_pages */
start += nr << PAGE_SHIFT;
pages += nr;
ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0)
ret = (ret < 0) ? nr : ret + nr;

3
arch/sh/mm/gup.c
View file

@ -258,7 +258,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
pages += nr;
ret = get_user_pages_unlocked(start,
(end - start) >> PAGE_SHIFT, write, 0, pages);
(end - start) >> PAGE_SHIFT, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

3
arch/sparc/mm/gup.c
View file

@ -238,7 +238,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
pages += nr;
ret = get_user_pages_unlocked(start,
(end - start) >> PAGE_SHIFT, write, 0, pages);
(end - start) >> PAGE_SHIFT, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

2
arch/x86/mm/gup.c
View file

@ -435,7 +435,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
ret = get_user_pages_unlocked(start,
(end - start) >> PAGE_SHIFT,
write, 0, pages);
pages, write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

4
drivers/media/pci/ivtv/ivtv-udma.c
View file

@ -124,8 +124,8 @@ int ivtv_udma_setup(struct ivtv *itv, unsigned long ivtv_dest_addr,
}
/* Get user pages for DMA Xfer */
err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count, 0,
1, dma->map);
err = get_user_pages_unlocked(user_dma.uaddr, user_dma.page_count,
dma->map, FOLL_FORCE);
if (user_dma.page_count != err) {
IVTV_DEBUG_WARN("failed to map user pages, returned %d instead of %d\n",

5
drivers/media/pci/ivtv/ivtv-yuv.c
View file

@ -76,11 +76,12 @@ static int ivtv_yuv_prep_user_dma(struct ivtv *itv, struct ivtv_user_dma *dma,
/* Get user pages for DMA Xfer */
y_pages = get_user_pages_unlocked(y_dma.uaddr,
y_dma.page_count, 0, 1, &dma->map[0]);
y_dma.page_count, &dma->map[0], FOLL_FORCE);
uv_pages = 0; /* silence gcc. value is set and consumed only if: */
if (y_pages == y_dma.page_count) {
uv_pages = get_user_pages_unlocked(uv_dma.uaddr,
uv_dma.page_count, 0, 1, &dma->map[y_pages]);
uv_dma.page_count, &dma->map[y_pages],
FOLL_FORCE);
}
if (y_pages != y_dma.page_count || uv_pages != uv_dma.page_count) {

5
drivers/scsi/st.c
View file

@ -4922,9 +4922,8 @@ static int sgl_map_user_pages(struct st_buffer *STbp,
res = get_user_pages_unlocked(
uaddr,
nr_pages,
rw == READ,
0, /* don't force */
pages);
pages,
rw == READ ? FOLL_WRITE : 0); /* don't force */
/* Errors and no page mapped should return here */
if (res < nr_pages)

4
drivers/video/fbdev/pvr2fb.c
View file

@ -686,8 +686,8 @@ static ssize_t pvr2fb_write(struct fb_info *info, const char *buf,
if (!pages)
return -ENOMEM;
ret = get_user_pages_unlocked((unsigned long)buf, nr_pages, WRITE,
0, pages);
ret = get_user_pages_unlocked((unsigned long)buf, nr_pages, pages,
FOLL_WRITE);
if (ret < nr_pages) {
nr_pages = ret;

2
include/linux/mm.h
View file

@ -1287,7 +1287,7 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags);
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages);
struct page **pages, unsigned int gup_flags);
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);

14
mm/gup.c
View file

@ -907,17 +907,10 @@ EXPORT_SYMBOL(__get_user_pages_unlocked);
* "force" parameter).
*/
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages)
struct page **pages, unsigned int gup_flags)
{
unsigned int flags = FOLL_TOUCH;
if (write)
flags |= FOLL_WRITE;
if (force)
flags |= FOLL_FORCE;
return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
pages, flags);
pages, gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
@ -1535,7 +1528,8 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
start += nr << PAGE_SHIFT;
pages += nr;
ret = get_user_pages_unlocked(start, nr_pages - nr, write, 0, pages);
ret = get_user_pages_unlocked(start, nr_pages - nr, pages,
write ? FOLL_WRITE : 0);
/* Have to be a bit careful with return values */
if (nr > 0) {

11
mm/nommu.c
View file

@ -197,17 +197,10 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
EXPORT_SYMBOL(__get_user_pages_unlocked);
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
int write, int force, struct page **pages)
struct page **pages, unsigned int gup_flags)
{
unsigned int flags = 0;
if (write)
flags |= FOLL_WRITE;
if (force)
flags |= FOLL_FORCE;
return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
pages, flags);
pages, gup_flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);

3
mm/util.c
View file

@ -283,7 +283,8 @@ EXPORT_SYMBOL_GPL(__get_user_pages_fast);
int __weak get_user_pages_fast(unsigned long start,
int nr_pages, int write, struct page **pages)
{
return get_user_pages_unlocked(start, nr_pages, write, 0, pages);
return get_user_pages_unlocked(start, nr_pages, pages,
write ? FOLL_WRITE : 0);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast);

2
net/ceph/pagevec.c
View file

@ -26,7 +26,7 @@ struct page **ceph_get_direct_page_vector(const void __user *data,
while (got < num_pages) {
rc = get_user_pages_unlocked(
(unsigned long)data + ((unsigned long)got * PAGE_SIZE),
num_pages - got, write_page, 0, pages + got);
num_pages - got, pages + got, write_page ? FOLL_WRITE : 0);
if (rc < 0)
break;
BUG_ON(rc == 0);