[PATCH 4.4 76/88] mm: replace get_user_pages_unlocked() write/force parameters with gup_flags

Greg Kroah-Hartman
2018-12-14T12:18:32Z

From: Lorenzo Stoakes <lstoakes@gmail.com>

commit c164154f66f0c9b02673f07aa4f044f1d9c70274 upstream.

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>
[bwh: Backported to 4.4:
- Also update calls from process_vm_rw_single_vec() and async_pf_execute()
- Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/mips/mm/gup.c | 2 +-
arch/s390/mm/gup.c | 2 +-
arch/sh/mm/gup.c | 3 ++-
arch/sparc/mm/gup.c | 3 ++-
arch/x86/mm/gup.c | 2 +-
drivers/media/pci/ivtv/ivtv-udma.c | 3 ++-
drivers/media/pci/ivtv/ivtv-yuv.c | 8 ++++----
drivers/scsi/st.c | 5 ++---
drivers/video/fbdev/pvr2fb.c | 2 +-
include/linux/mm.h | 2 +-
mm/gup.c | 14 ++++----------
mm/nommu.c | 11 ++---------
mm/process_vm_access.c | 6 +++++-
mm/util.c | 2 +-
net/ceph/pagevec.c | 2 +-
virt/kvm/async_pf.c | 2 +-
16 files changed, 31 insertions(+), 38 deletions(-)

--- a/arch/mips/mm/gup.c
+++ b/arch/mips/mm/gup.c
@@ -303,7 +303,7 @@ slow_irqon:

ret = get_user_pages_unlocked(current, mm, 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) {
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -242,7 +242,7 @@ int get_user_pages_fast(unsigned long st
start += nr << PAGE_SHIFT;
pages += nr;
ret = get_user_pages_unlocked(current, mm, start,
- nr_pages - nr, write, 0, pages);
+ 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;
--- a/arch/sh/mm/gup.c
+++ b/arch/sh/mm/gup.c
@@ -258,7 +258,8 @@ slow_irqon:
pages += nr;

ret = get_user_pages_unlocked(current, mm, 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) {
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -250,7 +250,8 @@ slow:
pages += nr;

ret = get_user_pages_unlocked(current, mm, 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) {
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -388,7 +388,7 @@ slow_irqon:

ret = get_user_pages_unlocked(current, mm, 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) {
--- a/drivers/media/pci/ivtv/ivtv-udma.c
+++ b/drivers/media/pci/ivtv/ivtv-udma.c
@@ -125,7 +125,8 @@ int ivtv_udma_setup(struct ivtv *itv, un

/* Get user pages for DMA Xfer */
err = get_user_pages_unlocked(current, current->mm,
- user_dma.uaddr, user_dma.page_count, 0, 1, dma->map);
+ 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",
--- a/drivers/media/pci/ivtv/ivtv-yuv.c
+++ b/drivers/media/pci/ivtv/ivtv-yuv.c
@@ -76,13 +76,13 @@ static int ivtv_yuv_prep_user_dma(struct

/* Get user pages for DMA Xfer */
y_pages = get_user_pages_unlocked(current, current->mm,
- y_dma.uaddr, y_dma.page_count, 0, 1,
- &dma->map[0]);
+ y_dma.uaddr, 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(current, current->mm,
- uv_dma.uaddr, uv_dma.page_count, 0, 1,
- &dma->map[y_pages]);
+ uv_dma.uaddr, uv_dma.page_count,
+ &dma->map[y_pages], FOLL_FORCE);
}

if (y_pages != y_dma.page_count || uv_pages != uv_dma.page_count) {
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -4821,9 +4821,8 @@ static int sgl_map_user_pages(struct st_
current->mm,
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)
--- a/drivers/video/fbdev/pvr2fb.c
+++ b/drivers/video/fbdev/pvr2fb.c
@@ -687,7 +687,7 @@ static ssize_t pvr2fb_write(struct fb_in
return -ENOMEM;

ret = get_user_pages_unlocked(current, current->mm, (unsigned long)buf,
- nr_pages, WRITE, 0, pages);
+ nr_pages, pages, FOLL_WRITE);

if (ret < nr_pages) {
nr_pages = ret;
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1210,7 +1210,7 @@ long __get_user_pages_unlocked(struct ta
struct page **pages, unsigned int gup_flags);
long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
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);

--- a/mm/gup.c
+++ b/mm/gup.c
@@ -797,17 +797,10 @@ EXPORT_SYMBOL(__get_user_pages_unlocked)
*/
long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
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(tsk, mm, start, nr_pages,
- pages, flags);
+ pages, gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_unlocked);

@@ -1427,7 +1420,8 @@ int get_user_pages_fast(unsigned long st
pages += nr;

ret = get_user_pages_unlocked(current, mm, start,
- nr_pages - nr, write, 0, pages);
+ nr_pages - nr, pages,
+ write ? FOLL_WRITE : 0);

/* Have to be a bit careful with return values */
if (nr > 0) {
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -224,17 +224,10 @@ EXPORT_SYMBOL(__get_user_pages_unlocked)

long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
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(tsk, mm, start, nr_pages,
- pages, flags);
+ pages, gup_flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);

--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -88,19 +88,23 @@ static int process_vm_rw_single_vec(unsi
ssize_t rc = 0;
unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
/ sizeof(struct pages *);
+ unsigned int flags = 0;

/* Work out address and page range required */
if (len == 0)
return 0;
nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;

+ if (vm_write)
+ flags |= FOLL_WRITE;
+
while (!rc && nr_pages && iov_iter_count(iter)) {
int pages = min(nr_pages, max_pages_per_loop);
size_t bytes;

/* Get the pages we're interested in */
pages = get_user_pages_unlocked(task, mm, pa, pages,
- vm_write, 0, process_pages);
+ process_pages, flags);
if (pages <= 0)
return -EFAULT;

--- a/mm/util.c
+++ b/mm/util.c
@@ -278,7 +278,7 @@ int __weak get_user_pages_fast(unsigned
{
struct mm_struct *mm = current->mm;
return get_user_pages_unlocked(current, mm, start, nr_pages,
- write, 0, pages);
+ pages, write ? FOLL_WRITE : 0);
}
EXPORT_SYMBOL_GPL(get_user_pages_fast);

--- a/net/ceph/pagevec.c
+++ b/net/ceph/pagevec.c
@@ -26,7 +26,7 @@ struct page **ceph_get_direct_page_vecto
while (got < num_pages) {
rc = get_user_pages_unlocked(current, current->mm,
(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);
--- a/virt/kvm/async_pf.c
+++ b/virt/kvm/async_pf.c
@@ -80,7 +80,7 @@ static void async_pf_execute(struct work

might_sleep();

- get_user_pages_unlocked(NULL, mm, addr, 1, 1, 0, NULL);
+ get_user_pages_unlocked(NULL, mm, addr, 1, NULL, FOLL_WRITE);
kvm_async_page_present_sync(vcpu, apf);

spin_lock(&vcpu->async_pf.lock);