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authorLorenzo Stoakes <lstoakes@gmail.com>2016-10-13 01:20:12 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-18 14:13:37 -0700
commitd4944b0ecec0af882483fe44b66729316e575208 (patch)
tree0c16d81fa34c04dc63e4457e363edcfc21bfdfac /mm
parent859110d7497cdd0e6b21010d6f777049d676382c (diff)
mm: remove write/force parameters from __get_user_pages_unlocked()
This removes the redundant 'write' and 'force' parameters from __get_user_pages_unlocked() 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> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/gup.c17
-rw-r--r--mm/nommu.c12
-rw-r--r--mm/process_vm_access.c7
3 files changed, 23 insertions, 13 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 720eb9385204..e997f545b059 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -875,17 +875,11 @@ EXPORT_SYMBOL(get_user_pages_locked);
*/
__always_inline 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,
- unsigned int gup_flags)
+ struct page **pages, unsigned int gup_flags)
{
long ret;
int locked = 1;
- if (write)
- gup_flags |= FOLL_WRITE;
- if (force)
- gup_flags |= FOLL_FORCE;
-
down_read(&mm->mmap_sem);
ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL,
&locked, false, gup_flags);
@@ -915,8 +909,15 @@ 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)
{
+ 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,
- write, force, pages, FOLL_TOUCH);
+ pages, flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
diff --git a/mm/nommu.c b/mm/nommu.c
index 95daf81a4855..925dcc1fa2f3 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -185,8 +185,7 @@ EXPORT_SYMBOL(get_user_pages_locked);
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,
- unsigned int gup_flags)
+ struct page **pages, unsigned int gup_flags)
{
long ret;
down_read(&mm->mmap_sem);
@@ -200,8 +199,15 @@ 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)
{
+ 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,
- write, force, pages, 0);
+ pages, flags);
}
EXPORT_SYMBOL(get_user_pages_unlocked);
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 07514d41ebcc..be8dc8d1edb9 100644
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -88,12 +88,16 @@ static int process_vm_rw_single_vec(unsigned long addr,
ssize_t rc = 0;
unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
/ sizeof(struct pages *);
+ unsigned int flags = FOLL_REMOTE;
/* 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;
@@ -104,8 +108,7 @@ static int process_vm_rw_single_vec(unsigned long addr,
* current/current->mm
*/
pages = __get_user_pages_unlocked(task, mm, pa, pages,
- vm_write, 0, process_pages,
- FOLL_REMOTE);
+ process_pages, flags);
if (pages <= 0)
return -EFAULT;