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authorLorenzo Stoakes <lstoakes@gmail.com>2016-10-13 01:20:18 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-19 08:12:13 -0700
commit442486ec1096781c50227b73f721a63974b0fdda (patch)
tree3ceb6dcdc8cfdf930f924f6bed75b329c753b61b /mm/nommu.c
parent9beae1ea89305a9667ceaab6d0bf46a045ad71e7 (diff)
downloadlwn-442486ec1096781c50227b73f721a63974b0fdda.tar.gz
lwn-442486ec1096781c50227b73f721a63974b0fdda.zip
mm: replace __access_remote_vm() write parameter with gup_flags
This removes the 'write' argument from __access_remote_vm() and replaces it with 'gup_flags' as use of this function previously silently implied FOLL_FORCE, whereas after this patch callers explicitly pass this flag. We make this explicit as use of FOLL_FORCE can result in surprising behaviour (and hence bugs) within the mm subsystem. Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
-rw-r--r--mm/nommu.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index 70cb844dfd95..bde7df35118b 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1809,9 +1809,10 @@ void filemap_map_pages(struct fault_env *fe,
EXPORT_SYMBOL(filemap_map_pages);
static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
- unsigned long addr, void *buf, int len, int write)
+ unsigned long addr, void *buf, int len, unsigned int gup_flags)
{
struct vm_area_struct *vma;
+ int write = gup_flags & FOLL_WRITE;
down_read(&mm->mmap_sem);
@@ -1853,7 +1854,8 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
void *buf, int len, int write)
{
- return __access_remote_vm(NULL, mm, addr, buf, len, write);
+ return __access_remote_vm(NULL, mm, addr, buf, len,
+ write ? FOLL_WRITE : 0);
}
/*
@@ -1871,7 +1873,8 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in
if (!mm)
return 0;
- len = __access_remote_vm(tsk, mm, addr, buf, len, write);
+ len = __access_remote_vm(tsk, mm, addr, buf, len,
+ write ? FOLL_WRITE : 0);
mmput(mm);
return len;