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| author | Lorenzo Stoakes <lstoakes@gmail.com> | 2016-10-13 01:20:20 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-19 08:31:25 -0700 |
| commit | f307ab6dcea03f9d8e4d70508fd7d1ca57cfa7f9 (patch) | |
| tree | 94a96ebae9957cf1252231a69f8904796aa2563e /mm | |
| parent | 6347e8d5bcce33fc36e651901efefbe2c93a43ef (diff) | |
| download | linux-f307ab6dcea03f9d8e4d70508fd7d1ca57cfa7f9.tar.bz2 | |
mm: replace access_process_vm() write parameter with gup_flags
This removes the 'write' argument from access_process_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: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memory.c | 8 | ||||
| -rw-r--r-- | mm/nommu.c | 6 | ||||
| -rw-r--r-- | mm/util.c | 5 |
3 files changed, 8 insertions, 11 deletions
diff --git a/mm/memory.c b/mm/memory.c index bac2d994850e..e18c57bdc75c 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3951,20 +3951,16 @@ int access_remote_vm(struct mm_struct *mm, unsigned long addr, * Do not walk the page table directly, use get_user_pages */ int access_process_vm(struct task_struct *tsk, unsigned long addr, - void *buf, int len, int write) + void *buf, int len, unsigned int gup_flags) { struct mm_struct *mm; int ret; - unsigned int flags = FOLL_FORCE; mm = get_task_mm(tsk); if (!mm) return 0; - if (write) - flags |= FOLL_WRITE; - - ret = __access_remote_vm(tsk, mm, addr, buf, len, flags); + ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); mmput(mm); diff --git a/mm/nommu.c b/mm/nommu.c index 93d5bb53fc63..db5fd1795298 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1861,7 +1861,8 @@ int access_remote_vm(struct mm_struct *mm, unsigned long addr, * Access another process' address space. * - source/target buffer must be kernel space */ -int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) +int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, + unsigned int gup_flags) { struct mm_struct *mm; @@ -1872,8 +1873,7 @@ 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 ? FOLL_WRITE : 0); + len = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags); mmput(mm); return len; diff --git a/mm/util.c b/mm/util.c index 4c685bde5ebc..952cbe7ad7b7 100644 --- a/mm/util.c +++ b/mm/util.c @@ -624,7 +624,7 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (len > buflen) len = buflen; - res = access_process_vm(task, arg_start, buffer, len, 0); + res = access_process_vm(task, arg_start, buffer, len, FOLL_FORCE); /* * If the nul at the end of args has been overwritten, then @@ -639,7 +639,8 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (len > buflen - res) len = buflen - res; res += access_process_vm(task, env_start, - buffer+res, len, 0); + buffer+res, len, + FOLL_FORCE); res = strnlen(buffer, res); } } |