path: root/mm
diff options
authorLorenzo Stoakes <>2016-12-14 15:06:52 -0800
committerLinus Torvalds <>2016-12-14 16:04:08 -0800
commit5b56d49fc31dbb0487e14ead790fc81ca9fb2c99 (patch)
treee9170cf8e9e0c2820d97c9ed9a418189a1bdf9c3 /mm
parent370b262c896e5565b271a3ea3abee4d0914ba443 (diff)
mm: add locked parameter to get_user_pages_remote()
Patch series "mm: unexport __get_user_pages_unlocked()". This patch series continues the cleanup of get_user_pages*() functions taking advantage of the fact we can now pass gup_flags as we please. It firstly adds an additional 'locked' parameter to get_user_pages_remote() to allow for its callers to utilise VM_FAULT_RETRY functionality. This is necessary as the invocation of __get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of this and no other existing higher level function would allow it to do so. Secondly existing callers of __get_user_pages_unlocked() are replaced with the appropriate higher-level replacement - get_user_pages_unlocked() if the current task and memory descriptor are referenced, or get_user_pages_remote() if other task/memory descriptors are referenced (having acquiring mmap_sem.) This patch (of 2): Add a int *locked parameter to get_user_pages_remote() to allow VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked(). Taking into account the previous adjustments to get_user_pages*() functions allowing for the passing of gup_flags, we are now in a position where __get_user_pages_unlocked() need only be exported for his ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to subsequently unexport __get_user_pages_unlocked() as well as allowing for future flexibility in the use of get_user_pages_remote(). [ merge fix for get_user_pages_remote API change] Link: Link: Signed-off-by: Lorenzo Stoakes <> Acked-by: Michal Hocko <> Cc: Jan Kara <> Cc: Hugh Dickins <> Cc: Dave Hansen <> Cc: Rik van Riel <> Cc: Mel Gorman <> Cc: Paolo Bonzini <> Cc: Radim Krcmar <> Signed-off-by: Stephen Rothwell <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'mm')
2 files changed, 9 insertions, 5 deletions
diff --git a/mm/gup.c b/mm/gup.c
index e50178c58b97..b64c907aa4f0 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -917,6 +917,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
* only intends to ensure the pages are faulted in.
* @vmas: array of pointers to vmas corresponding to each page.
* Or NULL if the caller does not require them.
+ * @locked: pointer to lock flag indicating whether lock is held and
+ * subsequently whether VM_FAULT_RETRY functionality can be
+ * utilised. Lock must initially be held.
* Returns number of pages pinned. This may be fewer than the number
* requested. If nr_pages is 0 or negative, returns 0. If no pages
@@ -960,10 +963,10 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
+ struct vm_area_struct **vmas, int *locked)
return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas,
- NULL, false,
+ locked, true,
gup_flags | FOLL_TOUCH | FOLL_REMOTE);
@@ -971,8 +974,9 @@ EXPORT_SYMBOL(get_user_pages_remote);
* This is the same as get_user_pages_remote(), just with a
* less-flexible calling convention where we assume that the task
- * and mm being operated on are the current task's. We also
- * obviously don't pass FOLL_REMOTE in here.
+ * and mm being operated on are the current task's and don't allow
+ * passing of a locked parameter. We also obviously don't pass
+ * FOLL_REMOTE in here.
long get_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
diff --git a/mm/memory.c b/mm/memory.c
index c264f7cd3e47..3a6a1239c42b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3919,7 +3919,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
struct page *page = NULL;
ret = get_user_pages_remote(tsk, mm, addr, 1,
- gup_flags, &page, &vma);
+ gup_flags, &page, &vma, NULL);
if (ret <= 0) {