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-rw-r--r--mm/gup.c44
1 files changed, 21 insertions, 23 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 5168665da584..7e7f0054d628 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -846,12 +846,12 @@ unmap:
}
/*
- * mmap_sem must be held on entry. If @nonblocking != NULL and
- * *@flags does not include FOLL_NOWAIT, the mmap_sem may be released.
- * If it is, *@nonblocking will be set to 0 and -EBUSY returned.
+ * mmap_sem must be held on entry. If @locked != NULL and *@flags
+ * does not include FOLL_NOWAIT, the mmap_sem may be released. If it
+ * is, *@locked will be set to 0 and -EBUSY returned.
*/
static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
- unsigned long address, unsigned int *flags, int *nonblocking)
+ unsigned long address, unsigned int *flags, int *locked)
{
unsigned int fault_flags = 0;
vm_fault_t ret;
@@ -863,7 +863,7 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
fault_flags |= FAULT_FLAG_WRITE;
if (*flags & FOLL_REMOTE)
fault_flags |= FAULT_FLAG_REMOTE;
- if (nonblocking)
+ if (locked)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (*flags & FOLL_NOWAIT)
fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
@@ -889,8 +889,8 @@ static int faultin_page(struct task_struct *tsk, struct vm_area_struct *vma,
}
if (ret & VM_FAULT_RETRY) {
- if (nonblocking && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
- *nonblocking = 0;
+ if (locked && !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
+ *locked = 0;
return -EBUSY;
}
@@ -967,7 +967,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
* 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.
- * @nonblocking: whether waiting for disk IO or mmap_sem contention
+ * @locked: whether we're still with the mmap_sem held
*
* Returns either number of pages pinned (which may be less than the
* number requested), or an error. Details about the return value:
@@ -1002,13 +1002,11 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
* appropriate) must be called after the page is finished with, and
* before put_page is called.
*
- * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
- * or mmap_sem contention, and if waiting is needed to pin all pages,
- * *@nonblocking will be set to 0. Further, if @gup_flags does not
- * include FOLL_NOWAIT, the mmap_sem will be released via up_read() in
- * this case.
+ * If @locked != NULL, *@locked will be set to 0 when mmap_sem is
+ * released by an up_read(). That can happen if @gup_flags does not
+ * have FOLL_NOWAIT.
*
- * A caller using such a combination of @nonblocking and @gup_flags
+ * A caller using such a combination of @locked and @gup_flags
* must therefore hold the mmap_sem for reading only, and recognize
* when it's been released. Otherwise, it must be held for either
* reading or writing and will not be released.
@@ -1020,7 +1018,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
static long __get_user_pages(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, int *nonblocking)
+ struct vm_area_struct **vmas, int *locked)
{
long ret = 0, i = 0;
struct vm_area_struct *vma = NULL;
@@ -1066,7 +1064,7 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (is_vm_hugetlb_page(vma)) {
i = follow_hugetlb_page(mm, vma, pages, vmas,
&start, &nr_pages, i,
- gup_flags, nonblocking);
+ gup_flags, locked);
continue;
}
}
@@ -1084,7 +1082,7 @@ retry:
page = follow_page_mask(vma, start, foll_flags, &ctx);
if (!page) {
ret = faultin_page(tsk, vma, start, &foll_flags,
- nonblocking);
+ locked);
switch (ret) {
case 0:
goto retry;
@@ -1345,7 +1343,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
* @vma: target vma
* @start: start address
* @end: end address
- * @nonblocking:
+ * @locked: whether the mmap_sem is still held
*
* This takes care of mlocking the pages too if VM_LOCKED is set.
*
@@ -1353,14 +1351,14 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
*
* vma->vm_mm->mmap_sem must be held.
*
- * If @nonblocking is NULL, it may be held for read or write and will
+ * If @locked is NULL, it may be held for read or write and will
* be unperturbed.
*
- * If @nonblocking is non-NULL, it must held for read only and may be
- * released. If it's released, *@nonblocking will be set to 0.
+ * If @locked is non-NULL, it must held for read only and may be
+ * released. If it's released, *@locked will be set to 0.
*/
long populate_vma_page_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end, int *nonblocking)
+ unsigned long start, unsigned long end, int *locked)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long nr_pages = (end - start) / PAGE_SIZE;
@@ -1395,7 +1393,7 @@ long populate_vma_page_range(struct vm_area_struct *vma,
* not result in a stack expansion that recurses back here.
*/
return __get_user_pages(current, mm, start, nr_pages, gup_flags,
- NULL, NULL, nonblocking);
+ NULL, NULL, locked);
}
/*