On Sun, Nov 03, 2019 at 01:18:03PM -0800, John Hubbard wrote:
Convert process_vm_access to use the new pin_user_pages_remote() call, which sets FOLL_PIN. Setting FOLL_PIN is now required for code that requires tracking of pinned pages.
Also, release the pages via put_user_page*().
Also, rename "pages" to "pinned_pages", as this makes for easier reading of process_vm_rw_single_vec().
Reviewed-by: Ira Weiny ira.weiny@intel.com Signed-off-by: John Hubbard jhubbard@nvidia.com
Reviewed-by: Jérôme Glisse jglisse@redhat.com
mm/process_vm_access.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c index 357aa7bef6c0..fd20ab675b85 100644 --- a/mm/process_vm_access.c +++ b/mm/process_vm_access.c @@ -42,12 +42,11 @@ static int process_vm_rw_pages(struct page **pages, if (copy > len) copy = len;
if (vm_write) {
if (vm_write) copied = copy_page_from_iter(page, offset, copy, iter);
set_page_dirty_lock(page);
} else {
else copied = copy_page_to_iter(page, offset, copy, iter);
}
- len -= copied; if (copied < copy && iov_iter_count(iter)) return -EFAULT;
@@ -96,7 +95,7 @@ static int process_vm_rw_single_vec(unsigned long addr, flags |= FOLL_WRITE; while (!rc && nr_pages && iov_iter_count(iter)) {
int pages = min(nr_pages, max_pages_per_loop);
int locked = 1; size_t bytes;int pinned_pages = min(nr_pages, max_pages_per_loop);
@@ -106,14 +105,15 @@ static int process_vm_rw_single_vec(unsigned long addr, * current/current->mm */ down_read(&mm->mmap_sem);
pages = get_user_pages_remote(task, mm, pa, pages, flags,
process_pages, NULL, &locked);
pinned_pages = pin_user_pages_remote(task, mm, pa, pinned_pages,
flags, process_pages,
if (locked) up_read(&mm->mmap_sem);NULL, &locked);
if (pages <= 0)
if (pinned_pages <= 0) return -EFAULT;
bytes = pages * PAGE_SIZE - start_offset;
if (bytes > len) bytes = len;bytes = pinned_pages * PAGE_SIZE - start_offset;
@@ -122,10 +122,12 @@ static int process_vm_rw_single_vec(unsigned long addr, vm_write); len -= bytes; start_offset = 0;
nr_pages -= pages;
pa += pages * PAGE_SIZE;
while (pages)
put_page(process_pages[--pages]);
nr_pages -= pinned_pages;
pa += pinned_pages * PAGE_SIZE;
/* If vm_write is set, the pages need to be made dirty: */
put_user_pages_dirty_lock(process_pages, pinned_pages,
}vm_write);
return rc; -- 2.23.0