mm: cleanup flags usage in faultin_page

Patch series "mm: some small page fault cleanups".

I was recently wreaking havoc in the page fault code and I noticed some
things that could be cleaned up.  We no longer modify the gup flags in
faultin_page, so we can clean up how we pass the flags in and remove the
extra variable in __get_user_pages.

This patch (of 2):

We're passing a pointer to the foll_flags for faultin_page, however we
never modify the flags in this call.  Change this to just take the flags
value instead.

Link: https://lkml.kernel.org/r/2df51a54c06bdf93e1cb09a19a9ef1df6557b59e.1721337845.git.josef@toxicpanda.com
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/gup.c b/mm/gup.c
index 54d0dc3831fbaaae1f8c12c02f3f91148ceca3e3..985d5141592ff06c7a9bce32b3fd9dfc502bc15c 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1153,19 +1153,19 @@ unmap:
  * to 0 and -EBUSY returned.
  */
 static int faultin_page(struct vm_area_struct *vma,
-               unsigned long address, unsigned int *flags, bool unshare,
+               unsigned long address, unsigned int flags, bool unshare,
                int *locked)
 {
        unsigned int fault_flags = 0;
        vm_fault_t ret;
 
-       if (*flags & FOLL_NOFAULT)
+       if (flags & FOLL_NOFAULT)
                return -EFAULT;
-       if (*flags & FOLL_WRITE)
+       if (flags & FOLL_WRITE)
                fault_flags |= FAULT_FLAG_WRITE;
-       if (*flags & FOLL_REMOTE)
+       if (flags & FOLL_REMOTE)
                fault_flags |= FAULT_FLAG_REMOTE;
-       if (*flags & FOLL_UNLOCKABLE) {
+       if (flags & FOLL_UNLOCKABLE) {
                fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
                /*
                 * FAULT_FLAG_INTERRUPTIBLE is opt-in. GUP callers must set
@@ -1173,12 +1173,12 @@ static int faultin_page(struct vm_area_struct *vma,
                 * That's because some callers may not be prepared to
                 * handle early exits caused by non-fatal signals.
                 */
-               if (*flags & FOLL_INTERRUPTIBLE)
+               if (flags & FOLL_INTERRUPTIBLE)
                        fault_flags |= FAULT_FLAG_INTERRUPTIBLE;
        }
-       if (*flags & FOLL_NOWAIT)
+       if (flags & FOLL_NOWAIT)
                fault_flags |= FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT;
-       if (*flags & FOLL_TRIED) {
+       if (flags & FOLL_TRIED) {
                /*
                 * Note: FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_TRIED
                 * can co-exist
@@ -1212,7 +1212,7 @@ static int faultin_page(struct vm_area_struct *vma,
        }
 
        if (ret & VM_FAULT_ERROR) {
-               int err = vm_fault_to_errno(ret, *flags);
+               int err = vm_fault_to_errno(ret, flags);
 
                if (err)
                        return err;
@@ -1490,7 +1490,7 @@ retry:
 
                page = follow_page_mask(vma, start, foll_flags, &ctx);
                if (!page || PTR_ERR(page) == -EMLINK) {
-                       ret = faultin_page(vma, start, &foll_flags,
+                       ret = faultin_page(vma, start, foll_flags,
                                           PTR_ERR(page) == -EMLINK, locked);
                        switch (ret) {
                        case 0: