[PATCH RFC 11/17] userfaultfd: mfill_atomic() remove retry logic

[Mike Rapoport]

From: "Mike Rapoport (Microsoft)" <r...@kernel.org>

Since __mfill_atomic_pte() handles the retry for both anonymous and
shmem, there is no need to retry copying the date from the userspace in
the loop in mfill_atomic().

Drop the retry logic from mfill_atomic().

Signed-off-by: Mike Rapoport (Microsoft) <r...@kernel.org>
---
 mm/userfaultfd.c | 24 ------------------------
 1 file changed, 24 deletions(-)

diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 54aa195237ba..1bd7631463c6 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -29,7 +29,6 @@ struct mfill_state {
        struct vm_area_struct *vma;
        unsigned long src_addr;
        unsigned long dst_addr;
-       struct folio *folio;
        pmd_t *pmd;
 };
 
@@ -889,7 +888,6 @@ static __always_inline ssize_t mfill_atomic(struct 
userfaultfd_ctx *ctx,
        VM_WARN_ON_ONCE(src_start + len <= src_start);
        VM_WARN_ON_ONCE(dst_start + len <= dst_start);
 
-retry:
        err = mfill_get_vma(&state);
        if (err)
                goto out;
@@ -916,26 +914,6 @@ static __always_inline ssize_t mfill_atomic(struct 
userfaultfd_ctx *ctx,
                err = mfill_atomic_pte(&state);
                cond_resched();
 
-               if (unlikely(err == -ENOENT)) {
-                       void *kaddr;
-
-                       mfill_put_vma(&state);
-                       VM_WARN_ON_ONCE(!state.folio);
-
-                       kaddr = kmap_local_folio(state.folio, 0);
-                       err = copy_from_user(kaddr,
-                                            (const void __user 
*)state.src_addr,
-                                            PAGE_SIZE);
-                       kunmap_local(kaddr);
-                       if (unlikely(err)) {
-                               err = -EFAULT;
-                               goto out;
-                       }
-                       flush_dcache_folio(state.folio);
-                       goto retry;
-               } else
-                       VM_WARN_ON_ONCE(state.folio);
-
                if (!err) {
                        state.dst_addr += PAGE_SIZE;
                        state.src_addr += PAGE_SIZE;
@@ -951,8 +929,6 @@ static __always_inline ssize_t mfill_atomic(struct 
userfaultfd_ctx *ctx,
        if (state.vma)
                mfill_put_vma(&state);
 out:
-       if (state.folio)
-               folio_put(state.folio);
        VM_WARN_ON_ONCE(copied < 0);
        VM_WARN_ON_ONCE(err > 0);
        VM_WARN_ON_ONCE(!copied && !err);
-- 
2.51.0