From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Wed, 29 Oct 2025 22:59:13 +0000 (-0400)
Subject: mm/userfaultfd: Inline mfill_atomic into zeropage implementation
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=fe000cef68d4a8fc160910f8a569efd22e4a3187;p=users%2Fjedix%2Flinux-maple.git

mm/userfaultfd: Inline mfill_atomic into zeropage implementation

zeropage can use the normal mfill_atomic() loop, but inlining means that
the uffd_ops->op setup can be removed.

Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
---

diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 34539a142d38..c3e765dadfdb 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -167,9 +167,8 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd, struct vm_area_struct *dst_vma,
 
 ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
 		unsigned long src_start, unsigned long len, bool wp);
-extern ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
-				     unsigned long dst_start,
-				     unsigned long len);
+ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
+		unsigned long dst_start, unsigned long len);
 extern ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long dst_start,
 				     unsigned long len, uffd_flags_t flags);
 extern ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index e9b6e3e1882a..1d1b70f914d3 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -688,8 +688,12 @@ out_unlock:
 
 static __always_inline ssize_t mfill_loop(struct uffd_info *info)
 {
-	ssize_t err = 0;
+	ssize_t err = -EINVAL;
+
+	if (!info->op)
+		goto out_unlock;
 
+	err = 0;
 	while (!err && (info->src_addr < info->src_last)) {
 		VM_WARN_ON_ONCE(info->dst_addr >= info->dst_last);
 		err = info->op(info);
@@ -701,6 +705,7 @@ static __always_inline ssize_t mfill_loop(struct uffd_info *info)
 		}
 	}
 
+out_unlock:
 	uffd_ctx_unlock(info);
 	return err;
 }
@@ -798,11 +803,25 @@ out:
 }
 
 ssize_t mfill_atomic_zeropage(struct userfaultfd_ctx *ctx,
-			      unsigned long start,
-			      unsigned long len)
+		unsigned long dst_start, unsigned long len)
 {
-	return mfill_atomic(ctx, start, 0, len,
-			    uffd_flags_set_mode(0, MFILL_ATOMIC_ZEROPAGE));
+	ssize_t err;
+	struct uffd_info info = UFFD_STRUCT_INIT(dst_start, 0, len, ctx,
+						 false);
+
+	mfill_atomic_validate(&info);
+	err = mfill_setup(&info);
+	if (err)
+		goto out;
+
+	info.op = info.uffd_ops->zeropage;
+	err = mfill_loop(&info);
+
+out:
+	VM_WARN_ON_ONCE(info.copied < 0);
+	VM_WARN_ON_ONCE(err > 0);
+	VM_WARN_ON_ONCE(!info.copied && !err);
+	return info.copied ? info.copied : err;
 }
 
 ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,