From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Thu, 30 Oct 2025 01:20:44 +0000 (-0400)
Subject: mm/userfaultfd: Inline mfill_atomic into continue implementation
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=d20facf4ce16eabf35011f415ab5863255f23212;p=users%2Fjedix%2Flinux-maple.git

mm/userfaultfd: Inline mfill_atomic into continue implementation

continue 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/fs/userfaultfd.c b/fs/userfaultfd.c
index 1b7d6dae53be..972c6f75b550 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1754,7 +1754,7 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
 	struct uffdio_continue uffdio_continue;
 	struct uffdio_continue __user *user_uffdio_continue;
 	struct userfaultfd_wake_range range;
-	uffd_flags_t flags = 0;
+	bool wp = false;
 
 	user_uffdio_continue = (struct uffdio_continue __user *)arg;
 
@@ -1781,11 +1781,11 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
 				     UFFDIO_CONTINUE_MODE_WP))
 		goto out;
 	if (uffdio_continue.mode & UFFDIO_CONTINUE_MODE_WP)
-		flags |= MFILL_ATOMIC_WP;
+		wp = true;
 
 	if (mmget_not_zero(ctx->mm)) {
 		ret = mfill_atomic_continue(ctx, uffdio_continue.range.start,
-					    uffdio_continue.range.len, flags);
+					    uffdio_continue.range.len, wp);
 		mmput(ctx->mm);
 	} else {
 		return -ESRCH;
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index c3e765dadfdb..4154fad2af55 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -169,8 +169,8 @@ ssize_t mfill_atomic_copy(struct userfaultfd_ctx *ctx, unsigned long dst_start,
 		unsigned long src_start, unsigned long len, bool wp);
 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);
+ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx,
+		unsigned long dst_start, unsigned long len, bool wp);
 extern ssize_t mfill_atomic_poison(struct userfaultfd_ctx *ctx, unsigned long start,
 				   unsigned long len, uffd_flags_t flags);
 extern int mwriteprotect_range(struct userfaultfd_ctx *ctx, unsigned long start,
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 1d1b70f914d3..0b4df1488811 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -824,10 +824,13 @@ out:
 	return info.copied ? info.copied : err;
 }
 
-ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
-			      unsigned long len, uffd_flags_t flags)
+ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx,
+		unsigned long dst_start, unsigned long len, bool wp)
 {
 
+	ssize_t err;
+	struct uffd_info info = UFFD_STRUCT_INIT(dst_start, 0, len, ctx,
+						 wp);
 	/*
 	 * A caller might reasonably assume that UFFDIO_CONTINUE contains an
 	 * smp_wmb() to ensure that any writes to the about-to-be-mapped page by
@@ -835,9 +838,19 @@ ssize_t mfill_atomic_continue(struct userfaultfd_ctx *ctx, unsigned long start,
 	 * subsequent loads from the page through the newly mapped address range.
 	 */
 	smp_wmb();
+	mfill_atomic_validate(&info);
+	err = mfill_setup(&info);
+	if (err)
+		goto out;
 
-	return mfill_atomic(ctx, start, 0, len,
-			    uffd_flags_set_mode(flags, MFILL_ATOMIC_CONTINUE));
+	info.op = info.uffd_ops->cont;
+	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_poison(struct userfaultfd_ctx *ctx, unsigned long start,