linux-kernel - [PATCH 3/5] uaccess.h: Use with() and and_with() in __scoped_user

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Message-Id: <20251220215608.434614-4-david.laight.linux@gmail.com>
Date: Sat, 20 Dec 2025 21:56:06 +0000
From: david.laight.linux@...il.com
To: Thomas Gleixner <tglx@...utronix.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	Kees Cook <kees@...nel.org>,
	linux-kernel@...r.kernel.org,
	akpm@...ux-foundation.org,
	Al Viro <viro@...iv.linux.org.uk>
Cc: David Laight <david.laight.linux@...il.com>
Subject: [PATCH 3/5] uaccess.h: Use with() and and_with() in __scoped_user_access()

From: David Laight <david.laight.linux@...il.com>

Wrappers for autoterminating nested for() loops have been added to
compiler.h, use them to hide the gory details.

Signed-off-by: David Laight <david.laight.linux@...il.com>
---
 include/linux/uaccess.h | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h
index c5d5f2d395bc..589cb2ef2e7b 100644
--- a/include/linux/uaccess.h
+++ b/include/linux/uaccess.h
@@ -751,12 +751,10 @@ USER_ACCESS_GUARD(rw, void)
  * Don't use directly. Use scoped_masked_user_$MODE_access() instead.
  */
 #define __scoped_user_access(mode, uptr, size, elbl)					\
-for (bool done = false; !done; done = true)						\
-	for (typeof(uptr) _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl); \
-	     !done; done = true)							\
-		for (CLASS(user_##mode##_access, scope)(_tmpptr); !done; done = true)	\
-			/* Force modified pointer usage within the scope */		\
-			for (const typeof(uptr) uptr = _tmpptr; !done; done = true)
+	with (typeof(uptr) _tmpptr = __scoped_user_access_begin(mode, uptr, size, elbl)) \
+		and_with (CLASS(user_##mode##_access, scope)(_tmpptr))			\
+		/* Force modified pointer usage within the scope */			\
+		and_with (const typeof(uptr) uptr = _tmpptr)
 
 /**
  * scoped_user_read_access_size - Start a scoped user read access with given size
-- 
2.39.5