linux-kernel - [PATCH v1 08/14] futex: Add flags2 argument to futex

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Message-ID: <20230721105744.230243724@infradead.org>
Date:   Fri, 21 Jul 2023 12:22:45 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     tglx@...utronix.de, axboe@...nel.dk
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        mingo@...hat.com, dvhart@...radead.org, dave@...olabs.net,
        andrealmeid@...lia.com, Andrew Morton <akpm@...ux-foundation.org>,
        urezki@...il.com, hch@...radead.org, lstoakes@...il.com,
        Arnd Bergmann <arnd@...db.de>, linux-api@...r.kernel.org,
        linux-mm@...ck.org, linux-arch@...r.kernel.org,
        malteskarupke@....de
Subject: [PATCH v1 08/14] futex: Add flags2 argument to futex_requeue()

In order to support mixed size requeue, add a second flags argument to
the internal futex_requeue() function.

Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 kernel/futex/futex.h    |    5 +++--
 kernel/futex/requeue.c  |   12 +++++++-----
 kernel/futex/syscalls.c |    6 +++---
 3 files changed, 13 insertions(+), 10 deletions(-)

--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -318,8 +318,9 @@ extern int futex_wait_requeue_pi(u32 __u
 				 val, ktime_t *abs_time, u32 bitset, u32 __user
 				 *uaddr2);
 
-extern int futex_requeue(u32 __user *uaddr1, unsigned int flags,
-			 u32 __user *uaddr2, int nr_wake, int nr_requeue,
+extern int futex_requeue(u32 __user *uaddr1, unsigned int flags1,
+			 u32 __user *uaddr2, unsigned int flags2,
+			 int nr_wake, int nr_requeue,
 			 u32 *cmpval, int requeue_pi);
 
 extern int __futex_wait(u32 __user *uaddr, unsigned int flags, u32 val,
--- a/kernel/futex/requeue.c
+++ b/kernel/futex/requeue.c
@@ -346,8 +346,9 @@ futex_proxy_trylock_atomic(u32 __user *p
 /**
  * futex_requeue() - Requeue waiters from uaddr1 to uaddr2
  * @uaddr1:	source futex user address
- * @flags:	futex flags (FLAGS_SHARED, etc.)
+ * @flags1:	futex flags (FLAGS_SHARED, etc.)
  * @uaddr2:	target futex user address
+ * @flags2:	futex flags (FLAGS_SHARED, etc.)
  * @nr_wake:	number of waiters to wake (must be 1 for requeue_pi)
  * @nr_requeue:	number of waiters to requeue (0-INT_MAX)
  * @cmpval:	@uaddr1 expected value (or %NULL)
@@ -361,7 +362,8 @@ futex_proxy_trylock_atomic(u32 __user *p
  *  - >=0 - on success, the number of tasks requeued or woken;
  *  -  <0 - on error
  */
-int futex_requeue(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
+int futex_requeue(u32 __user *uaddr1, unsigned int flags1,
+		  u32 __user *uaddr2, unsigned int flags2,
 		  int nr_wake, int nr_requeue, u32 *cmpval, int requeue_pi)
 {
 	union futex_key key1 = FUTEX_KEY_INIT, key2 = FUTEX_KEY_INIT;
@@ -424,10 +426,10 @@ int futex_requeue(u32 __user *uaddr1, un
 	}
 
 retry:
-	ret = get_futex_key(uaddr1, flags, &key1, FUTEX_READ);
+	ret = get_futex_key(uaddr1, flags1, &key1, FUTEX_READ);
 	if (unlikely(ret != 0))
 		return ret;
-	ret = get_futex_key(uaddr2, flags, &key2,
+	ret = get_futex_key(uaddr2, flags2, &key2,
 			    requeue_pi ? FUTEX_WRITE : FUTEX_READ);
 	if (unlikely(ret != 0))
 		return ret;
@@ -459,7 +461,7 @@ int futex_requeue(u32 __user *uaddr1, un
 			if (ret)
 				return ret;
 
-			if (!(flags & FLAGS_SHARED))
+			if (!(flags1 & FLAGS_SHARED))
 				goto retry_private;
 
 			goto retry;
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -106,9 +106,9 @@ long do_futex(u32 __user *uaddr, int op,
 	case FUTEX_WAKE_BITSET:
 		return futex_wake(uaddr, flags, val, val3);
 	case FUTEX_REQUEUE:
-		return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
+		return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, NULL, 0);
 	case FUTEX_CMP_REQUEUE:
-		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
+		return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, &val3, 0);
 	case FUTEX_WAKE_OP:
 		return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
 	case FUTEX_LOCK_PI:
@@ -125,7 +125,7 @@ long do_futex(u32 __user *uaddr, int op,
 		return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
 					     uaddr2);
 	case FUTEX_CMP_REQUEUE_PI:
-		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
+		return futex_requeue(uaddr, flags, uaddr2, flags, val, val2, &val3, 1);
 	}
 	return -ENOSYS;
 }