From: Jens Axboe <axboe@kernel.dk>
Date: Fri, 11 Oct 2024 19:19:25 +0000 (-0600)
Subject: blktrace: move user copies out of q->debugfs_mutex
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=refs%2Fheads%2Fbtrace-fault;p=linux-2.6-block.git

blktrace: move user copies out of q->debugfs_mutex

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 8fd292d34d89..cefcad120495 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -617,8 +617,8 @@ err:
 	return ret;
 }
 
-static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
-			     struct block_device *bdev, char __user *arg)
+int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
+		    struct block_device *bdev, char __user *arg)
 {
 	struct blk_user_trace_setup buts;
 	int ret;
@@ -627,28 +627,18 @@ static int __blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 	if (ret)
 		return -EFAULT;
 
+	mutex_lock(&q->debugfs_mutex);
 	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+	mutex_unlock(&q->debugfs_mutex);
 	if (ret)
 		return ret;
 
 	if (copy_to_user(arg, &buts, sizeof(buts))) {
-		__blk_trace_remove(q);
+		blk_trace_remove(q);
 		return -EFAULT;
 	}
-	return 0;
-}
 
-int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
-		    struct block_device *bdev,
-		    char __user *arg)
-{
-	int ret;
-
-	mutex_lock(&q->debugfs_mutex);
-	ret = __blk_trace_setup(q, name, dev, bdev, arg);
-	mutex_unlock(&q->debugfs_mutex);
-
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(blk_trace_setup);
 
@@ -673,12 +663,14 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
 		.pid = cbuts.pid,
 	};
 
+	mutex_lock(&q->debugfs_mutex);
 	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+	mutex_unlock(&q->debugfs_mutex);
 	if (ret)
 		return ret;
 
 	if (copy_to_user(arg, &buts.name, ARRAY_SIZE(buts.name))) {
-		__blk_trace_remove(q);
+		blk_trace_remove(q);
 		return -EFAULT;
 	}
 
@@ -732,12 +724,10 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 	int ret, start = 0;
 	char b[BDEVNAME_SIZE];
 
-	mutex_lock(&q->debugfs_mutex);
-
 	switch (cmd) {
 	case BLKTRACESETUP:
 		snprintf(b, sizeof(b), "%pg", bdev);
-		ret = __blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
+		ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 		break;
 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
 	case BLKTRACESETUP32:
@@ -749,17 +739,16 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 		start = 1;
 		fallthrough;
 	case BLKTRACESTOP:
-		ret = __blk_trace_startstop(q, start);
+		ret = blk_trace_startstop(q, start);
 		break;
 	case BLKTRACETEARDOWN:
-		ret = __blk_trace_remove(q);
+		ret = blk_trace_remove(q);
 		break;
 	default:
 		ret = -ENOTTY;
 		break;
 	}
 
-	mutex_unlock(&q->debugfs_mutex);
 	return ret;
 }