[PATCH 3/6] block: push BKL into blktrace ioctls

[Arnd Bergmann]

The blktrace driver currently needs the BKL, but
we should not need to take that in the block layer,
so just push it down into the driver itself.

Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
 block/compat_ioctl.c         |   56 ------------------------------------------
 block/ioctl.c                |    2 -
 include/linux/blktrace_api.h |   12 +++++++++
 kernel/trace/blktrace.c      |   43 ++++++++++++++++++++++++++++++++
 4 files changed, 55 insertions(+), 58 deletions(-)

diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index f26051f..d530856 100644
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -535,56 +535,6 @@ out:
 	return err;
 }
 
-struct compat_blk_user_trace_setup {
-	char name[32];
-	u16 act_mask;
-	u32 buf_size;
-	u32 buf_nr;
-	compat_u64 start_lba;
-	compat_u64 end_lba;
-	u32 pid;
-};
-#define BLKTRACESETUP32 _IOWR(0x12, 115, struct compat_blk_user_trace_setup)
-
-static int compat_blk_trace_setup(struct block_device *bdev, char __user *arg)
-{
-	struct blk_user_trace_setup buts;
-	struct compat_blk_user_trace_setup cbuts;
-	struct request_queue *q;
-	char b[BDEVNAME_SIZE];
-	int ret;
-
-	q = bdev_get_queue(bdev);
-	if (!q)
-		return -ENXIO;
-
-	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
-		return -EFAULT;
-
-	bdevname(bdev, b);
-
-	buts = (struct blk_user_trace_setup) {
-		.act_mask = cbuts.act_mask,
-		.buf_size = cbuts.buf_size,
-		.buf_nr = cbuts.buf_nr,
-		.start_lba = cbuts.start_lba,
-		.end_lba = cbuts.end_lba,
-		.pid = cbuts.pid,
-	};
-	memcpy(&buts.name, &cbuts.name, 32);
-
-	mutex_lock(&bdev->bd_mutex);
-	ret = do_blk_trace_setup(q, b, bdev->bd_dev, bdev, &buts);
-	mutex_unlock(&bdev->bd_mutex);
-	if (ret)
-		return ret;
-
-	if (copy_to_user(arg, &buts.name, 32))
-		return -EFAULT;
-
-	return 0;
-}
-
 static int compat_blkdev_driver_ioctl(struct block_device *bdev, fmode_t mode,
 			unsigned cmd, unsigned long arg)
 {
@@ -802,16 +752,10 @@ long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg)
 		return compat_put_u64(arg, bdev->bd_inode->i_size);
 
 	case BLKTRACESETUP32:
-		lock_kernel();
-		ret = compat_blk_trace_setup(bdev, compat_ptr(arg));
-		unlock_kernel();
-		return ret;
 	case BLKTRACESTART: /* compatible */
 	case BLKTRACESTOP:  /* compatible */
 	case BLKTRACETEARDOWN: /* compatible */
-		lock_kernel();
 		ret = blk_trace_ioctl(bdev, cmd, compat_ptr(arg));
-		unlock_kernel();
 		return ret;
 	default:
 		if (disk->fops->compat_ioctl)
diff --git a/block/ioctl.c b/block/ioctl.c
index 1cfa8d4..9d91e83 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -320,9 +320,7 @@ int blkdev_ioctl(struct block_device *bdev, fmode_t mode, unsigned cmd,
 	case BLKTRACESTOP:
 	case BLKTRACESETUP:
 	case BLKTRACETEARDOWN:
-		lock_kernel();
 		ret = blk_trace_ioctl(bdev, cmd, (char __user *) arg);
-		unlock_kernel();
 		break;
 	default:
 		ret = __blkdev_driver_ioctl(bdev, mode, cmd, arg);
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 416bf62..d4dd16c 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -5,6 +5,7 @@
 #ifdef __KERNEL__
 #include <linux/blkdev.h>
 #include <linux/relay.h>
+#include <linux/compat.h>
 #endif
 
 /*
@@ -203,6 +204,17 @@ extern int blk_trace_init_sysfs(struct device *dev);
 
 extern struct attribute_group blk_trace_attr_group;
 
+struct compat_blk_user_trace_setup {
+	char name[32];
+	u16 act_mask;
+	u32 buf_size;
+	u32 buf_nr;
+	compat_u64 start_lba;
+	compat_u64 end_lba;
+	u32 pid;
+};
+#define BLKTRACESETUP32 _IOWR(0x12, 115, struct compat_blk_user_trace_setup)
+
 #else /* !CONFIG_BLK_DEV_IO_TRACE */
 # define blk_trace_ioctl(bdev, cmd, arg)		(-ENOTTY)
 # define blk_trace_shutdown(q)				do { } while (0)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 638711c..ef4a294 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -549,6 +549,41 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
 }
 EXPORT_SYMBOL_GPL(blk_trace_setup);
 
+#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
+static int compat_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;
+	struct compat_blk_user_trace_setup cbuts;
+	int ret;
+
+	if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
+		return -EFAULT;
+
+	buts = (struct blk_user_trace_setup) {
+		.act_mask = cbuts.act_mask,
+		.buf_size = cbuts.buf_size,
+		.buf_nr = cbuts.buf_nr,
+		.start_lba = cbuts.start_lba,
+		.end_lba = cbuts.end_lba,
+		.pid = cbuts.pid,
+	};
+	memcpy(&buts.name, &cbuts.name, 32);
+
+	ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(arg, &buts.name, 32)) {
+		blk_trace_remove(q);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+#endif
+
 int blk_trace_startstop(struct request_queue *q, int start)
 {
 	int ret;
@@ -601,6 +636,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 	if (!q)
 		return -ENXIO;
 
+	lock_kernel();
 	mutex_lock(&bdev->bd_mutex);
 
 	switch (cmd) {
@@ -608,6 +644,12 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 		bdevname(bdev, b);
 		ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
 		break;
+#if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
+	case BLKTRACESETUP32:
+		bdevname(bdev, b);
+		ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
+		break;
+#endif
 	case BLKTRACESTART:
 		start = 1;
 	case BLKTRACESTOP:
@@ -622,6 +664,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
 	}
 
 	mutex_unlock(&bdev->bd_mutex);
+	unlock_kernel();
 	return ret;
 }
 
-- 
1.7.1

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