compat_ioctl: handle blk_trace ioctls

blk_trace_setup is broken on x86_64 compat systems,
this makes the code work correctly on all 64 bit architectures
in compat mode.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 34 insertions, 20 deletions

diff --git a/block/blktrace.c b/block/blktrace.c
index 20fa034..775471e 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -312,33 +312,26 @@ static struct rchan_callbacks blk_relay_callbacks = {
 /*
  * Setup everything required to start tracing
  */
-static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
-			   char __user *arg)
+int do_blk_trace_setup(struct request_queue *q, struct block_device *bdev,
+			struct blk_user_trace_setup *buts)
 {
-	struct blk_user_trace_setup buts;
 	struct blk_trace *old_bt, *bt = NULL;
 	struct dentry *dir = NULL;
 	char b[BDEVNAME_SIZE];
 	int ret, i;
 
-	if (copy_from_user(&buts, arg, sizeof(buts)))
-		return -EFAULT;
-
-	if (!buts.buf_size || !buts.buf_nr)
+	if (!buts->buf_size || !buts->buf_nr)
 		return -EINVAL;
 
-	strcpy(buts.name, bdevname(bdev, b));
+	strcpy(buts->name, bdevname(bdev, b));
 
 	/*
 	 * some device names have larger paths - convert the slashes
 	 * to underscores for this to work as expected
 	 */
-	for (i = 0; i < strlen(buts.name); i++)
-		if (buts.name[i] == '/')
-			buts.name[i] = '_';
-
-	if (copy_to_user(arg, &buts, sizeof(buts)))
-		return -EFAULT;
+	for (i = 0; i < strlen(buts->name); i++)
+		if (buts->name[i] == '/')
+			buts->name[i] = '_';
 
 	ret = -ENOMEM;
 	bt = kzalloc(sizeof(*bt), GFP_KERNEL);
@@ -350,7 +343,7 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
 		goto err;
 
 	ret = -ENOENT;
-	dir = blk_create_tree(buts.name);
+	dir = blk_create_tree(buts->name);
 	if (!dir)
 		goto err;
 
@@ -363,20 +356,21 @@ static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
 	if (!bt->dropped_file)
 		goto err;
 
-	bt->rchan = relay_open("trace", dir, buts.buf_size, buts.buf_nr, &blk_relay_callbacks, bt);
+	bt->rchan = relay_open("trace", dir, buts->buf_size,
+				buts->buf_nr, &blk_relay_callbacks, bt);
 	if (!bt->rchan)
 		goto err;
 
-	bt->act_mask = buts.act_mask;
+	bt->act_mask = buts->act_mask;
 	if (!bt->act_mask)
 		bt->act_mask = (u16) -1;
 
-	bt->start_lba = buts.start_lba;
-	bt->end_lba = buts.end_lba;
+	bt->start_lba = buts->start_lba;
+	bt->end_lba = buts->end_lba;
 	if (!bt->end_lba)
 		bt->end_lba = -1ULL;
 
-	bt->pid = buts.pid;
+	bt->pid = buts->pid;
 	bt->trace_state = Blktrace_setup;
 
 	ret = -EBUSY;
@@ -401,6 +395,26 @@ err:
 	return ret;
 }
 
+static int blk_trace_setup(struct request_queue *q, struct block_device *bdev,
+			   char __user *arg)
+{
+	struct blk_user_trace_setup buts;
+	int ret;
+
+	ret = copy_from_user(&buts, arg, sizeof(buts));
+	if (ret)
+		return -EFAULT;
+
+	ret = do_blk_trace_setup(q, bdev, &buts);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(arg, &buts, sizeof(buts)))
+		return -EFAULT;
+
+	return 0;
+}
+
 static int blk_trace_startstop(struct request_queue *q, int start)
 {
 	struct blk_trace *bt;