[PATCH 16/16] blktrace: handle BLKTRACESETUP2 ioctl

[Johannes Thumshirn]

Handle the BLKTRACESETUP2 ioctl, requesting an extended version of the
blktrace protocol from user-space.

Signed-off-by: Johannes Thumshirn <johannes.thumsh...@wdc.com>
---
 block/ioctl.c           |  1 +
 kernel/trace/blktrace.c | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/block/ioctl.c b/block/ioctl.c
index f7b0006ca45d..e7f83a58c8ae 100644
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -691,6 +691,7 @@ long blkdev_ioctl(struct file *file, unsigned cmd, unsigned 
long arg)
 
        /* Incompatible alignment on i386 */
        case BLKTRACESETUP:
+       case BLKTRACESETUP2:
                return blk_trace_ioctl(bdev, cmd, argp);
        default:
                break;
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 3e7cd8f46c0c..e16a3dbed527 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -742,6 +742,38 @@ int blk_trace_setup(struct request_queue *q, char *name, 
dev_t dev,
 }
 EXPORT_SYMBOL_GPL(blk_trace_setup);
 
+static int blk_trace_setup2(struct request_queue *q, char *name, dev_t dev,
+                           struct block_device *bdev, char __user *arg)
+{
+       struct blk_user_trace_setup2 buts2;
+       struct blk_trace *bt;
+       int ret;
+
+       ret = copy_from_user(&buts2, arg, sizeof(buts2));
+       if (ret)
+               return -EFAULT;
+
+       if (!buts2.buf_size || !buts2.buf_nr)
+               return -EINVAL;
+
+       mutex_lock(&q->debugfs_mutex);
+       bt = blk_trace_setup_prepare(q, name, dev, buts2.buf_size, buts2.buf_nr,
+                                    bdev);
+       if (IS_ERR(bt)) {
+               mutex_unlock(&q->debugfs_mutex);
+               return PTR_ERR(bt);
+       }
+       bt->version = 2;
+       blk_trace_setup_finalize(q, name, bt, &buts2);
+       mutex_unlock(&q->debugfs_mutex);
+
+       if (copy_to_user(arg, &buts2, sizeof(buts2))) {
+               blk_trace_remove(q);
+               return -EFAULT;
+       }
+       return 0;
+}
+
 #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,
@@ -833,6 +865,10 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned 
cmd, char __user *arg)
        char b[BDEVNAME_SIZE];
 
        switch (cmd) {
+       case BLKTRACESETUP2:
+               snprintf(b, sizeof(b), "%pg", bdev);
+               ret = blk_trace_setup2(q, b, bdev->bd_dev, bdev, arg);
+               break;
        case BLKTRACESETUP:
                snprintf(b, sizeof(b), "%pg", bdev);
                ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
-- 
2.51.0