block: push BKL into blktrace ioctls

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.

It is quite likely that the BKL is not actually
required in blktrace code and could be removed
in a follow-on patch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 43 insertions, 0 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 3b4a695051b..82499a5bdcb 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -552,6 +552,41 @@ 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;
@@ -604,6 +639,7 @@ 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) {
@@ -611,6 +647,12 @@ 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:
@@ -625,6 +667,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
         }
 
         mutex_unlock(&bdev->bd_mutex);
+        unlock_kernel();
         return ret;
 }