blktrace: remove sysfs_blk_trace_enable_show/store()

sysfs_blk_trace_enable_show()/store() share most of code with
sysfs_blk_trace_attr_show()/store().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <49C30EA3.1060004@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 14986afdbc1c92c87e680ab411eb6d44295287eb..dfee6f915179498494c5ac4107aae5a480a43653 100644 (file)
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -1284,72 +1284,6 @@ static int blk_trace_setup_queue(struct request_queue *q, dev_t dev)
  * sysfs interface to enable and configure tracing
  */
 
-static ssize_t sysfs_blk_trace_enable_show(struct device *dev,
-                                          struct device_attribute *attr,
-                                          char *buf)
-{
-       struct hd_struct *p = dev_to_part(dev);
-       struct block_device *bdev;
-       ssize_t ret = -ENXIO;
-
-       lock_kernel();
-       bdev = bdget(part_devt(p));
-       if (bdev != NULL) {
-               struct request_queue *q = bdev_get_queue(bdev);
-
-               if (q != NULL) {
-                       mutex_lock(&bdev->bd_mutex);
-                       ret = sprintf(buf, "%u\n", !!q->blk_trace);
-                       mutex_unlock(&bdev->bd_mutex);
-               }
-
-               bdput(bdev);
-       }
-
-       unlock_kernel();
-       return ret;
-}
-
-static ssize_t sysfs_blk_trace_enable_store(struct device *dev,
-                                           struct device_attribute *attr,
-                                           const char *buf, size_t count)
-{
-       struct block_device *bdev;
-       struct request_queue *q;
-       struct hd_struct *p;
-       int value;
-       ssize_t ret = -ENXIO;
-
-       if (count == 0 || sscanf(buf, "%d", &value) != 1)
-               goto out;
-
-       lock_kernel();
-       p = dev_to_part(dev);
-       bdev = bdget(part_devt(p));
-       if (bdev == NULL)
-               goto out_unlock_kernel;
-
-       q = bdev_get_queue(bdev);
-       if (q == NULL)
-               goto out_bdput;
-
-       mutex_lock(&bdev->bd_mutex);
-       if (value)
-               ret = blk_trace_setup_queue(q, bdev->bd_dev);
-       else
-               ret = blk_trace_remove_queue(q);
-       mutex_unlock(&bdev->bd_mutex);
-
-       if (ret == 0)
-               ret = count;
-out_bdput:
-       bdput(bdev);
-out_unlock_kernel:
-       unlock_kernel();
-out:
-       return ret;
-}
-
 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
                                         struct device_attribute *attr,
                                         char *buf);
@@ -1361,8 +1295,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
                    sysfs_blk_trace_attr_show, \
                    sysfs_blk_trace_attr_store)
 
-static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
-                  sysfs_blk_trace_enable_show, sysfs_blk_trace_enable_store);
+static BLK_TRACE_DEVICE_ATTR(enable);
 static BLK_TRACE_DEVICE_ATTR(act_mask);
 static BLK_TRACE_DEVICE_ATTR(pid);
 static BLK_TRACE_DEVICE_ATTR(start_lba);
@@ -1447,6 +1380,12 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
        if (q == NULL)
                goto out_bdput;
        mutex_lock(&bdev->bd_mutex);
+
+       if (attr == &dev_attr_enable) {
+               ret = sprintf(buf, "%u\n", !!q->blk_trace);
+               goto out_unlock_bdev;
+       }
+
        if (q->blk_trace == NULL)
                ret = sprintf(buf, "disabled\n");
        else if (attr == &dev_attr_act_mask)
@@ -1457,6 +1396,8 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
                ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
        else if (attr == &dev_attr_end_lba)
                ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
+
+out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
 out_bdput:
        bdput(bdev);
@@ -1499,6 +1440,15 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
                goto out_bdput;
 
        mutex_lock(&bdev->bd_mutex);
+
+       if (attr == &dev_attr_enable) {
+               if (value)
+                       ret = blk_trace_setup_queue(q, bdev->bd_dev);
+               else
+                       ret = blk_trace_remove_queue(q);
+               goto out_unlock_bdev;
+       }
+
        ret = 0;
        if (q->blk_trace == NULL)
                ret = blk_trace_setup_queue(q, bdev->bd_dev);
@@ -1512,13 +1462,15 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
                        q->blk_trace->start_lba = value;
                else if (attr == &dev_attr_end_lba)
                        q->blk_trace->end_lba = value;
-               ret = count;
        }
+
+out_unlock_bdev:
        mutex_unlock(&bdev->bd_mutex);
 out_bdput:
        bdput(bdev);
 out_unlock_kernel:
        unlock_kernel();
 out:
-       return ret;
+       return ret ? ret : count;
 }
+