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>

1 files changed, 22 insertions, 70 deletions

diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 14986afdbc1c..dfee6f915179 100644
--- 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;
 }
+