use simple_read_from_buffer() in fs/

Cleanup using simple_read_from_buffer() in binfmt_misc, configfs, and sysfs.

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 5 insertions, 74 deletions

diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c
index 18657f001b43..72d0b412c376 100644
--- a/fs/binfmt_misc.c
+++ b/fs/binfmt_misc.c
@@ -675,19 +675,8 @@ static ssize_t
 bm_status_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
 {
         char *s = enabled ? "enabled" : "disabled";
-        int len = strlen(s);
-        loff_t pos = *ppos;
 
-        if (pos < 0)
-                return -EINVAL;
-        if (pos >= len)
-                return 0;
-        if (len < pos + nbytes)
-                nbytes = len - pos;
-        if (copy_to_user(buf, s + pos, nbytes))
-                return -EFAULT;
-        *ppos = pos + nbytes;
-        return nbytes;
+        return simple_read_from_buffer(buf, nbytes, ppos, s, strlen(s));
 }
 
 static ssize_t bm_status_write(struct file * file, const char __user * buffer,
diff --git a/fs/configfs/file.c b/fs/configfs/file.c
index d98be5e01328..3527c7c6def8 100644
--- a/fs/configfs/file.c
+++ b/fs/configfs/file.c
@@ -77,36 +77,6 @@ static int fill_read_buffer(struct dentry * dentry, struct configfs_buffer * buf
         return ret;
 }
 
-
-/**
- *      flush_read_buffer - push buffer to userspace.
- *      @buffer:        data buffer for file.
- *      @userbuf:       user-passed buffer.
- *      @count:         number of bytes requested.
- *      @ppos:          file position.
- *
- *      Copy the buffer we filled in fill_read_buffer() to userspace.
- *      This is done at the reader's leisure, copying and advancing
- *      the amount they specify each time.
- *      This may be called continuously until the buffer is empty.
- */
-static int flush_read_buffer(struct configfs_buffer * buffer, char __user * buf,
-                             size_t count, loff_t * ppos)
-{
-        int error;
-
-        if (*ppos > buffer->count)
-                return 0;
-
-        if (count > (buffer->count - *ppos))
-                count = buffer->count - *ppos;
-
-        error = copy_to_user(buf,buffer->page + *ppos,count);
-        if (!error)
-                *ppos += count;
-        return error ? -EFAULT : count;
-}
-
 /**
  *      configfs_read_file - read an attribute.
  *      @file:  file pointer.
@@ -139,7 +109,8 @@ configfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *pp
         }
         pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
                  __FUNCTION__, count, *ppos, buffer->page);
-        retval = flush_read_buffer(buffer,buf,count,ppos);
+        retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
+                                         buffer->count);
 out:
         up(&buffer->sem);
         return retval;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 0e637adc2b87..b502c7197ec0 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -111,36 +111,6 @@ static int fill_read_buffer(struct dentry * dentry, struct sysfs_buffer * buffer
         return ret;
 }
 
-
-/**
- *      flush_read_buffer - push buffer to userspace.
- *      @buffer:        data buffer for file.
- *      @buf:           user-passed buffer.
- *      @count:         number of bytes requested.
- *      @ppos:          file position.
- *
- *      Copy the buffer we filled in fill_read_buffer() to userspace.
- *      This is done at the reader's leisure, copying and advancing 
- *      the amount they specify each time.
- *      This may be called continuously until the buffer is empty.
- */
-static int flush_read_buffer(struct sysfs_buffer * buffer, char __user * buf,
-                             size_t count, loff_t * ppos)
-{
-        int error;
-
-        if (*ppos > buffer->count)
-                return 0;
-
-        if (count > (buffer->count - *ppos))
-                count = buffer->count - *ppos;
-
-        error = copy_to_user(buf,buffer->page + *ppos,count);
-        if (!error)
-                *ppos += count;
-        return error ? -EFAULT : count;
-}
-
 /**
  *      sysfs_read_file - read an attribute. 
  *      @file:  file pointer.
@@ -177,7 +147,8 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
         }
         pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
                  __FUNCTION__, count, *ppos, buffer->page);
-        retval = flush_read_buffer(buffer,buf,count,ppos);
+        retval = simple_read_from_buffer(buf, count, ppos, buffer->page,
+                                         buffer->count);
 out:
         up(&buffer->sem);
         return retval;