random: drop weird m_time/a_time manipulation

No other driver does anything remotely like this that I know of except
for the tty drivers, and I can't see any reason for random/urandom to do
it. In fact, it's a (trivial, harmless) timing information leak. And
obviously, it generates power- and flash-cycle wasting I/O, especially
if combined with something like hwrngd. Also, it breaks ubifs's
expectations.

Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Matt Mackall 2010-01-29 21:50:36 +13:00 committed by Herbert Xu
parent 92dcffb916
commit a996996dd7

View File

@ -1051,12 +1051,6 @@ random_read(struct file *file, char __user *buf, size_t nbytes, loff_t *ppos)
/* like a named pipe */
}
/*
* If we gave the user some bytes, update the access time.
*/
if (count)
file_accessed(file);
return (count ? count : retval);
}
@ -1116,8 +1110,6 @@ static ssize_t random_write(struct file *file, const char __user *buffer,
if (ret)
return ret;
inode->i_mtime = current_fs_time(inode->i_sb);
mark_inode_dirty(inode);
return (ssize_t)count;
}