Re: Q: a_ops->readpage() && struct file

On 06/13, Peter Zijlstra wrote:

On Mon, 2012-06-11 at 21:09 +0200, Oleg Nesterov wrote:

quoted

Stupid question. I'm afraid the answer is "no" but I'll ask anyway.
Is it safe to pass filp == NULL to mapping->readpage()? In fact
I do not understand why it needs "struct file*" and I do not see
any example of actual usage.

Looking at afs_readpage it looks like its OK to pass in NULL. Same for
nfs_readpage. They use the file, if provided, to avoid some lookups, but
seem to deal with not having it.

Yes, and reiser4 does the same.

This answer by example is of course not authorative nor complete.

Yes... perhaps we should simply change this code to use NULL and
collect the bug-reports ;)

Oleg.