From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
lkml <linux-kernel@vger.kernel.org>,
Jim Keniston <jkenisto@us.ibm.com>,
Paul Mackerras <paulus@samba.org>,
Al Viro <viro@ZenIV.linux.org.uk>,
antonb@thinktux.localdomain, Ingo Molnar <mingo@elte.hu>,
linuxppc-dev@lists.ozlabs.org,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Subject: Re: Q: a_ops->readpage() && struct file
Date: Wed, 13 Jun 2012 21:19:28 +0200 [thread overview]
Message-ID: <20120613191928.GB14246@redhat.com> (raw)
In-Reply-To: <1339581492.31548.133.camel@twins>
On 06/13, Peter Zijlstra wrote:
>
> On Mon, 2012-06-11 at 21:09 +0200, Oleg Nesterov wrote:
> > 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.
WARNING: multiple messages have this Message-ID (diff)
From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@ZenIV.linux.org.uk>,
linuxppc-dev@lists.ozlabs.org,
lkml <linux-kernel@vger.kernel.org>,
michael@ellerman.id.au, antonb@thinktux.localdomain,
Paul Mackerras <paulus@samba.org>,
benh@kernel.crashing.org, Ingo Molnar <mingo@elte.hu>,
Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Jim Keniston <jkenisto@us.ibm.com>
Subject: Re: Q: a_ops->readpage() && struct file
Date: Wed, 13 Jun 2012 21:19:28 +0200 [thread overview]
Message-ID: <20120613191928.GB14246@redhat.com> (raw)
In-Reply-To: <1339581492.31548.133.camel@twins>
On 06/13, Peter Zijlstra wrote:
>
> On Mon, 2012-06-11 at 21:09 +0200, Oleg Nesterov wrote:
> > 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.
next prev parent reply other threads:[~2012-06-13 19:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-08 9:32 [PATCH v2 1/2] uprobes: Pass probed vaddr to arch_uprobe_analyze_insn() Ananth N Mavinakayanahalli
2012-06-08 9:32 ` Ananth N Mavinakayanahalli
2012-06-08 9:34 ` [PATCH v2 2/2] [POWERPC] uprobes: powerpc port Ananth N Mavinakayanahalli
2012-06-08 9:34 ` Ananth N Mavinakayanahalli
2012-06-08 14:58 ` [tip:perf/core] uprobes: Pass probed vaddr to arch_uprobe_analyze_insn() tip-bot for Ananth N Mavinakayanahalli
2012-06-11 16:12 ` [PATCH v2 1/2] " Oleg Nesterov
2012-06-11 16:12 ` Oleg Nesterov
2012-06-11 19:09 ` Q: a_ops->readpage() && struct file Oleg Nesterov
2012-06-11 19:09 ` Oleg Nesterov
2012-06-13 9:58 ` Peter Zijlstra
2012-06-13 9:58 ` Peter Zijlstra
2012-06-13 19:19 ` Oleg Nesterov [this message]
2012-06-13 19:19 ` Oleg Nesterov
2012-06-12 16:54 ` [PATCH v2 1/2] uprobes: Pass probed vaddr to arch_uprobe_analyze_insn() Srikar Dronamraju
2012-06-12 16:54 ` Srikar Dronamraju
2012-06-12 17:43 ` Oleg Nesterov
2012-06-12 17:43 ` Oleg Nesterov
2012-06-13 19:15 ` Oleg Nesterov
2012-06-13 19:15 ` Oleg Nesterov
2012-06-14 11:45 ` Srikar Dronamraju
2012-06-14 11:45 ` Srikar Dronamraju
2012-06-14 18:19 ` Oleg Nesterov
2012-06-14 18:19 ` Oleg Nesterov
2012-06-15 12:33 ` Srikar Dronamraju
2012-06-16 18:05 ` Oleg Nesterov
2012-06-18 12:06 ` Srikar Dronamraju
2012-06-20 17:15 ` Oleg Nesterov
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