From: Jan Kara <jack@suse.cz>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Jan Kara <jack@suse.cz>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-nvdimm@lists.01.org,
Andrew Morton <akpm@linux-foundation.org>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 16/21] mm: Provide helper for finishing mkwrite faults
Date: Wed, 16 Nov 2016 14:39:17 +0100 [thread overview]
Message-ID: <20161116133917.GM21785@quack2.suse.cz> (raw)
In-Reply-To: <20161115225210.GP23021@node>
On Wed 16-11-16 01:52:10, Kirill A. Shutemov wrote:
> On Fri, Nov 04, 2016 at 05:25:12AM +0100, Jan Kara wrote:
> > Provide a helper function for finishing write faults due to PTE being
> > read-only. The helper will be used by DAX to avoid the need of
> > complicating generic MM code with DAX locking specifics.
> >
> > Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > Signed-off-by: Jan Kara <jack@suse.cz>
...
> > - /*
> > - * Since we dropped the lock we need to revalidate
> > - * the PTE as someone else may have changed it. If
> > - * they did, we just return, as we can count on the
> > - * MMU to tell us if they didn't also make it writable.
> > - */
> > - vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
> > - vmf->address, &vmf->ptl);
> > - if (!pte_same(*vmf->pte, vmf->orig_pte)) {
> > + tmp = finish_mkwrite_fault(vmf);
> > + if (unlikely(!tmp || (tmp &
> > + (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
>
> Looks like the second part of condition is never true here, right? Not
> that it would matter, having the next patch in the queue.
Yeah, I had the condition like this to handle the standard set of return
values. And as you say, the next patch even makes this condition have a
real effect.
> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Thanks.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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next prev parent reply other threads:[~2016-11-16 13:39 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-04 4:24 [PATCH 0/21 v4 RESEND] dax: Clear dirty bits after flushing caches Jan Kara
2016-11-04 4:24 ` [PATCH 01/21] mm: Join struct fault_env and vm_fault Jan Kara
2016-11-15 21:50 ` Kirill A. Shutemov
2016-11-16 10:51 ` Peter Zijlstra
2016-11-16 11:01 ` Jan Kara
2016-11-16 17:21 ` Peter Zijlstra
2016-11-17 9:07 ` Jan Kara
2016-11-16 11:13 ` Kirill A. Shutemov
2016-11-04 4:24 ` [PATCH 02/21] mm: Use vmf->address instead of of vmf->virtual_address Jan Kara
2016-11-15 21:55 ` Kirill A. Shutemov
2016-11-16 11:05 ` Jan Kara
2016-11-16 11:32 ` Kirill A. Shutemov
2016-11-16 11:55 ` Jan Kara
2016-11-04 4:24 ` [PATCH 03/21] mm: Use pgoff in struct vm_fault instead of passing it separately Jan Kara
2016-11-15 22:01 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 04/21] mm: Use passed vm_fault structure in __do_fault() Jan Kara
2016-11-15 22:05 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 05/21] mm: Trim __do_fault() arguments Jan Kara
2016-11-15 22:10 ` Kirill A. Shutemov
2016-11-16 13:12 ` Jan Kara
2016-11-04 4:25 ` [PATCH 06/21] mm: Use passed vm_fault structure for in wp_pfn_shared() Jan Kara
2016-11-15 22:10 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 07/21] mm: Add orig_pte field into vm_fault Jan Kara
2016-11-15 22:14 ` Kirill A. Shutemov
2016-11-16 20:00 ` Ross Zwisler
2016-11-04 4:25 ` [PATCH 08/21] mm: Allow full handling of COW faults in ->fault handlers Jan Kara
2016-11-15 22:20 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 09/21] mm: Factor out functionality to finish page faults Jan Kara
2016-11-15 22:21 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 10/21] mm: Move handling of COW faults into DAX code Jan Kara
2016-11-15 22:22 ` Kirill A. Shutemov
2016-11-16 21:28 ` Ross Zwisler
2016-11-17 9:36 ` Jan Kara
2016-11-04 4:25 ` [PATCH 11/21] mm: Remove unnecessary vma->vm_ops check Jan Kara
2016-11-15 22:28 ` Kirill A. Shutemov
2016-11-16 13:29 ` Jan Kara
2016-11-16 14:27 ` Kirill A. Shutemov
2016-11-16 14:43 ` Jan Kara
2016-11-04 4:25 ` [PATCH 12/21] mm: Factor out common parts of write fault handling Jan Kara
2016-11-15 22:30 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 13/21] mm: Pass vm_fault structure into do_page_mkwrite() Jan Kara
2016-11-15 22:40 ` Kirill A. Shutemov
2016-11-16 13:34 ` Jan Kara
2016-11-04 4:25 ` [PATCH 14/21] mm: Use vmf->page during WP faults Jan Kara
2016-11-15 22:42 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 15/21] mm: Move part of wp_page_reuse() into the single call site Jan Kara
2016-11-15 22:44 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 16/21] mm: Provide helper for finishing mkwrite faults Jan Kara
2016-11-15 22:52 ` Kirill A. Shutemov
2016-11-16 13:39 ` Jan Kara [this message]
2016-11-04 4:25 ` [PATCH 17/21] mm: Change return values of finish_mkwrite_fault() Jan Kara
2016-11-15 22:57 ` Kirill A. Shutemov
2016-11-04 4:25 ` [PATCH 18/21] mm: Export follow_pte() Jan Kara
2016-11-04 4:25 ` [PATCH 19/21] dax: Make cache flushing protected by entry lock Jan Kara
2016-11-04 4:25 ` [PATCH 20/21] dax: Protect PTE modification on WP fault by radix tree " Jan Kara
2016-11-04 4:25 ` [PATCH 21/21] dax: Clear dirty entry tags on cache flush Jan Kara
-- strict thread matches above, loose matches on Subject: below --
2016-11-01 22:36 [PATCH 0/21 v4] dax: Clear dirty bits after flushing caches Jan Kara
2016-11-01 22:36 ` [PATCH 16/21] mm: Provide helper for finishing mkwrite faults Jan Kara
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