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From: Jan Kara <jack@suse.cz>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>, linux-mm@kvack.org, linux-media@vger.kernel.org
Subject: Re: [PATCH 1/9] mm: Provide new get_vaddr_pfns() helper
Date: Tue, 18 Mar 2014 11:25:50 +0100	[thread overview]
Message-ID: <20140318102550.GC10955@quack.suse.cz> (raw)
In-Reply-To: <532760CF.10704@intel.com>

On Mon 17-03-14 13:53:35, Dave Hansen wrote:
> On 03/17/2014 12:49 PM, Jan Kara wrote:
> > +int get_vaddr_pfns(unsigned long start, int nr_pfns, int write, int force,
> > +		   struct pinned_pfns *pfns)
> > +{
> ...
> > +	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
> > +		pfns->got_ref = 1;
> > +		pfns->is_pages = 1;
> > +		ret = get_user_pages(current, mm, start, nr_pfns, write, force,
> > +				     pfns_vector_pages(pfns), NULL);
> > +		goto out;
> > +	}
> 
> Have you given any thought to how this should deal with VM_MIXEDMAP
> vmas?  get_user_pages() will freak when it hits the !vm_normal_page()
> test on the pfnmapped ones, and jump out.  Shouldn't get_vaddr_pfns() be
> able to handle those too?
  It could and it doesn't seem as a big complication. Although none of the
converted drivers need this functionality, I guess it makes sense to
implement this to make the API more consistent. So I can have a look at it
for the next iteration.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

WARNING: multiple messages have this Message-ID (diff)
From: Jan Kara <jack@suse.cz>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Jan Kara <jack@suse.cz>, linux-mm@kvack.org, linux-media@vger.kernel.org
Subject: Re: [PATCH 1/9] mm: Provide new get_vaddr_pfns() helper
Date: Tue, 18 Mar 2014 11:25:50 +0100	[thread overview]
Message-ID: <20140318102550.GC10955@quack.suse.cz> (raw)
In-Reply-To: <532760CF.10704@intel.com>

On Mon 17-03-14 13:53:35, Dave Hansen wrote:
> On 03/17/2014 12:49 PM, Jan Kara wrote:
> > +int get_vaddr_pfns(unsigned long start, int nr_pfns, int write, int force,
> > +		   struct pinned_pfns *pfns)
> > +{
> ...
> > +	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
> > +		pfns->got_ref = 1;
> > +		pfns->is_pages = 1;
> > +		ret = get_user_pages(current, mm, start, nr_pfns, write, force,
> > +				     pfns_vector_pages(pfns), NULL);
> > +		goto out;
> > +	}
> 
> Have you given any thought to how this should deal with VM_MIXEDMAP
> vmas?  get_user_pages() will freak when it hits the !vm_normal_page()
> test on the pfnmapped ones, and jump out.  Shouldn't get_vaddr_pfns() be
> able to handle those too?
  It could and it doesn't seem as a big complication. Although none of the
converted drivers need this functionality, I guess it makes sense to
implement this to make the API more consistent. So I can have a look at it
for the next iteration.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

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  reply	other threads:[~2014-03-18 10:25 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-17 19:49 [RFC] Helper to abstract vma handling in media layer Jan Kara
2014-03-17 19:49 ` Jan Kara
2014-03-17 19:49 ` [PATCH 1/9] mm: Provide new get_vaddr_pfns() helper Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 20:53   ` Dave Hansen
2014-03-17 20:53     ` Dave Hansen
2014-03-18 10:25     ` Jan Kara [this message]
2014-03-18 10:25       ` Jan Kara
2015-04-24 16:21   ` Jan Kara
2015-04-24 16:21     ` Jan Kara
2014-03-17 19:49 ` [PATCH 2/9] media: omap_vout: Convert omap_vout_uservirt_to_phys() to use get_vaddr_pfns() Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 3/9] media: vb2: Teach vb2_queue_or_prepare_buf() to get pfns for user buffers Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 4/9] media: vb2: Convert vb2_dma_sg_get_userptr() to use pinned pfns Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 5/9] media: vb2: Convert vb2_vmalloc_get_userptr() to use pfns vector Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 6/9] media: vb2: Convert vb2_dc_get_userptr() " Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 7/9] media: vb2: Remove unused functions Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 8/9] drm/exynos: Convert g2d_userptr_get_dma_addr() to use get_vaddr_pfn() Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-03-17 19:49 ` [PATCH 9/9] staging: tidspbridge: Convert to get_vaddr_pfns() Jan Kara
2014-03-17 19:49   ` Jan Kara
2014-04-10 10:02 ` [RFC] Helper to abstract vma handling in media layer Marek Szyprowski
2014-04-10 10:02   ` Marek Szyprowski
2014-04-10 10:32   ` Jan Kara
2014-04-10 10:32     ` Jan Kara
2014-04-10 11:07     ` Hans Verkuil
2014-04-10 11:07       ` Hans Verkuil
2014-04-10 12:15       ` Jan Kara
2014-04-10 12:15         ` Jan Kara
2014-04-10 12:22         ` Hans Verkuil
2014-04-10 12:22           ` Hans Verkuil
2014-04-10 21:57           ` Jan Kara
2014-04-10 21:57             ` Jan Kara
2014-04-10 22:18             ` Jan Kara
2014-04-10 22:18               ` Jan Kara
2014-04-11  6:58               ` Hans Verkuil
2014-04-11  6:58                 ` Hans Verkuil
2014-04-14 21:19                 ` Jan Kara
2014-04-14 21:19                   ` Jan Kara

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