From: Oleksandr Andrushchenko <andr2000@gmail.com>
To: Boris Ostrovsky <boris.ostrovsky@oracle.com>,
xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org,
jgross@suse.com, konrad.wilk@oracle.com
Cc: daniel.vetter@intel.com, dongwon.kim@intel.com,
matthew.d.roper@intel.com,
Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Subject: Re: [PATCH v2 7/9] xen/gntdev: Implement dma-buf export functionality
Date: Fri, 8 Jun 2018 14:34:39 +0300 [thread overview]
Message-ID: <0c820b7d-d9e5-8a60-b9fc-86eb3ca81df8@gmail.com> (raw)
In-Reply-To: <b7f27688-f627-3fd9-9298-e02e6f35ca1e@oracle.com>
On 06/08/2018 01:30 AM, Boris Ostrovsky wrote:
> On 06/07/2018 04:44 AM, Oleksandr Andrushchenko wrote:
>> On 06/07/2018 12:48 AM, Boris Ostrovsky wrote:
>>> On 06/06/2018 08:10 AM, Oleksandr Andrushchenko wrote:
>>>> On 06/05/2018 01:07 AM, Boris Ostrovsky wrote:
>>>>> On 06/01/2018 07:41 AM, Oleksandr Andrushchenko wrote:
>>>>> +
>>>>> +static struct sg_table *
>>>>> +dmabuf_exp_ops_map_dma_buf(struct dma_buf_attachment *attach,
>>>>> + enum dma_data_direction dir)
>>>>> +{
>>>>> + struct gntdev_dmabuf_attachment *gntdev_dmabuf_attach =
>>>>> attach->priv;
>>>>> + struct gntdev_dmabuf *gntdev_dmabuf = attach->dmabuf->priv;
>>>>> + struct sg_table *sgt;
>>>>> +
>>>>> + pr_debug("Mapping %d pages for dev %p\n",
>>>>> gntdev_dmabuf->nr_pages,
>>>>> + attach->dev);
>>>>> +
>>>>> + if (WARN_ON(dir == DMA_NONE || !gntdev_dmabuf_attach))
>>>>>
>>>>> WARN_ON_ONCE. Here and elsewhere.
>>>> Why? The UAPI may be used by different applications, thus we might
>>>> lose warnings for some of them. Having WARN_ON will show problems
>>>> for multiple users, not for the first one.
>>>> Does this make sense to still use WARN_ON?
>>> Just as with pr_err call somewhere else the concern here is that
>>> userland (which I think is where this is eventually called from?) may
>>> intentionally trigger the error, flooding the log.
>>>
>>> And even this is not directly called from userland there is still a
>>> possibility of triggering this error multiple times.
>> Ok, will use WARN_ON_ONCE
>
> In fact, is there a reason to use WARN at all? Does this condition
> indicate some sort of internal inconsistency/error?
Well, the corresponding errors are anyways handled, so I will remove WARN
> -boris
>
>
>
next prev parent reply other threads:[~2018-06-08 11:34 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-01 11:41 [PATCH v2 0/9] xen: dma-buf support for grant device Oleksandr Andrushchenko
2018-06-01 11:41 ` [PATCH v2 1/9] xen/grant-table: Export gnttab_{alloc|free}_pages as GPL Oleksandr Andrushchenko
2018-06-04 9:27 ` Juergen Gross
2018-06-19 13:04 ` Juergen Gross
2018-06-01 11:41 ` [PATCH v2 2/9] xen/grant-table: Make set/clear page private code shared Oleksandr Andrushchenko
2018-06-01 11:44 ` Oleksandr Andrushchenko
2018-06-04 15:43 ` Boris Ostrovsky
2018-06-01 11:41 ` [PATCH v2 3/9] xen/balloon: Share common memory reservation routines Oleksandr Andrushchenko
2018-06-04 16:37 ` Boris Ostrovsky
2018-06-04 17:07 ` Oleksandr Andrushchenko
2018-06-06 7:24 ` Oleksandr Andrushchenko
2018-06-06 21:09 ` Boris Ostrovsky
2018-06-07 5:32 ` Oleksandr Andrushchenko
2018-06-01 11:41 ` [PATCH v2 4/9] xen/grant-table: Allow allocating buffers suitable for DMA Oleksandr Andrushchenko
2018-06-04 18:46 ` Boris Ostrovsky
2018-06-06 7:51 ` Oleksandr Andrushchenko
2018-06-01 11:41 ` [PATCH v2 5/9] xen/gntdev: Allow mappings for DMA buffers Oleksandr Andrushchenko
2018-06-04 20:12 ` Boris Ostrovsky
2018-06-06 8:14 ` [Xen-devel] " Oleksandr Andrushchenko
2018-06-06 21:19 ` Boris Ostrovsky
2018-06-07 6:39 ` Oleksandr Andrushchenko
2018-06-07 21:46 ` Boris Ostrovsky
2018-06-08 11:33 ` Oleksandr Andrushchenko
2018-06-08 17:59 ` Stefano Stabellini
2018-06-08 19:21 ` Boris Ostrovsky
2018-06-11 13:13 ` Oleksandr Andrushchenko
2018-06-11 16:51 ` Stefano Stabellini
2018-06-11 17:16 ` Oleksandr Andrushchenko
2018-06-11 17:46 ` Julien Grall
2018-06-11 17:49 ` Oleksandr Andrushchenko
2018-06-11 17:56 ` Julien Grall
2018-06-11 17:41 ` Julien Grall
2018-06-01 11:41 ` [PATCH v2 6/9] xen/gntdev: Add initial support for dma-buf UAPI Oleksandr Andrushchenko
2018-06-04 20:49 ` Boris Ostrovsky
2018-06-06 9:06 ` Oleksandr Andrushchenko
2018-06-06 21:32 ` Boris Ostrovsky
2018-06-07 7:17 ` Oleksandr Andrushchenko
2018-06-07 22:26 ` Boris Ostrovsky
2018-06-08 11:38 ` Oleksandr Andrushchenko
2018-06-01 11:41 ` [PATCH v2 7/9] xen/gntdev: Implement dma-buf export functionality Oleksandr Andrushchenko
2018-06-04 22:07 ` Boris Ostrovsky
2018-06-06 12:10 ` Oleksandr Andrushchenko
2018-06-06 21:48 ` Boris Ostrovsky
2018-06-07 8:44 ` Oleksandr Andrushchenko
2018-06-07 22:30 ` Boris Ostrovsky
2018-06-08 11:34 ` Oleksandr Andrushchenko [this message]
2018-06-01 11:41 ` [PATCH v2 8/9] xen/gntdev: Implement dma-buf import functionality Oleksandr Andrushchenko
2018-06-04 22:28 ` Boris Ostrovsky
2018-06-06 12:38 ` Oleksandr Andrushchenko
2018-06-01 11:41 ` [PATCH v2 9/9] xen/gntdev: Expose gntdev's dma-buf API for in-kernel use Oleksandr Andrushchenko
2018-06-04 22:36 ` Boris Ostrovsky
2018-06-06 12:46 ` Oleksandr Andrushchenko
2018-06-06 21:51 ` [Xen-devel] " Boris Ostrovsky
2018-06-06 22:05 ` Dongwon Kim
2018-06-07 7:33 ` Oleksandr Andrushchenko
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