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From: "Andrew F. Davis" <afd@ti.com>
To: Brian Starkey <Brian.Starkey@arm.com>,
	John Stultz <john.stultz@linaro.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Laura Abbott <labbott@redhat.com>,
	Benjamin Gaignard <benjamin.gaignard@linaro.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Liam Mark <lmark@codeaurora.org>, Chenbo Feng <fengc@google.com>,
	Alistair Strachan <astrachan@google.com>,
	"dri-devel@lists.freedesktop.org"
	<dri-devel@lists.freedesktop.org>, nd <nd@arm.com>
Subject: Re: [RFC][PATCH 2/5 v2] dma-buf: heaps: Add heap helpers
Date: Thu, 21 Mar 2019 15:35:10 -0500	[thread overview]
Message-ID: <9be37cc0-6eae-9bae-d8ee-89a91d7a4d89@ti.com> (raw)
In-Reply-To: <20190319142604.f6puq3ugxrcxsrjs@DESKTOP-E1NTVVP.localdomain>

On 3/19/19 9:26 AM, Brian Starkey wrote:
> Hi John,
> 
> On Tue, Mar 05, 2019 at 12:54:30PM -0800, John Stultz wrote:
> 
> ...
> 
>> +
>> +void dma_heap_buffer_destroy(struct dma_heap_buffer *heap_buffer)
>> +{
>> +	struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
>> +
>> +	if (buffer->kmap_cnt > 0) {
>> +		pr_warn_once("%s: buffer still mapped in the kernel\n",
>> +			     __func__);
> 
> Could be worth something louder like a full WARN.
> 
>> +		vunmap(buffer->vaddr);
>> +	}
>> +
>> +	buffer->free(buffer);
>> +}
>> +
> 
> ...
> 
>> +
>> +static void *dma_heap_dma_buf_kmap(struct dma_buf *dmabuf,
>> +					unsigned long offset)
>> +{
>> +	struct dma_heap_buffer *heap_buffer = dmabuf->priv;
>> +	struct heap_helper_buffer *buffer = to_helper_buffer(heap_buffer);
>> +
>> +	return buffer->vaddr + offset * PAGE_SIZE;
> 
> I think it'd be good to check for NULL vaddr and return NULL in that
> case. Less chance of an invalid pointer being accidentally used then.
> 

Why do we assume vaddr is set at all here? I'm guessing we expected
dma_heap_map_kernel to have been called, that is not going to always be
the case. kmap should perform it's own single page kmap here and not
rely on the clunky full buffer vmap (which is probably broken on 32bit
systems here when the buffers are large).

Andrew

> Thanks,
> -Brian
> 

  parent reply	other threads:[~2019-03-21 20:35 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-05 20:54 [RFC][PATCH 0/5 v2] DMA-BUF Heaps (destaging ION) John Stultz
2019-03-05 20:54 ` [RFC][PATCH 1/5 v2] dma-buf: Add dma-buf heaps framework John Stultz
2019-03-06 16:12   ` Benjamin Gaignard
2019-03-06 16:57     ` John Stultz
2019-03-15  8:55     ` Christoph Hellwig
2019-03-06 16:27   ` Andrew F. Davis
2019-03-06 19:03     ` John Stultz
2019-03-06 21:45       ` Andrew F. Davis
2019-03-15  8:54   ` Christoph Hellwig
2019-03-15 20:24     ` Andrew F. Davis
2019-03-15 20:18   ` Laura Abbott
2019-03-15 20:49     ` Andrew F. Davis
2019-03-15 21:29     ` John Stultz
2019-03-15 22:44       ` Laura Abbott
2019-03-18  4:38         ` Sumit Semwal
2019-03-18  4:41         ` Sumit Semwal
2019-03-19 12:08   ` Brian Starkey
2019-03-19 15:24     ` Andrew F. Davis
2019-03-21 21:16     ` John Stultz
2019-03-27 14:53   ` Greg KH
2019-03-28  6:09     ` John Stultz
2019-03-05 20:54 ` [RFC][PATCH 2/5 v2] dma-buf: heaps: Add heap helpers John Stultz
2019-03-13 20:18   ` Liam Mark
2019-03-13 21:48     ` Andrew F. Davis
2019-03-13 22:57       ` Liam Mark
2019-03-13 23:42         ` Andrew F. Davis
2019-03-15  9:06   ` Christoph Hellwig
2019-03-19 15:03     ` Andrew F. Davis
2019-03-21 20:01     ` John Stultz
2019-03-19 14:26   ` Brian Starkey
2019-03-21 20:11     ` John Stultz
2019-03-21 20:35     ` Andrew F. Davis [this message]
2019-03-21 20:43   ` Andrew F. Davis
2019-03-05 20:54 ` [RFC][PATCH 3/5 v2] dma-buf: heaps: Add system heap to dmabuf heaps John Stultz
2019-03-06 16:01   ` Benjamin Gaignard
2019-03-11  5:48     ` John Stultz
2019-03-13 20:20   ` Liam Mark
2019-03-13 22:49     ` John Stultz
2019-03-15  9:06   ` Christoph Hellwig
2019-03-05 20:54 ` [RFC][PATCH 4/5 v2] dma-buf: heaps: Add CMA heap to dmabuf heapss John Stultz
2019-03-06 16:05   ` Benjamin Gaignard
2019-03-21 20:15     ` John Stultz
2019-03-15  9:06   ` Christoph Hellwig
2019-03-15 20:08     ` John Stultz
2019-03-19 14:53   ` Brian Starkey
2019-03-05 20:54 ` [RFC][PATCH 5/5 v2] kselftests: Add dma-heap test John Stultz
2019-03-06 16:14   ` Benjamin Gaignard
2019-03-06 16:35     ` Andrew F. Davis
2019-03-06 18:19       ` John Stultz
2019-03-06 18:32         ` Andrew F. Davis
2019-03-06 17:01     ` John Stultz
2019-03-15 20:07       ` Laura Abbott
2019-03-15 20:13         ` John Stultz
2019-03-15 20:49           ` Laura Abbott
2019-03-13 20:23   ` Liam Mark
2019-03-13 20:11 ` [RFC][PATCH 0/5 v2] DMA-BUF Heaps (destaging ION) Liam Mark
2019-03-13 22:30   ` John Stultz
2019-03-13 23:29     ` Liam Mark
2019-03-19 16:54     ` Benjamin Gaignard
2019-03-19 16:59       ` Andrew F. Davis
2019-03-19 21:58         ` Rob Clark
2019-03-19 22:36           ` John Stultz
2019-03-20  9:16             ` Benjamin Gaignard
2019-03-20 14:44               ` Andrew F. Davis
2019-03-20 15:59                 ` Benjamin Gaignard
2019-03-20 16:11               ` John Stultz
2019-03-15 20:34 ` Laura Abbott
2019-03-15 23:15 ` Jerome Glisse
2019-03-16  0:16   ` John Stultz

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