linux-kernel - Re: [PATCH v19 17/30] drm/panfrost: Fix the error path in panfrost_mmu_map_fault

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Date: Fri, 26 Jan 2024 00:44:34 +0300
From: Dmitry Osipenko <dmitry.osipenko@...labora.com>
To: Steven Price <steven.price@....com>,
 Boris Brezillon <boris.brezillon@...labora.com>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 kernel@...labora.com, virtualization@...ts.linux-foundation.org,
 David Airlie <airlied@...il.com>, Gerd Hoffmann <kraxel@...hat.com>,
 Gurchetan Singh <gurchetansingh@...omium.org>, Chia-I Wu
 <olvaffe@...il.com>, Daniel Vetter <daniel@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>,
 Christian König <christian.koenig@....com>,
 Qiang Yu <yuq825@...il.com>, Emma Anholt <emma@...olt.net>,
 Melissa Wen <mwen@...lia.com>
Subject: Re: [PATCH v19 17/30] drm/panfrost: Fix the error path in
 panfrost_mmu_map_fault_addr()

On 1/26/24 00:41, Dmitry Osipenko wrote:
> On 1/5/24 21:46, Dmitry Osipenko wrote:
>>  	for (i = page_offset; i < page_offset + NUM_FAULT_PAGES; i++) {
>> +		/* Can happen if the last fault only partially filled this
>> +		 * section of the pages array before failing. In that case
>> +		 * we skip already filled pages.
>> +		 */
>> +		if (pages[i])
>> +			continue;
>> +
>>  		pages[i] = shmem_read_mapping_page(mapping, i);
> 
> Although, the shmem_read_mapping_page() should return same page if it
> was already allocated, isn't it? I.e. there was no bug here and the
> fixes/stable tags not needed.

Scratch that, I forgot that the patch is about the unbalanced
get/put_pages

-- 
Best regards,
Dmitry