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([2a02:908:1256:79a0:62ca:57d9:b533:6057]) by smtp.gmail.com with ESMTPSA id u18-20020a1709061db200b0073d6d760daesm1229270ejh.60.2022.08.24.07.10.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 24 Aug 2022 07:10:55 -0700 (PDT) Message-ID: Date: Wed, 24 Aug 2022 16:10:53 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH v3 9/9] dma-buf: Remove internal lock Content-Language: en-US To: Dmitry Osipenko , David Airlie , Gerd Hoffmann , Gurchetan Singh , Chia-I Wu , Daniel Vetter , Daniel Almeida , Gert Wollny , Gustavo Padovan , Daniel Stone , Tomeu Vizoso , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Rob Clark , Sumit Semwal , "Pan, Xinhui" , Thierry Reding , Tomasz Figa , Marek Szyprowski , Mauro Carvalho Chehab , Alex Deucher , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , Tvrtko Ursulin , =?UTF-8?Q?Thomas_Hellstr=c3=b6m?= , Qiang Yu Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dmitry Osipenko , linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, kernel@collabora.com, virtualization@lists.linux-foundation.org, linux-rdma@vger.kernel.org, linux-arm-msm@vger.kernel.org, lima@lists.freedesktop.org References: <20220824102248.91964-1-dmitry.osipenko@collabora.com> <20220824102248.91964-10-dmitry.osipenko@collabora.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= In-Reply-To: <20220824102248.91964-10-dmitry.osipenko@collabora.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am 24.08.22 um 12:22 schrieb Dmitry Osipenko: > The internal dma-buf lock isn't needed anymore because the updated > locking specification claims that dma-buf reservation must be locked > by importers, and thus, the internal data is already protected by the > reservation lock. Remove the obsoleted internal lock. > > Signed-off-by: Dmitry Osipenko Reviewed-by: Christian König > --- > drivers/dma-buf/dma-buf.c | 14 ++++---------- > include/linux/dma-buf.h | 9 --------- > 2 files changed, 4 insertions(+), 19 deletions(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 696d132b02f4..a0406254f0ae 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -656,7 +656,6 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) > > dmabuf->file = file; > > - mutex_init(&dmabuf->lock); > INIT_LIST_HEAD(&dmabuf->attachments); > > mutex_lock(&db_list.lock); > @@ -1503,7 +1502,7 @@ EXPORT_SYMBOL_NS_GPL(dma_buf_mmap_unlocked, DMA_BUF); > int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map) > { > struct iosys_map ptr; > - int ret = 0; > + int ret; > > iosys_map_clear(map); > > @@ -1515,28 +1514,25 @@ int dma_buf_vmap(struct dma_buf *dmabuf, struct iosys_map *map) > if (!dmabuf->ops->vmap) > return -EINVAL; > > - mutex_lock(&dmabuf->lock); > if (dmabuf->vmapping_counter) { > dmabuf->vmapping_counter++; > BUG_ON(iosys_map_is_null(&dmabuf->vmap_ptr)); > *map = dmabuf->vmap_ptr; > - goto out_unlock; > + return 0; > } > > BUG_ON(iosys_map_is_set(&dmabuf->vmap_ptr)); > > ret = dmabuf->ops->vmap(dmabuf, &ptr); > if (WARN_ON_ONCE(ret)) > - goto out_unlock; > + return ret; > > dmabuf->vmap_ptr = ptr; > dmabuf->vmapping_counter = 1; > > *map = dmabuf->vmap_ptr; > > -out_unlock: > - mutex_unlock(&dmabuf->lock); > - return ret; > + return 0; > } > EXPORT_SYMBOL_NS_GPL(dma_buf_vmap, DMA_BUF); > > @@ -1578,13 +1574,11 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct iosys_map *map) > BUG_ON(dmabuf->vmapping_counter == 0); > BUG_ON(!iosys_map_is_equal(&dmabuf->vmap_ptr, map)); > > - mutex_lock(&dmabuf->lock); > if (--dmabuf->vmapping_counter == 0) { > if (dmabuf->ops->vunmap) > dmabuf->ops->vunmap(dmabuf, map); > iosys_map_clear(&dmabuf->vmap_ptr); > } > - mutex_unlock(&dmabuf->lock); > } > EXPORT_SYMBOL_NS_GPL(dma_buf_vunmap, DMA_BUF); > > diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h > index d48d534dc55c..aed6695bbb50 100644 > --- a/include/linux/dma-buf.h > +++ b/include/linux/dma-buf.h > @@ -326,15 +326,6 @@ struct dma_buf { > /** @ops: dma_buf_ops associated with this buffer object. */ > const struct dma_buf_ops *ops; > > - /** > - * @lock: > - * > - * Used internally to serialize list manipulation, attach/detach and > - * vmap/unmap. Note that in many cases this is superseeded by > - * dma_resv_lock() on @resv. > - */ > - struct mutex lock; > - > /** > * @vmapping_counter: > *