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Mon, 11 Oct 2021 08:21:00 +0000 Subject: Re: [PATCH v2] dma-buf: remove restriction of IOCTL:DMA_BUF_SET_NAME To: guangming.cao@mediatek.com, rdunlap@infradead.org Cc: dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com, sumit.semwal@linaro.org, wsd_upstream@mediatek.com References: <20211009055504.68272-1-guangming.cao@mediatek.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= Message-ID: Date: Mon, 11 Oct 2021 10:20:52 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0 In-Reply-To: <20211009055504.68272-1-guangming.cao@mediatek.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US X-ClientProxiedBy: AS9PR06CA0246.eurprd06.prod.outlook.com (2603:10a6:20b:45f::12) To MWHPR1201MB0192.namprd12.prod.outlook.com (2603:10b6:301:5a::14) MIME-Version: 1.0 Received: from [IPv6:2a02:908:1252:fb60:a75c:41fc:3f29:351c] (2a02:908:1252:fb60:a75c:41fc:3f29:351c) by AS9PR06CA0246.eurprd06.prod.outlook.com (2603:10a6:20b:45f::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4587.24 via Frontend Transport; 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Sounds valid to me, but I have no idea why this restriction was added in the first place. Can you double check the git history and maybe identify when that was added? Mentioning this change in the commit message then might make things a bit easier to understand. Thanks, Christian. > > Signed-off-by: Guangming Cao > --- > drivers/dma-buf/dma-buf.c | 14 ++------------ > 1 file changed, 2 insertions(+), 12 deletions(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 511fe0d217a0..db2f4efdec32 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -325,10 +325,8 @@ static __poll_t dma_buf_poll(struct file *file, poll_table *poll) > > /** > * dma_buf_set_name - Set a name to a specific dma_buf to track the usage. > - * The name of the dma-buf buffer can only be set when the dma-buf is not > - * attached to any devices. It could theoritically support changing the > - * name of the dma-buf if the same piece of memory is used for multiple > - * purpose between different devices. > + * It could theoretically support changing the name of the dma-buf if the same > + * piece of memory is used for multiple purpose between different devices. > * > * @dmabuf: [in] dmabuf buffer that will be renamed. > * @buf: [in] A piece of userspace memory that contains the name of > @@ -346,19 +344,11 @@ static long dma_buf_set_name(struct dma_buf *dmabuf, const char __user *buf) > if (IS_ERR(name)) > return PTR_ERR(name); > > - dma_resv_lock(dmabuf->resv, NULL); > - if (!list_empty(&dmabuf->attachments)) { > - ret = -EBUSY; > - kfree(name); > - goto out_unlock; > - } > spin_lock(&dmabuf->name_lock); > kfree(dmabuf->name); > dmabuf->name = name; > spin_unlock(&dmabuf->name_lock); > > -out_unlock: > - dma_resv_unlock(dmabuf->resv); > return ret; > } >