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[85.223.209.22]) by smtp.gmail.com with ESMTPSA id q123-v6sm1323479ljb.60.2019.02.15.07.07.42 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Feb 2019 07:07:43 -0800 (PST) Subject: Re: [Xen-devel][PATCH 1/2] xen/gntdev: Do not destroy context while dma-bufs are in use To: Boris Ostrovsky , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, jgross@suse.com Cc: Oleksandr Andrushchenko References: <20190214142321.1138-1-andr2000@gmail.com> <143411a8-385d-2cce-9211-22ba7db25a15@oracle.com> From: Oleksandr Andrushchenko Message-ID: <1c8d1612-f1b9-b080-2d11-432d811b25d1@gmail.com> Date: Fri, 15 Feb 2019 17:07:42 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <143411a8-385d-2cce-9211-22ba7db25a15@oracle.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/15/19 5:03 PM, Boris Ostrovsky wrote: > On 2/14/19 9:23 AM, Oleksandr Andrushchenko wrote: >> >> /* DMA buffer export support. */ >> @@ -311,6 +317,7 @@ static void dmabuf_exp_release(struct kref *kref) >> >> dmabuf_exp_wait_obj_signal(gntdev_dmabuf->priv, gntdev_dmabuf); >> list_del(&gntdev_dmabuf->next); >> + fput(gntdev_dmabuf->priv->filp); >> kfree(gntdev_dmabuf); >> } >> >> @@ -423,6 +430,7 @@ static int dmabuf_exp_from_pages(struct gntdev_dmabuf_export_args *args) >> mutex_lock(&args->dmabuf_priv->lock); >> list_add(&gntdev_dmabuf->next, &args->dmabuf_priv->exp_list); >> mutex_unlock(&args->dmabuf_priv->lock); >> + get_file(gntdev_dmabuf->priv->filp); > Not fget()? fget wants file descriptor [1] and returns struct file *, but we already have struct file*, so I use get_file [2] which does what I need - increments the reference counter on the file > > -boris > > [1] https://elixir.bootlin.com/linux/v5.0-rc6/source/include/linux/file.h#L46 [2] https://elixir.bootlin.com/linux/v5.0-rc6/source/include/linux/fs.h#L949