Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964875Ab2HHKRt (ORCPT ); Wed, 8 Aug 2012 06:17:49 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:26875 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751454Ab2HHKRq (ORCPT ); Wed, 8 Aug 2012 06:17:46 -0400 Message-id: <50223CC5.9060007@samsung.com> Date: Wed, 08 Aug 2012 12:17:41 +0200 From: Tomasz Stanislawski User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-version: 1.0 To: linaro-mm-sig@lists.linaro.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org Cc: Sumit Semwal , Pawel Osciak , Rob Landley , Greg Kroah-Hartman , Inki Dae , Joonyoung Shim , Seung-Woo Kim , Kyungmin Park , David Airlie , Daniel Vetter , Vinod Koul , Dan Williams , Tomasz Stanislawski , Alex Deucher , Jerome Glisse , Rob Clark , linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, Marek Szyprowski Subject: [PATCH] dma-buf: add reference counting for exporter module Content-type: text/plain; charset=ISO-8859-1 Content-transfer-encoding: 7bit X-TM-AS-MML: No Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6280 Lines: 161 This patch adds reference counting on a module that exports dma-buf and implements its operations. This prevents the module from being unloaded while DMABUF file is in use. Signed-off-by: Tomasz Stanislawski --- Documentation/dma-buf-sharing.txt | 3 ++- drivers/base/dma-buf.c | 10 +++++++++- drivers/gpu/drm/exynos/exynos_drm_dmabuf.c | 1 + drivers/gpu/drm/i915/i915_gem_dmabuf.c | 1 + drivers/gpu/drm/nouveau/nouveau_prime.c | 1 + drivers/gpu/drm/radeon/radeon_prime.c | 1 + drivers/staging/omapdrm/omap_gem_dmabuf.c | 1 + include/linux/dma-buf.h | 2 ++ 8 files changed, 18 insertions(+), 2 deletions(-) diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt index ad86fb8..2613057 100644 --- a/Documentation/dma-buf-sharing.txt +++ b/Documentation/dma-buf-sharing.txt @@ -49,7 +49,8 @@ The dma_buf buffer sharing API usage contains the following steps: The buffer exporter announces its wish to export a buffer. In this, it connects its own private buffer data, provides implementation for operations that can be performed on the exported dma_buf, and flags for the file - associated with this buffer. + associated with this buffer. The operations structure has owner field. + You should initialize this to THIS_MODULE in most cases. Interface: struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops, diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index c30f3e1..d14b2f5 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -27,6 +27,7 @@ #include #include #include +#include static inline int is_dma_buf_file(struct file *); @@ -40,6 +41,7 @@ static int dma_buf_release(struct inode *inode, struct file *file) dmabuf = file->private_data; dmabuf->ops->release(dmabuf); + module_put(dmabuf->ops->owner); kfree(dmabuf); return 0; } @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, struct file *file; if (WARN_ON(!priv || !ops + || !ops->owner || !ops->map_dma_buf || !ops->unmap_dma_buf || !ops->release @@ -105,9 +108,14 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, return ERR_PTR(-EINVAL); } + if (!try_module_get(ops->owner)) + return ERR_PTR(-ENOENT); + dmabuf = kzalloc(sizeof(struct dma_buf), GFP_KERNEL); - if (dmabuf == NULL) + if (dmabuf == NULL) { + module_put(ops->owner); return ERR_PTR(-ENOMEM); + } dmabuf->priv = priv; dmabuf->ops = ops; diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c index 613bf8a..cf3bc6d 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c @@ -164,6 +164,7 @@ static void exynos_gem_dmabuf_kunmap(struct dma_buf *dma_buf, } static struct dma_buf_ops exynos_dmabuf_ops = { + .owner = THIS_MODULE, .map_dma_buf = exynos_gem_map_dma_buf, .unmap_dma_buf = exynos_gem_unmap_dma_buf, .kmap = exynos_gem_dmabuf_kmap, diff --git a/drivers/gpu/drm/i915/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/i915_gem_dmabuf.c index aa308e1..07ff03b 100644 --- a/drivers/gpu/drm/i915/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/i915_gem_dmabuf.c @@ -152,6 +152,7 @@ static int i915_gem_dmabuf_mmap(struct dma_buf *dma_buf, struct vm_area_struct * } static const struct dma_buf_ops i915_dmabuf_ops = { + .owner = THIS_MODULE, .map_dma_buf = i915_gem_map_dma_buf, .unmap_dma_buf = i915_gem_unmap_dma_buf, .release = i915_gem_dmabuf_release, diff --git a/drivers/gpu/drm/nouveau/nouveau_prime.c b/drivers/gpu/drm/nouveau/nouveau_prime.c index a25cf2c..8605033 100644 --- a/drivers/gpu/drm/nouveau/nouveau_prime.c +++ b/drivers/gpu/drm/nouveau/nouveau_prime.c @@ -127,6 +127,7 @@ static void nouveau_gem_prime_vunmap(struct dma_buf *dma_buf, void *vaddr) } static const struct dma_buf_ops nouveau_dmabuf_ops = { + .owner = THIS_MODULE, .map_dma_buf = nouveau_gem_map_dma_buf, .unmap_dma_buf = nouveau_gem_unmap_dma_buf, .release = nouveau_gem_dmabuf_release, diff --git a/drivers/gpu/drm/radeon/radeon_prime.c b/drivers/gpu/drm/radeon/radeon_prime.c index 6bef46a..4061fd3 100644 --- a/drivers/gpu/drm/radeon/radeon_prime.c +++ b/drivers/gpu/drm/radeon/radeon_prime.c @@ -127,6 +127,7 @@ static void radeon_gem_prime_vunmap(struct dma_buf *dma_buf, void *vaddr) mutex_unlock(&dev->struct_mutex); } const static struct dma_buf_ops radeon_dmabuf_ops = { + .owner = THIS_MODULE, .map_dma_buf = radeon_gem_map_dma_buf, .unmap_dma_buf = radeon_gem_unmap_dma_buf, .release = radeon_gem_dmabuf_release, diff --git a/drivers/staging/omapdrm/omap_gem_dmabuf.c b/drivers/staging/omapdrm/omap_gem_dmabuf.c index 42728e0..6a4dd67 100644 --- a/drivers/staging/omapdrm/omap_gem_dmabuf.c +++ b/drivers/staging/omapdrm/omap_gem_dmabuf.c @@ -179,6 +179,7 @@ out_unlock: } struct dma_buf_ops omap_dmabuf_ops = { + .owner = THIS_MODULE, .map_dma_buf = omap_gem_map_dma_buf, .unmap_dma_buf = omap_gem_unmap_dma_buf, .release = omap_gem_dmabuf_release, diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index eb48f38..22953de 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -37,6 +37,7 @@ struct dma_buf_attachment; /** * struct dma_buf_ops - operations possible on struct dma_buf + * @owner: the module that implements dma_buf operations * @attach: [optional] allows different devices to 'attach' themselves to the * given buffer. It might return -EBUSY to signal that backing storage * is already allocated and incompatible with the requirements @@ -70,6 +71,7 @@ struct dma_buf_attachment; * @vunmap: [optional] unmaps a vmap from the buffer */ struct dma_buf_ops { + struct module *owner; int (*attach)(struct dma_buf *, struct device *, struct dma_buf_attachment *); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/