Re: [PATCH] dma-buf: Release module reference on creation failure

Daniel Vetter
2016-07-18T12:10:30Z

On Mon, Jul 18, 2016 at 12:16:22PM +0100, Chris Wilson wrote:
> If we fail to create the anon file, we need to remember to release the
> module reference on the owner.
>
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Sumit Semwal <sumit.semwal@linaro.org>
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Cc: linux-media@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linaro-mm-sig@lists.linaro.org
> ---
> drivers/dma-buf/dma-buf.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 20ce0687b111..ddaee60ae52a 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -334,6 +334,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
> struct reservation_object *resv = exp_info->resv;
> struct file *file;
> size_t alloc_size = sizeof(struct dma_buf);
> + int ret;

Not sure this really helps readability, but meh. Will apply to drm-misc,
with a cc: stable.
-Daniel

>
> if (!exp_info->resv)
> alloc_size += sizeof(struct reservation_object);
> @@ -357,8 +358,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
>
> dmabuf = kzalloc(alloc_size, GFP_KERNEL);
> if (!dmabuf) {
> - module_put(exp_info->owner);
> - return ERR_PTR(-ENOMEM);
> + ret = -ENOMEM;
> + goto err_module;
> }
>
> dmabuf->priv = exp_info->priv;
> @@ -379,8 +380,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
> file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
> exp_info->flags);
> if (IS_ERR(file)) {
> - kfree(dmabuf);
> - return ERR_CAST(file);
> + ret = PTR_ERR(file);
> + goto err_dmabuf;
> }
>
> file->f_mode |= FMODE_LSEEK;
> @@ -394,6 +395,12 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
> mutex_unlock(&db_list.lock);
>
> return dmabuf;
> +
> +err_dmabuf:
> + kfree(dmabuf);
> +err_module:
> + module_put(exp_info->owner);
> + return ERR_PTR(ret);
> }
> EXPORT_SYMBOL_GPL(dma_buf_export);
>
> --
> 2.8.1
>

--
Daniel Vetter
Software Engineer, Intel Corporation