On 14 February 2013 16:16, Daniel Vetter <daniel.vetter@xxxxxxxx> wrote:
> On Tue, Feb 12, 2013 at 2:50 AM, <sheu@xxxxxxxxxx> wrote:
>> From: John Sheu <sheu@xxxxxxxxxx>
>>
>> Callers to dma_buf_mmap expect to fput() the vma struct's vm_file
>> themselves on failure. Not restoring the struct's data on failure
>> causes a double-decrement of the vm_file's refcount.
>>
>> Signed-off-by: John Sheu <sheu@xxxxxxxxxx>
>
> Yeah, makes sense that this little helper here cleans up any damage it
> caused when the callback fails.
>
> Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Thanks John, Daniel!
I'll pull it in the for-next soon.
Best regards,
~Sumit.
>>
>> ---
>> drivers/base/dma-buf.c | 21 +++++++++++++++------
>> 1 files changed, 15 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
>> index 09e6878..06c6225 100644
>> --- a/drivers/base/dma-buf.c
>> +++ b/drivers/base/dma-buf.c
>> @@ -536,6 +536,9 @@ EXPORT_SYMBOL_GPL(dma_buf_kunmap);
>> int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
>> unsigned long pgoff)
>> {
>> + struct file *oldfile;
>> + int ret;
>> +
>> if (WARN_ON(!dmabuf || !vma))
>> return -EINVAL;
>>
>> @@ -549,15 +552,21 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
>> return -EINVAL;
>>
>> /* readjust the vma */
>> - if (vma->vm_file)
>> - fput(vma->vm_file);
>> -
>> + get_file(dmabuf->file);
>> + oldfile = vma->vm_file;
>> vma->vm_file = dmabuf->file;
>> - get_file(vma->vm_file);
>> -
>> vma->vm_pgoff = pgoff;
>>
>> - return dmabuf->ops->mmap(dmabuf, vma);
>> + ret = dmabuf->ops->mmap(dmabuf, vma);
>> + if (ret) {
>> + /* restore old parameters on failure */
>> + vma->vm_file = oldfile;
>> + fput(dmabuf->file);
>> + } else {
>> + if (oldfile)
>> + fput(oldfile);
>> + }
>> + return ret;
>> }
>> EXPORT_SYMBOL_GPL(dma_buf_mmap);
>>
>> --
>> 1.7.8.6
>>
>>
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>> Linaro-mm-sig@xxxxxxxxxxxxxxxx
>> http://lists.linaro.org/mailman/listinfo/linaro-mm-sig
>
>
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch
--
Thanks and regards,
Sumit Semwal
Linaro Kernel Engineer - Graphics working group
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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