2022-11-24 18:31:49

by Dmitry Osipenko

[permalink] [raw]
Subject: Re: [PATCH 01/11] misc: fastrpc: Assert held reservation lock for dma-buf mmapping

On 11/24/22 20:51, Srinivas Kandagatla wrote:
> From: Dmitry Osipenko <[email protected]>
>
> When userspace mmaps dma-buf's fd, the dma-buf reservation lock must be
> held. Add locking sanity check to the dma-buf mmaping callback to ensure
> that the locking assumption won't regress in the future.
>
> Suggested-by: Daniel Vetter <[email protected]>
> Signed-off-by: Dmitry Osipenko <[email protected]>
> Signed-off-by: Srinivas Kandagatla <[email protected]>
> ---
> drivers/misc/fastrpc.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 80811e852d8f..c6b9ddaa698b 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -6,6 +6,7 @@
> #include <linux/device.h>
> #include <linux/dma-buf.h>
> #include <linux/dma-mapping.h>
> +#include <linux/dma-resv.h>
> #include <linux/idr.h>
> #include <linux/list.h>
> #include <linux/miscdevice.h>
> @@ -692,6 +693,8 @@ static int fastrpc_mmap(struct dma_buf *dmabuf,
> struct fastrpc_buf *buf = dmabuf->priv;
> size_t size = vma->vm_end - vma->vm_start;
>
> + dma_resv_assert_held(dmabuf->resv);
> +
> return dma_mmap_coherent(buf->dev, vma, buf->virt,
> FASTRPC_PHYS(buf->phys), size);
> }

This patch was already applied to DRM tree together with the rest of
prerequisite dma-buf patches. IOW, it shouldn't be applied separately
via the misc tree.

--
Best regards,
Dmitry


2022-11-25 07:30:06

by Srinivas Kandagatla

[permalink] [raw]
Subject: Re: [PATCH 01/11] misc: fastrpc: Assert held reservation lock for dma-buf mmapping



On 24/11/2022 18:03, Dmitry Osipenko wrote:
> On 11/24/22 20:51, Srinivas Kandagatla wrote:
>> From: Dmitry Osipenko <[email protected].com>
>>
>> When userspace mmaps dma-buf's fd, the dma-buf reservation lock must be
>> held. Add locking sanity check to the dma-buf mmaping callback to ensure
>> that the locking assumption won't regress in the future.
>>
>> Suggested-by: Daniel Vetter <[email protected]>
>> Signed-off-by: Dmitry Osipenko <[email protected]>
>> Signed-off-by: Srinivas Kandagatla <[email protected]>
>> ---
>> drivers/misc/fastrpc.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>> index 80811e852d8f..c6b9ddaa698b 100644
>> --- a/drivers/misc/fastrpc.c
>> +++ b/drivers/misc/fastrpc.c
>> @@ -6,6 +6,7 @@
>> #include <linux/device.h>
>> #include <linux/dma-buf.h>
>> #include <linux/dma-mapping.h>
>> +#include <linux/dma-resv.h>
>> #include <linux/idr.h>
>> #include <linux/list.h>
>> #include <linux/miscdevice.h>
>> @@ -692,6 +693,8 @@ static int fastrpc_mmap(struct dma_buf *dmabuf,
>> struct fastrpc_buf *buf = dmabuf->priv;
>> size_t size = vma->vm_end - vma->vm_start;
>>
>> + dma_resv_assert_held(dmabuf->resv);
>> +
>> return dma_mmap_coherent(buf->dev, vma, buf->virt,
>> FASTRPC_PHYS(buf->phys), size);
>> }
>
> This patch was already applied to DRM tree together with the rest of
> prerequisite dma-buf patches. IOW, it shouldn't be applied separately
> via the misc tree.
thanks, that is true.



---srini

>