diff mbox series

vfio_iommu_type1: increase the validity check of function parameters

Message ID 20221223072418.3728-1-kunyu@nfschina.com
State New
Headers
Series vfio_iommu_type1: increase the validity check of function parameters |

Commit Message

Li kunyu Dec. 23, 2022, 7:24 a.m. UTC 
  Added validity check for count variable, return if count variable does 
not meet the execution condition (do not execute mutex_lock and 
mutex_unlock function).

Signed-off-by: Li kunyu <kunyu@nfschina.com>
---
 drivers/vfio/vfio_iommu_type1.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Alex Williamson Dec. 23, 2022, 1:28 p.m. UTC | #1 
On Fri, 23 Dec 2022 15:24:18 +0800
Li kunyu <kunyu@nfschina.com> wrote:

> Added validity check for count variable, return if count variable does 
> not meet the execution condition (do not execute mutex_lock and 
> mutex_unlock function).
> 
> Signed-off-by: Li kunyu <kunyu@nfschina.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 23c24fe98c00..9bdf96d932e4 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -3137,6 +3137,9 @@ static int vfio_iommu_type1_dma_rw(void *iommu_data, dma_addr_t user_iova,
>  	int ret = 0;
>  	size_t done;
>  
> +	if (count <= 0)
> +		return ret;
> +
>  	mutex_lock(&iommu->lock);
>  	while (count > 0) {
>  		ret = vfio_iommu_type1_dma_rw_chunk(iommu, user_iova, data,

This is only optimizing a case that shouldn't exist, the return value
is the same.  Callers should be smart enough not to call the function
with such values.  As an internal API, we assume reasonable behavior by
the caller.  Thanks,

Alex
diff mbox series

Patch

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 23c24fe98c00..9bdf96d932e4 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -3137,6 +3137,9 @@  static int vfio_iommu_type1_dma_rw(void *iommu_data, dma_addr_t user_iova,
 	int ret = 0;
 	size_t done;
 
+	if (count <= 0)
+		return ret;
+
 	mutex_lock(&iommu->lock);
 	while (count > 0) {
 		ret = vfio_iommu_type1_dma_rw_chunk(iommu, user_iova, data,