This commit fixes the smatch static checker warning in function
mlxbf_tmfifo_rxtx_word() which complains data not initialized at
line 634 when IS_VRING_DROP() is TRUE.

Signed-off-by: Liming Sun <limings@nvidia.com>
---
v1->v2: Logic adjustment for Hans's comment
  - Adjust the logic to avoid confusion.
v1: Initial version.
---
 drivers/platform/mellanox/mlxbf-tmfifo.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
index f3696a54a2bd..d9615ad60012 100644
--- a/drivers/platform/mellanox/mlxbf-tmfifo.c
+++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
@@ -607,24 +607,25 @@ static void mlxbf_tmfifo_rxtx_word(struct mlxbf_tmfifo_vring *vring,
 
 	if (vring->cur_len + sizeof(u64) <= len) {
 		/* The whole word. */
-		if (!IS_VRING_DROP(vring)) {
-			if (is_rx)
+		if (is_rx) {
+			if (!IS_VRING_DROP(vring))
 				memcpy(addr + vring->cur_len, &data,
 				       sizeof(u64));
-			else
-				memcpy(&data, addr + vring->cur_len,
-				       sizeof(u64));
+		} else {
+			memcpy(&data, addr + vring->cur_len,
+			       sizeof(u64));
 		}
 		vring->cur_len += sizeof(u64);
 	} else {
 		/* Leftover bytes. */
-		if (!IS_VRING_DROP(vring)) {
-			if (is_rx)
+		if (is_rx) {
+			if (!IS_VRING_DROP(vring))
 				memcpy(addr + vring->cur_len, &data,
 				       len - vring->cur_len);
-			else
-				memcpy(&data, addr + vring->cur_len,
-				       len - vring->cur_len);
+		} else {
+			data = 0;
+			memcpy(&data, addr + vring->cur_len,
+			       len - vring->cur_len);
 		}
 		vring->cur_len = len;
 	}
-- 
2.30.1

Hi,

On 10/13/23 01:02, Liming Sun wrote:
> This commit fixes the smatch static checker warning in function
> mlxbf_tmfifo_rxtx_word() which complains data not initialized at
> line 634 when IS_VRING_DROP() is TRUE.
> 
> Signed-off-by: Liming Sun <limings@nvidia.com>
> ---
> v1->v2: Logic adjustment for Hans's comment
>   - Adjust the logic to avoid confusion.

Thank you for your patch/series, I've applied this patch
(series) to the pdx86 fixes branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=fixes

I will include this patch in my next fixes pull-req to Linus
for the current kernel development cycle.

Regards,

Hans






> v1: Initial version.
> ---
>  drivers/platform/mellanox/mlxbf-tmfifo.c | 21 +++++++++++----------
>  1 file changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c
> index f3696a54a2bd..d9615ad60012 100644
> --- a/drivers/platform/mellanox/mlxbf-tmfifo.c
> +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c
> @@ -607,24 +607,25 @@ static void mlxbf_tmfifo_rxtx_word(struct mlxbf_tmfifo_vring *vring,
>  
>  	if (vring->cur_len + sizeof(u64) <= len) {
>  		/* The whole word. */
> -		if (!IS_VRING_DROP(vring)) {
> -			if (is_rx)
> +		if (is_rx) {
> +			if (!IS_VRING_DROP(vring))
>  				memcpy(addr + vring->cur_len, &data,
>  				       sizeof(u64));
> -			else
> -				memcpy(&data, addr + vring->cur_len,
> -				       sizeof(u64));
> +		} else {
> +			memcpy(&data, addr + vring->cur_len,
> +			       sizeof(u64));
>  		}
>  		vring->cur_len += sizeof(u64);
>  	} else {
>  		/* Leftover bytes. */
> -		if (!IS_VRING_DROP(vring)) {
> -			if (is_rx)
> +		if (is_rx) {
> +			if (!IS_VRING_DROP(vring))
>  				memcpy(addr + vring->cur_len, &data,
>  				       len - vring->cur_len);
> -			else
> -				memcpy(&data, addr + vring->cur_len,
> -				       len - vring->cur_len);
> +		} else {
> +			data = 0;
> +			memcpy(&data, addr + vring->cur_len,
> +			       len - vring->cur_len);
>  		}
>  		vring->cur_len = len;
>  	}