* [PATCH] accel/qaic: Use overflow check function instead of division
@ 2025-10-07 17:42 Youssef Samir
2025-10-07 20:07 ` Jeff Hugo
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Youssef Samir @ 2025-10-07 17:42 UTC (permalink / raw)
To: jeff.hugo, carl.vanderlip, troy.hanson, zachary.mckevitt
Cc: ogabbay, lizhi.hou, karol.wachowski, linux-arm-msm, dri-devel
From: Carl Vanderlip <quic_carlv@quicinc.com>
Division is an expensive operation. Overflow check functions exist
already. Use existing overflow check functions rather than dividing to
check for overflow.
Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com>
Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
---
drivers/accel/qaic/qaic_control.c | 5 +++--
drivers/accel/qaic/qaic_data.c | 5 +++--
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/accel/qaic/qaic_control.c b/drivers/accel/qaic/qaic_control.c
index d8bdab69f800..7c809757c325 100644
--- a/drivers/accel/qaic/qaic_control.c
+++ b/drivers/accel/qaic/qaic_control.c
@@ -655,8 +655,9 @@ static int encode_activate(struct qaic_device *qdev, void *trans, struct wrapper
return -EINVAL;
nelem = in_trans->queue_size;
- size = (get_dbc_req_elem_size() + get_dbc_rsp_elem_size()) * nelem;
- if (size / nelem != get_dbc_req_elem_size() + get_dbc_rsp_elem_size())
+ if (check_mul_overflow((u32)(get_dbc_req_elem_size() + get_dbc_rsp_elem_size()),
+ nelem,
+ &size))
return -EINVAL;
if (size + QAIC_DBC_Q_GAP + QAIC_DBC_Q_BUF_ALIGN < size)
diff --git a/drivers/accel/qaic/qaic_data.c b/drivers/accel/qaic/qaic_data.c
index 797289e9d780..7c304a9e5048 100644
--- a/drivers/accel/qaic/qaic_data.c
+++ b/drivers/accel/qaic/qaic_data.c
@@ -953,8 +953,9 @@ int qaic_attach_slice_bo_ioctl(struct drm_device *dev, void *data, struct drm_fi
if (args->hdr.count == 0)
return -EINVAL;
- arg_size = args->hdr.count * sizeof(*slice_ent);
- if (arg_size / args->hdr.count != sizeof(*slice_ent))
+ if (check_mul_overflow((unsigned long)args->hdr.count,
+ (unsigned long)sizeof(*slice_ent),
+ &arg_size))
return -EINVAL;
if (!(args->hdr.dir == DMA_TO_DEVICE || args->hdr.dir == DMA_FROM_DEVICE))
--
2.43.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] accel/qaic: Use overflow check function instead of division
2025-10-07 17:42 [PATCH] accel/qaic: Use overflow check function instead of division Youssef Samir
@ 2025-10-07 20:07 ` Jeff Hugo
2025-10-13 23:22 ` Carl Vanderlip
2025-10-14 15:53 ` Jeff Hugo
2 siblings, 0 replies; 4+ messages in thread
From: Jeff Hugo @ 2025-10-07 20:07 UTC (permalink / raw)
To: Youssef Samir, carl.vanderlip, troy.hanson, zachary.mckevitt
Cc: ogabbay, lizhi.hou, karol.wachowski, linux-arm-msm, dri-devel
On 10/7/2025 11:42 AM, Youssef Samir wrote:
> From: Carl Vanderlip <quic_carlv@quicinc.com>
>
> Division is an expensive operation. Overflow check functions exist
> already. Use existing overflow check functions rather than dividing to
> check for overflow.
>
> Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com>
> Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
Reviewed-by: Jeff Hugo <jeff.hugo@oss.qualcomm.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] accel/qaic: Use overflow check function instead of division
2025-10-07 17:42 [PATCH] accel/qaic: Use overflow check function instead of division Youssef Samir
2025-10-07 20:07 ` Jeff Hugo
@ 2025-10-13 23:22 ` Carl Vanderlip
2025-10-14 15:53 ` Jeff Hugo
2 siblings, 0 replies; 4+ messages in thread
From: Carl Vanderlip @ 2025-10-13 23:22 UTC (permalink / raw)
To: Youssef Samir, jeff.hugo, troy.hanson, zachary.mckevitt
Cc: ogabbay, lizhi.hou, karol.wachowski, linux-arm-msm, dri-devel
On 10/7/2025 10:42 AM, Youssef Samir wrote:
> From: Carl Vanderlip <quic_carlv@quicinc.com>
>
> Division is an expensive operation. Overflow check functions exist
> already. Use existing overflow check functions rather than dividing to
> check for overflow.
>
> Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com>
> Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
> ---
Reviewed-by: Carl Vanderlip <carl.vanderlip@oss.qualcomm.com>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] accel/qaic: Use overflow check function instead of division
2025-10-07 17:42 [PATCH] accel/qaic: Use overflow check function instead of division Youssef Samir
2025-10-07 20:07 ` Jeff Hugo
2025-10-13 23:22 ` Carl Vanderlip
@ 2025-10-14 15:53 ` Jeff Hugo
2 siblings, 0 replies; 4+ messages in thread
From: Jeff Hugo @ 2025-10-14 15:53 UTC (permalink / raw)
To: Youssef Samir, carl.vanderlip, troy.hanson, zachary.mckevitt
Cc: ogabbay, lizhi.hou, karol.wachowski, linux-arm-msm, dri-devel
On 10/7/2025 11:42 AM, Youssef Samir wrote:
> From: Carl Vanderlip <quic_carlv@quicinc.com>
>
> Division is an expensive operation. Overflow check functions exist
> already. Use existing overflow check functions rather than dividing to
> check for overflow.
>
> Signed-off-by: Carl Vanderlip <quic_carlv@quicinc.com>
> Signed-off-by: Youssef Samir <youssef.abdulrahman@oss.qualcomm.com>
Pushed to drm-misc-next.
-Jeff
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-10-07 17:42 [PATCH] accel/qaic: Use overflow check function instead of division Youssef Samir
2025-10-07 20:07 ` Jeff Hugo
2025-10-13 23:22 ` Carl Vanderlip
2025-10-14 15:53 ` Jeff Hugo
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