Re: [PATCH v6 01/30] drm/xe: Add NULL checks to scratch LRC allocation

["Lis, Tomasz" <tomasz.lis@intel.com>]

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On 10/6/2025 1:10 PM, Matthew Brost wrote:
> kmalloc can fail, the returned value must have a NULL check. This should
> be immediately after kmalloc for clarity.
>
> v5:
>   - Assert state->buffer in setup_bo if buffer is iomem (Tomasz)
Repeating as I sent it to rev5 late:

Reviewed-by: Tomasz Lis <tomasz.lis@intel.com>

-Tomasz

> Signed-off-by: Matthew Brost<matthew.brost@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_lrc.c | 13 +++++++++----
>   1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_lrc.c b/drivers/gpu/drm/xe/xe_lrc.c
> index af09f70f6e78..2c6eae2de1f2 100644
> --- a/drivers/gpu/drm/xe/xe_lrc.c
> +++ b/drivers/gpu/drm/xe/xe_lrc.c
> @@ -1214,8 +1214,7 @@ static int setup_bo(struct bo_setup_state *state)
>   	ssize_t remain;
>   
>   	if (state->lrc->bo->vmap.is_iomem) {
> -		if (!state->buffer)
> -			return -ENOMEM;
> +		xe_gt_assert(state->hwe->gt, state->buffer);
>   		state->ptr = state->buffer;
>   	} else {
>   		state->ptr = state->lrc->bo->vmap.vaddr + state->offset;
> @@ -1303,8 +1302,11 @@ static int setup_wa_bb(struct xe_lrc *lrc, struct xe_hw_engine *hwe)
>   	u32 *buf = NULL;
>   	int ret;
>   
> -	if (lrc->bo->vmap.is_iomem)
> +	if (lrc->bo->vmap.is_iomem) {
>   		buf = kmalloc(LRC_WA_BB_SIZE, GFP_KERNEL);
> +		if (!buf)
> +			return -ENOMEM;
> +	}
>   
>   	ret = xe_lrc_setup_wa_bb_with_scratch(lrc, hwe, buf);
>   
> @@ -1347,8 +1349,11 @@ setup_indirect_ctx(struct xe_lrc *lrc, struct xe_hw_engine *hwe)
>   	if (xe_gt_WARN_ON(lrc->gt, !state.funcs))
>   		return 0;
>   
> -	if (lrc->bo->vmap.is_iomem)
> +	if (lrc->bo->vmap.is_iomem) {
>   		state.buffer = kmalloc(state.max_size, GFP_KERNEL);
> +		if (!state.buffer)
> +			return -ENOMEM;
> +	}
>   
>   	ret = setup_bo(&state);
>   	if (ret) {

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