Re: [PATCH] firmware: ti_sci: simplify resource allocation

[Nishanth Menon]

On 15:11-20260430, Rosen Penev wrote:
> Use a flexible array member to combine allocations.
> 
> Add __counted_by for extra runtime analysis.
> 
> Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
> ---
>  drivers/firmware/ti_sci.c              | 7 +------
>  include/linux/soc/ti/ti_sci_protocol.h | 2 +-
>  2 files changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/firmware/ti_sci.c b/drivers/firmware/ti_sci.c
> index e027a2bd8f26..04d99c1fafa1 100644
> --- a/drivers/firmware/ti_sci.c
> +++ b/drivers/firmware/ti_sci.c
> @@ -3574,16 +3574,11 @@ devm_ti_sci_get_resource_sets(const struct ti_sci_handle *handle,
>  	bool valid_set = false;
>  	int i, ret, res_count;
>  
> -	res = devm_kzalloc(dev, sizeof(*res), GFP_KERNEL);
> +	res = devm_kzalloc(dev, struct_size(res, desc, sets), GFP_KERNEL);
>  	if (!res)
>  		return ERR_PTR(-ENOMEM);
>  
>  	res->sets = sets;
> -	res->desc = devm_kcalloc(dev, res->sets, sizeof(*res->desc),
> -				 GFP_KERNEL);
> -	if (!res->desc)
> -		return ERR_PTR(-ENOMEM);
> -
>  	for (i = 0; i < res->sets; i++) {
>  		ret = handle->ops.rm_core_ops.get_range(handle, dev_id,
>  							sub_types[i],
> diff --git a/include/linux/soc/ti/ti_sci_protocol.h b/include/linux/soc/ti/ti_sci_protocol.h
> index fd104b666836..7632bb11c862 100644
> --- a/include/linux/soc/ti/ti_sci_protocol.h
> +++ b/include/linux/soc/ti/ti_sci_protocol.h
> @@ -599,7 +599,7 @@ struct ti_sci_handle {
>  struct ti_sci_resource {
>  	u16 sets;
>  	raw_spinlock_t lock;
> -	struct ti_sci_resource_desc *desc;
> +	struct ti_sci_resource_desc desc[] __counted_by(sets);
>  };
>  
>  #if IS_ENABLED(CONFIG_TI_SCI_PROTOCOL)
> -- 
> 2.54.0
> 

drivers/dma/ti/k3-udma.c: In function 'udma_setup_resources':
drivers/dma/ti/k3-udma.c:4689:22: error: invalid use of flexible array member
 4689 |         irq_res.desc = kzalloc_objs(*irq_res.desc, irq_res.sets);
      |                      ^
drivers/dma/ti/k3-udma.c:4690:13: warning: the comparison will always evaluate as 'true' for the address of 'desc' will never be NULL [-Waddress]
 4690 |         if (!irq_res.desc)
      |             ^
In file included from drivers/dma/ti/k3-udma.c:27:
./include/linux/soc/ti/ti_sci_protocol.h:602:37: note: 'desc' declared here
  602 |         struct ti_sci_resource_desc desc[] __counted_by(sets);
      |                                     ^~~~
drivers/dma/ti/k3-udma.c: In function 'bcdma_setup_resources':
drivers/dma/ti/k3-udma.c:4881:22: error: invalid use of flexible array member
 4881 |         irq_res.desc = kzalloc_objs(*irq_res.desc, irq_res.sets);
      |                      ^
drivers/dma/ti/k3-udma.c:4882:13: warning: the comparison will always evaluate as 'true' for the address of 'desc' will never be NULL [-Waddress]
 4882 |         if (!irq_res.desc)
      |             ^
./include/linux/soc/ti/ti_sci_protocol.h:602:37: note: 'desc' declared here
  602 |         struct ti_sci_resource_desc desc[] __counted_by(sets);
      |                                     ^~~~
drivers/dma/ti/k3-udma.c: In function 'pktdma_setup_resources':
drivers/dma/ti/k3-udma.c:5083:22: error: invalid use of flexible array member
 5083 |         irq_res.desc = kzalloc_objs(*irq_res.desc, irq_res.sets);
      |                      ^
drivers/dma/ti/k3-udma.c:5084:13: warning: the comparison will always evaluate as 'true' for the address of 'desc' will never be NULL [-Waddress]
 5084 |         if (!irq_res.desc)
      |             ^
./include/linux/soc/ti/ti_sci_protocol.h:602:37: note: 'desc' declared here
  602 |         struct ti_sci_resource_desc desc[] __counted_by(sets);
      |                                     ^~~~
drivers/dma/ti/k3-udma.c: At top level:
drivers/dma/ti/k3-udma.c:53:9: warning: macro "UDMA_RFLOW_DSTTAG_FLOW_ID" is not used [-Wunused-macros]
   53 | #define UDMA_RFLOW_DSTTAG_FLOW_ID       2
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/dma/ti/k3-udma.c:52:9: warning: macro "UDMA_RFLOW_DSTTAG_CFG_TAG" is not used [-Wunused-macros]
   52 | #define UDMA_RFLOW_DSTTAG_CFG_TAG       1
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/dma/ti/k3-udma.c:48:9: warning: macro "UDMA_RFLOW_SRCTAG_FLOW_ID" is not used [-Wunused-macros]
   48 | #define UDMA_RFLOW_SRCTAG_FLOW_ID       2
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/dma/ti/k3-udma.c:51:9: warning: macro "UDMA_RFLOW_DSTTAG_NONE" is not used [-Wunused-macros]
   51 | #define UDMA_RFLOW_DSTTAG_NONE          0
      |         ^~~~~~~~~~~~~~~~~~~~~~
drivers/dma/ti/k3-udma.c:47:9: warning: macro "UDMA_RFLOW_SRCTAG_CFG_TAG" is not used [-Wunused-macros]
   47 | #define UDMA_RFLOW_SRCTAG_CFG_TAG       1
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~
make[5]: *** [scripts/Makefile.build:290: drivers/dma/ti/k3-udma.o] Error 1
make[4]: *** [scripts/Makefile.build:551: drivers/dma/ti] Error 2
make[3]: *** [scripts/Makefile.build:551: drivers/dma] Error 2
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [scripts/Makefile.build:551: drivers] Error 2
make[1]: *** [/workdir/Makefile:2232: .] Error 2
make: *** [Makefile:248: __sub-make] Error 2


If I am not mistaken, k3-udma.c and k3-ringacc.c will be impacted. can
you check and update the patch?


Additionally, please CC LAKML.

-- 
Regards,
Nishanth Menon
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