[PATCH] i3c: dw: make struct dw_i3c_cmd smaller

[PATCH] i3c: dw: make struct dw_i3c_cmd smaller

[Jisheng Zhang]

The dw_i3c_cmd is dynamically allocated, make it smaller. For example
on 64bit platforms, we reduce the size from 48 bytes to 32 bytes.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
 drivers/i3c/master/dw-i3c-master.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
index 6ba84a97765f..d6f84f0f4c2d 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -247,10 +247,10 @@ struct dw_i3c_cmd {
 	u32 cmd_lo;
 	u32 cmd_hi;
 	u16 tx_len;
-	const void *tx_buf;
 	u16 rx_len;
-	void *rx_buf;
 	u8 error;
+	const void *tx_buf;
+	void *rx_buf;
 };
 
 struct dw_i3c_xfer {
-- 
2.51.0


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Re: [PATCH] i3c: dw: make struct dw_i3c_cmd smaller

[Frank Li]

On Thu, Aug 13, 2026 at 12:46:03PM +0800, Jisheng Zhang wrote:
> The dw_i3c_cmd is dynamically allocated, make it smaller. For example
> on 64bit platforms, we reduce the size from 48 bytes to 32 bytes.
>
> Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> ---
>  drivers/i3c/master/dw-i3c-master.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/i3c/master/dw-i3c-master.c b/drivers/i3c/master/dw-i3c-master.c
> index 6ba84a97765f..d6f84f0f4c2d 100644
> --- a/drivers/i3c/master/dw-i3c-master.c
> +++ b/drivers/i3c/master/dw-i3c-master.c
> @@ -247,10 +247,10 @@ struct dw_i3c_cmd {
>  	u32 cmd_lo;
>  	u32 cmd_hi;
>  	u16 tx_len;
> -	const void *tx_buf;
>  	u16 rx_len;

only switch rx_len and tx_buf should be enough. otherwise there are data
pad after u8 error.

Frank

> -	void *rx_buf;
>  	u8 error;
> +	const void *tx_buf;
> +	void *rx_buf;
>  };
>
>  struct dw_i3c_xfer {
> --
> 2.51.0
>

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