Re: [PATCH 04/16] blktrace: add definitions for struct blk_io_trace2

On Tue, Sep 09, 2025 at 01:05:59PM +0200, Johannes Thumshirn wrote:
> +struct blk_io_trace2 {
> +	__u32 magic;		/* MAGIC << 8 | BLK_IO_TRACE2_VERSION */
> +	__u32 sequence;		/* event number */
> +	__u64 time;		/* in nanoseconds */
> +	__u64 sector;		/* disk offset */
> +	__u32 bytes;		/* transfer length */
> +	__u32 pid;		/* who did it */
> +	__u64 action;		/* what happened */
> +	__u32 device;		/* device number */
> +	__u32 cpu;		/* on what cpu did it happen */
> +	__u16 error;		/* completion error */
> +	__u16 pdu_len;		/* length of data after this trace */
> +	/* cgroup id will be stored here if exists */
> +};

This structure is not u64-aligned, which means it will have different
sizes for x86-32 vs all other architectures, making it a pain to handle.

Also maybe add some extra padding so that we can extend this?