Thanks for looking into this. On 5/1/19 5:31 AM, Christoph Hellwig wrote: > On Tue, Apr 30, 2019 at 09:28:15PM -0700, Chaitanya Kulkarni wrote: >> @@ -104,7 +120,12 @@ struct blk_io_trace { >> __u64 time; /* in nanoseconds */ >> __u64 sector; /* disk offset */ >> __u32 bytes; /* transfer length */ >> + >> +#ifdef CONFIG_BLKTRACE_EXT >> + __u64 action; /* what happened */ >> +#else >> __u32 action; /* what happened */ >> +#endif /* CONFIG_BLKTRACE_EXT */ > > You can't use CONFIG_ symbols in UAPI headers, as userspace > applications won't set it. You also can't ever change the layout of an > existing structure in UAPI headers in not backward compatible way. > Jeff has suggested another approach, if everyone is okay with that approach will send out the series with that change. Please let me know if you have more comments.