Re: [PATCH] Support single byte reads from integers published in procfs by kernel/sysctl.c

[Earl Chew <echew@ixiacom.com>]

> I suspect what we want for writes is to read the existing value into an
> internal buffer, and then allow partial writes to the internal buffer.

Oh I see. Hmm ... I get the feeling that doubles the scope of the exercise ;-)

I'll give it some more thought.

> I don't know if writable seq_files exist.

No, they don't -- at least not out-of-the-box. From fs/seq_file.c :

>         /*
>          * seq_files support lseek() and pread().  They do not implement
>          * write() at all, but we clear FMODE_PWRITE here for historical
>          * reasons.
>          *
>          * If a client of seq_files a) implements file.write() and b) wishes to
>          * support pwrite() then that client will need to implement its own
>          * file.open() which calls seq_open() and then sets FMODE_PWRITE.
>          */
>         file->f_mode &= ~FMODE_PWRITE;

Earl