[LTP] [PATCH v2] lib: introduce safe_write() retry

[Jan Stancek]

On Tue, Oct 4, 2022 at 2:20 PM Petr Vorel <pvorel@suse.cz> wrote:
>
> Hi Jan,
>
> > Turn safe_write() len_strict parameter into 3-way switch, introducing
> > one additional mode of operation "retry". On short writes, this
> > resumes write() with remainder of the buffer.
>
> Reviewed-by: Petr Vorel <pvorel@suse.cz>
>
> > ---
> >  include/safe_macros_fn.h    | 11 ++++++++--
> >  lib/safe_macros.c           | 42 ++++++++++++++++++++++++++++---------
> >  lib/tests/tst_safe_macros.c |  6 +++---
> >  3 files changed, 44 insertions(+), 15 deletions(-)
>
> LGTM. I just wonder if we need to add it to lib/safe_macros.c,

It's currently shared code.

> which implements it for the old API. Would it work to add it only to
> tst_safe_macros.c and tst_safe_macros.h (instead of safe_macros_fn.h)?

We could have 2 implementations for safe_write, but modifying existing one
seemed better option. There's no harm supporting new option in old API too.

> Not a requirement, just if it makes sense to you.
>
> ...
> > +++ b/include/safe_macros_fn.h
> > @@ -24,6 +24,13 @@
> >  #include <unistd.h>
> >  #include <dirent.h>
>
> > +/* supported values for safe_write() len_strict parameter */
> > +enum safe_write_opts {
> > +        SAFE_WRITE_ANY = 0,  // no length strictness, short writes are ok
> > +        SAFE_WRITE_ALL = 1,  // strict length, short writes raise TBROK
> > +        SAFE_WRITE_RETRY = 2,        // retry/resume after short write
> > +};
>
> Maybe use /* */ and for readability, maybe put into it's own line?
>
> enum safe_write_opts {
>         /* no length strictness, short writes are ok */
>         SAFE_WRITE_ANY = 0,
>
>         /* strict length, short writes raise TBROK */
>         SAFE_WRITE_ALL = 1,
>
>         /* retry/resume after short write */
>         SAFE_WRITE_RETRY = 2,   //
> };
>
> Also checkpatch.pl complains:
>
> safe_macros_fn.h:29: ERROR: code indent should use tabs where possible
> safe_macros_fn.h:29: WARNING: please, no spaces at the start of a line
> safe_macros_fn.h:30: ERROR: code indent should use tabs where possible
> safe_macros_fn.h:30: WARNING: please, no spaces at the start of a line
> safe_macros_fn.h:31: ERROR: code indent should use tabs where possible
> safe_macros_fn.h:31: WARNING: please, no spaces at the start of a line

thanks, I missed that.

>
> Kind regards,
> Petr
>