Re: [PATCH v7 3/5] tcp: Resend SYN for inbound connections

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Nov 10, 2025 at 10:52:05AM +0800, Yumei Huang wrote:
> On Fri, Nov 7, 2025 at 6:05 PM Stefano Brivio <sbrivio@redhat.com> wrote:
> >
> > On Fri, 7 Nov 2025 17:56:54 +0800
> > Yumei Huang <yuhuang@redhat.com> wrote:
> >
> > > On Wed, Nov 5, 2025 at 3:01 PM Stefano Brivio <sbrivio@redhat.com> wrote:
> > > >
> > > > On Wed, 5 Nov 2025 15:24:44 +1100
> > > > David Gibson <david@gibson.dropbear.id.au> wrote:
> > > >
> > > > > On Tue, Nov 04, 2025 at 05:42:33AM +0100, Stefano Brivio wrote:
> > > > > > On Fri, 31 Oct 2025 13:42:40 +0800
> > > > > > Yumei Huang <yuhuang@redhat.com> wrote:
> > > > > [snip]
> > > > > > > +/**
> > > > > > > + * tcp_get_rto_params() - Get host kernel RTO parameters
> > > > > > > + * @c:           Execution context
> > > > > > > +*/
> > > > > > > +void tcp_get_rto_params(struct ctx *c)
> > > > > > > +{
> > > > > > > + intmax_t tcp_syn_retries, syn_linear_timeouts;
> > > > > > > +
> > > > > > > + tcp_syn_retries = read_file_integer(
> > > > > > > +         TCP_SYN_RETRIES, TCP_SYN_RETRIES_DEFAULT);
> > > > > > > + syn_linear_timeouts = read_file_integer(
> > > > > > > +         TCP_SYN_LINEAR_TIMEOUTS, TCP_SYN_LINEAR_TIMEOUTS_DEFAULT);
> > > > > >
> > > > > > I think this is a bit hard to read. Now:
> > > > > >
> > > > > >     tcp_syn_retries = read_file_integer(TCP_SYN_RETRIES,
> > > > > >                                         TCP_SYN_RETRIES_DEFAULT);
> > > > > >     syn_linear_timeouts = read_file_integer(TCP_SYN_LINEAR_TIMEOUTS,
> > > > > >                                             TCP_SYN_LINEAR_TIMEOUTS_DEFAULT);
> > > > > >
> > > > > > would be a bit closer to the coding style we're adopting, but I wonder:
> > > > > >
> > > > > > - does read_file_integer() really need to have "integer" in the name?
> > > > >
> > > > > >   In a language where integers are called 'int', perhaps
> > > > > >   read_file_int() is clear enough?
> > > > >
> > > > > I think the idea is that read_file_integer() can be used for any
> > > > > (signed) integer type (with range checking performed after the call).
> > > > > read_file_int() might suggest it reads exactly an 'int', not anything
> > > > > bigger or smaller.
> > > >
> > > > Oh, I see. It could be read_file_num() then, even if it's slightly less
> > > > accurate, or it can even remain read_file_integer(). If something like
> > > > this:
> > > >
> > > >         v = read_file_integer(SYN_RETRIES, SYN_RETRIES_DEFAULT);
> > > >         c->tcp.tcp_syn_retries = MIN(v, UINT8_MAX);
> > > >
> > > >         v = read_file_integer(SYN_LINEAR_TIMEOUTS, SYN_LINEAR_TIMEOUTS_DEFAULT);
> > > >         c->tcp.syn_linear_timeouts = MIN(v, UINT8_MAX);
> > > >
> > > > fits 80 columns, I'm taking it as a sign that the function name isn't
> > > > exceedingly long. No particular preference from me.
> > >
> > > The longest line just exceeds 80 columns.
> >
> > No, why? It's 80 columns, look:
> >
> >         v = read_file_integer(SYN_LINEAR_TIMEOUTS, SYN_LINEAR_TIMEOUTS_DEFAULT);
> > 01234567890123456789012345678901234567890123456789012345678901234567890123456789
> 
> You are right. Somehow I counted 81 columns. Then I will keep the name
> as it is.  (To me, read_file_num() sounds like it can read any kind of
> number.)

I also slightly prefer read_file_integer().

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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