netdev - Re: [PATCH v2 2/2] selftests/net: replace ternary operator with min()/max()

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Message-ID: <CAF=yD-JPL6M9_q_W2OZH=4wis3GSfpYAo5Y7Jp+SyhA+NLeE3g@mail.gmail.com>
Date: Thu, 24 Aug 2023 17:22:01 -0400
From: Willem de Bruijn <willemdebruijn.kernel@...il.com>
To: Willem de Bruijn <willemdebruijn.kernel@...il.com>, keescook@...omium.org, 
	edumazet@...gle.com, wad@...omium.org, luto@...capital.net, 
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org, kuba@...nel.org, 
	shuah@...nel.org, pabeni@...hat.com, linux-kselftest@...r.kernel.org, 
	davem@...emloft.net, linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH v2 2/2] selftests/net: replace ternary operator with min()/max()

On Thu, Aug 24, 2023 at 5:13 PM Mahmoud Matook
<mahmoudmatook.mm@...il.com> wrote:
>
> On 08/24, Willem de Bruijn wrote:
>
> > On Thu, Aug 24, 2023 at 4:25 PM Mahmoud Maatuq
> > <mahmoudmatook.mm@...il.com> wrote:
> > >
> > > Fix the following coccicheck warning:
> > > tools/testing/selftests/net/udpgso_bench_tx.c:297:18-19: WARNING opportunity for min()
> > > tools/testing/selftests/net/udpgso_bench_tx.c:354:27-28: WARNING opportunity for min()
> > > tools/testing/selftests/net/so_txtime.c:129:24-26: WARNING opportunity for max()
> > > tools/testing/selftests/net/so_txtime.c:96:30-31: WARNING opportunity for max()
> > >
> > > Signed-off-by: Mahmoud Maatuq <mahmoudmatook.mm@...il.com>
> > > Suggested-by: Willem de Bruijn <willemdebruijn.kernel@...il.com>
> >
> > I did not suggest this change.
> >
> the suggestion i meant here is about the following part
> "Note that a more strict version that includes __typecheck would
> warn on the type difference between total_len and cfg_mss. Fine
> with changing the type of cfg_mss in the follow-on patch to address
> that."
> as mentioned here https://lore.kernel.org/all/CAF=yD-+6cWTiDgpsu=hUV+OvzDFRaT2ZUmtQo9qTrCB9i-+7ng@mail.gmail.com/
> I tried to change the type of cfg_mss but it creates a different warn
> at udpgso_bench_tx.c:354 between cfg_mss and left that's way i casted
> instead.
> apology if i misunderstood your point.

Thanks. It's fine to avoid changing the type or cast if it does not
set of any alarms.

I think Suggested-by is for when the main idea of the patch is
someone's suggestion. Not a big deal, but please drop in v3. It's your
hard work and yours only. I'll add my Reviewed-by.



> > > ---
> > > changes in v2:
> > > cast var cfg_mss to int to avoid static assertion
> > > after providing a stricter version of min() that does signedness checking.
> > > ---
> > >  tools/testing/selftests/net/Makefile          | 2 ++
> > >  tools/testing/selftests/net/so_txtime.c       | 7 ++++---
> > >  tools/testing/selftests/net/udpgso_bench_tx.c | 6 +++---
> > >  3 files changed, 9 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
> > > index 7f3ab2a93ed6..a06cc25489f9 100644
> > > --- a/tools/testing/selftests/net/Makefile
> > > +++ b/tools/testing/selftests/net/Makefile
> > > @@ -3,6 +3,8 @@
> > >
> > >  CFLAGS =  -Wall -Wl,--no-as-needed -O2 -g
> > >  CFLAGS += -I../../../../usr/include/ $(KHDR_INCLUDES)
> > > +# Additional include paths needed by kselftest.h
> > > +CFLAGS += -I../
> >
> > Why does kselftest.h need this? It does not include anything else?
> >
> > I'd just add #include "../kselftests.h" to so_txtime.c and remove the
> > path change from udpgso_bench_tx.c
> >
> > Fine with this approach. Just don't understand the comment
> >
>
> the comment here is wrong and it should be changed to include path
> needed to include kselftest.h or to be deleted
>
> > >
> > >  TEST_PROGS := run_netsocktests run_afpackettests test_bpf.sh netdevice.sh \
> > >               rtnetlink.sh xfrm_policy.sh test_blackhole_dev.sh
> > > diff --git a/tools/testing/selftests/net/so_txtime.c b/tools/testing/selftests/net/so_txtime.c
> > > index 2672ac0b6d1f..2936174e7de4 100644
> > > --- a/tools/testing/selftests/net/so_txtime.c
> > > +++ b/tools/testing/selftests/net/so_txtime.c
> > > @@ -33,6 +33,8 @@
> > >  #include <unistd.h>
> > >  #include <poll.h>
> > >
> > > +#include "kselftest.h"
> > > +
> > >  static int     cfg_clockid     = CLOCK_TAI;
> > >  static uint16_t        cfg_port        = 8000;
> > >  static int     cfg_variance_us = 4000;
> > > @@ -93,8 +95,7 @@ static void do_send_one(int fdt, struct timed_send *ts)
> > >                 msg.msg_controllen = sizeof(control);
> > >
> > >                 tdeliver = glob_tstart + ts->delay_us * 1000;
> > > -               tdeliver_max = tdeliver_max > tdeliver ?
> > > -                              tdeliver_max : tdeliver;
> > > +               tdeliver_max = max(tdeliver_max, tdeliver);
> > >
> > >                 cm = CMSG_FIRSTHDR(&msg);
> > >                 cm->cmsg_level = SOL_SOCKET;
> > > @@ -126,7 +127,7 @@ static void do_recv_one(int fdr, struct timed_send *ts)
> > >                 error(1, 0, "read: %dB", ret);
> > >
> > >         tstop = (gettime_ns(cfg_clockid) - glob_tstart) / 1000;
> > > -       texpect = ts->delay_us >= 0 ? ts->delay_us : 0;
> > > +       texpect = max(ts->delay_us, 0);
> > >
> > >         fprintf(stderr, "payload:%c delay:%lld expected:%lld (us)\n",
> > >                         rbuf[0], (long long)tstop, (long long)texpect);
> > > diff --git a/tools/testing/selftests/net/udpgso_bench_tx.c b/tools/testing/selftests/net/udpgso_bench_tx.c
> > > index 477392715a9a..6bd32a312901 100644
> > > --- a/tools/testing/selftests/net/udpgso_bench_tx.c
> > > +++ b/tools/testing/selftests/net/udpgso_bench_tx.c
> > > @@ -25,7 +25,7 @@
> > >  #include <sys/types.h>
> > >  #include <unistd.h>
> > >
> > > -#include "../kselftest.h"
> > > +#include "kselftest.h"
> > >
> > >  #ifndef ETH_MAX_MTU
> > >  #define ETH_MAX_MTU 0xFFFFU
> > > @@ -294,7 +294,7 @@ static int send_udp(int fd, char *data)
> > >         total_len = cfg_payload_len;
> > >
> > >         while (total_len) {
> > > -               len = total_len < cfg_mss ? total_len : cfg_mss;
> > > +               len = min(total_len, (int)cfg_mss);
> > >
> > >                 ret = sendto(fd, data, len, cfg_zerocopy ? MSG_ZEROCOPY : 0,
> > >                              cfg_connected ? NULL : (void *)&cfg_dst_addr,
> > > @@ -351,7 +351,7 @@ static int send_udp_sendmmsg(int fd, char *data)
> > >                         error(1, 0, "sendmmsg: exceeds max_nr_msg");
> > >
> > >                 iov[i].iov_base = data + off;
> > > -               iov[i].iov_len = cfg_mss < left ? cfg_mss : left;
> > > +               iov[i].iov_len = min(cfg_mss, left);
> > >
> > >                 mmsgs[i].msg_hdr.msg_iov = iov + i;
> > >                 mmsgs[i].msg_hdr.msg_iovlen = 1;
> > > --
> > > 2.34.1
> > >