Messages in this thread | | | Date | Fri, 25 Nov 2022 12:58:23 +0100 | From | Maciej Fijalkowski <> | Subject | Re: [PATCH net-next] Revert "net: stmmac: use sysfs_streq() instead of strncmp()" |
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On Fri, Nov 25, 2022 at 12:53:04PM +0200, Vladimir Oltean wrote: > This reverts commit f72cd76b05ea1ce9258484e8127932d0ea928f22. > This patch is so broken, it hurts. Apparently no one reviewed it and it > passed the build testing (because the code was compiled out), but it was > obviously never compile-tested, since it produces the following build > error, due to an incomplete conversion where an extra argument was left, > although the function being called was left: > > stmmac_main.c: In function ‘stmmac_cmdline_opt’: > stmmac_main.c:7586:28: error: too many arguments to function ‘sysfs_streq’ > 7586 | } else if (sysfs_streq(opt, "pause:", 6)) { > | ^~~~~~~~~~~ > In file included from ../include/linux/bitmap.h:11, > from ../include/linux/cpumask.h:12, > from ../include/linux/smp.h:13, > from ../include/linux/lockdep.h:14, > from ../include/linux/mutex.h:17, > from ../include/linux/notifier.h:14, > from ../include/linux/clk.h:14, > from ../drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:17: > ../include/linux/string.h:185:13: note: declared here > 185 | extern bool sysfs_streq(const char *s1, const char *s2); > | ^~~~~~~~~~~ > > What's even worse is that the patch is flat out wrong. The stmmac_cmdline_opt() > function does not parse sysfs input, but cmdline input such as > "stmmaceth=tc:1,pause:1". The pattern of using strsep() followed by > strncmp() for such strings is not unique to stmmac, it can also be found > mainly in drivers under drivers/video/fbdev/. > > With strncmp("tc:", 3), the code matches on the "tc:1" token properly. > With sysfs_streq("tc:"), it doesn't. > > Fixes: f72cd76b05ea ("net: stmmac: use sysfs_streq() instead of strncmp()") > Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Ah the infamous string handling in C...
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Even when there would be no build error I agree that we should have kept the code as it was.
> --- > .../net/ethernet/stmicro/stmmac/stmmac_main.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index 1a86e66e4560..3affb7d3a005 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -7565,31 +7565,31 @@ static int __init stmmac_cmdline_opt(char *str) > if (!str || !*str) > return 1; > while ((opt = strsep(&str, ",")) != NULL) { > - if (sysfs_streq(opt, "debug:")) { > + if (!strncmp(opt, "debug:", 6)) { > if (kstrtoint(opt + 6, 0, &debug)) > goto err; > - } else if (sysfs_streq(opt, "phyaddr:")) { > + } else if (!strncmp(opt, "phyaddr:", 8)) { > if (kstrtoint(opt + 8, 0, &phyaddr)) > goto err; > - } else if (sysfs_streq(opt, "buf_sz:")) { > + } else if (!strncmp(opt, "buf_sz:", 7)) { > if (kstrtoint(opt + 7, 0, &buf_sz)) > goto err; > - } else if (sysfs_streq(opt, "tc:")) { > + } else if (!strncmp(opt, "tc:", 3)) { > if (kstrtoint(opt + 3, 0, &tc)) > goto err; > - } else if (sysfs_streq(opt, "watchdog:")) { > + } else if (!strncmp(opt, "watchdog:", 9)) { > if (kstrtoint(opt + 9, 0, &watchdog)) > goto err; > - } else if (sysfs_streq(opt, "flow_ctrl:")) { > + } else if (!strncmp(opt, "flow_ctrl:", 10)) { > if (kstrtoint(opt + 10, 0, &flow_ctrl)) > goto err; > - } else if (sysfs_streq(opt, "pause:", 6)) { > + } else if (!strncmp(opt, "pause:", 6)) { > if (kstrtoint(opt + 6, 0, &pause)) > goto err; > - } else if (sysfs_streq(opt, "eee_timer:")) { > + } else if (!strncmp(opt, "eee_timer:", 10)) { > if (kstrtoint(opt + 10, 0, &eee_timer)) > goto err; > - } else if (sysfs_streq(opt, "chain_mode:")) { > + } else if (!strncmp(opt, "chain_mode:", 11)) { > if (kstrtoint(opt + 11, 0, &chain_mode)) > goto err; > } > -- > 2.34.1 >
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