Messages in this thread | | | From | Valentin Schneider <> | Subject | Re: [RFC PATCH v2 06/20] tracing/filters: Optimise scalar vs cpumask filtering when the user mask is a single CPU | Date | Mon, 31 Jul 2023 18:20:49 +0100 |
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On 31/07/23 19:03, Dan Carpenter wrote: > On Mon, Jul 31, 2023 at 11:54:53AM -0400, Steven Rostedt wrote: >> On Mon, 31 Jul 2023 15:07:52 +0300 >> Dan Carpenter <dan.carpenter@linaro.org> wrote: >> >> > On Sat, Jul 29, 2023 at 03:55:47PM -0400, Steven Rostedt wrote: >> > > > @@ -1761,6 +1761,11 @@ static int parse_pred(const char *str, void *data, >> > > > FILTER_PRED_FN_CPUMASK; >> > > > } else if (field->filter_type == FILTER_CPU) { >> > > > pred->fn_num = FILTER_PRED_FN_CPU_CPUMASK; >> > > > + } else if (single) { >> > > > + pred->op = pred->op == OP_BAND ? OP_EQ : pred->op; >> > > >> > > Nit, the above can be written as: >> > > >> > > pred->op = pret->op != OP_BAND ? : OP_EQ; >> > > >> > >> > Heh. Those are not equivalent. The right way to write this is: >> >> You mean because of my typo? > > No, I hadn't seen the s/pred/pret/ typo. Your code does: > > if (pred->op != OP_BAND) > pred->op = true; > else > pred->op OP_EQ; > > Realy we should probably trigger a static checker warning any time > someone does a compare operations as part of a "x = comparison ?: bar; > Years ago, someone asked me to do that with regards to error codes like: > > return ret < 0 ?: -EINVAL; > > but I don't remember the results. >
FWIW this is caught by GCC:
error: the omitted middle operand in ?: will always be ‘true’, suggest explicit middle operand [-Werror=parentheses] pred->op = pred->op != OP_BAND ? : OP_EQ;
> regards, > dan carpenter
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