Messages in this thread | | | From | Uwe Kleine-König <> | Subject | Re: [PATCH v2] printf: add support for printing symbolic error codes | Date | Mon, 16 Sep 2019 14:23:34 +0200 |
| |
Hello Rasmus,
On 9/9/19 10:38 PM, Rasmus Villemoes wrote: > It has been suggested several times to extend vsnprintf() to be able > to convert the numeric value of ENOSPC to print "ENOSPC". This is yet > another attempt. Rather than adding another %p extension, simply teach > plain %p to convert ERR_PTRs. While the primary use case is > > if (IS_ERR(foo)) { > pr_err("Sorry, can't do that: %p\n", foo); > return PTR_ERR(foo); > } > > it is also more helpful to get a symbolic error code (or, worst case, > a decimal number) in case an ERR_PTR is accidentally passed to some > %p<something>, rather than the (efault) that check_pointer() would > result in. > > With my embedded hat on, I've made it possible to remove this. > > I've tested that the #ifdeffery in errcode.c is sufficient to make > this compile on arm, arm64, mips, powerpc, s390, x86 - I'm sure the > 0day bot will tell me which ones I've missed. > > The symbols to include have been found by massaging the output of > > find arch include -iname 'errno*.h' | xargs grep -E 'define\s*E' > > In the cases where some common aliasing exists > (e.g. EAGAIN=EWOULDBLOCK on all platforms, EDEADLOCK=EDEADLK on most), > I've moved the more popular one (in terms of 'git grep -w Efoo | wc) > to the bottom so that one takes precedence. > > Acked-by: Uwe Kleine-König <uwe@kleine-koenig.org> > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Even with my ack already given I still think having %pE (or %pe) for ints holding an error code is sensible. So I wonder if it would be a good idea to split this patch into one that introduces errcode() and then the patch that teaches vsprintf about emitting its return value for error valued pointers. Then I could rebase my initial patch for %pe on top of your first one.
Other than that I wonder how we can go forward from here. So I think it is time for v3 which picks up the few suggestions.
Best regards Uwe
[unhandled content-type:application/pgp-signature] | |