Re: [RFC PATCH 28/30] Improved symbolic error names

Joe Perches
2022-09-01T23:35:42Z

On Tue, 2022-08-30 at 14:49 -0700, Suren Baghdasaryan wrote:
> From: Kent Overstreet <kent.overstreet@linux.dev>
>
> This patch adds per-error-site error codes, with error strings that
> include their file and line number.
>
> To use, change code that returns an error, e.g.
> return -ENOMEM;
> to
> return -ERR(ENOMEM);
>
> Then, errname() will return a string that includes the file and line
> number of the ERR() call, for example
> printk("Got error %s!\n", errname(err));
> will result in
> Got error ENOMEM at foo.c:1234

Why? Something wrong with just using %pe ?

printk("Got error %pe at %s:%d!\n", ERR_PTR(err), __FILE__, __LINE__);

Likely __FILE__ and __LINE__ aren't particularly useful.

And using ERR would add rather a lot of bloat as each codetag_error_code
struct would be unique.

+#define ERR(_err) \
+({ \
+ static struct codetag_error_code \
+ __used \
+ __section("error_code_tags") \
+ __aligned(8) e = { \
+ .str = #_err " at " __FILE__ ":" __stringify(__LINE__),\
+ .err = _err, \
+ }; \
+ \
+ e.err; \
+})