PCI/AER sysfs files violate the rules of how sysfs works

From: Greg KH
Date: Fri Jun 21 2019 - 03:29:16 EST


Hi,

When working on some documentation scripts to show the
Documentation/ABI/ files in an automated way, I ran across this "gem" of
a sysfs file: Documentation/ABI/testing/sysfs-bus-pci-devices-aer_stats

In it you describe how the files
/sys/bus/pci/devices/<dev>/aer_dev_correctable and
/sys/bus/pci/devices/<dev>/aer_dev_fatal and
/sys/bus/pci/devices/<dev>/aer_dev_nonfatal
all display a bunch of text on multiple lines.

This violates the "one value per sysfs file" rule, and should never have
been merged as-is :(

Please fix it up to be a lot of individual files if your really need all
of those different values.

Remember, sysfs files should never have to have a parser to read them
other than a simple "what is this single value", and you should NEVER
have fun macros like:

for (i = 0; i < ARRAY_SIZE(strings_array); i++) { \
if (strings_array[i]) \
str += sprintf(str, "%s %llu\n", \
strings_array[i], stats[i]); \
else if (stats[i]) \
str += sprintf(str, #stats_array "_bit[%d] %llu\n",\
i, stats[i]); \
} \
str += sprintf(str, "TOTAL_%s %llu\n", total_string, \
pdev->aer_stats->total_field); \

spit out sysfs information.

Note, I am all for not properly checking the length of the sysfs file
when writing to it, but that is ONLY because you "know" that a single
integer will never overflow anything. Here you are writing a ton of
different values, with no error checking at all. So just when I thought
it couldn't be any worse...

Please fix.

thanks,

greg k-h