Hi David, >> + } else { >> port_spec = hso_get_config_data(interface); >> + if (IS_ERR_VALUE((long)port_spec)) >> + goto exit; > > 'port_spec' is an 'int', it makes no sense to cast it 3 times all the > way back to 'int' to figure out if it is a negative error value or > not. (--> long --> void * --> int) > Passing an int to the macro results in a compiler warning. One option would be to test for the individual errors (instead of using the macro) with the drawback that future extensions that return different errors may be missed. Another alternative is to test for negative values with the drawback that this bypasses the existing test macros. Also, the macro does not cast back to int but unsigned long: https://elixir.bootlin.com/linux/v4.20-rc5/source/include/linux/err.h#L22 #define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO) The cast chain is int -> long -> void * -> unsigned long. What other check would you propose? Thanks, Mathias
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