On 03/12/2018 05:00 PM, Andrew Morton wrote: > On Mon, 12 Mar 2018 16:15:41 -0400 Waiman Long <longman@xxxxxxxxxx> wrote: > >> Even with clamped sysctl parameters, it is still not that straight >> forward to figure out the exact range of those parameters. One may >> try to write extreme parameter values to see if they get clamped. >> To make it easier, a warning with the expected range will now be >> printed into the kernel ring buffer when a clamped sysctl parameter >> receives an out of range value. >> >> The pr_warn_ratelimited() macro is used to limit the number of warning >> messages that can be printed within a given period of time. >> >> ... >> >> +#ifdef pr_fmt >> +#undef pr_fmt >> +#endif >> +#define pr_fmt(fmt) "sysctl: " fmt > Why is it necessary to undefine pr_fmt? That's a somewhat unusual > thing to do. > > Because it is defined in the printk.h. I should have put the pr_fmt definition before the iinclude file to eliminate the need to undefine it. -Longman
