Nobody uses explicit slots anymore:
/*
* Make both: kmap_atomic(page, idx) and kmap_atomic(page) work.
*/
#define kmap_atomic(page, args...) __kmap_atomic(page)
All instances of KM_foo are deprecated and in need of a cleanup.
With the current 20 slots on x86, its 80k per CPU, you need 25 CPUs to
cross the 2M boundary, 32bit kernels having that many CPUs deserve to
suffer.
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