The timestamps for the cache are all in boottime seconds, so they
don't overflow 32-bit values, but the use of time_t is deprecated
because it generally does overflow when used with wall-clock time.
There are multiple possible ways of avoiding it:
- leave time_t, which is safe here, but forces others to
look into this code to determine that it is over and over.
- use a more generic type, like 'int' or 'long', which is known
to be sufficient here but loses the documentation of referring
to timestamps
- use ktime_t everywhere, and convert into seconds in the few
places where we want realtime-seconds. The conversion is
sometimes expensive, but not more so than the conversion we
do today.
- use time64_t to clarify that this code is safe. Nothing would
change for 64-bit architectures, but it is slightly less
efficient on 32-bit architectures.
Without a clear winner of the three approaches above, this picks
the last one, favouring readability over a small performance
loss on 32-bit architectures.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
f559935e7c