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author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-05-03 15:30:45 +0200 |
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committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-05-19 16:54:10 +0200 |
commit | f5bda35fba615ace70a656d4700423fa6c9bebee (patch) | |
tree | a4f1f7267646d1c170f57c5c6e91bb1e65afdce7 /certs/blacklist.c | |
parent | 12e45a2a6308105469968951e6d563e8f4fea187 (diff) |
random: use static branch for crng_ready()
Since crng_ready() is only false briefly during initialization and then
forever after becomes true, we don't need to evaluate it after, making
it a prime candidate for a static branch.
One complication, however, is that it changes state in a particular call
to credit_init_bits(), which might be made from atomic context, which
means we must kick off a workqueue to change the static key. Further
complicating things, credit_init_bits() may be called sufficiently early
on in system initialization such that system_wq is NULL.
Fortunately, there exists the nice function execute_in_process_context(),
which will immediately execute the function if !in_interrupt(), and
otherwise defer it to a workqueue. During early init, before workqueues
are available, in_interrupt() is always false, because interrupts
haven't even been enabled yet, which means the function in that case
executes immediately. Later on, after workqueues are available,
in_interrupt() might be true, but in that case, the work is queued in
system_wq and all goes well.
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Sultan Alsawaf <sultan@kerneltoast.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'certs/blacklist.c')
0 files changed, 0 insertions, 0 deletions