linux/drivers/char
Jason A. Donenfeld f5bda35fba 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>
2022-05-19 16:54:10 +02:00
..
agp dma-mapping updates for Linux 5.18 2022-03-29 08:50:14 -07:00
hw_random ARM driver updates for 5.18 2022-03-23 18:23:13 -07:00
ipmi ipmi:ipmi_ipmb: Fix null-ptr-deref in ipmi_unregister_smi() 2022-04-29 10:06:52 -05:00
mwave
pcmcia
tpm xen: branch for v5.18-rc1 2022-03-28 14:32:39 -07:00
xilinx_hwicap xilinx_hwicap: cleanup comments 2022-02-25 12:08:57 +01:00
xillybus
adi.c
apm-emulation.c
applicom.c
applicom.h
bsr.c powerpc/BSR: Make use of the helper macro LIST_HEAD() 2022-02-25 12:10:15 +01:00
ds1620.c
dsp56k.c
dtlk.c
hangcheck-timer.c
hpet.c hpet: remove unused writeq/readq function definitions 2022-02-04 16:45:39 +01:00
Kconfig random: treat bootloader trust toggle the same way as cpu trust toggle 2022-03-25 08:49:40 -06:00
lp.c
Makefile
mem.c Revert "random: block in /dev/urandom" 2022-03-22 09:17:20 -07:00
misc.c
mspec.c
nsc_gpio.c
nvram.c
nwbutton.c
nwbutton.h
nwflash.c
pc8736x_gpio.c
powernv-op-panel.c
ppdev.c
ps3flash.c
random.c random: use static branch for crng_ready() 2022-05-19 16:54:10 +02:00
scx200_gpio.c
sonypi.c
tb0219.c
tlclk.c
toshiba.c
ttyprintk.c
uv_mmtimer.c
virtio_console.c Char/Misc and other driver updates for 5.18-rc1 2022-03-28 12:27:35 -07:00