crypto: x86/aes-gcm - fix PREEMPT_RT issue in gcm_crypt()
On PREEMPT_RT, kfree() takes sleeping locks and must not be called with
preemption disabled. Therefore, on PREEMPT_RT skcipher_walk_done() must
not be called from within a kernel_fpu_{begin,end}() pair, even when
it's the last call which is guaranteed to not allocate memory.
Therefore, move the last skcipher_walk_done() in gcm_crypt() to the end
of the function so that it goes after the kernel_fpu_end(). To make
this work cleanly, rework the data processing loop to handle only
non-last data segments.
Fixes: b06affb1cb58 ("crypto: x86/aes-gcm - add VAES and AVX512 / AVX10 optimized AES-GCM") Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Closes: https://lore.kernel.org/linux-crypto/20240802102333.itejxOsJ@linutronix.de Signed-off-by: Eric Biggers <ebiggers@google.com> Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>