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e81cff1ced
commit 9abffc6f2e upstream.
mcryptd_enqueue_request() grabs the per-CPU queue struct and protects
access to it with disabled preemption. Then it schedules a worker on the
same CPU. The worker in mcryptd_queue_worker() guards access to the same
per-CPU variable with disabled preemption.
If we take CPU-hotplug into account then it is possible that between
queue_work_on() and the actual invocation of the worker the CPU goes
down and the worker will be scheduled on _another_ CPU. And here the
preempt_disable() protection does not work anymore. The easiest thing is
to add a spin_lock() to guard access to the list.
Another detail: mcryptd_queue_worker() is not processing more than
MCRYPTD_BATCH invocation in a row. If there are still items left, then
it will invoke queue_work() to proceed with more later. *I* would
suggest to simply drop that check because it does not use a system
workqueue and the workqueue is already marked as "CPU_INTENSIVE". And if
preemption is required then the scheduler should do it.
However if queue_work() is used then the work item is marked as CPU
unbound. That means it will try to run on the local CPU but it may run
on another CPU as well. Especially with CONFIG_DEBUG_WQ_FORCE_RR_CPU=y.
Again, the preempt_disable() won't work here but lock which was
introduced will help.
In order to keep work-item on the local CPU (and avoid RR) I changed it
to queue_work_on().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
114 lines
2.3 KiB
C
114 lines
2.3 KiB
C
/*
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* Software async multibuffer crypto daemon headers
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*
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* Author:
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* Tim Chen <tim.c.chen@linux.intel.com>
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*
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* Copyright (c) 2014, Intel Corporation.
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*/
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#ifndef _CRYPTO_MCRYPT_H
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#define _CRYPTO_MCRYPT_H
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#include <linux/crypto.h>
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#include <linux/kernel.h>
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#include <crypto/hash.h>
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struct mcryptd_ahash {
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struct crypto_ahash base;
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};
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static inline struct mcryptd_ahash *__mcryptd_ahash_cast(
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struct crypto_ahash *tfm)
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{
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return (struct mcryptd_ahash *)tfm;
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}
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struct mcryptd_cpu_queue {
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struct crypto_queue queue;
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spinlock_t q_lock;
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struct work_struct work;
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};
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struct mcryptd_queue {
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struct mcryptd_cpu_queue __percpu *cpu_queue;
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};
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struct mcryptd_instance_ctx {
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struct crypto_spawn spawn;
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struct mcryptd_queue *queue;
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};
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struct mcryptd_hash_ctx {
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struct crypto_ahash *child;
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struct mcryptd_alg_state *alg_state;
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};
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struct mcryptd_tag {
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/* seq number of request */
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unsigned seq_num;
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/* arrival time of request */
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unsigned long arrival;
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unsigned long expire;
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int cpu;
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};
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struct mcryptd_hash_request_ctx {
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struct list_head waiter;
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crypto_completion_t complete;
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struct mcryptd_tag tag;
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struct crypto_hash_walk walk;
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u8 *out;
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int flag;
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struct ahash_request areq;
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};
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struct mcryptd_ahash *mcryptd_alloc_ahash(const char *alg_name,
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u32 type, u32 mask);
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struct crypto_ahash *mcryptd_ahash_child(struct mcryptd_ahash *tfm);
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struct ahash_request *mcryptd_ahash_desc(struct ahash_request *req);
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void mcryptd_free_ahash(struct mcryptd_ahash *tfm);
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void mcryptd_flusher(struct work_struct *work);
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enum mcryptd_req_type {
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MCRYPTD_NONE,
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MCRYPTD_UPDATE,
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MCRYPTD_FINUP,
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MCRYPTD_DIGEST,
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MCRYPTD_FINAL
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};
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struct mcryptd_alg_cstate {
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unsigned long next_flush;
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unsigned next_seq_num;
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bool flusher_engaged;
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struct delayed_work flush;
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int cpu;
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struct mcryptd_alg_state *alg_state;
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void *mgr;
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spinlock_t work_lock;
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struct list_head work_list;
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struct list_head flush_list;
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};
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struct mcryptd_alg_state {
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struct mcryptd_alg_cstate __percpu *alg_cstate;
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unsigned long (*flusher)(struct mcryptd_alg_cstate *cstate);
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};
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/* return delay in jiffies from current time */
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static inline unsigned long get_delay(unsigned long t)
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{
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long delay;
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delay = (long) t - (long) jiffies;
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if (delay <= 0)
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return 0;
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else
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return (unsigned long) delay;
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}
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void mcryptd_arm_flusher(struct mcryptd_alg_cstate *cstate, unsigned long delay);
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#endif
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