2dc9b5dbde
When padata_do_parallel() is called from multiple cpus for the same padata instance, we can get object reordering on sequence number wrap because testing for sequence number wrap and reseting the sequence number must happen atomically but is implemented with two atomic operations. This patch fixes this by converting the sequence number from atomic_t to an unsigned int and protect the access with a spin_lock. As a side effect, we get rid of the sequence number wrap handling because the seqence number wraps back to null now without the need to do anything. Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
191 lines
6.4 KiB
C
191 lines
6.4 KiB
C
/*
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* padata.h - header for the padata parallelization interface
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*
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* Copyright (C) 2008, 2009 secunet Security Networks AG
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* Copyright (C) 2008, 2009 Steffen Klassert <steffen.klassert@secunet.com>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#ifndef PADATA_H
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#define PADATA_H
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#include <linux/workqueue.h>
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#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/timer.h>
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#include <linux/notifier.h>
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#include <linux/kobject.h>
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#define PADATA_CPU_SERIAL 0x01
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#define PADATA_CPU_PARALLEL 0x02
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/**
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* struct padata_priv - Embedded to the users data structure.
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*
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* @list: List entry, to attach to the padata lists.
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* @pd: Pointer to the internal control structure.
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* @cb_cpu: Callback cpu for serializatioon.
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* @seq_nr: Sequence number of the parallelized data object.
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* @info: Used to pass information from the parallel to the serial function.
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* @parallel: Parallel execution function.
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* @serial: Serial complete function.
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*/
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struct padata_priv {
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struct list_head list;
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struct parallel_data *pd;
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int cb_cpu;
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int info;
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void (*parallel)(struct padata_priv *padata);
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void (*serial)(struct padata_priv *padata);
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};
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/**
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* struct padata_list
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*
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* @list: List head.
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* @lock: List lock.
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*/
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struct padata_list {
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struct list_head list;
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spinlock_t lock;
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};
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/**
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* struct padata_serial_queue - The percpu padata serial queue
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*
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* @serial: List to wait for serialization after reordering.
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* @work: work struct for serialization.
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* @pd: Backpointer to the internal control structure.
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*/
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struct padata_serial_queue {
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struct padata_list serial;
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struct work_struct work;
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struct parallel_data *pd;
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};
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/**
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* struct padata_parallel_queue - The percpu padata parallel queue
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*
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* @parallel: List to wait for parallelization.
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* @reorder: List to wait for reordering after parallel processing.
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* @serial: List to wait for serialization after reordering.
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* @pwork: work struct for parallelization.
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* @swork: work struct for serialization.
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* @pd: Backpointer to the internal control structure.
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* @work: work struct for parallelization.
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* @num_obj: Number of objects that are processed by this cpu.
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* @cpu_index: Index of the cpu.
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*/
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struct padata_parallel_queue {
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struct padata_list parallel;
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struct padata_list reorder;
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struct parallel_data *pd;
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struct work_struct work;
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atomic_t num_obj;
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int cpu_index;
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};
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/**
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* struct padata_cpumask - The cpumasks for the parallel/serial workers
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*
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* @pcpu: cpumask for the parallel workers.
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* @cbcpu: cpumask for the serial (callback) workers.
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*/
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struct padata_cpumask {
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cpumask_var_t pcpu;
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cpumask_var_t cbcpu;
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};
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/**
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* struct parallel_data - Internal control structure, covers everything
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* that depends on the cpumask in use.
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*
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* @pinst: padata instance.
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* @pqueue: percpu padata queues used for parallelization.
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* @squeue: percpu padata queues used for serialuzation.
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* @reorder_objects: Number of objects waiting in the reorder queues.
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* @refcnt: Number of objects holding a reference on this parallel_data.
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* @max_seq_nr: Maximal used sequence number.
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* @cpumask: The cpumasks in use for parallel and serial workers.
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* @lock: Reorder lock.
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* @processed: Number of already processed objects.
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* @timer: Reorder timer.
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*/
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struct parallel_data {
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struct padata_instance *pinst;
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struct padata_parallel_queue __percpu *pqueue;
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struct padata_serial_queue __percpu *squeue;
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atomic_t reorder_objects;
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atomic_t refcnt;
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struct padata_cpumask cpumask;
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spinlock_t lock ____cacheline_aligned;
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spinlock_t seq_lock;
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unsigned int seq_nr;
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unsigned int processed;
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struct timer_list timer;
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};
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/**
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* struct padata_instance - The overall control structure.
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*
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* @cpu_notifier: cpu hotplug notifier.
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* @wq: The workqueue in use.
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* @pd: The internal control structure.
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* @cpumask: User supplied cpumasks for parallel and serial works.
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* @cpumask_change_notifier: Notifiers chain for user-defined notify
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* callbacks that will be called when either @pcpu or @cbcpu
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* or both cpumasks change.
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* @kobj: padata instance kernel object.
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* @lock: padata instance lock.
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* @flags: padata flags.
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*/
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struct padata_instance {
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struct notifier_block cpu_notifier;
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struct workqueue_struct *wq;
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struct parallel_data *pd;
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struct padata_cpumask cpumask;
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struct blocking_notifier_head cpumask_change_notifier;
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struct kobject kobj;
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struct mutex lock;
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u8 flags;
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#define PADATA_INIT 1
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#define PADATA_RESET 2
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#define PADATA_INVALID 4
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};
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extern struct padata_instance *padata_alloc_possible(
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struct workqueue_struct *wq);
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extern struct padata_instance *padata_alloc(struct workqueue_struct *wq,
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const struct cpumask *pcpumask,
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const struct cpumask *cbcpumask);
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extern void padata_free(struct padata_instance *pinst);
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extern int padata_do_parallel(struct padata_instance *pinst,
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struct padata_priv *padata, int cb_cpu);
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extern void padata_do_serial(struct padata_priv *padata);
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extern int padata_set_cpumask(struct padata_instance *pinst, int cpumask_type,
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cpumask_var_t cpumask);
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extern int padata_set_cpumasks(struct padata_instance *pinst,
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cpumask_var_t pcpumask,
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cpumask_var_t cbcpumask);
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extern int padata_add_cpu(struct padata_instance *pinst, int cpu, int mask);
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extern int padata_remove_cpu(struct padata_instance *pinst, int cpu, int mask);
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extern int padata_start(struct padata_instance *pinst);
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extern void padata_stop(struct padata_instance *pinst);
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extern int padata_register_cpumask_notifier(struct padata_instance *pinst,
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struct notifier_block *nblock);
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extern int padata_unregister_cpumask_notifier(struct padata_instance *pinst,
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struct notifier_block *nblock);
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#endif
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