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Commit 1dd6c834 authored by Anna-Maria Gleixner's avatar Anna-Maria Gleixner Committed by Thomas Gleixner
Browse files

zram: Convert to hotplug state machine 



Install the callbacks via the state machine with multi instance support and let
the core invoke the callbacks on the already online CPUs.

[bigeasy: wire up the multi instance stuff]
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: rt@linutronix.de
Cc: Nitin Gupta <ngupta@vflare.org>
Link: http://lkml.kernel.org/r/20161126231350.10321-19-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 3f7cd919

drivers/block/zram/zcomp.c

+25 −51
Original line number Diff line number Diff line
@@ -160,82 +160,56 @@ int zcomp_decompress(struct zcomp_strm *zstrm, 
			dst, &dst_len);

}



static int __zcomp_cpu_notifier(struct zcomp *comp,

		unsigned long action, unsigned long cpu)

int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node)

{

	struct zcomp *comp = hlist_entry(node, struct zcomp, node);

	struct zcomp_strm *zstrm;



	switch (action) {

	case CPU_UP_PREPARE:

	if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))

			break;

		return 0;



	zstrm = zcomp_strm_alloc(comp);

	if (IS_ERR_OR_NULL(zstrm)) {

		pr_err("Can't allocate a compression stream\n");

			return NOTIFY_BAD;

		return -ENOMEM;

	}

	*per_cpu_ptr(comp->stream, cpu) = zstrm;

		break;

	case CPU_DEAD:

	case CPU_UP_CANCELED:

		zstrm = *per_cpu_ptr(comp->stream, cpu);

		if (!IS_ERR_OR_NULL(zstrm))

			zcomp_strm_free(zstrm);

		*per_cpu_ptr(comp->stream, cpu) = NULL;

		break;

	default:

		break;

	}

	return NOTIFY_OK;

	return 0;

}



static int zcomp_cpu_notifier(struct notifier_block *nb,

		unsigned long action, void *pcpu)

int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)

{

	unsigned long cpu = (unsigned long)pcpu;

	struct zcomp *comp = container_of(nb, typeof(*comp), notifier);

	struct zcomp *comp = hlist_entry(node, struct zcomp, node);

	struct zcomp_strm *zstrm;



	return __zcomp_cpu_notifier(comp, action, cpu);

	zstrm = *per_cpu_ptr(comp->stream, cpu);

	if (!IS_ERR_OR_NULL(zstrm))

		zcomp_strm_free(zstrm);

	*per_cpu_ptr(comp->stream, cpu) = NULL;

	return 0;

}



static int zcomp_init(struct zcomp *comp)

{

	unsigned long cpu;

	int ret;



	comp->notifier.notifier_call = zcomp_cpu_notifier;



	comp->stream = alloc_percpu(struct zcomp_strm *);

	if (!comp->stream)

		return -ENOMEM;



	cpu_notifier_register_begin();

	for_each_online_cpu(cpu) {

		ret = __zcomp_cpu_notifier(comp, CPU_UP_PREPARE, cpu);

		if (ret == NOTIFY_BAD)

	ret = cpuhp_state_add_instance(CPUHP_ZCOMP_PREPARE, &comp->node);

	if (ret < 0)

		goto cleanup;

	}

	__register_cpu_notifier(&comp->notifier);

	cpu_notifier_register_done();

	return 0;



cleanup:

	for_each_online_cpu(cpu)

		__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);

	cpu_notifier_register_done();

	return -ENOMEM;

	free_percpu(comp->stream);

	return ret;

}



void zcomp_destroy(struct zcomp *comp)

{

	unsigned long cpu;



	cpu_notifier_register_begin();

	for_each_online_cpu(cpu)

		__zcomp_cpu_notifier(comp, CPU_UP_CANCELED, cpu);

	__unregister_cpu_notifier(&comp->notifier);

	cpu_notifier_register_done();



	cpuhp_state_remove_instance(CPUHP_ZCOMP_PREPARE, &comp->node);

	free_percpu(comp->stream);

	kfree(comp);

}

drivers/block/zram/zcomp.h

+3 −2
Original line number Diff line number Diff line
@@ -19,11 +19,12 @@ struct zcomp_strm { 
/* dynamic per-device compression frontend */

struct zcomp {

	struct zcomp_strm * __percpu *stream;

	struct notifier_block notifier;



	const char *name;

	struct hlist_node node;

};



int zcomp_cpu_up_prepare(unsigned int cpu, struct hlist_node *node);

int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node);

ssize_t zcomp_available_show(const char *comp, char *buf);

bool zcomp_available_algorithm(const char *comp);

drivers/block/zram/zram_drv.c

+9 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ 
#include <linux/err.h>

#include <linux/idr.h>

#include <linux/sysfs.h>

#include <linux/cpuhotplug.h>



#include "zram_drv.h"
@@ -1436,15 +1437,22 @@ static void destroy_devices(void) 
	idr_for_each(&zram_index_idr, &zram_remove_cb, NULL);

	idr_destroy(&zram_index_idr);

	unregister_blkdev(zram_major, "zram");

	cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);

}



static int __init zram_init(void)

{

	int ret;



	ret = cpuhp_setup_state_multi(CPUHP_ZCOMP_PREPARE, "block/zram:prepare",

				      zcomp_cpu_up_prepare, zcomp_cpu_dead);

	if (ret < 0)

		return ret;



	ret = class_register(&zram_control_class);

	if (ret) {

		pr_err("Unable to register zram-control class\n");

		cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);

		return ret;

	}
@@ -1452,6 +1460,7 @@ static int __init zram_init(void) 
	if (zram_major <= 0) {

		pr_err("Unable to get major number\n");

		class_unregister(&zram_control_class);

		cpuhp_remove_multi_state(CPUHP_ZCOMP_PREPARE);

		return -EBUSY;

	}

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -69,6 +69,7 @@ enum cpuhp_state { 
	CPUHP_MM_ZSWP_MEM_PREPARE,

	CPUHP_MM_ZSWP_POOL_PREPARE,

	CPUHP_KVM_PPC_BOOK3S_PREPARE,

	CPUHP_ZCOMP_PREPARE,

	CPUHP_TIMERS_DEAD,

	CPUHP_NOTF_ERR_INJ_PREPARE,

	CPUHP_MIPS_SOC_PREPARE,