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Commit 85508ec6 authored by Sergey Senozhatsky's avatar Sergey Senozhatsky Committed by Linus Torvalds
Browse files

zram: use idr instead of `zram_devices' array 



This patch makes some preparations for on-demand device add/remove
functionality.

Remove `zram_devices' array and switch to id-to-pointer translation (idr).
idr doesn't bloat zram struct with additional members, f.e.  list_head,
yet still provides ability to match the device_id with the device pointer.

No user-space visible changes.

[Julia.Lawall@lip6.fr: return -ENOMEM when `queue' alloc fails]
Signed-off-by: default avatarSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3bca3ef7

drivers/block/zram/zram_drv.c

+49 −37
Original line number Diff line number Diff line
@@ -28,12 +28,12 @@ 
#include <linux/string.h>

#include <linux/vmalloc.h>

#include <linux/err.h>

#include <linux/idr.h>



#include "zram_drv.h"



/* Globals */

static DEFINE_IDR(zram_index_idr);

static int zram_major;

static struct zram *zram_devices;

static const char *default_compressor = "lzo";



/* Module params (documentation at end) */
@@ -1154,10 +1154,20 @@ static struct attribute_group zram_disk_attr_group = { 
	.attrs = zram_disk_attrs,

};



static int create_device(struct zram *zram, int device_id)

static int zram_add(int device_id)

{

	struct zram *zram;

	struct request_queue *queue;

	int ret = -ENOMEM;

	int ret;



	zram = kzalloc(sizeof(struct zram), GFP_KERNEL);

	if (!zram)

		return -ENOMEM;



	ret = idr_alloc(&zram_index_idr, zram, device_id,

			device_id + 1, GFP_KERNEL);

	if (ret < 0)

		goto out_free_dev;



	init_rwsem(&zram->init_lock);
@@ -1165,7 +1175,8 @@ static int create_device(struct zram *zram, int device_id) 
	if (!queue) {

		pr_err("Error allocating disk queue for device %d\n",

			device_id);

		goto out;

		ret = -ENOMEM;

		goto out_free_idr;

	}



	blk_queue_make_request(queue, zram_make_request);
@@ -1235,17 +1246,15 @@ static int create_device(struct zram *zram, int device_id) 
	put_disk(zram->disk);

out_free_queue:

	blk_cleanup_queue(queue);

out:

out_free_idr:

	idr_remove(&zram_index_idr, device_id);

out_free_dev:

	kfree(zram);

	return ret;

}



static void destroy_devices(unsigned int nr)

static void zram_remove(struct zram *zram)

{

	struct zram *zram;

	unsigned int i;



	for (i = 0; i < nr; i++) {

		zram = &zram_devices[i];

	/*

	 * Remove sysfs first, so no one will perform a disksize

	 * store while we destroy the devices
@@ -1254,15 +1263,25 @@ static void destroy_devices(unsigned int nr) 
			&zram_disk_attr_group);



	zram_reset_device(zram);



	idr_remove(&zram_index_idr, zram->disk->first_minor);

	blk_cleanup_queue(zram->disk->queue);

	del_gendisk(zram->disk);

	put_disk(zram->disk);

	kfree(zram);

}



static int zram_remove_cb(int id, void *ptr, void *data)

{

	zram_remove(ptr);

	return 0;

}



	kfree(zram_devices);

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");

	pr_info("Destroyed %u device(s)\n", nr);

	pr_info("Destroyed device(s)\n");

}



static int __init zram_init(void)
@@ -1281,16 +1300,9 @@ static int __init zram_init(void) 
		return -EBUSY;

	}



	/* Allocate the device array and initialize each one */

	zram_devices = kzalloc(num_devices * sizeof(struct zram), GFP_KERNEL);

	if (!zram_devices) {

		unregister_blkdev(zram_major, "zram");

		return -ENOMEM;

	}



	for (dev_id = 0; dev_id < num_devices; dev_id++) {

		ret = create_device(&zram_devices[dev_id], dev_id);

		if (ret)

		ret = zram_add(dev_id);

		if (ret != 0)

			goto out_error;

	}
@@ -1298,13 +1310,13 @@ static int __init zram_init(void) 
	return 0;



out_error:

	destroy_devices(dev_id);

	destroy_devices();

	return ret;

}



static void __exit zram_exit(void)

{

	destroy_devices(num_devices);

	destroy_devices();

}



module_init(zram_init);