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zram: use idr instead of `zram_devices' array

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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: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Sergey Senozhatsky 2015-06-25 15:00:06 -07:00 committed by Linus Torvalds
parent 3bca3ef769
commit 85508ec6cb
1 changed files with 49 additions and 37 deletions
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86
drivers/block/zram/zram_drv.c
View File

@ -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);
@ -1165,12 +1175,13 @@ 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);
/* gendisk structure */
/* gendisk structure */
zram->disk = alloc_disk(1);
if (!zram->disk) {
pr_warn("Error allocating disk structure for device %d\n",
@ -1235,34 +1246,42 @@ out_free_disk:
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;
/*
* Remove sysfs first, so no one will perform a disksize
* store while we destroy the devices
*/
sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
&zram_disk_attr_group);
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
*/
sysfs_remove_group(&disk_to_dev(zram->disk)->kobj,
&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);
}
zram_reset_device(zram);
static int zram_remove_cb(int id, void *ptr, void *data)
{
zram_remove(ptr);
return 0;
}
blk_cleanup_queue(zram->disk->queue);
del_gendisk(zram->disk);
put_disk(zram->disk);
}
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);