From 85508ec6cbc21645927b6ac05e3b2748119a3e23 Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Thu, 25 Jun 2015 15:00:06 -0700 Subject: [PATCH] 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: Sergey Senozhatsky Reported-by: Julia Lawall Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/zram/zram_drv.c | 86 ++++++++++++++++++++++++------------------- 1 file changed, 49 insertions(+), 37 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 7814e68..addb18d 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -28,12 +28,12 @@ #include #include #include +#include #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; - - 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); + /* + * 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); + 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); +} - blk_cleanup_queue(zram->disk->queue); - del_gendisk(zram->disk); - put_disk(zram->disk); - } +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); -- 2.7.4