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Subject[PATCHv5 08/10] zram: return zram device_id from zram_add()
Date
This patch prepares zram to enable on-demand device creation.
zram_add() performs automatic device_id assignment and returns
new device id (>= 0) or error code (< 0).

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
---
drivers/block/zram/zram_drv.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 37a753c..3df4394 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1151,20 +1151,24 @@ static struct attribute_group zram_disk_attr_group = {
.attrs = zram_disk_attrs,
};

-static int zram_add(int device_id)
+/*
+ * Allocate and initialize new zram device. the function returns
+ * '>= 0' device_id upon success, and negative value otherwise.
+ */
+static int zram_add(void)
{
struct zram *zram;
struct request_queue *queue;
- int ret;
+ int ret, device_id;

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);
+ ret = idr_alloc(&zram_index_idr, zram, 0, 0, GFP_KERNEL);
if (ret < 0)
goto out_free_dev;
+ device_id = ret;

init_rwsem(&zram->init_lock);

@@ -1238,7 +1242,7 @@ static int zram_add(int device_id)
zram->max_comp_streams = 1;

pr_info("Added device: %s\n", zram->disk->disk_name);
- return 0;
+ return device_id;

out_free_disk:
del_gendisk(zram->disk);
@@ -1285,7 +1289,7 @@ static void destroy_devices(void)

static int __init zram_init(void)
{
- int ret, dev_id;
+ int ret;

zram_major = register_blkdev(0, "zram");
if (zram_major <= 0) {
@@ -1293,10 +1297,11 @@ static int __init zram_init(void)
return -EBUSY;
}

- for (dev_id = 0; dev_id < num_devices; dev_id++) {
- ret = zram_add(dev_id);
- if (ret != 0)
+ while (num_devices != 0) {
+ ret = zram_add();
+ if (ret < 0)
goto out_error;
+ num_devices--;
}

return 0;
--
2.4.0


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