[PATCHv2 09/10] zram: return zram device_id value from zram_add()

Sergey Senozhatsky
2015-04-16T11:56:28Z

zram_add requires valid device_id to be provided, that can be a bit
inconvenient. Change zram_add() to return negative value upon new device
creation failure, and device_id (>= 0) value otherwise.

This prepares zram_add to perform automatic device_id assignment. New
device_id will be returned back to user-space (so user can reference that
device as /dev/zramX).

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
drivers/block/zram/zram_drv.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index f26251a..2c2e7cc 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1154,6 +1154,10 @@ static struct attribute_group zram_disk_attr_group = {
.attrs = zram_disk_attrs,
};

+/*
+ * Allocate and initialize new zram device. the function returns
+ * '>= 0' device_id upon success, and negative value otherwise.
+ */
static int zram_add(int device_id)
{
struct zram *zram;
@@ -1241,7 +1245,7 @@ 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);
@@ -1299,7 +1303,7 @@ static int __init zram_init(void)

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

--
2.4.0.rc2