linux-kernel - [PATCHv2 06/10] zram: remove max_num

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Date:	Thu, 16 Apr 2015 20:55:52 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan@...nel.org>
Cc:	Nitin Gupta <ngupta@...are.org>, linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: [PATCHv2 06/10] zram: remove max_num_devices limitation

Limiting the number of zram devices to 32 (default max_num_devices value)
is confusing, let's drop it.  A user with 2TB or 4TB of RAM, for example,
can request as many devices as he can handle.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
---
 Documentation/blockdev/zram.txt | 8 +++++++-
 drivers/block/zram/zram_drv.c   | 8 +-------
 drivers/block/zram/zram_drv.h   | 6 ------
 3 files changed, 8 insertions(+), 14 deletions(-)

diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index bef4998..2ccc741 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -19,7 +19,9 @@ Following shows a typical sequence of steps for using zram.
 1) Load Module:
 	modprobe zram num_devices=4
 	This creates 4 devices: /dev/zram{0,1,2,3}
-	(num_devices parameter is optional. Default: 1)
+
+num_devices parameter is optional and tells zram how many devices should be
+pre-created. Default: 1.
 
 2) Set max number of compression streams
 	Compression backend may use up to max_comp_streams compression streams,
@@ -128,6 +130,7 @@ mem_limit         RW    the maximum amount of memory ZRAM can use to store
 num_migrated      RO    the number of objects migrated migrated by compaction
 compact           WO    trigger memory compaction
 
+
 WARNING
 =======
 per-stat sysfs attributes are considered to be deprecated.
@@ -149,6 +152,7 @@ File /sys/block/zram<id>/stat
 Represents block layer statistics. Read Documentation/block/stat.txt for
 details.
 
+
 File /sys/block/zram<id>/io_stat
 
 The stat file represents device's I/O statistics not accounted by block
@@ -160,6 +164,7 @@ whitespace:
 	invalid_io
 	notify_free
 
+
 File /sys/block/zram<id>/mm_stat
 
 The stat file represents device's mm statistics. It consists of a single
@@ -172,6 +177,7 @@ line of text and contains the following stats separated by whitespace:
 	zero_pages
 	num_migrated
 
+
 8) Deactivate:
 	swapoff /dev/zram0
 	umount /dev/zram1
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e526fe1..c2d9b76 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1288,12 +1288,6 @@ static int __init zram_init(void)
 {
 	int ret, dev_id;
 
-	if (num_devices > max_num_devices) {
-		pr_warn("Invalid value for num_devices: %u\n",
-				num_devices);
-		return -EINVAL;
-	}
-
 	zram_major = register_blkdev(0, "zram");
 	if (zram_major <= 0) {
 		pr_warn("Unable to get major number\n");
@@ -1323,7 +1317,7 @@ module_init(zram_init);
 module_exit(zram_exit);
 
 module_param(num_devices, uint, 0);
-MODULE_PARM_DESC(num_devices, "Number of zram devices");
+MODULE_PARM_DESC(num_devices, "Number of pre-created zram devices");
 
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_AUTHOR("Nitin Gupta <ngupta@...are.org>");
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
index 570c598..042994e 100644
--- a/drivers/block/zram/zram_drv.h
+++ b/drivers/block/zram/zram_drv.h
@@ -20,12 +20,6 @@
 
 #include "zcomp.h"
 
-/*
- * Some arbitrary value. This is just to catch
- * invalid value for num_devices module parameter.
- */
-static const unsigned max_num_devices = 32;
-
 /*-- Configurable parameters */
 
 /*
-- 
2.4.0.rc2

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