Staging: zram: Replace ioctls with sysfs interface

Creates per-device sysfs nodes in /sys/block/zram<id>/
Currently following stats are exported:
 - disksize
 - num_reads
 - num_writes
 - invalid_io
 - zero_pages
 - orig_data_size
 - compr_data_size
 - mem_used_total

By default, disksize is set to 0. So, to start using
a zram device, fist write a disksize value and then
initialize device by writing any positive value to
initstate. For example:

        # initialize /dev/zram0 with 50MB disksize
        echo 50*1024*1024 | bc > /sys/block/zram0/disksize
        echo 1 > /sys/block/zram0/initstate

When done using a disk, issue reset to free its memory
by writing any positive value to reset node:

        echo 1 > /sys/block/zram0/reset

This change also obviates the need for 'rzscontrol' utility.

Signed-off-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 10 insertions, 45 deletions

diff --git a/drivers/staging/zram/zram_drv.h b/drivers/staging/zram/zram_drv.h
index 945f974..2ef93cc 100644
--- a/drivers/staging/zram/zram_drv.h
+++ b/drivers/staging/zram/zram_drv.h
@@ -18,7 +18,6 @@
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
 
-#include "zram_ioctl.h"
 #include "xvmalloc.h"
 
 /*
@@ -85,11 +84,7 @@ struct table {
 } __attribute__((aligned(4)));
 
 struct zram_stats {
-	/* basic stats */
-	size_t compr_size;	/* compressed size of pages stored -
-				 * needed to enforce memlimit */
-	/* more stats */
-#if defined(CONFIG_ZRAM_STATS)
+	u64 compr_size;		/* compressed size of pages stored */
 	u64 num_reads;		/* failed + successful */
 	u64 num_writes;		/* --do-- */
 	u64 failed_reads;	/* should NEVER! happen */
@@ -100,7 +95,6 @@ struct zram_stats {
 	u32 pages_stored;	/* no. of pages currently stored */
 	u32 good_compress;	/* % of pages with compression ratio<=50% */
 	u32 pages_expand;	/* % of incompressible pages */
-#endif
 };
 
 struct zram {
@@ -118,47 +112,18 @@ struct zram {
 	 * This is the limit on amount of *uncompressed* worth of data
 	 * we can store in a disk.
 	 */
-	size_t disksize;	/* bytes */
+	u64 disksize;	/* bytes */
 
 	struct zram_stats stats;
 };
 
-/*-- */
-
-/* Debugging and Stats */
-#if defined(CONFIG_ZRAM_STATS)
-static void zram_stat_inc(u32 *v)
-{
-	*v = *v + 1;
-}
-
-static void zram_stat_dec(u32 *v)
-{
-	*v = *v - 1;
-}
-
-static void zram_stat64_inc(struct zram *zram, u64 *v)
-{
-	spin_lock(&zram->stat64_lock);
-	*v = *v + 1;
-	spin_unlock(&zram->stat64_lock);
-}
-
-static u64 zram_stat64_read(struct zram *zram, u64 *v)
-{
-	u64 val;
-
-	spin_lock(&zram->stat64_lock);
-	val = *v;
-	spin_unlock(&zram->stat64_lock);
-
-	return val;
-}
-#else
-#define zram_stat_inc(v)
-#define zram_stat_dec(v)
-#define zram_stat64_inc(r, v)
-#define zram_stat64_read(r, v)
-#endif /* CONFIG_ZRAM_STATS */
+extern struct zram *devices;
+extern unsigned int num_devices;
+#ifdef CONFIG_SYSFS
+extern struct attribute_group zram_disk_attr_group;
+#endif
+
+extern int zram_init_device(struct zram *zram);
+extern void zram_reset_device(struct zram *zram);
 
 #endif