Subject: [merged] zram-propagate-error-to-user.patch removed from -mm tree
To: minchan@xxxxxxxxxx,fengguang.wu@xxxxxxxxx,jmarchan@xxxxxxxxxx,ngupta@xxxxxxxxxx,sergey.senozhatsky@xxxxxxxxx,sfr@xxxxxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 08 Apr 2014 14:10:53 -0700
The patch titled
Subject: zram: propagate error to user
has been removed from the -mm tree. Its filename was
zram-propagate-error-to-user.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: zram: propagate error to user
When we initialized zcomp with single, we couldn't change max_comp_streams
without zram reset but current interface doesn't show any error to user
and even it changes max_comp_streams's value without any effect so it
would make user very confusing.
This patch prevents max_comp_streams's change when zcomp was initialized
as single zcomp and emit the error to user(ex, echo).
[akpm@xxxxxxxxxxxxxxxxxxxx: don't return with the lock held, per Sergey]
[fengguang.wu@xxxxxxxxx: fix coccinelle warnings]
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Jerome Marchand <jmarchan@xxxxxxxxxx>
Acked-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Signed-off-by: Fengguang Wu <fengguang.wu@xxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/blockdev/zram.txt | 9 +++++----
drivers/block/zram/zcomp.c | 10 +++++-----
drivers/block/zram/zcomp.h | 4 ++--
drivers/block/zram/zram_drv.c | 17 +++++++++++++----
4 files changed, 25 insertions(+), 15 deletions(-)
diff -puN Documentation/blockdev/zram.txt~zram-propagate-error-to-user Documentation/blockdev/zram.txt
--- a/Documentation/blockdev/zram.txt~zram-propagate-error-to-user
+++ a/Documentation/blockdev/zram.txt
@@ -37,10 +37,11 @@ Note:
In order to enable compression backend's multi stream support max_comp_streams
must be initially set to desired concurrency level before ZRAM device
initialisation. Once the device initialised as a single stream compression
-backend (max_comp_streams equals to 0) changing the value of max_comp_streams
-will not take any effect, because single stream compression backend implemented
-as a special case and does not support dynamic max_comp_streams. Only multi
-stream backend supports dynamic max_comp_streams adjustment.
+backend (max_comp_streams equals to 1), you will see error if you try to change
+the value of max_comp_streams because single stream compression backend
+implemented as a special case by lock overhead issue and does not support
+dynamic max_comp_streams. Only multi stream backend supports dynamic
+max_comp_streams adjustment.
3) Select compression algorithm
Using comp_algorithm device attribute one can see available and
diff -puN drivers/block/zram/zcomp.c~zram-propagate-error-to-user drivers/block/zram/zcomp.c
--- a/drivers/block/zram/zcomp.c~zram-propagate-error-to-user
+++ a/drivers/block/zram/zcomp.c
@@ -153,7 +153,7 @@ static void zcomp_strm_multi_release(str
}
/* change max_strm limit */
-static int zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
+static bool zcomp_strm_multi_set_max_streams(struct zcomp *comp, int num_strm)
{
struct zcomp_strm_multi *zs = comp->stream;
struct zcomp_strm *zstrm;
@@ -172,7 +172,7 @@ static int zcomp_strm_multi_set_max_stre
zs->avail_strm--;
}
spin_unlock(&zs->strm_lock);
- return 0;
+ return true;
}
static void zcomp_strm_multi_destroy(struct zcomp *comp)
@@ -232,10 +232,10 @@ static void zcomp_strm_single_release(st
mutex_unlock(&zs->strm_lock);
}
-static int zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
+static bool zcomp_strm_single_set_max_streams(struct zcomp *comp, int num_strm)
{
/* zcomp_strm_single support only max_comp_streams == 1 */
- return -ENOTSUPP;
+ return false;
}
static void zcomp_strm_single_destroy(struct zcomp *comp)
@@ -284,7 +284,7 @@ ssize_t zcomp_available_show(const char
return sz;
}
-int zcomp_set_max_streams(struct zcomp *comp, int num_strm)
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm)
{
return comp->set_max_streams(comp, num_strm);
}
diff -puN drivers/block/zram/zcomp.h~zram-propagate-error-to-user drivers/block/zram/zcomp.h
--- a/drivers/block/zram/zcomp.h~zram-propagate-error-to-user
+++ a/drivers/block/zram/zcomp.h
@@ -46,7 +46,7 @@ struct zcomp {
struct zcomp_strm *(*strm_find)(struct zcomp *comp);
void (*strm_release)(struct zcomp *comp, struct zcomp_strm *zstrm);
- int (*set_max_streams)(struct zcomp *comp, int num_strm);
+ bool (*set_max_streams)(struct zcomp *comp, int num_strm);
void (*destroy)(struct zcomp *comp);
};
@@ -64,5 +64,5 @@ int zcomp_compress(struct zcomp *comp, s
int zcomp_decompress(struct zcomp *comp, const unsigned char *src,
size_t src_len, unsigned char *dst);
-int zcomp_set_max_streams(struct zcomp *comp, int num_strm);
+bool zcomp_set_max_streams(struct zcomp *comp, int num_strm);
#endif /* _ZCOMP_H_ */
diff -puN drivers/block/zram/zram_drv.c~zram-propagate-error-to-user drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-propagate-error-to-user
+++ a/drivers/block/zram/zram_drv.c
@@ -127,19 +127,28 @@ static ssize_t max_comp_streams_store(st
{
int num;
struct zram *zram = dev_to_zram(dev);
+ int ret;
- if (kstrtoint(buf, 0, &num))
- return -EINVAL;
+ ret = kstrtoint(buf, 0, &num);
+ if (ret < 0)
+ return ret;
if (num < 1)
return -EINVAL;
+
down_write(&zram->init_lock);
if (init_done(zram)) {
- if (zcomp_set_max_streams(zram->comp, num))
+ if (!zcomp_set_max_streams(zram->comp, num)) {
pr_info("Cannot change max compression streams\n");
+ ret = -EINVAL;
+ goto out;
+ }
}
+
zram->max_comp_streams = num;
+ ret = len;
+out:
up_write(&zram->init_lock);
- return len;
+ return ret;
}
static ssize_t comp_algorithm_show(struct device *dev,
_
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
origin.patch
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