Subject: + zram-propagate-error-to-user.patch added to -mm tree
To: minchan@xxxxxxxxxx,jmarchan@xxxxxxxxxx,ngupta@xxxxxxxxxx,sergey.senozhatsky@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Mon, 10 Mar 2014 12:17:46 -0700
The patch titled
Subject: zram: propagate error to user
has been added to the -mm tree. Its filename is
zram-propagate-error-to-user.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/zram-propagate-error-to-user.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/zram-propagate-error-to-user.patch
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------------------------------------------------------
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).
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: 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 | 15 +++++++++++----
4 files changed, 23 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
@@ -152,7 +152,7 @@ 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;
@@ -171,7 +171,7 @@ 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)
@@ -231,10 +231,10 @@ 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 0;
}
static void zcomp_strm_single_destroy(struct zcomp *comp)
@@ -283,7 +283,7 @@ 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
@@ -128,17 +128,24 @@ static ssize_t max_comp_streams_store(st
struct zram *zram = dev_to_zram(dev);
if (kstrtoint(buf, 0, &num))
- return -EINVAL;
+ goto out;
if (num < 1)
- return -EINVAL;
+ goto out;
+
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");
+ goto out_unlock;
+ }
}
+
zram->max_comp_streams = num;
- up_write(&zram->init_lock);
return len;
+out_unlock:
+ up_write(&zram->init_lock);
+out:
+ return -EINVAL;
}
static ssize_t comp_algorithm_show(struct device *dev,
_
Patches currently in -mm which might be from minchan@xxxxxxxxxx are
mm-compaction-break-out-of-loop-on-pagebuddy-in-isolate_freepages_block.patch
mm-kconfig-fix-url-for-zsmalloc-benchmark.patch
fs-cachefiles-use-add_to_page_cache_lru.patch
lib-radix-tree-radix_tree_delete_item.patch
mm-shmem-save-one-radix-tree-lookup-when-truncating-swapped-pages.patch
mm-filemap-move-radix-tree-hole-searching-here.patch
mm-fs-prepare-for-non-page-entries-in-page-cache-radix-trees.patch
mm-fs-prepare-for-non-page-entries-in-page-cache-radix-trees-fix.patch
mm-fs-store-shadow-entries-in-page-cache.patch
mm-thrash-detection-based-file-cache-sizing.patch
mm-keep-page-cache-radix-tree-nodes-in-check.patch
mm-keep-page-cache-radix-tree-nodes-in-check-fix.patch
mm-keep-page-cache-radix-tree-nodes-in-check-fix-fix.patch
mm-compactionc-isolate_freepages_block-small-tuneup.patch
zram-drop-init_done-struct-zram-member.patch
zram-do-not-pass-rw-argument-to-__zram_make_request.patch
zram-remove-good-and-bad-compress-stats.patch
zram-use-atomic64_t-for-all-zram-stats.patch
zram-remove-zram-stats-code-duplication.patch
zram-report-failed-read-and-write-stats.patch
zram-drop-not-used-table-count-member.patch
zram-move-zram-size-warning-to-documentation.patch
zram-document-failed_reads-failed_writes-stats.patch
zram-delete-zram_init_device.patch
zram-delete-zram_init_device-fix.patch
zram-introduce-compressing-backend-abstraction.patch
zram-use-zcomp-compressing-backends.patch
zram-use-zcomp-compressing-backends-fix.patch
zram-factor-out-single-stream-compression.patch
zram-add-multi-stream-functionality.patch
zram-add-set_max_streams-knob.patch
zram-make-compression-algorithm-selection-possible.patch
zram-add-lz4-algorithm-backend.patch
zram-move-comp-allocation-out-of-init_lock.patch
zram-return-error-valued-pointer-from-zcomp_create.patch
zram-return-error-valued-pointer-from-zcomp_create-fix.patch
zram-propagate-error-to-user.patch
mm-zswap-fix-trivial-typo-and-arrange-indentation.patch
mm-zswap-update-zsmalloc-in-comment-to-zbud.patch
mm-zswap-support-multiple-swap-devices.patch
debugging-keep-track-of-page-owners.patch
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