diff options
| -rw-r--r-- | Documentation/blockdev/zram.txt | 9 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.c | 10 | ||||
| -rw-r--r-- | drivers/block/zram/zcomp.h | 4 | ||||
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 17 |
4 files changed, 25 insertions, 15 deletions
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 2604ffed51db..0595c3f56ccf 100644 --- a/Documentation/blockdev/zram.txt +++ b/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 --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 5647d8fe1dc1..b0e7592c44d8 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -153,7 +153,7 @@ static void zcomp_strm_multi_release(struct zcomp *comp, struct zcomp_strm *zstr } /* 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_streams(struct zcomp *comp, int num_strm) 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(struct zcomp *comp, 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 *comp, char *buf) 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 --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index 8b8997f8613b..c59d1fca72c0 100644 --- a/drivers/block/zram/zcomp.h +++ b/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, struct zcomp_strm *zstrm, 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 --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 6b462d27e7d7..80a1cfca1bf0 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -127,19 +127,28 @@ static ssize_t max_comp_streams_store(struct device *dev, { 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, |
