| Message ID | 1444808304-29320-9-git-send-email-iamjoonsoo.kim@lge.com (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Herbert Xu |
| Headers | show |
Hi, On (10/14/15 16:38), Joonsoo Kim wrote: [..] > static const char * const backends[] = { > "lzo", > -#ifdef CONFIG_ZRAM_LZ4_COMPRESS > "lz4", > -#endif > NULL > }; > > static const char *find_backend(const char *compress) > { > - int i = 0; > - while (backends[i]) { > - if (sysfs_streq(compress, backends[i]) && > - crypto_has_comp(backends[i], 0, 0)) > - break; > - i++; > - } > - return backends[i]; > + if (crypto_has_comp(compress, 0, 0)) > + return compress; > + > + return NULL; > } > > static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) > @@ -277,6 +271,9 @@ ssize_t zcomp_available_show(const char *comp, char *buf) > int i = 0; > > while (backends[i]) { > + if (!crypto_has_comp(backends[i], 0, 0)) > + continue; > + hm... this sort of looks a bit `unnatural' to me. we have two _independent_ sets -- what zram supports and what crypto supports. that's why you have to do extra work and consult crypto. can we return back the old scheme: use ifdef CONFIG in backends, but replace CONFIG_ZRAM with CONFIG_CRYPTO? e.g. static const char * const backends[] = { "lzo", #ifdef CONFIG_CRYPTO_LZ4 "lz4", #endif NULL }; so you can remove `crypto_has_comp(backends[i], 0, 0)' from zcomp_available_show(), because zram will support *only* what crypto supports. -ss > if (!strcmp(comp, backends[i])) > sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, > "[%s] ", backends[i]); > diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c > index 6f04fb2..6b4cf85 100644 > --- a/drivers/block/zram/zram_drv.c > +++ b/drivers/block/zram/zram_drv.c > @@ -352,6 +352,7 @@ static ssize_t comp_algorithm_show(struct device *dev, > size_t sz; > struct zram *zram = dev_to_zram(dev); > > + deprecated_attr_warn("comp_algorithm"); > down_read(&zram->init_lock); > sz = zcomp_available_show(zram->compressor, buf); > up_read(&zram->init_lock); > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Oct 15, 2015 at 09:29:03AM +0900, Sergey Senozhatsky wrote: > Hi, > > On (10/14/15 16:38), Joonsoo Kim wrote: > [..] > > static const char * const backends[] = { > > "lzo", > > -#ifdef CONFIG_ZRAM_LZ4_COMPRESS > > "lz4", > > -#endif > > NULL > > }; > > > > static const char *find_backend(const char *compress) > > { > > - int i = 0; > > - while (backends[i]) { > > - if (sysfs_streq(compress, backends[i]) && > > - crypto_has_comp(backends[i], 0, 0)) > > - break; > > - i++; > > - } > > - return backends[i]; > > + if (crypto_has_comp(compress, 0, 0)) > > + return compress; > > + > > + return NULL; > > } > > > > static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) > > @@ -277,6 +271,9 @@ ssize_t zcomp_available_show(const char *comp, char *buf) > > int i = 0; > > > > while (backends[i]) { > > + if (!crypto_has_comp(backends[i], 0, 0)) > > + continue; > > + > > hm... this sort of looks a bit `unnatural' to me. we have two _independent_ > sets -- what zram supports and what crypto supports. that's why you have > to do extra work and consult crypto. can we return back the old scheme: > use ifdef CONFIG in backends, but replace CONFIG_ZRAM with CONFIG_CRYPTO? > > e.g. > > static const char * const backends[] = { > "lzo", > #ifdef CONFIG_CRYPTO_LZ4 > "lz4", > #endif > NULL > }; > > > so you can remove `crypto_has_comp(backends[i], 0, 0)' from > zcomp_available_show(), because zram will support *only* what > crypto supports. Hello, Sergey. Okay. I will change it in next spin. Anyway, now I noticed that crypto_has_comp() is not proper API to check contextless compression algorithm. I will change it, too. Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt index 5bda503..7a165c2 100644 --- a/Documentation/blockdev/zram.txt +++ b/Documentation/blockdev/zram.txt @@ -81,15 +81,32 @@ 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 - currently selected (shown in square brackets) compression algorithms, - change selected compression algorithm (once the device is initialised - there is no way to change compression algorithm). + You can find available compression algorithms by searching contextless + compression algorithm (type: ccomp) in /proc/crypto. + Using comp_algorithm device attribute one can change selected + compression algorithm (once the device is initialised there is no way + to change compression algorithm). Examples: #show supported compression algorithms - cat /sys/block/zram0/comp_algorithm - lzo [lz4] + cat /proc/crypto | grep ccomp -B 7 + name : lz4 + driver : lz4-generic + module : kernel + priority : 0 + refcnt : 1 + selftest : passed + internal : no + type : ccomp + -- + name : lzo + driver : lzo-generic + module : kernel + priority : 0 + refcnt : 1 + selftest : passed + internal : no + type : ccomp #select lzo compression algorithm echo lzo > /sys/block/zram0/comp_algorithm diff --git a/drivers/block/zram/Kconfig b/drivers/block/zram/Kconfig index 7619bed..36ec96f 100644 --- a/drivers/block/zram/Kconfig +++ b/drivers/block/zram/Kconfig @@ -13,12 +13,3 @@ config ZRAM disks and maybe many more. See zram.txt for more information. - -config ZRAM_LZ4_COMPRESS - bool "Enable LZ4 algorithm support" - depends on ZRAM - select CRYPTO_LZ4 - default n - help - This option enables LZ4 compression algorithm support. Compression - algorithm can be changed using `comp_algorithm' device attribute. diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 9be83db..f91c0659 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -41,22 +41,16 @@ struct zcomp_strm_multi { static const char * const backends[] = { "lzo", -#ifdef CONFIG_ZRAM_LZ4_COMPRESS "lz4", -#endif NULL }; static const char *find_backend(const char *compress) { - int i = 0; - while (backends[i]) { - if (sysfs_streq(compress, backends[i]) && - crypto_has_comp(backends[i], 0, 0)) - break; - i++; - } - return backends[i]; + if (crypto_has_comp(compress, 0, 0)) + return compress; + + return NULL; } static void zcomp_strm_free(struct zcomp *comp, struct zcomp_strm *zstrm) @@ -277,6 +271,9 @@ ssize_t zcomp_available_show(const char *comp, char *buf) int i = 0; while (backends[i]) { + if (!crypto_has_comp(backends[i], 0, 0)) + continue; + if (!strcmp(comp, backends[i])) sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2, "[%s] ", backends[i]); diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 6f04fb2..6b4cf85 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -352,6 +352,7 @@ static ssize_t comp_algorithm_show(struct device *dev, size_t sz; struct zram *zram = dev_to_zram(dev); + deprecated_attr_warn("comp_algorithm"); down_read(&zram->init_lock); sz = zcomp_available_show(zram->compressor, buf); up_read(&zram->init_lock);
Now, zram uses contextless compression API and there is no reason to limit compression algorithm through hard-wired string. This patch remove it so enable all contextless compression algorithm in the system. After this patch, available compression algorithm for zram can be retrieved by searching contextless compression in /proc/crypto. cat /proc/crypto | grep ccomp -B 7 name : lz4 [snip...] type : ccomp Previous interface comp_algorithm attr will remain to set new algorithm. Read from previous interface also works for compatibility but it will be wrong. Note that after this patch is applied, there is no way to know current compression algorithm so it's really bad thing. Please let me know proper solution if someone have better idea. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> --- Documentation/blockdev/zram.txt | 29 +++++++++++++++++++++++------ drivers/block/zram/Kconfig | 9 --------- drivers/block/zram/zcomp.c | 17 +++++++---------- drivers/block/zram/zram_drv.c | 1 + 4 files changed, 31 insertions(+), 25 deletions(-)