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authorLuis Henriques <luis.henriques@canonical.com>2015-11-07 03:29:01 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-07 04:50:42 +0300
commit1d5b43bfb60f7ba2b51792978a6b0781d4ebba93 (patch)
tree4e107fdb7a3e75d1b69f7b6f6d89a6c92db3023e /drivers
parent6f6461562e8805784538fa469e9a538cd2b3d553 (diff)
downloadlinux-1d5b43bfb60f7ba2b51792978a6b0781d4ebba93.tar.xz
zram: introduce comp algorithm fallback functionality
When the user supplies an unsupported compression algorithm, keep the previously selected one (knowingly supported) or the default one (if the compression algorithm hasn't been changed yet). Note that previously this operation (i.e. setting an invalid algorithm) would result in no algorithm being selected, which means that this represents a small change in the default behaviour. Minchan said: For initializing zram, we need to set up 3 optional parameters in advance. 1. the number of compression streams 2. memory limitation 3. compression algorithm Although user pass completely wrong value to set up for 1 and 2 parameters, it's okay because they have default value so zram will be initialized with the default value (of course, when user passes a wrong value via *echo*, sysfs returns -EINVAL so the user can notice it). But 3 is not consistent with other optional parameters. IOW, if the user passes a wrong value to set up 3 parameter, zram's initialization would fail unlike other optional parameters. So this patch makes them consistent. Signed-off-by: Luis Henriques <luis.henriques@canonical.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/zram/zram_drv.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9fa15bb9d118..c93aeb876125 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -365,6 +365,9 @@ static ssize_t comp_algorithm_store(struct device *dev,
struct zram *zram = dev_to_zram(dev);
size_t sz;
+ if (!zcomp_available_algorithm(buf))
+ return -EINVAL;
+
down_write(&zram->init_lock);
if (init_done(zram)) {
up_write(&zram->init_lock);
@@ -378,9 +381,6 @@ static ssize_t comp_algorithm_store(struct device *dev,
if (sz > 0 && zram->compressor[sz - 1] == '\n')
zram->compressor[sz - 1] = 0x00;
- if (!zcomp_available_algorithm(zram->compressor))
- len = -EINVAL;
-
up_write(&zram->init_lock);
return len;
}