From 60a726e33375a1096e85399cfa1327081b4c38be Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Mon, 7 Apr 2014 15:38:21 -0700 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@linux-foundation.org: don't return with the lock held, per Sergey] [fengguang.wu@intel.com: fix coccinelle warnings] Signed-off-by: Minchan Kim Cc: Nitin Gupta Cc: Jerome Marchand Acked-by: Sergey Senozhatsky Signed-off-by: Fengguang Wu Cc: Stephen Rothwell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/blockdev/zram.txt | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'Documentation/blockdev/zram.txt') 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 -- cgit v1.2.3