linux/drivers/staging/zcache, branch v3.6

staging: zcache: fix cleancache race condition with shrinker

2012-09-05T19:06:48Z

This patch fixes a race condition that results in memory corruption when using cleancache. The race exists between the zcache shrinker handler, shrink_zcache_memory() and cleancache_get_page(). In most cases, the shrinker will both evict a zbpg from its buddy list and flush it from tmem before a cleancache_get_page() occurs on that page. A subsequent cleancache_get_page() will fail in the tmem layer. In the rare case that two occur together and the cleancache_get_page() path gets through the tmem layer before the shrinker path can flush tmem, zbud_decompress() does a check to see if the zbpg is a "zombie", i.e. not on a buddy list, which means the shrinker is in the process of reclaiming it. If the zbpg is a zombie, zbud_decompress() returns -EINVAL. However, this return code is being ignored by the caller, zcache_pampd_get_data_and_free(), which results in the caller of cleancache_get_page() thinking that the page has been properly retrieved when it has not. This patch modifies zcache_pampd_get_data_and_free() to convey the failure up the stack so that the caller of cleancache_get_page() knows the page retrieval failed. This needs to be applied to stable trees as well. zcache-main.c was named zcache.c before v3.1, so I'm not sure how you want to handle trees earlier than that. Signed-off-by: Seth Jennings Cc: stable Reviewed-by: Konrad Rzeszutek Wilk Reviewed-by: Minchan Kim Signed-off-by: Greg Kroah-Hartman

staging: zsmalloc: add mapping modes

2012-07-09T18:35:00Z

This patch improves mapping performance in zsmalloc by getting usage information from the user in the form of a "mapping mode" and using it to avoid unnecessary copying for objects that span pages. Signed-off-by: Seth Jennings Signed-off-by: Greg Kroah-Hartman

staging: zcache: cleanup the code between tmem_obj_init and tmem_obj_find

2012-07-09T18:31:16Z

tmem_obj_find and insertion tmem-obj have the some logic, we can integrate the code Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: introduce get_zcache_client

2012-07-09T18:31:16Z

Introduce get_zcache_client to remove the common code Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: cleanup zcache_do_preload and zcache_put_page

2012-07-09T18:31:16Z

Cleanup the code for zcache_do_preload and zcache_put_page Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: optimize zcache_do_preload

2012-07-09T18:31:16Z

zcache_do_preload is called in zcache_put_page where IRQ is disabled, so, need not care preempt Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: cleanup zbud_init

2012-07-09T18:31:16Z

Need not set global parameters to 0 Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: mark zbud_init/zcache_comp_init as __init

2012-07-09T18:31:15Z

These functions are called only when system is initializing, so mark __init for them to free memory Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: remove unnecessary config option dependence

2012-07-09T18:31:15Z

zcache is enabled only if one of CONFIG_CLEANCACHE and CONFIG_FRONTSWAP is enabled, see the Kconfig: depends on (CLEANCACHE || FRONTSWAP) && CRYPTO=y && X86 So, we can remove the check in the source code Acked-by: Seth Jennings Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman

staging: zcache: fix a compile warning

2012-07-09T18:31:15Z

Fix: drivers/staging/zcache/zcache-main.c: In function ‘zcache_comp_op’: drivers/staging/zcache/zcache-main.c:112:2: warning: ‘ret’ may be used uninitial Signed-off-by: Xiao Guangrong Acked-by: Konrad Rzeszutek Wilk Signed-off-by: Greg Kroah-Hartman