linux.git/drivers/staging/zram, branch v3.7

staging: zram: Fix handling of incompressible pages

2012-10-22T20:45:19+00:00

Change 130f315a (staging: zram: remove special handle of uncompressed page)
introduced a bug in the handling of incompressible pages which resulted in
memory allocation failure for such pages.

When a page expands on compression, say from 4K to 4K+30, we were trying to
do zsmalloc(pool, 4K+30). However, the maximum size which zsmalloc can
allocate is PAGE_SIZE (for obvious reasons), so such allocation requests
always return failure (0).

For a page that has compressed size larger than the original size (this may
happen with already compressed or random data), there is no point storing
the compressed version as that would take more space and would also require
time for decompression when needed again. So, the fix is to store any page,
whose compressed size exceeds a threshold (max_zpage_size), as-it-is i.e.
without compression.  Memory required for storing this uncompressed page can
then be requested from zsmalloc which supports PAGE_SIZE sized allocations.

Lastly, the fix checks that we do not attempt to "decompress" the page which
we stored in the uncompressed form -- we just memcpy() out such pages.

Signed-off-by: Nitin Gupta 
Reported-by: viechweg@gmail.com
Reported-by: paerley@gmail.com
Reported-by: wu.tommy@gmail.com
Acked-by: Minchan Kim 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

staging: zsmalloc: add mapping modes

2012-07-09T18:35:00+00:00

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: zram/zcache: swtich Kconfig dependency from X86 to ZSMALLOC

2012-06-25T17:00:53+00:00

This patch switches zcache and zram dependency to ZSMALLOC
rather than X86.  There is no net change since ZSMALLOC
depends on X86, however, this prevent further changes to
these files as zsmalloc dependencies change.

Signed-off-by: Seth Jennings 
Signed-off-by: Greg Kroah-Hartman

staging: zram: conventions, __aligned() attribute

2012-06-11T16:04:15+00:00

Using the __aligned() attribute in favor of __attribute__((aligned(size)))

Signed-off-by: Sam Hansen 
Signed-off-by: Greg Kroah-Hartman

staging: zram: conventions pr_warning -> pr_warn()

2012-06-11T16:04:14+00:00

Porting zram to use the pr_warn() function instead of the deprecated
pr_warning().

Signed-off-by: Sam Hansen 
Signed-off-by: Greg Kroah-Hartman

staging: zram: remove special handle of uncompressed page

2012-06-11T16:00:01+00:00

xvmalloc can't handle PAGE_SIZE page so that zram have to
handle it specially but zsmalloc can do it so let's remove
unnecessary special handling code.

Quote from Nitin
"I think page vs handle distinction was added since xvmalloc could not
handle full page allocation. Now that zsmalloc allows full page
allocation, we can just use it for both cases. This would also allow
removing the ZRAM_UNCOMPRESSED flag. The only downside will be slightly
slower code path for full page allocation but this event is anyways
supposed to be rare, so should be fine."

1. This patch reduces code very much.

 drivers/staging/zram/zram_drv.c   |  104 +++++--------------------------------
 drivers/staging/zram/zram_drv.h   |   17 +-----
 drivers/staging/zram/zram_sysfs.c |    6 +--
 3 files changed, 15 insertions(+), 112 deletions(-)

2. change pages_expand with bad_compress so it can count
   bad compression(above 75%) ratio.

3. remove zobj_header which is for back-reference for defragmentation
   because firstly, it's not used at the moment and zsmalloc can't handle
   bigger size than PAGE_SIZE so zram can't do it any more without redesign.

Cc: Seth Jennings 
Signed-off-by: Minchan Kim 
Acked-by: Nitin Gupta 
Signed-off-by: Greg Kroah-Hartman

staging: zram: fix random data read

2012-06-11T15:59:47+00:00

fd1a30de makes a bug that it uses (struct page *) as zsmalloc's handle
although it's a uncompressed page so that it can access random page,
return random data or even crashed by get_first_page in zs_map_object.

Cc: Seth Jennings 
Cc: Jerome Marchand 
Signed-off-by: Minchan Kim 
Acked-by: Nitin Gupta 
Signed-off-by: Greg Kroah-Hartman

staging: zsmalloc: zsmalloc: use unsigned long instead of void *

2012-06-11T15:57:47+00:00

We should use unsigned long as handle instead of void * to avoid any
confusion. Without this, users may just treat zs_malloc return value as
a pointer and try to deference it.

This patch passed compile test(zram, zcache and ramster) and zram is
tested on qemu.

changelog
  * from v2
	- remove hval pointed out by Nitin
	- based on next-20120607
  * from v1
	- change zcache's zv_create return value
	- baesd on next-20120604

Cc: Dan Magenheimer 
Acked-by: Seth Jennings 
Acked-by: Konrad Rzeszutek Wilk 
Signed-off-by: Minchan Kim 
Acked-by: Nitin Gupta 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'kmap_atomic' of git://github.com/congwang/linux

2012-03-21T16:40:26+00:00

Pull kmap_atomic cleanup from Cong Wang.

It's been in -next for a long time, and it gets rid of the (no longer
used) second argument to k[un]map_atomic().

Fix up a few trivial conflicts in various drivers, and do an "evil
merge" to catch some new uses that have come in since Cong's tree.

* 'kmap_atomic' of git://github.com/congwang/linux: (59 commits)
  feature-removal-schedule.txt: schedule the deprecated form of kmap_atomic() for removal
  highmem: kill all __kmap_atomic() [swarren@nvidia.com: highmem: Fix ARM build break due to __kmap_atomic rename]
  drbd: remove the second argument of k[un]map_atomic()
  zcache: remove the second argument of k[un]map_atomic()
  gma500: remove the second argument of k[un]map_atomic()
  dm: remove the second argument of k[un]map_atomic()
  tomoyo: remove the second argument of k[un]map_atomic()
  sunrpc: remove the second argument of k[un]map_atomic()
  rds: remove the second argument of k[un]map_atomic()
  net: remove the second argument of k[un]map_atomic()
  mm: remove the second argument of k[un]map_atomic()
  lib: remove the second argument of k[un]map_atomic()
  power: remove the second argument of k[un]map_atomic()
  kdb: remove the second argument of k[un]map_atomic()
  udf: remove the second argument of k[un]map_atomic()
  ubifs: remove the second argument of k[un]map_atomic()
  squashfs: remove the second argument of k[un]map_atomic()
  reiserfs: remove the second argument of k[un]map_atomic()
  ocfs2: remove the second argument of k[un]map_atomic()
  ntfs: remove the second argument of k[un]map_atomic()
  ...

zram: remove the second argument of k[un]map_atomic()

2012-03-20T13:48:20+00:00

Acked-by: Greg Kroah-Hartman 
Signed-off-by: Cong Wang