linux.git/drivers/staging/zram, branch v3.11

staging: zram: protect zram_reset_device() call

2013-07-23T22:08:50+00:00

Commit 9b3bb7abcdf2df0f1b2657e6cbc9d06bc2b3b36f (remove
zram_sysfs file (v2)) accidentally made zram_reset_device()
racy. Protect zram_reset_device() call with zram->lock.

Signed-off-by: Sergey Senozhatsky 
Acked-by: Jerome Marchand 
Signed-off-by: Greg Kroah-Hartman

zram: allow request end to coincide with disksize

2013-06-24T23:08:32+00:00

Pass valid_io_request() checks if request end coincides with disksize
(end equals bound), only fail if we attempt to read beyond the bound.

mkfs.ext2 produces numerous errors:
[ 2164.632747] quiet_error: 1 callbacks suppressed
[ 2164.633260] Buffer I/O error on device zram0, logical block 153599
[ 2164.633265] lost page write due to I/O error on zram0

Signed-off-by: Sergey Senozhatsky 
Signed-off-by: Greg Kroah-Hartman

zram: remove zram_sysfs file (v2)

2013-06-24T22:59:03+00:00

Move zram sysfs code to zram drv and remove zram_sysfs.c
file. This gives ability to make static a number of previously
exported zram functions, used from zram sysfs, e.g. internal zram
zram_meta_alloc/free(). We also can drop zram_drv wrapper
functions, used from zram sysfs:
e.g. zram_reset_device()/__zram_reset_device() pair.

v2: as suggested by Greg K-H, move MODULE description to the
bottom of the file.

Signed-off-by: Sergey Senozhatsky 
Signed-off-by: Greg Kroah-Hartman

zram: use atomic64_xxx() to replace zram_stat64_xxx()

2013-06-06T19:12:21+00:00

Use atomic64_xxx() to replace open-coded zram_stat64_xxx().
Some architectures have native support of atomic64 operations,
so we can get rid of the spin_lock() in zram_stat64_xxx().
On the other hand, for platforms use generic version of atomic64
implement, it may cause an extra save/restore of the interrupt
flag.  So it's a tradeoff.

Signed-off-by: Jiang Liu 
Signed-off-by: Greg Kroah-Hartman

zram: optimize memory operations with clear_page()/copy_page()

2013-06-06T19:12:21+00:00

Some architectures provides architecture-specific, optimized version of
clear_page()/copy_page(), which may have better performance than
memset()/memcpy(). So use clear_page()/copy_page() to optimize zram
performance if possible.

Signed-off-by: Jiang Liu 
Signed-off-by: Greg Kroah-Hartman

zram: kill unused zram_get_num_devices()

2013-06-06T19:12:21+00:00

Now there's no caller of zram_get_num_devices(), so kill it.
And change zram_devices to static because it's only used in zram_drv.c.

Signed-off-by: Jiang Liu 
Signed-off-by: Greg Kroah-Hartman

zram: simplify and optimize dev_to_zram()

2013-06-06T19:12:20+00:00

Simplify and optimize dev_to_zram() without walking the zram_devices
array.

Signed-off-by: Jiang Liu 
Signed-off-by: Greg Kroah-Hartman

zram: protect sysfs handler from invalid memory access

2013-06-06T19:12:20+00:00

Use zram->init_lock to protect access to zram->meta, otherwise it
may cause invalid memory access if zram->meta has been freed by
zram_reset_device().

This issue may be triggered by:
Thread 1:
while true; do cat mem_used_total; done
Thread 2:
while true; do echo 8M > disksize; echo 1 > reset; done

Signed-off-by: Jiang Liu 
Acked-by: Minchan Kim 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

zram: avoid access beyond the zram device

2013-06-06T19:12:20+00:00

Function valid_io_request() should verify the entire request are within
the zram device address range. Otherwise it may cause invalid memory
access when accessing/modifying zram->meta->table[index] because the
'index' is out of range. Then it may access non-exist memory, randomly
modify memory belong to other subsystems, which is hard to track down.

Signed-off-by: Jiang Liu 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman

zram: avoid double free in function zram_bvec_write()

2013-06-06T19:12:20+00:00

When doing a patial write and the whole page is filled with zero,
zram_bvec_write() will free uncmem twice.

Signed-off-by: Jiang Liu 
Acked-by: Minchan Kim 
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman