Not all shells define a variable UID. This is a bash and zsh feature only.
In other shells, the UID variable is not defined, so here test command
expands to [ != 0 ] which is a syntax error.

Without this patch:
root@HGH1000007090:/opt/work/linux/tools/testing/selftests/zram# sh zram.sh
zram.sh: 8: [: !=: unexpected operator
zram.sh : No zram.ko module or /dev/zram0 device file not found
zram.sh : CONFIG_ZRAM is not set

With this patch:
root@HGH1000007090:/opt/work/linux/tools/testing/selftests/zram# sh ./zram.sh
zram.sh : No zram.ko module or /dev/zram0 device file not found
zram.sh : CONFIG_ZRAM is not set

Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

Do not override run_tests, The default rule will just run TEST_PROGS

Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

Adding new functionality check_prereqs() to check test must be run as root

Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>

zram: Compressed RAM based block devices
----------------------------------------
The zram module creates RAM based block devices named /dev/zram<id>
(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
in memory itself. These disks allow very fast I/O and compression provides
good amounts of memory savings. Some of the usecases include /tmp storage,
use as swap disks, various caches under /var and maybe many more :)

Statistics for individual zram devices are exported through sysfs nodes at
/sys/block/zram<id>/

This patch is to validate the zram functionality. Test interacts with block
device /dev/zram<id> and sysfs nodes /sys/block/zram<id>/

zram.sh: sanity check of CONFIG_ZRAM and to run zram01 and zram02 tests
zram01.sh: creates general purpose ram disks with different filesystems
zram02.sh: creates block device for swap
zram_lib.sh: create library with initialization/cleanup functions
README: ZRAM introduction and Kconfig required.
Makefile: To run zram tests

zram test output
-----------------
./zram.sh
--------------------
running zram tests
--------------------
/dev/zram0 device file found: OK
set max_comp_streams to zram device(s)
/sys/block/zram0/max_comp_streams = '2' (1/1)
zram max streams: OK
test that we can set compression algorithm
supported algs: [lzo] lz4
/sys/block/zram0/comp_algorithm = 'lzo' (1/1)
zram set compression algorithm: OK
set disk size to zram device(s)
/sys/block/zram0/disksize = '2097152' (1/1)
zram set disksizes: OK
set memory limit to zram device(s)
/sys/block/zram0/mem_limit = '2M' (1/1)
zram set memory limit: OK
make ext4 filesystem on /dev/zram0
zram mkfs.ext4: OK
mount /dev/zram0
zram mount of zram device(s): OK
fill zram0...
zram0 can be filled with '1932' KB
zram used 3M, zram disk sizes 2097152M
zram compression ratio: 699050.66:1: OK
zram cleanup
zram01 : [PASS]

/dev/zram0 device file found: OK
set max_comp_streams to zram device(s)
/sys/block/zram0/max_comp_streams = '2' (1/1)
zram max streams: OK
set disk size to zram device(s)
/sys/block/zram0/disksize = '1048576' (1/1)
zram set disksizes: OK
set memory limit to zram device(s)
/sys/block/zram0/mem_limit = '1M' (1/1)
zram set memory limit: OK
make swap with zram device(s)
done with /dev/zram0
zram making zram mkswap and swapon: OK
zram swapoff: OK
zram cleanup
zram02 : [PASS]

CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Tyler Baker <tyler.baker@linaro.org>
CC: Milosz Wasilewski <milosz.wasilewski@linaro.org>
CC: Alexey Kodanev <alexey.kodanev@oracle.com>
Signed-off-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Alexey Kodanev <alexey.kodanev@oracle.com>
Reviewed-By: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>