On Sun, Mar 15, 2020 at 03:13:19PM -0700, Bart Van Assche wrote:
> Introduce a function for creating a null_blk device instance through
> configfs.
>
> Suggested-by: Chaitanya Kulkarni <Chaitanya.Kulkarni@xxxxxxx>
> Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
> ---
> common/multipath-over-rdma | 17 +++++------------
> common/null_blk | 14 ++++++++++++++
> tests/block/029 | 16 ++--------------
> 3 files changed, 21 insertions(+), 26 deletions(-)
>
> diff --git a/common/multipath-over-rdma b/common/multipath-over-rdma
> index a56e7a8269db..7e610a0ccbbb 100644
> --- a/common/multipath-over-rdma
> +++ b/common/multipath-over-rdma
> @@ -620,18 +620,11 @@ run_fio() {
> configure_null_blk() {
> local i
>
> - (
> - cd /sys/kernel/config/nullb || return $?
> - for i in nullb0 nullb1; do (
> - { mkdir -p $i &&
> - cd $i &&
> - echo 0 > completion_nsec &&
> - echo 512 > blocksize &&
> - echo $((ramdisk_size>>20)) > size &&
> - echo 1 > memory_backed &&
> - echo 1 > power; } || exit $?
> - ) done
> - )
> + for i in nullb0 nullb1; do
> + _configure_null_blk nullb$i completion_nsec=0 blocksize=512 \
> + size=$((ramdisk_size>>20)) memory_backed=1 \
> + power=1 || return $?
> + done
> ls -l /dev/nullb* &>>"$FULL"
> }
>
> diff --git a/common/null_blk b/common/null_blk
> index 6a5f99aaae9d..3c31db1ed4ac 100644
> --- a/common/null_blk
> +++ b/common/null_blk
> @@ -28,6 +28,20 @@ _init_null_blk() {
> return 0
> }
>
> +# Configure one null_blk instance with name $1 and parameters $2..${$#}.
> +_configure_null_blk() {
> + local nullb=/sys/kernel/config/nullb/$1 param val
> +
> + shift
> + mkdir "$nullb" &&
Just make this mkdir "$nullb" || return $?
> + while [ -n "$1" ]; do
The intention is clearer with while [[ $# > 0 ]]
> + param="${1//=*}"
> + val="${1#${param}=}"
These are all arcane bash incantations, but the following seem slighly
clearer to me:
param="${1%%=*}"
val="${1#*=}"
I.e., for param we remove the equal sign and everything after it, and
for val we remove everything up to the equal sign.
> + shift
> + echo "$val" > "$nullb/$param" || return $?
> + done
> +}
> +
