loop: Improve the hw_queue_depth kernel module parameter implementation
Make the following minor changes which were reported by colleagues
while reviewing this code:
- Remove the parentheses from around the LOOP_DEFAULT_HW_Q_DEPTH
definition since these are superfluous.
- Accept other number formats than decimal, e.g. hexadecimal.
- Do not set hw_queue_depth to an out-of-range value, even if that value
won't be used.
- Use the LOOP_DEFAULT_HW_Q_DEPTH macro in the kernel module parameter
description to prevent that the description gets out of sync.
This patch has been tested as follows:
# modprobe -r loop
# modprobe loop hw_queue_depth=-1
modprobe: ERROR: could not insert 'loop': Invalid argument
# modprobe loop hw_queue_depth=0
modprobe: ERROR: could not insert 'loop': Invalid argument
# modprobe loop hw_queue_depth=1; cat /sys/module/loop/parameters/hw_queue_depth
1
# modprobe -r loop; modprobe loop; cat /sys/module/loop/parameters/hw_queue_depth hw_queue_depth=0x10
16
# modprobe -r loop; modprobe loop; cat /sys/module/loop/parameters/hw_queue_depth hw_queue_depth=128
128
# modprobe -r loop; modprobe loop hw_queue_depth=129; cat /sys/module/loop/parameters/hw_queue_depth
129
# modprobe -r loop; modprobe loop hw_queue_depth=$((1<<32))
modprobe: ERROR: could not insert 'loop': Numerical result out of range
See also commit ef44c50837ab ("loop: allow user to set the queue
depth").
Cc: Chaitanya Kulkarni <kch@nvidia.com>
Cc: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Link: https://lore.kernel.org/r/20230130211347.832110-1-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed
