From e152a05fa054170c05f1d5e04e93e2e75ea11405 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 30 Jan 2023 13:13:47 -0800 Subject: 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 Cc: Himanshu Madhani Signed-off-by: Bart Van Assche Reviewed-by: Chaitanya Kulkarni Link: https://lore.kernel.org/r/20230130211347.832110-1-bvanassche@acm.org Signed-off-by: Jens Axboe --- drivers/block/loop.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) (limited to 'drivers') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 1518a6423279..5f04235e4ff7 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -90,7 +90,7 @@ struct loop_cmd { }; #define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ) -#define LOOP_DEFAULT_HW_Q_DEPTH (128) +#define LOOP_DEFAULT_HW_Q_DEPTH 128 static DEFINE_IDR(loop_index_idr); static DEFINE_MUTEX(loop_ctl_mutex); @@ -1792,9 +1792,15 @@ static int hw_queue_depth = LOOP_DEFAULT_HW_Q_DEPTH; static int loop_set_hw_queue_depth(const char *s, const struct kernel_param *p) { - int ret = kstrtoint(s, 10, &hw_queue_depth); + int qd, ret; - return (ret || (hw_queue_depth < 1)) ? -EINVAL : 0; + ret = kstrtoint(s, 0, &qd); + if (ret < 0) + return ret; + if (qd < 1) + return -EINVAL; + hw_queue_depth = qd; + return 0; } static const struct kernel_param_ops loop_hw_qdepth_param_ops = { @@ -1803,7 +1809,7 @@ static const struct kernel_param_ops loop_hw_qdepth_param_ops = { }; device_param_cb(hw_queue_depth, &loop_hw_qdepth_param_ops, &hw_queue_depth, 0444); -MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: 128"); +MODULE_PARM_DESC(hw_queue_depth, "Queue depth for each hardware queue. Default: " __stringify(LOOP_DEFAULT_HW_Q_DEPTH)); MODULE_LICENSE("GPL"); MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR); -- cgit v1.2.3-70-g09d2