Re: [PATCH v6 1/3] scsi: ufs: add ioctl interface for query request

Akinobu Mita
2015-03-12T13:30:42Z

2015-03-12 21:27 GMT+09:00 Gilad Broner <gbroner@codeaurora.org>:
> From: Dolev Raviv <draviv@codeaurora.org>
>
> This patch exposes the ioctl interface for UFS driver via SCSI device
> ioctl interface. As of now UFS driver would provide the ioctl for query
> interface to connected UFS device.
>
> Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
> Signed-off-by: Noa Rubens <noag@codeaurora.org>
> Signed-off-by: Raviv Shvili <rshvili@codeaurora.org>
> Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>

Sorry to bother you again. Could you read two comments below?

> +/**
> + * ufshcd_ioctl - ufs ioctl callback registered in scsi_host
> + * @dev: scsi device required for per LUN queries
> + * @cmd: command opcode
> + * @buffer: user space buffer for transferring data
> + *
> + * Supported commands:
> + * UFS_IOCTL_QUERY
> + */
> +static int ufshcd_ioctl(struct scsi_device *dev, int cmd, void __user *buffer)
> +{
> + struct ufs_hba *hba = shost_priv(dev->host);
> + int err = 0;
> +
> + BUG_ON(!hba);
> + if (!buffer) {
> + dev_err(hba->dev, "%s: User buffer is NULL!\n", __func__);
> + return -EINVAL;
> + }
> +

Should we remove this check or move it into ufshcd_query_ioctl()?
For example, BLKFLS ioctl without argument is correct usage, but
it always triggers this message. (blkdev_ioctl -> __blkdev_driver_ioctl
-> sd_ioctl -> scsi_ioctl -> ufshcd_ioctl)

> + switch (cmd) {
> + case UFS_IOCTL_QUERY:
> + pm_runtime_get_sync(hba->dev);
> + err = ufshcd_query_ioctl(hba, ufshcd_scsi_to_upiu_lun(dev->lun),
> + buffer);
> + pm_runtime_put_sync(hba->dev);
> + break;
> + case UFS_IOCTL_BLKROSET:
> + err = -ENOIOCTLCMD;
> + break;
> + default:
> + err = -EINVAL;
> + dev_err(hba->dev, "%s: Illegal ufs-IOCTL cmd %d\n", __func__,
> + cmd);
> + break;
> + }
> +
> + return err;
> +}
> +
> static struct scsi_host_template ufshcd_driver_template = {
> .module = THIS_MODULE,
> .name = UFSHCD,
> @@ -4213,6 +4433,7 @@ static struct scsi_host_template ufshcd_driver_template = {
> .eh_abort_handler = ufshcd_abort,
> .eh_device_reset_handler = ufshcd_eh_device_reset_handler,
> .eh_host_reset_handler = ufshcd_eh_host_reset_handler,
> + .ioctl = ufshcd_ioctl,
> .this_id = -1,
> .sg_tablesize = SG_ALL,
> .cmd_per_lun = UFSHCD_CMD_PER_LUN,

...

> diff --git a/include/uapi/scsi/ufs/ioctl.h b/include/uapi/scsi/ufs/ioctl.h
> new file mode 100644
> index 0000000..bc4eed7
> --- /dev/null
> +++ b/include/uapi/scsi/ufs/ioctl.h
> @@ -0,0 +1,57 @@
> +#ifndef UAPI_UFS_IOCTL_H_
> +#define UAPI_UFS_IOCTL_H_
> +
> +#include <linux/types.h>
> +
> +/*
> + * IOCTL opcode for ufs queries has the following opcode after
> + * SCSI_IOCTL_GET_PCI
> + */
> +#define UFS_IOCTL_QUERY 0x5388

Should we also need some comments near SCSI_IOCTL_GET_PCI in
include/scsi/scsi.h in order to avoid someone trying to define
the same ioctl code in the future?