@@ -137,6 +137,8 @@ struct ublk_device {
spinlock_t mm_lock;
struct mm_struct *mm;
+ struct ublk_param_header *params[UBLK_PARAM_TYPE_LAST];
+
struct completion completion;
unsigned int nr_queues_ready;
atomic_t nr_aborted_queues;
@@ -160,6 +162,28 @@ static DEFINE_MUTEX(ublk_ctl_mutex);
static struct miscdevice ublk_misc;
+static int ublk_validate_param_header(const struct ublk_device *ub,
+ const struct ublk_param_header *h)
+{
+ if (h->type >= UBLK_PARAM_TYPE_LAST)
+ return -EINVAL;
+ if (h->len > UBLK_MAX_PARAM_LEN)
+ return -EINVAL;
+ return 0;
+}
+
+/* Old parameter with same type will be overridden */
+static int ublk_install_param(struct ublk_device *ub,
+ struct ublk_param_header *h)
+{
+ struct ublk_param_header *old = ub->params[h->type];
+
+ kfree(old);
+ ub->params[h->type] = h;
+
+ return 0;
+}
+
static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq)
{
if (IS_BUILTIN(CONFIG_BLK_DEV_UBLK) &&
@@ -1447,6 +1471,87 @@ static int ublk_ctrl_get_dev_info(struct io_uring_cmd *cmd)
return ret;
}
+static int ublk_ctrl_get_param(struct io_uring_cmd *cmd)
+{
+ struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+ void __user *argp = (void __user *)(unsigned long)header->addr;
+ struct ublk_device *ub;
+ struct ublk_param_header ph;
+ struct ublk_param_header *param = NULL;
+ int ret = 0;
+
+ if (header->len <= sizeof(ph) || !header->addr)
+ return -EINVAL;
+
+ ub = ublk_get_device_from_id(header->dev_id);
+ if (!ub)
+ return -EINVAL;
+
+ ret = -EFAULT;
+ if (copy_from_user(&ph, argp, sizeof(ph)))
+ goto out_put;
+
+ ret = ublk_validate_param_header(ub, &ph);
+ if (ret)
+ goto out_put;
+
+ mutex_lock(&ub->mutex);
+ param = ub->params[ph.type];
+ mutex_unlock(&ub->mutex);
+ if (!param)
+ ret = -EINVAL;
+ else if (copy_to_user(argp, param, ph.len))
+ ret = -EFAULT;
+out_put:
+ ublk_put_device(ub);
+ return ret;
+}
+
+static int ublk_ctrl_set_param(struct io_uring_cmd *cmd)
+{
+ struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
+ void __user *argp = (void __user *)(unsigned long)header->addr;
+ struct ublk_device *ub;
+ struct ublk_param_header ph;
+ struct ublk_param_header *param = NULL;
+ int ret = -EFAULT;
+
+ if (header->len <= sizeof(ph) || !header->addr)
+ return -EINVAL;
+
+ ub = ublk_get_device_from_id(header->dev_id);
+ if (!ub)
+ return -EINVAL;
+
+ if (copy_from_user(&ph, argp, sizeof(ph)))
+ goto out_put;
+
+ ret = ublk_validate_param_header(ub, &ph);
+ if (ret)
+ goto out_put;
+
+ param = kmalloc(ph.len, GFP_KERNEL);
+ if (!param) {
+ ret = -ENOMEM;
+ } else if (copy_from_user(param, argp, ph.len)) {
+ ret = -EFAULT;
+ } else {
+ /* parameters can only be changed when device isn't live */
+ mutex_lock(&ub->mutex);
+ if (ub->dev_info.state != UBLK_S_DEV_LIVE)
+ ret = ublk_install_param(ub, param);
+ else
+ ret = -EACCES;
+ mutex_unlock(&ub->mutex);
+ }
+out_put:
+ ublk_put_device(ub);
+ if (ret)
+ kfree(param);
+
+ return ret;
+}
+
static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
unsigned int issue_flags)
{
@@ -1482,6 +1587,12 @@ static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd,
case UBLK_CMD_GET_QUEUE_AFFINITY:
ret = ublk_ctrl_get_queue_affinity(cmd);
break;
+ case UBLK_CMD_GET_PARAM:
+ ret = ublk_ctrl_get_param(cmd);
+ break;
+ case UBLK_CMD_SET_PARAM:
+ ret = ublk_ctrl_set_param(cmd);
+ break;
default:
break;
}
@@ -15,6 +15,8 @@
#define UBLK_CMD_DEL_DEV 0x05
#define UBLK_CMD_START_DEV 0x06
#define UBLK_CMD_STOP_DEV 0x07
+#define UBLK_CMD_SET_PARAM 0x08
+#define UBLK_CMD_GET_PARAM 0x09
/*
* IO commands, issued by ublk server, and handled by ublk driver.
@@ -158,4 +160,16 @@ struct ublksrv_io_cmd {
__u64 addr;
};
+/* 512 is big enough for single parameter */
+#define UBLK_MAX_PARAM_LEN 512
+
+enum {
+ UBLK_PARAM_TYPE_LAST,
+};
+
+struct ublk_param_header {
+ __u16 type;
+ __u16 len;
+};
+
#endif
Add two commands to set/get parameters generically. One important goal of ublk is to provide generic framework for making block device by userspace flexibly. As one generic block device, there are still lots of block parameters, such as max_sectors, write_cache/fua, discard related limits, zoned parameters, ...., so this patch starts to add mechanism for set/get device parameters. Both generic block parameters(all kinds of queue settings) and ublk feature related parameters can be covered with this way, then it becomes quite easy to extend in future. The parameter passed from userspace is added to one array, and the type is used as index of the array. The following patch will add two parameter types: basic(covers basic queue setting and misc settings which can't be grouped easily) and discard. Also segment, zoned[1], userspace recovery[2] and userspace backing buffer(in my todo list) parameters will be added in near future. This way provides mechanism to simulate any kind of generic block device from userspace easily, from both block queue setting viewpoint or ublk feature viewpoint. [1] https://lore.kernel.org/qemu-devel/fa7de750-8def-c532-8c86-64c7505608e0@opensource.wdc.com/T/#u [2] https://lore.kernel.org/linux-block/60bc9e53-605e-ee1d-9bd2-020693768339@linux.alibaba.com/ Signed-off-by: Ming Lei <ming.lei@redhat.com> --- drivers/block/ublk_drv.c | 111 ++++++++++++++++++++++++++++++++++ include/uapi/linux/ublk_cmd.h | 14 +++++ 2 files changed, 125 insertions(+)