[PATCH v7 2/2] dm ioctl: add a device mapper ioctl function.

From: Enric Balletbo i Serra
Date: Thu May 18 2017 - 12:29:58 EST


Add a dm_ioctl_cmd to issue the equivalent of a DM ioctl call in kernel.

Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
---
drivers/md/dm-ioctl.c | 45 +++++++++++++++++++++++++++++++++++++++++++
include/linux/device-mapper.h | 6 ++++++
2 files changed, 51 insertions(+)

diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
index 4951bf9..d79a41a 100644
--- a/drivers/md/dm-ioctl.c
+++ b/drivers/md/dm-ioctl.c
@@ -1954,3 +1954,48 @@ int dm_copy_name_and_uuid(struct mapped_device *md, char *name, char *uuid)

return r;
}
+
+/**
+ * dm_ioctl_cmd - Device mapper ioctl's
+ * @command: ioctl command
+ * @param: Pointer to device mapped ioctl struct
+ */
+int dm_ioctl_cmd(uint command, struct dm_ioctl *param)
+{
+ int r = 0;
+ int ioctl_flags;
+ unsigned int cmd;
+ ioctl_fn fn = NULL;
+ size_t input_param_size;
+
+ if (_IOC_TYPE(command) != DM_IOCTL)
+ return -ENOTTY;
+
+ cmd = _IOC_NR(command);
+
+ /*
+ * Nothing more to do for the version command.
+ */
+ if (cmd == DM_VERSION_CMD)
+ return 0;
+
+ fn = lookup_ioctl(cmd, &ioctl_flags);
+ if (!fn) {
+ DMWARN("dm_ioctl: unknown command 0x%x", command);
+ return -ENOTTY;
+ }
+
+ input_param_size = param->data_size;
+ r = validate_params(cmd, param);
+ if (r)
+ return r;
+
+ param->data_size = sizeof(*param);
+ r = fn(param, input_param_size);
+
+ if (unlikely(param->flags & DM_BUFFER_FULL_FLAG) &&
+ unlikely(ioctl_flags & IOCTL_FLAGS_NO_PARAMS))
+ DMERR("ioctl %d tried to output some data but has IOCTL_FLAGS_NO_PARAMS set", cmd);
+
+ return r;
+}
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 81272c8..efa83ff 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -12,6 +12,7 @@
#include <linux/blkdev.h>
#include <linux/math64.h>
#include <linux/ratelimit.h>
+#include <linux/dm-ioctl.h>

struct dm_dev;
struct dm_target;
@@ -444,6 +445,11 @@ int dm_noflush_suspending(struct dm_target *ti);
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors);
union map_info *dm_get_rq_mapinfo(struct request *rq);

+/*
+ * Device mapper ioctl function.
+ */
+int dm_ioctl_cmd(unsigned int command, struct dm_ioctl *param);
+
struct queue_limits *dm_get_queue_limits(struct mapped_device *md);

/*
--
2.9.3