[PATCH] device-mapper: [1/2] Add DM_TARGET_MSG

From: Alasdair G Kergon
Date: Thu Nov 11 2004 - 13:19:10 EST


Add DM_TARGET_MSG ioctl so data can be passed to a dm target
after its table has been loaded.

Signed-Off-By: Alasdair G Kergon <agk@xxxxxxxxxx>
--- diff/drivers/md/dm-ioctl.c 2004-06-30 14:25:46.000000000 +0100
+++ source/drivers/md/dm-ioctl.c 2004-11-10 15:05:36.000000000 +0000
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -1097,6 +1098,67 @@
return r;
}

+/*
+ * Pass a message to the target that's at the supplied device offset.
+ */
+static int target_message(struct dm_ioctl *param, size_t param_size)
+{
+ int r, argc;
+ char **argv;
+ struct mapped_device *md;
+ struct dm_table *table;
+ struct dm_target *ti;
+ struct dm_target_msg *tmsg = (void *) param + param->data_start;
+
+ md = find_device(param);
+ if (!md)
+ return -ENXIO;
+
+ r = __dev_status(md, param);
+ if (r)
+ goto out;
+
+ if (tmsg < (struct dm_target_msg *) (param + 1) ||
+ invalid_str(tmsg->message, (void *) param + param_size)) {
+ DMWARN("Invalid target message parameters.");
+ r = -EINVAL;
+ goto out;
+ }
+
+ r = dm_split_args(&argc, &argv, tmsg->message);
+ if (r) {
+ DMWARN("Failed to split target message parameters");
+ goto out;
+ }
+
+ table = dm_get_table(md);
+ if (!table)
+ goto out_argv;
+
+ if (tmsg->sector >= dm_table_get_size(table)) {
+ DMWARN("Target message sector outside device.");
+ r = -EINVAL;
+ goto out_table;
+ }
+
+ ti = dm_table_find_target(table, tmsg->sector);
+ if (ti->type->message)
+ r = ti->type->message(ti, argc, argv);
+ else {
+ DMWARN("Target type does not support messages");
+ r = -EINVAL;
+ }
+
+ out_table:
+ dm_table_put(table);
+ out_argv:
+ kfree(argv);
+ out:
+ param->data_size = 0;
+ dm_put(md);
+ return r;
+}
+
/*-----------------------------------------------------------------
* Implementation of open/close/ioctl on the special char
* device.
@@ -1123,7 +1185,9 @@
{DM_TABLE_DEPS_CMD, table_deps},
{DM_TABLE_STATUS_CMD, table_status},

- {DM_LIST_VERSIONS_CMD, list_versions}
+ {DM_LIST_VERSIONS_CMD, list_versions},
+
+ {DM_TARGET_MSG_CMD, target_message}
};

return (cmd >= ARRAY_SIZE(_ioctls)) ? NULL : _ioctls[cmd].fn;
--- diff/drivers/md/dm-table.c 2004-10-19 16:47:25.000000000 +0100
+++ source/drivers/md/dm-table.c 2004-11-10 15:05:36.000000000 +0000
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
@@ -575,7 +576,7 @@
/*
* Destructively splits up the argument list to pass to ctr.
*/
-static int split_args(int *argc, char ***argvp, char *input)
+int dm_split_args(int *argc, char ***argvp, char *input)
{
char *start, *end = input, *out, **argv = NULL;
unsigned array_size = 0;
@@ -688,7 +689,7 @@
goto bad;
}

- r = split_args(&argc, &argv, params);
+ r = dm_split_args(&argc, &argv, params);
if (r) {
tgt->error = "couldn't split parameters (insufficient memory)";
goto bad;
--- diff/drivers/md/dm.h 2004-11-10 15:05:30.000000000 +0000
+++ source/drivers/md/dm.h 2004-11-10 15:05:36.000000000 +0000
@@ -2,6 +2,7 @@
* Internal header file for device mapper
*
* Copyright (C) 2001, 2002 Sistina Software
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
@@ -165,6 +166,8 @@
return (n << 9);
}

+int dm_split_args(int *argc, char ***argvp, char *input);
+
/*
* The device-mapper can be driven through one of two interfaces;
* ioctl or filesystem, depending which patch you have applied.
--- diff/include/linux/compat_ioctl.h 2004-10-28 23:14:44.000000000 +0100
+++ source/include/linux/compat_ioctl.h 2004-11-10 15:05:36.000000000 +0000
@@ -140,6 +140,7 @@
COMPATIBLE_IOCTL(DM_TABLE_DEPS_32)
COMPATIBLE_IOCTL(DM_TABLE_STATUS_32)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS_32)
+COMPATIBLE_IOCTL(DM_TARGET_MSG_32)
COMPATIBLE_IOCTL(DM_VERSION)
COMPATIBLE_IOCTL(DM_REMOVE_ALL)
COMPATIBLE_IOCTL(DM_LIST_DEVICES)
@@ -154,6 +155,7 @@
COMPATIBLE_IOCTL(DM_TABLE_DEPS)
COMPATIBLE_IOCTL(DM_TABLE_STATUS)
COMPATIBLE_IOCTL(DM_LIST_VERSIONS)
+COMPATIBLE_IOCTL(DM_TARGET_MSG)
/* Big K */
COMPATIBLE_IOCTL(PIO_FONT)
COMPATIBLE_IOCTL(GIO_FONT)
--- diff/include/linux/device-mapper.h 2004-05-19 22:12:59.000000000 +0100
+++ source/include/linux/device-mapper.h 2004-11-10 15:05:36.000000000 +0000
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2001 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
@@ -57,6 +58,8 @@
typedef int (*dm_status_fn) (struct dm_target *ti, status_type_t status_type,
char *result, unsigned int maxlen);

+typedef int (*dm_message_fn) (struct dm_target *ti, unsigned argc, char **argv);
+
void dm_error(const char *message);

/*
@@ -82,6 +85,7 @@
dm_suspend_fn suspend;
dm_resume_fn resume;
dm_status_fn status;
+ dm_message_fn message;
};

struct io_restrictions {
--- diff/include/linux/dm-ioctl.h 2004-05-19 22:12:59.000000000 +0100
+++ source/include/linux/dm-ioctl.h 2004-11-10 15:05:36.000000000 +0000
@@ -1,5 +1,6 @@
/*
* Copyright (C) 2001 - 2003 Sistina Software (UK) Limited.
+ * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
*
* This file is released under the LGPL.
*/
@@ -76,6 +77,9 @@
*
* DM_TABLE_STATUS:
* Return the targets status for the 'active' table.
+ *
+ * DM_TARGET_MSG:
+ * Pass a message string to the target at a specific offset of a device.
*/

/*
@@ -179,6 +183,15 @@
};

/*
+ * Used to pass message to a target
+ */
+struct dm_target_msg {
+ uint64_t sector; /* Device sector */
+
+ char message[0];
+};
+
+/*
* If you change this make sure you make the corresponding change
* to dm-ioctl.c:lookup_ioctl()
*/
@@ -204,6 +217,7 @@

/* Added later */
DM_LIST_VERSIONS_CMD,
+ DM_TARGET_MSG_CMD,
};

/*
@@ -232,6 +246,7 @@
#define DM_TABLE_DEPS_32 _IOWR(DM_IOCTL, DM_TABLE_DEPS_CMD, ioctl_struct)
#define DM_TABLE_STATUS_32 _IOWR(DM_IOCTL, DM_TABLE_STATUS_CMD, ioctl_struct)
#define DM_LIST_VERSIONS_32 _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, ioctl_struct)
+#define DM_TARGET_MSG_32 _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, ioctl_struct)
#endif

#define DM_IOCTL 0xfd
@@ -254,10 +269,12 @@

#define DM_LIST_VERSIONS _IOWR(DM_IOCTL, DM_LIST_VERSIONS_CMD, struct dm_ioctl)

+#define DM_TARGET_MSG _IOWR(DM_IOCTL, DM_TARGET_MSG_CMD, struct dm_ioctl)
+
#define DM_VERSION_MAJOR 4
-#define DM_VERSION_MINOR 1
+#define DM_VERSION_MINOR 2
#define DM_VERSION_PATCHLEVEL 0
-#define DM_VERSION_EXTRA "-ioctl (2003-12-10)"
+#define DM_VERSION_EXTRA "-ioctl (2004-06-08)"

/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
-
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