dm table: share target argument parsing functions

Move multipath target argument parsing code into dm-table so other
targets can share it.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

3 files changed, 104 insertions, 112 deletions

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f5406766ece3..b79e7472a9b3 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -30,7 +30,6 @@
 #include <linux/device-mapper.h>
 
 #define DM_MSG_PREFIX "crypt"
-#define MESG_STR(x) x, sizeof(x)
 
 /*
  * context holding the current state of a multi-part conversion
@@ -1770,12 +1769,12 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
         if (argc < 2)
                 goto error;
 
-        if (!strnicmp(argv[0], MESG_STR("key"))) {
+        if (!strcasecmp(argv[0], "key")) {
                 if (!test_bit(DM_CRYPT_SUSPENDED, &cc->flags)) {
                         DMWARN("not suspended during key manipulation.");
                         return -EINVAL;
                 }
-                if (argc == 3 && !strnicmp(argv[1], MESG_STR("set"))) {
+                if (argc == 3 && !strcasecmp(argv[1], "set")) {
                         ret = crypt_set_key(cc, argv[2]);
                         if (ret)
                                 return ret;
@@ -1783,7 +1782,7 @@ static int crypt_message(struct dm_target *ti, unsigned argc, char **argv)
                                 ret = cc->iv_gen_ops->init(cc);
                         return ret;
                 }
-                if (argc == 2 && !strnicmp(argv[1], MESG_STR("wipe"))) {
+                if (argc == 2 && !strcasecmp(argv[1], "wipe")) {
                         if (cc->iv_gen_ops && cc->iv_gen_ops->wipe) {
                                 ret = cc->iv_gen_ops->wipe(cc);
                                 if (ret)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index adf851a081bd..5e0090ef4182 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -22,7 +22,6 @@
 #include <linux/atomic.h>
 
 #define DM_MSG_PREFIX "multipath"
-#define MESG_STR(x) x, sizeof(x)
 #define DM_PG_INIT_DELAY_MSECS 2000
 #define DM_PG_INIT_DELAY_DEFAULT ((unsigned) -1)
 
@@ -505,80 +504,29 @@ static void trigger_event(struct work_struct *work)
  *      <#paths> <#per-path selector args>
  *         [<path> [<arg>]* ]+ ]+
  *---------------------------------------------------------------*/
-struct param {
-        unsigned min;
-        unsigned max;
-        char *error;
-};
-
-static int read_param(struct param *param, char *str, unsigned *v, char **error)
-{
-        if (!str ||
-            (sscanf(str, "%u", v) != 1) ||
-            (*v < param->min) ||
-            (*v > param->max)) {
-                *error = param->error;
-                return -EINVAL;
-        }
-
-        return 0;
-}
-
-struct arg_set {
-        unsigned argc;
-        char **argv;
-};
-
-static char *shift(struct arg_set *as)
-{
-        char *r;
-
-        if (as->argc) {
-                as->argc--;
-                r = *as->argv;
-                as->argv++;
-                return r;
-        }
-
-        return NULL;
-}
-
-static void consume(struct arg_set *as, unsigned n)
-{
-        BUG_ON (as->argc < n);
-        as->argc -= n;
-        as->argv += n;
-}
-
-static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
+static int parse_path_selector(struct dm_arg_set *as, struct priority_group *pg,
                                struct dm_target *ti)
 {
         int r;
         struct path_selector_type *pst;
         unsigned ps_argc;
 
-        static struct param _params[] = {
+        static struct dm_arg _args[] = {
                 {0, 1024, "invalid number of path selector args"},
         };
 
-        pst = dm_get_path_selector(shift(as));
+        pst = dm_get_path_selector(dm_shift_arg(as));
         if (!pst) {
                 ti->error = "unknown path selector type";
                 return -EINVAL;
         }
 
-        r = read_param(_params, shift(as), &ps_argc, &ti->error);
+        r = dm_read_arg_group(_args, as, &ps_argc, &ti->error);
         if (r) {
                 dm_put_path_selector(pst);
                 return -EINVAL;
         }
 
-        if (ps_argc > as->argc) {
-                dm_put_path_selector(pst);
-                ti->error = "not enough arguments for path selector";
-                return -EINVAL;
-        }
-
         r = pst->create(&pg->ps, ps_argc, as->argv);
         if (r) {
                 dm_put_path_selector(pst);
@@ -587,12 +535,12 @@ static int parse_path_selector(struct arg_set *as, struct priority_group *pg,
         }
 
         pg->ps.type = pst;
-        consume(as, ps_argc);
+        dm_consume_args(as, ps_argc);
 
         return 0;
 }
 
-static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
+static struct pgpath *parse_path(struct dm_arg_set *as, struct path_selector *ps,
                                struct dm_target *ti)
 {
         int r;
@@ -609,7 +557,7 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
         if (!p)
                 return ERR_PTR(-ENOMEM);
 
-        r = dm_get_device(ti, shift(as), dm_table_get_mode(ti->table),
+        r = dm_get_device(ti, dm_shift_arg(as), dm_table_get_mode(ti->table),
                           &p->path.dev);
         if (r) {
                 ti->error = "error getting device";
@@ -660,16 +608,16 @@ static struct pgpath *parse_path(struct arg_set *as, struct path_selector *ps,
         return ERR_PTR(r);
 }
 
-static struct priority_group *parse_priority_group(struct arg_set *as,
+static struct priority_group *parse_priority_group(struct dm_arg_set *as,
                                                    struct multipath *m)
 {
-        static struct param _params[] = {
+        static struct dm_arg _args[] = {
                 {1, 1024, "invalid number of paths"},
                 {0, 1024, "invalid number of selector args"}
         };
 
         int r;
-        unsigned i, nr_selector_args, nr_params;
+        unsigned i, nr_selector_args, nr_args;
         struct priority_group *pg;
         struct dm_target *ti = m->ti;
 
@@ -693,26 +641,26 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
         /*
          * read the paths
          */
-        r = read_param(_params, shift(as), &pg->nr_pgpaths, &ti->error);
+        r = dm_read_arg(_args, as, &pg->nr_pgpaths, &ti->error);
         if (r)
                 goto bad;
 
-        r = read_param(_params + 1, shift(as), &nr_selector_args, &ti->error);
+        r = dm_read_arg(_args + 1, as, &nr_selector_args, &ti->error);
         if (r)
                 goto bad;
 
-        nr_params = 1 + nr_selector_args;
+        nr_args = 1 + nr_selector_args;
         for (i = 0; i < pg->nr_pgpaths; i++) {
                 struct pgpath *pgpath;
-                struct arg_set path_args;
+                struct dm_arg_set path_args;
 
-                if (as->argc < nr_params) {
+                if (as->argc < nr_args) {
                         ti->error = "not enough path parameters";
                         r = -EINVAL;
                         goto bad;
                 }
 
-                path_args.argc = nr_params;
+                path_args.argc = nr_args;
                 path_args.argv = as->argv;
 
                 pgpath = parse_path(&path_args, &pg->ps, ti);
@@ -723,7 +671,7 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
 
                 pgpath->pg = pg;
                 list_add_tail(&pgpath->list, &pg->pgpaths);
-                consume(as, nr_params);
+                dm_consume_args(as, nr_args);
         }
 
         return pg;
@@ -733,28 +681,23 @@ static struct priority_group *parse_priority_group(struct arg_set *as,
         return ERR_PTR(r);
 }
 
-static int parse_hw_handler(struct arg_set *as, struct multipath *m)
+static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
 {
         unsigned hw_argc;
         int ret;
         struct dm_target *ti = m->ti;
 
-        static struct param _params[] = {
+        static struct dm_arg _args[] = {
                 {0, 1024, "invalid number of hardware handler args"},
         };
 
-        if (read_param(_params, shift(as), &hw_argc, &ti->error))
+        if (dm_read_arg_group(_args, as, &hw_argc, &ti->error))
                 return -EINVAL;
 
         if (!hw_argc)
                 return 0;
 
-        if (hw_argc > as->argc) {
-                ti->error = "not enough arguments for hardware handler";
-                return -EINVAL;
-        }
-
-        m->hw_handler_name = kstrdup(shift(as), GFP_KERNEL);
+        m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
         request_module("scsi_dh_%s", m->hw_handler_name);
         if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
                 ti->error = "unknown hardware handler type";
@@ -778,7 +721,7 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
                 for (i = 0, p+=j+1; i <= hw_argc - 2; i++, p+=j+1)
                         j = sprintf(p, "%s", as->argv[i]);
         }
-        consume(as, hw_argc - 1);
+        dm_consume_args(as, hw_argc - 1);
 
         return 0;
 fail:
@@ -787,52 +730,45 @@ fail:
         return ret;
 }
 
-static int parse_features(struct arg_set *as, struct multipath *m)
+static int parse_features(struct dm_arg_set *as, struct multipath *m)
 {
         int r;
         unsigned argc;
         struct dm_target *ti = m->ti;
-        const char *param_name;
+        const char *arg_name;
 
-        static struct param _params[] = {
+        static struct dm_arg _args[] = {
                 {0, 5, "invalid number of feature args"},
                 {1, 50, "pg_init_retries must be between 1 and 50"},
                 {0, 60000, "pg_init_delay_msecs must be between 0 and 60000"},
         };
 
-        r = read_param(_params, shift(as), &argc, &ti->error);
+        r = dm_read_arg_group(_args, as, &argc, &ti->error);
         if (r)
                 return -EINVAL;
 
         if (!argc)
                 return 0;
 
-        if (argc > as->argc) {
-                ti->error = "not enough arguments for features";
-                return -EINVAL;
-        }
-
         do {
-                param_name = shift(as);
+                arg_name = dm_shift_arg(as);
                 argc--;
 
-                if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
+                if (!strcasecmp(arg_name, "queue_if_no_path")) {
                         r = queue_if_no_path(m, 1, 0);
                         continue;
                 }
 
-                if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
+                if (!strcasecmp(arg_name, "pg_init_retries") &&
                     (argc >= 1)) {
-                        r = read_param(_params + 1, shift(as),
-                                       &m->pg_init_retries, &ti->error);
+                        r = dm_read_arg(_args + 1, as, &m->pg_init_retries, &ti->error);
                         argc--;
                         continue;
                 }
 
-                if (!strnicmp(param_name, MESG_STR("pg_init_delay_msecs")) &&
+                if (!strcasecmp(arg_name, "pg_init_delay_msecs") &&
                     (argc >= 1)) {
-                        r = read_param(_params + 2, shift(as),
-                                       &m->pg_init_delay_msecs, &ti->error);
+                        r = dm_read_arg(_args + 2, as, &m->pg_init_delay_msecs, &ti->error);
                         argc--;
                         continue;
                 }
@@ -847,15 +783,15 @@ static int parse_features(struct arg_set *as, struct multipath *m)
 static int multipath_ctr(struct dm_target *ti, unsigned int argc,
                          char **argv)
 {
-        /* target parameters */
-        static struct param _params[] = {
+        /* target arguments */
+        static struct dm_arg _args[] = {
                 {0, 1024, "invalid number of priority groups"},
                 {0, 1024, "invalid initial priority group number"},
         };
 
         int r;
         struct multipath *m;
-        struct arg_set as;
+        struct dm_arg_set as;
         unsigned pg_count = 0;
         unsigned next_pg_num;
 
@@ -876,11 +812,11 @@ static int multipath_ctr(struct dm_target *ti, unsigned int argc,
         if (r)
                 goto bad;
 
-        r = read_param(_params, shift(&as), &m->nr_priority_groups, &ti->error);
+        r = dm_read_arg(_args, &as, &m->nr_priority_groups, &ti->error);
         if (r)
                 goto bad;
 
-        r = read_param(_params + 1, shift(&as), &next_pg_num, &ti->error);
+        r = dm_read_arg(_args + 1, &as, &next_pg_num, &ti->error);
         if (r)
                 goto bad;
 
@@ -1510,10 +1446,10 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
         }
 
         if (argc == 1) {
-                if (!strnicmp(argv[0], MESG_STR("queue_if_no_path"))) {
+                if (!strcasecmp(argv[0], "queue_if_no_path")) {
                         r = queue_if_no_path(m, 1, 0);
                         goto out;
-                } else if (!strnicmp(argv[0], MESG_STR("fail_if_no_path"))) {
+                } else if (!strcasecmp(argv[0], "fail_if_no_path")) {
                         r = queue_if_no_path(m, 0, 0);
                         goto out;
                 }
@@ -1524,18 +1460,18 @@ static int multipath_message(struct dm_target *ti, unsigned argc, char **argv)
                 goto out;
         }
 
-        if (!strnicmp(argv[0], MESG_STR("disable_group"))) {
+        if (!strcasecmp(argv[0], "disable_group")) {
                 r = bypass_pg_num(m, argv[1], 1);
                 goto out;
-        } else if (!strnicmp(argv[0], MESG_STR("enable_group"))) {
+        } else if (!strcasecmp(argv[0], "enable_group")) {
                 r = bypass_pg_num(m, argv[1], 0);
                 goto out;
-        } else if (!strnicmp(argv[0], MESG_STR("switch_group"))) {
+        } else if (!strcasecmp(argv[0], "switch_group")) {
                 r = switch_pg_num(m, argv[1]);
                 goto out;
-        } else if (!strnicmp(argv[0], MESG_STR("reinstate_path")))
+        } else if (!strcasecmp(argv[0], "reinstate_path"))
                 action = reinstate_path;
-        else if (!strnicmp(argv[0], MESG_STR("fail_path")))
+        else if (!strcasecmp(argv[0], "fail_path"))
                 action = fail_path;
         else {
                 DMWARN("Unrecognised multipath message received.");
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 03516c7f5be1..259ce99302fc 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -797,6 +797,63 @@ int dm_table_add_target(struct dm_table *t, const char *type,
         return r;
 }
 
+/*
+ * Target argument parsing helpers.
+ */
+static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                             unsigned *value, char **error, unsigned grouped)
+{
+        const char *arg_str = dm_shift_arg(arg_set);
+
+        if (!arg_str ||
+            (sscanf(arg_str, "%u", value) != 1) ||
+            (*value < arg->min) ||
+            (*value > arg->max) ||
+            (grouped && arg_set->argc < *value)) {
+                *error = arg->error;
+                return -EINVAL;
+        }
+
+        return 0;
+}
+
+int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                unsigned *value, char **error)
+{
+        return validate_next_arg(arg, arg_set, value, error, 0);
+}
+EXPORT_SYMBOL(dm_read_arg);
+
+int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
+                      unsigned *value, char **error)
+{
+        return validate_next_arg(arg, arg_set, value, error, 1);
+}
+EXPORT_SYMBOL(dm_read_arg_group);
+
+const char *dm_shift_arg(struct dm_arg_set *as)
+{
+        char *r;
+
+        if (as->argc) {
+                as->argc--;
+                r = *as->argv;
+                as->argv++;
+                return r;
+        }
+
+        return NULL;
+}
+EXPORT_SYMBOL(dm_shift_arg);
+
+void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
+{
+        BUG_ON(as->argc < num_args);
+        as->argc -= num_args;
+        as->argv += num_args;
+}
+EXPORT_SYMBOL(dm_consume_args);
+
 static int dm_table_set_type(struct dm_table *t)
 {
         unsigned i;