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Go Back   Linux Archive > Redhat > Device-mapper Development

 
 
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Old 06-27-2011, 07:53 PM
Mike Snitzer
 
Default dm: factor out target argument parsing helpers

Other targets may need to handle target arguments with a variable
count (as are widely used in the multipath target).

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
drivers/md/dm-mpath.c | 119 +++++++++++++----------------------------
drivers/md/dm-table.c | 40 ++++++++++++++
include/linux/device-mapper.h | 18 ++++++
3 files changed, 95 insertions(+), 82 deletions(-)

diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index a550a05..b5149b9 100644
--- a/drivers/md/dm-mpath.c
+++ b/drivers/md/dm-mpath.c
@@ -505,69 +505,24 @@ 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(_args, dm_shift_arg(as), &ps_argc, &ti->error);
if (r) {
dm_put_path_selector(pst);
return -EINVAL;
@@ -587,12 +542,12 @@ 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 +564,7 @@ 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 +615,16 @@ 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 +648,26 @@ 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, dm_shift_arg(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, dm_shift_arg(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 +678,7 @@ 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;
@@ -733,17 +688,17 @@ 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(_args, dm_shift_arg(as), &hw_argc, &ti->error))
return -EINVAL;

if (!hw_argc)
@@ -754,7 +709,7 @@ static int parse_hw_handler(struct arg_set *as, struct multipath *m)
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 +733,7 @@ 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:
@@ -787,20 +742,20 @@ 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(_args, dm_shift_arg(as), &argc, &ti->error);
if (r)
return -EINVAL;

@@ -808,25 +763,25 @@ static int parse_features(struct arg_set *as, struct multipath *m)
return 0;

do {
- param_name = shift(as);
+ arg_name = dm_shift_arg(as);
argc--;

- if (!strnicmp(param_name, MESG_STR("queue_if_no_path"))) {
+ if (!strnicmp(arg_name, MESG_STR("queue_if_no_path"))) {
r = queue_if_no_path(m, 1, 0);
continue;
}

- if (!strnicmp(param_name, MESG_STR("pg_init_retries")) &&
+ if (!strnicmp(arg_name, MESG_STR("pg_init_retries")) &&
(argc >= 1)) {
- r = read_param(_params + 1, shift(as),
+ r = dm_read_arg(_args + 1, dm_shift_arg(as),
&m->pg_init_retries, &ti->error);
argc--;
continue;
}

- if (!strnicmp(param_name, MESG_STR("pg_init_delay_msecs")) &&
+ if (!strnicmp(arg_name, MESG_STR("pg_init_delay_msecs")) &&
(argc >= 1)) {
- r = read_param(_params + 2, shift(as),
+ r = dm_read_arg(_args + 2, dm_shift_arg(as),
&m->pg_init_delay_msecs, &ti->error);
argc--;
continue;
@@ -842,15 +797,15 @@ 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;

@@ -871,11 +826,11 @@ 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, dm_shift_arg(&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, dm_shift_arg(&as), &next_pg_num, &ti->error);
if (r)
goto bad;

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 5570d4b..db75414 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -785,6 +785,46 @@ int dm_table_add_target(struct dm_table *t, const char *type,
return r;
}

+/*
+ * Target argument parsing helpers.
+ */
+int dm_read_arg(struct dm_arg *arg, char *str, unsigned *v, char **error)
+{
+ if (!str ||
+ (sscanf(str, "%u", v) != 1) ||
+ (*v < arg->min) ||
+ (*v > arg->max)) {
+ *error = arg->error;
+ return -EINVAL;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(dm_read_arg);
+
+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 n)
+{
+ BUG_ON (as->argc < n);
+ as->argc -= n;
+ as->argv += n;
+}
+EXPORT_SYMBOL(dm_consume_args);
+
static int dm_table_set_type(struct dm_table *t)
{
unsigned i;
diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 5ad7eb7..0e187cb 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -202,6 +202,24 @@ struct dm_target_callbacks {
int dm_register_target(struct target_type *t);
void dm_unregister_target(struct target_type *t);

+/*
+ * Target argument parsing
+ */
+struct dm_arg_set {
+ unsigned argc;
+ char **argv;
+};
+
+struct dm_arg {
+ unsigned min;
+ unsigned max;
+ char *error;
+};
+
+int dm_read_arg(struct dm_arg *arg, char *str, unsigned *v, char **error);
+char *dm_shift_arg(struct dm_arg_set *as);
+void dm_consume_args(struct dm_arg_set *as, unsigned n);
+
/*-----------------------------------------------------------------
* Functions for creating and manipulating mapped devices.
* Drop the reference with dm_put when you finish with the object.
--
1.7.1

--
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