dm flakey: support feature args

Add the ability to specify arbitrary feature flags when creating a
flakey target.  This code uses the same target argument helpers that
the multipath target does.

Also remove the superfluous 'dm-flakey' prefixes from the error messages,
as they already contain the prefix 'flakey'.

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

1 files changed, 64 insertions, 19 deletions

diff --git a/drivers/md/dm-flakey.c b/drivers/md/dm-flakey.c
index 70a69b2f93d2..dd963dc3ca08 100644
--- a/drivers/md/dm-flakey.c
+++ b/drivers/md/dm-flakey.c
@@ -27,54 +27,99 @@ struct flakey_c {
         unsigned down_interval;
 };
 
+static int parse_features(struct dm_arg_set *as, struct dm_target *ti)
+{
+        int r;
+        unsigned argc;
+        const char *arg_name;
+
+        static struct dm_arg _args[] = {
+                {0, 0, "Invalid number of feature args"},
+        };
+
+        /* No feature arguments supplied. */
+        if (!as->argc)
+                return 0;
+
+        r = dm_read_arg_group(_args, as, &argc, &ti->error);
+        if (r)
+                return -EINVAL;
+
+        while (argc && !r) {
+                arg_name = dm_shift_arg(as);
+                argc--;
+
+                ti->error = "Unrecognised flakey feature requested";
+                r = -EINVAL;
+        }
+
+        return r;
+}
+
 /*
- * Construct a flakey mapping: <dev_path> <offset> <up interval> <down interval>
+ * Construct a flakey mapping:
+ * <dev_path> <offset> <up interval> <down interval> [<#feature args> [<arg>]*]
  */
 static int flakey_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
+        static struct dm_arg _args[] = {
+                {0, UINT_MAX, "Invalid up interval"},
+                {0, UINT_MAX, "Invalid down interval"},
+        };
+
+        int r;
         struct flakey_c *fc;
-        unsigned long long tmp;
+        unsigned long long tmpll;
+        struct dm_arg_set as;
+        const char *devname;
 
-        if (argc != 4) {
-                ti->error = "dm-flakey: Invalid argument count";
+        as.argc = argc;
+        as.argv = argv;
+
+        if (argc < 4) {
+                ti->error = "Invalid argument count";
                 return -EINVAL;
         }
 
         fc = kmalloc(sizeof(*fc), GFP_KERNEL);
         if (!fc) {
-                ti->error = "dm-flakey: Cannot allocate linear context";
+                ti->error = "Cannot allocate linear context";
                 return -ENOMEM;
         }
         fc->start_time = jiffies;
 
-        if (sscanf(argv[1], "%llu", &tmp) != 1) {
-                ti->error = "dm-flakey: Invalid device sector";
+        devname = dm_shift_arg(&as);
+
+        if (sscanf(dm_shift_arg(&as), "%llu", &tmpll) != 1) {
+                ti->error = "Invalid device sector";
                 goto bad;
         }
-        fc->start = tmp;
+        fc->start = tmpll;
 
-        if (sscanf(argv[2], "%u", &fc->up_interval) != 1) {
-                ti->error = "dm-flakey: Invalid up interval";
+        r = dm_read_arg(_args, &as, &fc->up_interval, &ti->error);
+        if (r)
                 goto bad;
-        }
 
-        if (sscanf(argv[3], "%u", &fc->down_interval) != 1) {
-                ti->error = "dm-flakey: Invalid down interval";
+        r = dm_read_arg(_args, &as, &fc->down_interval, &ti->error);
+        if (r)
                 goto bad;
-        }
 
         if (!(fc->up_interval + fc->down_interval)) {
-                ti->error = "dm-flakey: Total (up + down) interval is zero";
+                ti->error = "Total (up + down) interval is zero";
                 goto bad;
         }
 
         if (fc->up_interval + fc->down_interval < fc->up_interval) {
-                ti->error = "dm-flakey: Interval overflow";
+                ti->error = "Interval overflow";
                 goto bad;
         }
 
-        if (dm_get_device(ti, argv[0], dm_table_get_mode(ti->table), &fc->dev)) {
-                ti->error = "dm-flakey: Device lookup failed";
+        r = parse_features(&as, ti);
+        if (r)
+                goto bad;
+
+        if (dm_get_device(ti, devname, dm_table_get_mode(ti->table), &fc->dev)) {
+                ti->error = "Device lookup failed";
                 goto bad;
         }
 
@@ -178,7 +223,7 @@ static int flakey_iterate_devices(struct dm_target *ti, iterate_devices_callout_
 
 static struct target_type flakey_target = {
         .name   = "flakey",
-        .version = {1, 1, 0},
+        .version = {1, 2, 0},
         .module = THIS_MODULE,
         .ctr    = flakey_ctr,
         .dtr    = flakey_dtr,