[PATCH] dm: Support arbitrary number of target params

Support an arbitrary number of target parameters.  [Alasdair Kergon]

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index aae61522d1f7ea577d4c4b2d1e5df09d3a66fd3e..421f4de1066c2a03d448be2a3affb2342da118dc 100644 (file)
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -533,13 +533,37 @@ static int adjoin(struct dm_table *table, struct dm_target *ti)
        return (ti->begin == (prev->begin + prev->len));
 }
 
+/*
+ * Used to dynamically allocate the arg array.
+ */
+static char **realloc_argv(unsigned *array_size, char **old_argv)
+{
+       char **argv;
+       unsigned new_size;
+
+       new_size = *array_size ? *array_size * 2 : 64;
+       argv = kmalloc(new_size * sizeof(*argv), GFP_KERNEL);
+       if (argv) {
+               memcpy(argv, old_argv, *array_size * sizeof(*argv));
+               *array_size = new_size;
+       }
+
+       kfree(old_argv);
+       return argv;
+}
+
 /*
  * Destructively splits up the argument list to pass to ctr.
  */
-static int split_args(int max, int *argc, char **argv, char *input)
+static int split_args(int *argc, char ***argvp, char *input)
 {
-       char *start, *end = input, *out;
+       char *start, *end = input, *out, **argv = NULL;
+       unsigned array_size = 0;
+
        *argc = 0;
+       argv = realloc_argv(&array_size, argv);
+       if (!argv)
+               return -ENOMEM;
 
        while (1) {
                start = end;
@@ -568,8 +592,11 @@ static int split_args(int max, int *argc, char **argv, char *input)
                }
 
                /* have we already filled the array ? */
-               if ((*argc + 1) > max)
-                       return -EINVAL;
+               if ((*argc + 1) > array_size) {
+                       argv = realloc_argv(&array_size, argv);
+                       if (!argv)
+                               return -ENOMEM;
+               }
 
                /* we know this is whitespace */
                if (*end)
@@ -581,6 +608,7 @@ static int split_args(int max, int *argc, char **argv, char *input)
                (*argc)++;
        }
 
+       *argvp = argv;
        return 0;
 }
 
@@ -588,7 +616,7 @@ int dm_table_add_target(struct dm_table *t, const char *type,
                        sector_t start, sector_t len, char *params)
 {
        int r = -EINVAL, argc;
-       char *argv[32];
+       char **argv;
        struct dm_target *tgt;
 
        if ((r = check_space(t)))
@@ -617,13 +645,14 @@ int dm_table_add_target(struct dm_table *t, const char *type,
                goto bad;
        }
 
-       r = split_args(ARRAY_SIZE(argv), &argc, argv, params);
+       r = split_args(&argc, &argv, params);
        if (r) {
-               tgt->error = "couldn't split parameters";
+               tgt->error = "couldn't split parameters (insufficient memory)";
                goto bad;
        }
 
        r = tgt->type->ctr(tgt, argc, argv);
+       kfree(argv);
        if (r)
                goto bad;