Re: [PATCH RFC 3/3] depmod: handle nested loops
From: Lucas De Marchi <hidden>
Date: 2017-02-13 08:30:53
On Fri, Nov 11, 2016 at 3:43 AM, Yauheni Kaliuta [off-list ref] wrote:
quoted hunk ↗ jump to hunk
This is a rework of depmod report cycles logic to make it tolerant to more complex loops. The patch tries to remember own path for vertexes which makes it possible to handle configurations with common edges and non-cyclic modules. It assumes that the previous dependency calculations can not give as input something like mod_a -> mod_b -> <loop>, but <loop> -> mod_a -> mod_b should be fine. Signed-off-by: Yauheni Kaliuta <redacted> --- tools/depmod.c | 287 ++++++++++++++++++++++++++++++++++++++++----------------- 1 file changed, 204 insertions(+), 83 deletions(-)diff --git a/tools/depmod.c b/tools/depmod.c index f2b370f146bb..c110635ff517 100644 --- a/tools/depmod.c +++ b/tools/depmod.c@@ -785,6 +785,7 @@ static void cfg_free(struct cfg *cfg) /* depmod calculations ***********************************************/ +struct vertex; struct mod { struct kmod_module *kmod; char *path;@@ -800,6 +801,7 @@ struct mod { uint16_t idx; /* index in depmod->modules.array */ uint16_t users; /* how many modules depend on this one */ bool visited; /* helper field to report cycles */ + struct vertex *vertex; /* helper field to report cycles */ char modname[]; };@@ -1450,105 +1452,225 @@ static void depmod_sort_dependencies(struct depmod *depmod) } } -static void depmod_report_cycles(struct depmod *depmod, uint16_t n_mods, - uint16_t n_roots, uint16_t *users, - uint16_t *stack, uint16_t *edges) +struct vertex { + struct vertex *parent; + struct mod *mod; +}; + +static struct vertex *vertex_new(struct mod *mod, struct vertex *parent) +{ + struct vertex *v; + + v = malloc(sizeof(*v)); + if (v == NULL) + return NULL; + + v->parent = parent; + v->mod = mod; + return v; +} + +static void depmod_list_remove_data(struct kmod_list **list, void *data) +{ + struct kmod_list *l; + + l = kmod_list_remove_data(*list, data); + *list = l; +} + +static void depmod_report_one_cycle(struct depmod *depmod, + struct vertex *vertex, + struct kmod_list **roots, + struct hash *loop_set) { const char sep[] = " -> "; - int ir = 0; - int num_cyclic = 0; + size_t sz; + char *buf; + struct array reverse; + int i; + int n; + struct vertex *v; - while (n_roots > 0) { - int is, ie; + array_init(&reverse, 2);
In a loop we will usually have more than 2 modules involved so this should be 3.
- for (; ir < n_mods; ir++) {
- if (users[ir] > 0) {
- break;
- }
+ sz = 0;
+ for (v = vertex->parent, n = 0;
+ v != NULL;
+ v = v->parent, n++) {
+
+ sz += v->mod->modnamesz - 1;
+ array_append(&reverse, v);
+ hash_add(loop_set, v->mod->modname, NULL);
+ }
+ sz += vertex->mod->modnamesz - 1;
+
+ buf = malloc(sz + n * strlen(sep) + 1);
+
+ sz = 0;
+ for (i = reverse.count - 1; i >= 0; i--) {
+ v = reverse.array[i];
+
+ strcpy(buf + sz, v->mod->modname);memcpy() here suffices since we have the str len on modnamesz. size_t len = v->mod->modnamesz - 1; memcpy(buf + sz, v->mod->modname, len); sz + = len;
+static int depmod_report_cycles_from_root(struct depmod *depmod,
+ struct mod *root_mod,
+ struct kmod_list **roots,
+ void **stack,
+ size_t stack_size,
+ struct hash *loop_set)
+{
+ struct kmod_list *free_list = NULL; /* struct vertex */
+ struct kmod_list *l;
+ struct vertex *root;
+ struct vertex *vertex;
+ struct vertex *v;
+ struct mod *m;
+ struct mod **itr, **itr_end;
+ size_t is;
+
+ root = vertex_new(root_mod, NULL);
+ if (root == NULL) {
+ ERR("No memory to report cycles\n");
+ return -ENOMEM;
+ }
+
+ l = kmod_list_append(free_list, root);
+ if (l == NULL) {
+ ERR("No memory to report cycles\n");
+ return -ENOMEM;
+ }
+ free_list = l;
+
+ is = 0;
+ stack[is++] = (void *)root;
+
+ while (is > 0) {
+ vertex = stack[--is];
+ m = vertex->mod;
+ /*
+ * because of the topological sort we can start only
+ * from part of a loop or from a branch after a loop
+ */
+ if (m->visited && m == root->mod) {
+ depmod_report_one_cycle(depmod, vertex,
+ roots, loop_set);
+ continue;
}
- if (ir >= n_mods)
- break;
+ m->visited = true;
+ if (m->deps.count == 0) {
+ /*
+ * boundary condition: if there is more than one
+ * single node branch (not a loop), it is
+ * recognized as a loop by the code above:
+ * m->visited because more then one,
+ * m == root->mod because it is a single node.This needs to be rephrased removing the 2 because.
--
Rest looks good. thanks Lucas De Marchi