fdt: Move shared-fdt structure preparation into separate fn

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

files.c

@@ -646,3 +646,30 @@ int get_filemap_fd(int pid, VmaEntry *vma_entry)
 {
 	return open_reg_by_id(vma_entry->shmid);
 }
+
+int shared_fdt_prepare(struct pstree_item *item)
+{
+	struct pstree_item *parent = item->parent;
+	struct fdt *fdt;
+
+	if (!parent->rst->fdt) {
+		fdt = shmalloc(sizeof(*item->rst->fdt));
+		if (fdt == NULL)
+			return -1;
+
+		parent->rst->fdt = fdt;
+
+		futex_init(&fdt->fdt_lock);
+		fdt->nr = 1;
+		fdt->pid = parent->pid.virt;
+	} else
+		fdt = parent->rst->fdt;
+
+	item->rst->fdt = fdt;
+	item->rst->service_fd_id = fdt->nr;
+	fdt->nr++;
+	if (fdt->pid > item->pid.virt)
+		fdt->pid = item->pid.virt;
+
+	return 0;
+}

include/files.h

@@ -101,4 +101,6 @@ extern int close_old_fds(struct pstree_item *me);
 
 #define LREMAP_PARAM	"link-remap"
 
+int shared_fdt_prepare(struct pstree_item *item);
+
 #endif /* __CR_FILES_H__ */

pstree.c

@@ -7,6 +7,7 @@
 #include "util.h"
 #include "lock.h"
 #include "namespaces.h"
+#include "files.h"
 
 #include "protobuf.h"
 #include "protobuf/pstree.pb-c.h"
@@ -446,7 +447,6 @@ static int prepare_pstree_kobj_ids(void)
 	/* Find a process with minimal pid for shared fd tables */
 	for_each_pstree_item(item) {
 		struct pstree_item *parent = item->parent;
-		struct fdt *fdt;
 
 		if (item->state == TASK_HELPER)
 			continue;
@@ -457,27 +457,13 @@ static int prepare_pstree_kobj_ids(void)
 		if (parent == NULL)
 			continue;
 
-		if (!shared_fdtable(item))
-			continue;
-
-		if (!parent->rst->fdt) {
-			fdt = shmalloc(sizeof(*item->rst->fdt));
-			if (fdt == NULL)
-				return -1;
-
-			parent->rst->fdt = fdt;
-
-			futex_init(&fdt->fdt_lock);
-			fdt->nr = 1;
-			fdt->pid = parent->pid.virt;
-		} else
-			fdt = parent->rst->fdt;
+		if (shared_fdtable(item)) {
+			int ret;
 
-		item->rst->fdt = fdt;
-		item->rst->service_fd_id = fdt->nr;
-		fdt->nr++;
-		if (fdt->pid > item->pid.virt)
-			fdt->pid = item->pid.virt;
+			ret = shared_fdt_prepare(item);
+			if (ret)
+				return ret;
+		}
 	}
 
 	return 0;