From 5063e25a302e6a83f6590d9a06bd5f6400b17430 Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Fri, 3 Oct 2014 16:28:27 +0100 Subject: [PATCH] of: Eliminate of_allnodes list The device tree structure is composed of two lists; the 'allnodes' list which is a singly linked list containing every node in the tree, and the child->parent structure where each parent node has a singly linked list of children. All of the data in the allnodes list can be easily reproduced with the parent-child lists, so of_allnodes is actually unnecessary. Remove it entirely which saves a bit of memory and simplifies the data structure quite a lot. Signed-off-by: Grant Likely Cc: Rob Herring Cc: Gaurav Minocha Cc: Pantelis Antoniou --- Documentation/devicetree/of_selftest.txt | 20 +------ Documentation/devicetree/todo.txt | 1 - drivers/mfd/vexpress-sysreg.c | 2 +- drivers/of/base.c | 53 ++++++++++-------- drivers/of/dynamic.c | 13 ----- drivers/of/fdt.c | 30 +++++----- drivers/of/pdt.c | 27 +++------ drivers/of/selftest.c | 71 +++++++++++------------- include/linux/of.h | 11 ++-- include/linux/of_pdt.h | 3 +- 10 files changed, 98 insertions(+), 133 deletions(-) diff --git a/Documentation/devicetree/of_selftest.txt b/Documentation/devicetree/of_selftest.txt index 1e3d5c92b5e3..57a808b588bf 100644 --- a/Documentation/devicetree/of_selftest.txt +++ b/Documentation/devicetree/of_selftest.txt @@ -63,7 +63,6 @@ struct device_node { struct device_node *parent; struct device_node *child; struct device_node *sibling; - struct device_node *allnext; /* next in list of all nodes */ ... }; @@ -99,12 +98,6 @@ child11 -> sibling12 -> sibling13 -> sibling14 -> null Figure 1: Generic structure of un-flattened device tree -*allnext: it is used to link all the nodes of DT into a list. So, for the - above tree the list would be as follows: - -root->child1->child11->sibling12->sibling13->child131->sibling14->sibling2-> -child21->sibling22->sibling23->sibling3->child31->sibling32->sibling4->null - Before executing OF selftest, it is required to attach the test data to machine's device tree (if present). So, when selftest_data_add() is called, at first it reads the flattened device tree data linked into the kernel image @@ -131,11 +124,6 @@ root ('/') test-child01 null null null -allnext list: - -root->testcase-data->test-child0->test-child01->test-sibling1->test-sibling2 -->test-sibling3->null - Figure 2: Example test data tree to be attached to live tree. According to the scenario above, the live tree is already present so it isn't @@ -204,8 +192,6 @@ detached and then moving up the parent nodes are removed, and eventually the whole tree). selftest_data_remove() calls detach_node_and_children() that uses of_detach_node() to detach the nodes from the live device tree. -To detach a node, of_detach_node() first updates all_next linked list, by -attaching the previous node's allnext to current node's allnext pointer. And -then, it either updates the child pointer of given node's parent to its -sibling or attaches the previous sibling to the given node's sibling, as -appropriate. That is it :) +To detach a node, of_detach_node() either updates the child pointer of given +node's parent to its sibling or attaches the previous sibling to the given +node's sibling, as appropriate. That is it :) diff --git a/Documentation/devicetree/todo.txt b/Documentation/devicetree/todo.txt index c3cf0659bd19..b5139d1de811 100644 --- a/Documentation/devicetree/todo.txt +++ b/Documentation/devicetree/todo.txt @@ -2,7 +2,6 @@ Todo list for devicetree: === General structure === - Switch from custom lists to (h)list_head for nodes and properties structure -- Remove of_allnodes list and iterate using list of child nodes alone === CONFIG_OF_DYNAMIC === - Switch to RCU for tree updates and get rid of global spinlock diff --git a/drivers/mfd/vexpress-sysreg.c b/drivers/mfd/vexpress-sysreg.c index 9e21e4fc9599..8f43ab8fd2d6 100644 --- a/drivers/mfd/vexpress-sysreg.c +++ b/drivers/mfd/vexpress-sysreg.c @@ -223,7 +223,7 @@ static int vexpress_sysreg_probe(struct platform_device *pdev) vexpress_config_set_master(vexpress_sysreg_get_master()); /* Confirm board type against DT property, if available */ - if (of_property_read_u32(of_allnodes, "arm,hbi", &dt_hbi) == 0) { + if (of_property_read_u32(of_root, "arm,hbi", &dt_hbi) == 0) { u32 id = vexpress_get_procid(VEXPRESS_SITE_MASTER); u32 hbi = (id >> SYS_PROCIDx_HBI_SHIFT) & SYS_HBI_MASK; diff --git a/drivers/of/base.c b/drivers/of/base.c index 3823edf2d012..1f61a908a767 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -32,8 +32,8 @@ LIST_HEAD(aliases_lookup); -struct device_node *of_allnodes; -EXPORT_SYMBOL(of_allnodes); +struct device_node *of_root; +EXPORT_SYMBOL(of_root); struct device_node *of_chosen; struct device_node *of_aliases; struct device_node *of_stdout; @@ -48,7 +48,7 @@ struct kset *of_kset; */ DEFINE_MUTEX(of_mutex); -/* use when traversing tree through the allnext, child, sibling, +/* use when traversing tree through the child, sibling, * or parent members of struct device_node. */ DEFINE_RAW_SPINLOCK(devtree_lock); @@ -204,7 +204,7 @@ static int __init of_init(void) mutex_unlock(&of_mutex); /* Symlink in /proc as required by userspace ABI */ - if (of_allnodes) + if (of_root) proc_symlink("device-tree", NULL, "/sys/firmware/devicetree/base"); return 0; @@ -245,6 +245,23 @@ struct property *of_find_property(const struct device_node *np, } EXPORT_SYMBOL(of_find_property); +struct device_node *__of_find_all_nodes(struct device_node *prev) +{ + struct device_node *np; + if (!prev) { + np = of_root; + } else if (prev->child) { + np = prev->child; + } else { + /* Walk back up looking for a sibling, or the end of the structure */ + np = prev; + while (np->parent && !np->sibling) + np = np->parent; + np = np->sibling; /* Might be null at the end of the tree */ + } + return np; +} + /** * of_find_all_nodes - Get next node in global list * @prev: Previous node or NULL to start iteration @@ -259,10 +276,8 @@ struct device_node *of_find_all_nodes(struct device_node *prev) unsigned long flags; raw_spin_lock_irqsave(&devtree_lock, flags); - np = prev ? prev->allnext : of_allnodes; - for (; np != NULL; np = np->allnext) - if (of_node_get(np)) - break; + np = __of_find_all_nodes(prev); + of_node_get(np); of_node_put(prev); raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; @@ -736,7 +751,7 @@ struct device_node *of_find_node_by_path(const char *path) unsigned long flags; if (strcmp(path, "/") == 0) - return of_node_get(of_allnodes); + return of_node_get(of_root); /* The path could begin with an alias */ if (*path != '/') { @@ -761,7 +776,7 @@ struct device_node *of_find_node_by_path(const char *path) /* Step down the tree matching path components */ raw_spin_lock_irqsave(&devtree_lock, flags); if (!np) - np = of_node_get(of_allnodes); + np = of_node_get(of_root); while (np && *path == '/') { path++; /* Increment past '/' delimiter */ np = __of_find_node_by_path(np, path); @@ -790,8 +805,7 @@ struct device_node *of_find_node_by_name(struct device_node *from, unsigned long flags; raw_spin_lock_irqsave(&devtree_lock, flags); - np = from ? from->allnext : of_allnodes; - for (; np; np = np->allnext) + for_each_of_allnodes_from(from, np) if (np->name && (of_node_cmp(np->name, name) == 0) && of_node_get(np)) break; @@ -820,8 +834,7 @@ struct device_node *of_find_node_by_type(struct device_node *from, unsigned long flags; raw_spin_lock_irqsave(&devtree_lock, flags); - np = from ? from->allnext : of_allnodes; - for (; np; np = np->allnext) + for_each_of_allnodes_from(from, np) if (np->type && (of_node_cmp(np->type, type) == 0) && of_node_get(np)) break; @@ -852,12 +865,10 @@ struct device_node *of_find_compatible_node(struct device_node *from, unsigned long flags; raw_spin_lock_irqsave(&devtree_lock, flags); - np = from ? from->allnext : of_allnodes; - for (; np; np = np->allnext) { + for_each_of_allnodes_from(from, np) if (__of_device_is_compatible(np, compatible, type, NULL) && of_node_get(np)) break; - } of_node_put(from); raw_spin_unlock_irqrestore(&devtree_lock, flags); return np; @@ -884,8 +895,7 @@ struct device_node *of_find_node_with_property(struct device_node *from, unsigned long flags; raw_spin_lock_irqsave(&devtree_lock, flags); - np = from ? from->allnext : of_allnodes; - for (; np; np = np->allnext) { + for_each_of_allnodes_from(from, np) { for (pp = np->properties; pp; pp = pp->next) { if (of_prop_cmp(pp->name, prop_name) == 0) { of_node_get(np); @@ -967,8 +977,7 @@ struct device_node *of_find_matching_node_and_match(struct device_node *from, *match = NULL; raw_spin_lock_irqsave(&devtree_lock, flags); - np = from ? from->allnext : of_allnodes; - for (; np; np = np->allnext) { + for_each_of_allnodes_from(from, np) { m = __of_match_node(matches, np); if (m && of_node_get(np)) { if (match) @@ -1025,7 +1034,7 @@ struct device_node *of_find_node_by_phandle(phandle handle) return NULL; raw_spin_lock_irqsave(&devtree_lock, flags); - for (np = of_allnodes; np; np = np->allnext) + for_each_of_allnodes(np) if (np->phandle == handle) break; of_node_get(np); diff --git a/drivers/of/dynamic.c b/drivers/of/dynamic.c index f297891d8529..da2509d639c8 100644 --- a/drivers/of/dynamic.c +++ b/drivers/of/dynamic.c @@ -117,8 +117,6 @@ void __of_attach_node(struct device_node *np) np->child = NULL; np->sibling = np->parent->child; - np->allnext = np->parent->allnext; - np->parent->allnext = np; np->parent->child = np; of_node_clear_flag(np, OF_DETACHED); } @@ -154,17 +152,6 @@ void __of_detach_node(struct device_node *np) if (WARN_ON(!parent)) return; - if (of_allnodes == np) - of_allnodes = np->allnext; - else { - struct device_node *prev; - for (prev = of_allnodes; - prev->allnext != np; - prev = prev->allnext) - ; - prev->allnext = np->allnext; - } - if (parent->child == np) parent->child = np->sibling; else { diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c index d1ffca8b34ea..1d30b9f96466 100644 --- a/drivers/of/fdt.c +++ b/drivers/of/fdt.c @@ -145,15 +145,15 @@ static void *unflatten_dt_alloc(void **mem, unsigned long size, * @mem: Memory chunk to use for allocating device nodes and properties * @p: pointer to node in flat tree * @dad: Parent struct device_node - * @allnextpp: pointer to ->allnext from last allocated device_node * @fpsize: Size of the node path up at the current depth. */ static void * unflatten_dt_node(void *blob, void *mem, int *poffset, struct device_node *dad, - struct device_node ***allnextpp, - unsigned long fpsize) + struct device_node **nodepp, + unsigned long fpsize, + bool dryrun) { const __be32 *p; struct device_node *np; @@ -200,7 +200,7 @@ static void * unflatten_dt_node(void *blob, np = unflatten_dt_alloc(&mem, sizeof(struct device_node) + allocl, __alignof__(struct device_node)); - if (allnextpp) { + if (!dryrun) { char *fn; of_node_init(np); np->full_name = fn = ((char *)np) + sizeof(*np); @@ -222,8 +222,6 @@ static void * unflatten_dt_node(void *blob, memcpy(fn, pathp, l); prev_pp = &np->properties; - **allnextpp = np; - *allnextpp = &np->allnext; if (dad != NULL) { np->parent = dad; /* we temporarily use the next field as `last_child'*/ @@ -254,7 +252,7 @@ static void * unflatten_dt_node(void *blob, has_name = 1; pp = unflatten_dt_alloc(&mem, sizeof(struct property), __alignof__(struct property)); - if (allnextpp) { + if (!dryrun) { /* We accept flattened tree phandles either in * ePAPR-style "phandle" properties, or the * legacy "linux,phandle" properties. If both @@ -296,7 +294,7 @@ static void * unflatten_dt_node(void *blob, sz = (pa - ps) + 1; pp = unflatten_dt_alloc(&mem, sizeof(struct property) + sz, __alignof__(struct property)); - if (allnextpp) { + if (!dryrun) { pp->name = "name"; pp->length = sz; pp->value = pp + 1; @@ -308,7 +306,7 @@ static void * unflatten_dt_node(void *blob, (char *)pp->value); } } - if (allnextpp) { + if (!dryrun) { *prev_pp = NULL; np->name = of_get_property(np, "name", NULL); np->type = of_get_property(np, "device_type", NULL); @@ -324,11 +322,13 @@ static void * unflatten_dt_node(void *blob, if (depth < 0) depth = 0; while (*poffset > 0 && depth > old_depth) - mem = unflatten_dt_node(blob, mem, poffset, np, allnextpp, - fpsize); + mem = unflatten_dt_node(blob, mem, poffset, np, NULL, + fpsize, dryrun); if (*poffset < 0 && *poffset != -FDT_ERR_NOTFOUND) pr_err("unflatten: error %d processing FDT\n", *poffset); + if (nodepp) + *nodepp = np; return mem; } @@ -352,7 +352,6 @@ static void __unflatten_device_tree(void *blob, unsigned long size; int start; void *mem; - struct device_node **allnextp = mynodes; pr_debug(" -> unflatten_device_tree()\n"); @@ -373,7 +372,7 @@ static void __unflatten_device_tree(void *blob, /* First pass, scan for size */ start = 0; - size = (unsigned long)unflatten_dt_node(blob, NULL, &start, NULL, NULL, 0); + size = (unsigned long)unflatten_dt_node(blob, NULL, &start, NULL, NULL, 0, true); size = ALIGN(size, 4); pr_debug(" size is %lx, allocating...\n", size); @@ -388,11 +387,10 @@ static void __unflatten_device_tree(void *blob, /* Second pass, do actual unflattening */ start = 0; - unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0); + unflatten_dt_node(blob, mem, &start, NULL, mynodes, 0, false); if (be32_to_cpup(mem + size) != 0xdeadbeef) pr_warning("End of tree marker overwritten: %08x\n", be32_to_cpup(mem + size)); - *allnextp = NULL; pr_debug(" <- unflatten_device_tree()\n"); } @@ -1041,7 +1039,7 @@ bool __init early_init_dt_scan(void *params) */ void __init unflatten_device_tree(void) { - __unflatten_device_tree(initial_boot_params, &of_allnodes, + __unflatten_device_tree(initial_boot_params, &of_root, early_init_dt_alloc_memory_arch); /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ diff --git a/drivers/of/pdt.c b/drivers/of/pdt.c index 36b4035881b0..d2acae825af9 100644 --- a/drivers/of/pdt.c +++ b/drivers/of/pdt.c @@ -25,8 +25,7 @@ static struct of_pdt_ops *of_pdt_prom_ops __initdata; -void __initdata (*of_pdt_build_more)(struct device_node *dp, - struct device_node ***nextp); +void __initdata (*of_pdt_build_more)(struct device_node *dp); #if defined(CONFIG_SPARC) unsigned int of_pdt_unique_id __initdata; @@ -192,8 +191,7 @@ static struct device_node * __init of_pdt_create_node(phandle node, } static struct device_node * __init of_pdt_build_tree(struct device_node *parent, - phandle node, - struct device_node ***nextp) + phandle node) { struct device_node *ret = NULL, *prev_sibling = NULL; struct device_node *dp; @@ -210,16 +208,12 @@ static struct device_node * __init of_pdt_build_tree(struct device_node *parent, ret = dp; prev_sibling = dp; - *(*nextp) = dp; - *nextp = &dp->allnext; - dp->full_name = of_pdt_build_full_name(dp); - dp->child = of_pdt_build_tree(dp, - of_pdt_prom_ops->getchild(node), nextp); + dp->child = of_pdt_build_tree(dp, of_pdt_prom_ops->getchild(node)); if (of_pdt_build_more) - of_pdt_build_more(dp, nextp); + of_pdt_build_more(dp); node = of_pdt_prom_ops->getsibling(node); } @@ -234,20 +228,17 @@ static void * __init kernel_tree_alloc(u64 size, u64 align) void __init of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops) { - struct device_node **nextp; - BUG_ON(!ops); of_pdt_prom_ops = ops; - of_allnodes = of_pdt_create_node(root_node, NULL); + of_root = of_pdt_create_node(root_node, NULL); #if defined(CONFIG_SPARC) - of_allnodes->path_component_name = ""; + of_root->path_component_name = ""; #endif - of_allnodes->full_name = "/"; + of_root->full_name = "/"; - nextp = &of_allnodes->allnext; - of_allnodes->child = of_pdt_build_tree(of_allnodes, - of_pdt_prom_ops->getchild(of_allnodes->phandle), &nextp); + of_root->child = of_pdt_build_tree(of_root, + of_pdt_prom_ops->getchild(of_root->phandle)); /* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */ of_alias_scan(kernel_tree_alloc); diff --git a/drivers/of/selftest.c b/drivers/of/selftest.c index 11b873c54a77..bf7d99317a94 100644 --- a/drivers/of/selftest.c +++ b/drivers/of/selftest.c @@ -148,7 +148,7 @@ static void __init of_selftest_dynamic(void) static int __init of_selftest_check_node_linkage(struct device_node *np) { - struct device_node *child, *allnext_index = np; + struct device_node *child; int count = 0, rc; for_each_child_of_node(np, child) { @@ -158,14 +158,6 @@ static int __init of_selftest_check_node_linkage(struct device_node *np) return -EINVAL; } - while (allnext_index && allnext_index != child) - allnext_index = allnext_index->allnext; - if (allnext_index != child) { - pr_err("Node %s is ordered differently in sibling and allnode lists\n", - child->name); - return -EINVAL; - } - rc = of_selftest_check_node_linkage(child); if (rc < 0) return rc; @@ -180,12 +172,12 @@ static void __init of_selftest_check_tree_linkage(void) struct device_node *np; int allnode_count = 0, child_count; - if (!of_allnodes) + if (!of_root) return; for_each_of_allnodes(np) allnode_count++; - child_count = of_selftest_check_node_linkage(of_allnodes); + child_count = of_selftest_check_node_linkage(of_root); selftest(child_count > 0, "Device node data structure is corrupted\n"); selftest(child_count == allnode_count, "allnodes list size (%i) doesn't match" @@ -775,33 +767,29 @@ static void update_node_properties(struct device_node *np, */ static int attach_node_and_children(struct device_node *np) { - struct device_node *next, *root = np, *dup; + struct device_node *next, *dup, *child; - /* skip root node */ - np = np->child; - /* storing a copy in temporary node */ - dup = np; + dup = of_find_node_by_path(np->full_name); + if (dup) { + update_node_properties(np, dup); + return 0; + } - while (dup) { + /* Children of the root need to be remembered for removal */ + if (np->parent == of_root) { if (WARN_ON(last_node_index >= NO_OF_NODES)) return -EINVAL; - nodes[last_node_index++] = dup; - dup = dup->sibling; + nodes[last_node_index++] = np; } - dup = NULL; - while (np) { - next = np->allnext; - dup = of_find_node_by_path(np->full_name); - if (dup) - update_node_properties(np, dup); - else { - np->child = NULL; - if (np->parent == root) - np->parent = of_allnodes; - of_attach_node(np); - } - np = next; + child = np->child; + np->child = NULL; + np->sibling = NULL; + of_attach_node(np); + while (child) { + next = child->sibling; + attach_node_and_children(child); + child = next; } return 0; @@ -846,10 +834,10 @@ static int __init selftest_data_add(void) return -EINVAL; } - if (!of_allnodes) { + if (!of_root) { /* enabling flag for removing nodes */ selftest_live_tree = true; - of_allnodes = selftest_data_node; + of_root = selftest_data_node; for_each_of_allnodes(np) __of_attach_node_sysfs(np); @@ -859,7 +847,14 @@ static int __init selftest_data_add(void) } /* attach the sub-tree to live tree */ - return attach_node_and_children(selftest_data_node); + np = selftest_data_node->child; + while (np) { + struct device_node *next = np->sibling; + np->parent = of_root; + attach_node_and_children(np); + np = next; + } + return 0; } /** @@ -889,10 +884,10 @@ static void selftest_data_remove(void) of_node_put(of_chosen); of_aliases = NULL; of_chosen = NULL; - for_each_child_of_node(of_allnodes, np) + for_each_child_of_node(of_root, np) detach_node_and_children(np); - __of_detach_node_sysfs(of_allnodes); - of_allnodes = NULL; + __of_detach_node_sysfs(of_root); + of_root = NULL; return; } diff --git a/include/linux/of.h b/include/linux/of.h index 30912939a610..f54da3b699a8 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -56,7 +56,6 @@ struct device_node { struct device_node *child; struct device_node *sibling; struct device_node *next; /* next device of same type */ - struct device_node *allnext; /* next in list of all nodes */ struct kobject kobj; unsigned long _flags; void *data; @@ -108,7 +107,7 @@ static inline void of_node_put(struct device_node *node) { } #ifdef CONFIG_OF /* Pointer for first entry in chain of all nodes. */ -extern struct device_node *of_allnodes; +extern struct device_node *of_root; extern struct device_node *of_chosen; extern struct device_node *of_aliases; extern struct device_node *of_stdout; @@ -116,7 +115,7 @@ extern raw_spinlock_t devtree_lock; static inline bool of_have_populated_dt(void) { - return of_allnodes != NULL; + return of_root != NULL; } static inline bool of_node_is_root(const struct device_node *node) @@ -160,6 +159,7 @@ static inline void of_property_clear_flag(struct property *p, unsigned long flag clear_bit(flag, &p->_flags); } +extern struct device_node *__of_find_all_nodes(struct device_node *prev); extern struct device_node *of_find_all_nodes(struct device_node *prev); /* @@ -215,8 +215,9 @@ static inline const char *of_node_full_name(const struct device_node *np) return np ? np->full_name : ""; } -#define for_each_of_allnodes(dn) \ - for (dn = of_allnodes; dn; dn = dn->allnext) +#define for_each_of_allnodes_from(from, dn) \ + for (dn = __of_find_all_nodes(from); dn; dn = __of_find_all_nodes(dn)) +#define for_each_of_allnodes(dn) for_each_of_allnodes_from(NULL, dn) extern struct device_node *of_find_node_by_name(struct device_node *from, const char *name); extern struct device_node *of_find_node_by_type(struct device_node *from, diff --git a/include/linux/of_pdt.h b/include/linux/of_pdt.h index c65a18a0cfdf..7e09244bb679 100644 --- a/include/linux/of_pdt.h +++ b/include/linux/of_pdt.h @@ -39,7 +39,6 @@ extern void *prom_early_alloc(unsigned long size); /* for building the device tree */ extern void of_pdt_build_devicetree(phandle root_node, struct of_pdt_ops *ops); -extern void (*of_pdt_build_more)(struct device_node *dp, - struct device_node ***nextp); +extern void (*of_pdt_build_more)(struct device_node *dp); #endif /* _LINUX_OF_PDT_H */ -- 2.20.1