Revision 3808d34838184fd29088d6b3a364ba2f1c018fb6 authored by Stanislaw Gruszka on 02 February 2017, 12:32:10 UTC, committed by David S. Miller on 03 February 2017, 16:13:00 UTC
If ->get_regs_len() callback return 0, we allocate 0 bytes of memory, what print ugly warning in dmesg, which can be found further below. This happen on mac80211 devices where ieee80211_get_regs_len() just return 0 and driver only fills ethtool_regs structure and actually do not provide any dump. However I assume this can happen on other drivers i.e. when for some devices driver provide regs dump and for others do not. Hence preventing to to print warning in ethtool code seems to be reasonable. ethtool: vmalloc: allocation failure: 0 bytes, mode:0x24080c2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO) <snip> Call Trace: [<ffffffff813bde47>] dump_stack+0x63/0x8c [<ffffffff811b0a1f>] warn_alloc+0x13f/0x170 [<ffffffff811f0476>] __vmalloc_node_range+0x1e6/0x2c0 [<ffffffff811f0874>] vzalloc+0x54/0x60 [<ffffffff8169986c>] dev_ethtool+0xb4c/0x1b30 [<ffffffff816adbb1>] dev_ioctl+0x181/0x520 [<ffffffff816714d2>] sock_do_ioctl+0x42/0x50 <snip> Mem-Info: active_anon:435809 inactive_anon:173951 isolated_anon:0 active_file:835822 inactive_file:196932 isolated_file:0 unevictable:0 dirty:8 writeback:0 unstable:0 slab_reclaimable:157732 slab_unreclaimable:10022 mapped:83042 shmem:306356 pagetables:9507 bounce:0 free:130041 free_pcp:1080 free_cma:0 Node 0 active_anon:1743236kB inactive_anon:695804kB active_file:3343288kB inactive_file:787728kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:332168kB dirty:32kB writeback:0kB shmem:0kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 1225424kB writeback_tmp:0kB unstable:0kB pages_scanned:0 all_unreclaimable? no Node 0 DMA free:15900kB min:136kB low:168kB high:200kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15984kB managed:15900kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 3187 7643 7643 Node 0 DMA32 free:419732kB min:28124kB low:35152kB high:42180kB active_anon:541180kB inactive_anon:248988kB active_file:1466388kB inactive_file:389632kB unevictable:0kB writepending:0kB present:3370280kB managed:3290932kB mlocked:0kB slab_reclaimable:217184kB slab_unreclaimable:4180kB kernel_stack:160kB pagetables:984kB bounce:0kB free_pcp:2236kB local_pcp:660kB free_cma:0kB lowmem_reserve[]: 0 0 4456 4456 Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 013e816
rbtree.c
/*
Red Black Trees
(C) 1999 Andrea Arcangeli <andrea@suse.de>
(C) 2002 David Woodhouse <dwmw2@infradead.org>
(C) 2012 Michel Lespinasse <walken@google.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
linux/lib/rbtree.c
*/
#include <linux/rbtree_augmented.h>
#include <linux/export.h>
/*
* red-black trees properties: http://en.wikipedia.org/wiki/Rbtree
*
* 1) A node is either red or black
* 2) The root is black
* 3) All leaves (NULL) are black
* 4) Both children of every red node are black
* 5) Every simple path from root to leaves contains the same number
* of black nodes.
*
* 4 and 5 give the O(log n) guarantee, since 4 implies you cannot have two
* consecutive red nodes in a path and every red node is therefore followed by
* a black. So if B is the number of black nodes on every simple path (as per
* 5), then the longest possible path due to 4 is 2B.
*
* We shall indicate color with case, where black nodes are uppercase and red
* nodes will be lowercase. Unknown color nodes shall be drawn as red within
* parentheses and have some accompanying text comment.
*/
/*
* Notes on lockless lookups:
*
* All stores to the tree structure (rb_left and rb_right) must be done using
* WRITE_ONCE(). And we must not inadvertently cause (temporary) loops in the
* tree structure as seen in program order.
*
* These two requirements will allow lockless iteration of the tree -- not
* correct iteration mind you, tree rotations are not atomic so a lookup might
* miss entire subtrees.
*
* But they do guarantee that any such traversal will only see valid elements
* and that it will indeed complete -- does not get stuck in a loop.
*
* It also guarantees that if the lookup returns an element it is the 'correct'
* one. But not returning an element does _NOT_ mean it's not present.
*
* NOTE:
*
* Stores to __rb_parent_color are not important for simple lookups so those
* are left undone as of now. Nor did I check for loops involving parent
* pointers.
*/
static inline void rb_set_black(struct rb_node *rb)
{
rb->__rb_parent_color |= RB_BLACK;
}
static inline struct rb_node *rb_red_parent(struct rb_node *red)
{
return (struct rb_node *)red->__rb_parent_color;
}
/*
* Helper function for rotations:
* - old's parent and color get assigned to new
* - old gets assigned new as a parent and 'color' as a color.
*/
static inline void
__rb_rotate_set_parents(struct rb_node *old, struct rb_node *new,
struct rb_root *root, int color)
{
struct rb_node *parent = rb_parent(old);
new->__rb_parent_color = old->__rb_parent_color;
rb_set_parent_color(old, new, color);
__rb_change_child(old, new, parent, root);
}
static __always_inline void
__rb_insert(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
struct rb_node *parent = rb_red_parent(node), *gparent, *tmp;
while (true) {
/*
* Loop invariant: node is red
*
* If there is a black parent, we are done.
* Otherwise, take some corrective action as we don't
* want a red root or two consecutive red nodes.
*/
if (!parent) {
rb_set_parent_color(node, NULL, RB_BLACK);
break;
} else if (rb_is_black(parent))
break;
gparent = rb_red_parent(parent);
tmp = gparent->rb_right;
if (parent != tmp) { /* parent == gparent->rb_left */
if (tmp && rb_is_red(tmp)) {
/*
* Case 1 - color flips
*
* G g
* / \ / \
* p u --> P U
* / /
* n n
*
* However, since g's parent might be red, and
* 4) does not allow this, we need to recurse
* at g.
*/
rb_set_parent_color(tmp, gparent, RB_BLACK);
rb_set_parent_color(parent, gparent, RB_BLACK);
node = gparent;
parent = rb_parent(node);
rb_set_parent_color(node, parent, RB_RED);
continue;
}
tmp = parent->rb_right;
if (node == tmp) {
/*
* Case 2 - left rotate at parent
*
* G G
* / \ / \
* p U --> n U
* \ /
* n p
*
* This still leaves us in violation of 4), the
* continuation into Case 3 will fix that.
*/
tmp = node->rb_left;
WRITE_ONCE(parent->rb_right, tmp);
WRITE_ONCE(node->rb_left, parent);
if (tmp)
rb_set_parent_color(tmp, parent,
RB_BLACK);
rb_set_parent_color(parent, node, RB_RED);
augment_rotate(parent, node);
parent = node;
tmp = node->rb_right;
}
/*
* Case 3 - right rotate at gparent
*
* G P
* / \ / \
* p U --> n g
* / \
* n U
*/
WRITE_ONCE(gparent->rb_left, tmp); /* == parent->rb_right */
WRITE_ONCE(parent->rb_right, gparent);
if (tmp)
rb_set_parent_color(tmp, gparent, RB_BLACK);
__rb_rotate_set_parents(gparent, parent, root, RB_RED);
augment_rotate(gparent, parent);
break;
} else {
tmp = gparent->rb_left;
if (tmp && rb_is_red(tmp)) {
/* Case 1 - color flips */
rb_set_parent_color(tmp, gparent, RB_BLACK);
rb_set_parent_color(parent, gparent, RB_BLACK);
node = gparent;
parent = rb_parent(node);
rb_set_parent_color(node, parent, RB_RED);
continue;
}
tmp = parent->rb_left;
if (node == tmp) {
/* Case 2 - right rotate at parent */
tmp = node->rb_right;
WRITE_ONCE(parent->rb_left, tmp);
WRITE_ONCE(node->rb_right, parent);
if (tmp)
rb_set_parent_color(tmp, parent,
RB_BLACK);
rb_set_parent_color(parent, node, RB_RED);
augment_rotate(parent, node);
parent = node;
tmp = node->rb_left;
}
/* Case 3 - left rotate at gparent */
WRITE_ONCE(gparent->rb_right, tmp); /* == parent->rb_left */
WRITE_ONCE(parent->rb_left, gparent);
if (tmp)
rb_set_parent_color(tmp, gparent, RB_BLACK);
__rb_rotate_set_parents(gparent, parent, root, RB_RED);
augment_rotate(gparent, parent);
break;
}
}
}
/*
* Inline version for rb_erase() use - we want to be able to inline
* and eliminate the dummy_rotate callback there
*/
static __always_inline void
____rb_erase_color(struct rb_node *parent, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
struct rb_node *node = NULL, *sibling, *tmp1, *tmp2;
while (true) {
/*
* Loop invariants:
* - node is black (or NULL on first iteration)
* - node is not the root (parent is not NULL)
* - All leaf paths going through parent and node have a
* black node count that is 1 lower than other leaf paths.
*/
sibling = parent->rb_right;
if (node != sibling) { /* node == parent->rb_left */
if (rb_is_red(sibling)) {
/*
* Case 1 - left rotate at parent
*
* P S
* / \ / \
* N s --> p Sr
* / \ / \
* Sl Sr N Sl
*/
tmp1 = sibling->rb_left;
WRITE_ONCE(parent->rb_right, tmp1);
WRITE_ONCE(sibling->rb_left, parent);
rb_set_parent_color(tmp1, parent, RB_BLACK);
__rb_rotate_set_parents(parent, sibling, root,
RB_RED);
augment_rotate(parent, sibling);
sibling = tmp1;
}
tmp1 = sibling->rb_right;
if (!tmp1 || rb_is_black(tmp1)) {
tmp2 = sibling->rb_left;
if (!tmp2 || rb_is_black(tmp2)) {
/*
* Case 2 - sibling color flip
* (p could be either color here)
*
* (p) (p)
* / \ / \
* N S --> N s
* / \ / \
* Sl Sr Sl Sr
*
* This leaves us violating 5) which
* can be fixed by flipping p to black
* if it was red, or by recursing at p.
* p is red when coming from Case 1.
*/
rb_set_parent_color(sibling, parent,
RB_RED);
if (rb_is_red(parent))
rb_set_black(parent);
else {
node = parent;
parent = rb_parent(node);
if (parent)
continue;
}
break;
}
/*
* Case 3 - right rotate at sibling
* (p could be either color here)
*
* (p) (p)
* / \ / \
* N S --> N sl
* / \ \
* sl Sr S
* \
* Sr
*
* Note: p might be red, and then both
* p and sl are red after rotation(which
* breaks property 4). This is fixed in
* Case 4 (in __rb_rotate_set_parents()
* which set sl the color of p
* and set p RB_BLACK)
*
* (p) (sl)
* / \ / \
* N sl --> P S
* \ / \
* S N Sr
* \
* Sr
*/
tmp1 = tmp2->rb_right;
WRITE_ONCE(sibling->rb_left, tmp1);
WRITE_ONCE(tmp2->rb_right, sibling);
WRITE_ONCE(parent->rb_right, tmp2);
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
/*
* Case 4 - left rotate at parent + color flips
* (p and sl could be either color here.
* After rotation, p becomes black, s acquires
* p's color, and sl keeps its color)
*
* (p) (s)
* / \ / \
* N S --> P Sr
* / \ / \
* (sl) sr N (sl)
*/
tmp2 = sibling->rb_left;
WRITE_ONCE(parent->rb_right, tmp2);
WRITE_ONCE(sibling->rb_left, parent);
rb_set_parent_color(tmp1, sibling, RB_BLACK);
if (tmp2)
rb_set_parent(tmp2, parent);
__rb_rotate_set_parents(parent, sibling, root,
RB_BLACK);
augment_rotate(parent, sibling);
break;
} else {
sibling = parent->rb_left;
if (rb_is_red(sibling)) {
/* Case 1 - right rotate at parent */
tmp1 = sibling->rb_right;
WRITE_ONCE(parent->rb_left, tmp1);
WRITE_ONCE(sibling->rb_right, parent);
rb_set_parent_color(tmp1, parent, RB_BLACK);
__rb_rotate_set_parents(parent, sibling, root,
RB_RED);
augment_rotate(parent, sibling);
sibling = tmp1;
}
tmp1 = sibling->rb_left;
if (!tmp1 || rb_is_black(tmp1)) {
tmp2 = sibling->rb_right;
if (!tmp2 || rb_is_black(tmp2)) {
/* Case 2 - sibling color flip */
rb_set_parent_color(sibling, parent,
RB_RED);
if (rb_is_red(parent))
rb_set_black(parent);
else {
node = parent;
parent = rb_parent(node);
if (parent)
continue;
}
break;
}
/* Case 3 - left rotate at sibling */
tmp1 = tmp2->rb_left;
WRITE_ONCE(sibling->rb_right, tmp1);
WRITE_ONCE(tmp2->rb_left, sibling);
WRITE_ONCE(parent->rb_left, tmp2);
if (tmp1)
rb_set_parent_color(tmp1, sibling,
RB_BLACK);
augment_rotate(sibling, tmp2);
tmp1 = sibling;
sibling = tmp2;
}
/* Case 4 - right rotate at parent + color flips */
tmp2 = sibling->rb_right;
WRITE_ONCE(parent->rb_left, tmp2);
WRITE_ONCE(sibling->rb_right, parent);
rb_set_parent_color(tmp1, sibling, RB_BLACK);
if (tmp2)
rb_set_parent(tmp2, parent);
__rb_rotate_set_parents(parent, sibling, root,
RB_BLACK);
augment_rotate(parent, sibling);
break;
}
}
}
/* Non-inline version for rb_erase_augmented() use */
void __rb_erase_color(struct rb_node *parent, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
____rb_erase_color(parent, root, augment_rotate);
}
EXPORT_SYMBOL(__rb_erase_color);
/*
* Non-augmented rbtree manipulation functions.
*
* We use dummy augmented callbacks here, and have the compiler optimize them
* out of the rb_insert_color() and rb_erase() function definitions.
*/
static inline void dummy_propagate(struct rb_node *node, struct rb_node *stop) {}
static inline void dummy_copy(struct rb_node *old, struct rb_node *new) {}
static inline void dummy_rotate(struct rb_node *old, struct rb_node *new) {}
static const struct rb_augment_callbacks dummy_callbacks = {
dummy_propagate, dummy_copy, dummy_rotate
};
void rb_insert_color(struct rb_node *node, struct rb_root *root)
{
__rb_insert(node, root, dummy_rotate);
}
EXPORT_SYMBOL(rb_insert_color);
void rb_erase(struct rb_node *node, struct rb_root *root)
{
struct rb_node *rebalance;
rebalance = __rb_erase_augmented(node, root, &dummy_callbacks);
if (rebalance)
____rb_erase_color(rebalance, root, dummy_rotate);
}
EXPORT_SYMBOL(rb_erase);
/*
* Augmented rbtree manipulation functions.
*
* This instantiates the same __always_inline functions as in the non-augmented
* case, but this time with user-defined callbacks.
*/
void __rb_insert_augmented(struct rb_node *node, struct rb_root *root,
void (*augment_rotate)(struct rb_node *old, struct rb_node *new))
{
__rb_insert(node, root, augment_rotate);
}
EXPORT_SYMBOL(__rb_insert_augmented);
/*
* This function returns the first node (in sort order) of the tree.
*/
struct rb_node *rb_first(const struct rb_root *root)
{
struct rb_node *n;
n = root->rb_node;
if (!n)
return NULL;
while (n->rb_left)
n = n->rb_left;
return n;
}
EXPORT_SYMBOL(rb_first);
struct rb_node *rb_last(const struct rb_root *root)
{
struct rb_node *n;
n = root->rb_node;
if (!n)
return NULL;
while (n->rb_right)
n = n->rb_right;
return n;
}
EXPORT_SYMBOL(rb_last);
struct rb_node *rb_next(const struct rb_node *node)
{
struct rb_node *parent;
if (RB_EMPTY_NODE(node))
return NULL;
/*
* If we have a right-hand child, go down and then left as far
* as we can.
*/
if (node->rb_right) {
node = node->rb_right;
while (node->rb_left)
node=node->rb_left;
return (struct rb_node *)node;
}
/*
* No right-hand children. Everything down and left is smaller than us,
* so any 'next' node must be in the general direction of our parent.
* Go up the tree; any time the ancestor is a right-hand child of its
* parent, keep going up. First time it's a left-hand child of its
* parent, said parent is our 'next' node.
*/
while ((parent = rb_parent(node)) && node == parent->rb_right)
node = parent;
return parent;
}
EXPORT_SYMBOL(rb_next);
struct rb_node *rb_prev(const struct rb_node *node)
{
struct rb_node *parent;
if (RB_EMPTY_NODE(node))
return NULL;
/*
* If we have a left-hand child, go down and then right as far
* as we can.
*/
if (node->rb_left) {
node = node->rb_left;
while (node->rb_right)
node=node->rb_right;
return (struct rb_node *)node;
}
/*
* No left-hand children. Go up till we find an ancestor which
* is a right-hand child of its parent.
*/
while ((parent = rb_parent(node)) && node == parent->rb_left)
node = parent;
return parent;
}
EXPORT_SYMBOL(rb_prev);
void rb_replace_node(struct rb_node *victim, struct rb_node *new,
struct rb_root *root)
{
struct rb_node *parent = rb_parent(victim);
/* Copy the pointers/colour from the victim to the replacement */
*new = *victim;
/* Set the surrounding nodes to point to the replacement */
if (victim->rb_left)
rb_set_parent(victim->rb_left, new);
if (victim->rb_right)
rb_set_parent(victim->rb_right, new);
__rb_change_child(victim, new, parent, root);
}
EXPORT_SYMBOL(rb_replace_node);
void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new,
struct rb_root *root)
{
struct rb_node *parent = rb_parent(victim);
/* Copy the pointers/colour from the victim to the replacement */
*new = *victim;
/* Set the surrounding nodes to point to the replacement */
if (victim->rb_left)
rb_set_parent(victim->rb_left, new);
if (victim->rb_right)
rb_set_parent(victim->rb_right, new);
/* Set the parent's pointer to the new node last after an RCU barrier
* so that the pointers onwards are seen to be set correctly when doing
* an RCU walk over the tree.
*/
__rb_change_child_rcu(victim, new, parent, root);
}
EXPORT_SYMBOL(rb_replace_node_rcu);
static struct rb_node *rb_left_deepest_node(const struct rb_node *node)
{
for (;;) {
if (node->rb_left)
node = node->rb_left;
else if (node->rb_right)
node = node->rb_right;
else
return (struct rb_node *)node;
}
}
struct rb_node *rb_next_postorder(const struct rb_node *node)
{
const struct rb_node *parent;
if (!node)
return NULL;
parent = rb_parent(node);
/* If we're sitting on node, we've already seen our children */
if (parent && node == parent->rb_left && parent->rb_right) {
/* If we are the parent's left node, go to the parent's right
* node then all the way down to the left */
return rb_left_deepest_node(parent->rb_right);
} else
/* Otherwise we are the parent's right node, and the parent
* should be next */
return (struct rb_node *)parent;
}
EXPORT_SYMBOL(rb_next_postorder);
struct rb_node *rb_first_postorder(const struct rb_root *root)
{
if (!root->rb_node)
return NULL;
return rb_left_deepest_node(root->rb_node);
}
EXPORT_SYMBOL(rb_first_postorder);
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