[PATCH] fib-trie: code cleanup

Mathieu Desnoyers
2009-12-08T18:53:40Z

[Impact: cleanup]

Here is a standard janitor-style cleanup patch for the fib_trie code. I thought
that while I was looking at how it works by pure interest, I could as well
cleanup the coding style.

- I moved static const that were hidden in the middle of the file to defines on
top.
- Standardize spacing around operations (-, +, <<, >>, ...).
- White-space removal.

Then the checkpath checks:

WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>

ERROR: do not use assignment in if condition
fib_route_get_idx contained a if() with an assignment. The code change I made
keep the exact same semantic, but puts the assignment outside of the if().

The size of the resulting objects stays the same:

net/ipv4$ size fib_trie.o.orig
text data bss dec hex filename
17661 52 24 17737 4549 fib_trie.o.orig
net/ipv4$ size fib_trie.o
text data bss dec hex filename
17661 52 24 17737 4549 fib_trie.o

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Robert Olsson <robert.olsson@its.uu.se>
CC: Jens Laas <jens.laas@data.slu.se>
CC: Hans Liss <hans.liss@its.uu.se>
CC: David S. Miller <davem@davemloft.net>
CC: Stephen Hemminger <shemminger@osdl.org>
CC: Paul E. McKenney <paulmck@us.ibm.com>
CC: Patrick McHardy <kaber@trash.net>
---
net/ipv4/fib_trie.c | 163 ++++++++++++++++++++++++++--------------------------
1 file changed, 83 insertions(+), 80 deletions(-)

Index: linux-2.6-lttng/net/ipv4/fib_trie.c
===================================================================
--- linux-2.6-lttng.orig/net/ipv4/fib_trie.c 2009-12-08 13:36:31.000000000 -0500
+++ linux-2.6-lttng/net/ipv4/fib_trie.c 2009-12-08 13:37:43.000000000 -0500
@@ -50,7 +50,7 @@

#define VERSION "0.409"

-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
#include <asm/system.h>
#include <linux/bitops.h>
#include <linux/types.h>
@@ -91,8 +91,20 @@ typedef unsigned int t_key;
#define NODE_TYPE_MASK 0x1UL
#define NODE_TYPE(node) ((node)->parent & NODE_TYPE_MASK)

-#define IS_TNODE(n) (!(n->parent & T_LEAF))
-#define IS_LEAF(n) (n->parent & T_LEAF)
+#define IS_TNODE(n) (!((n)->parent & T_LEAF))
+#define IS_LEAF(n) ((n)->parent & T_LEAF)
+
+/*
+ * synchronize_rcu after call_rcu for that many pages; it should be especially
+ * useful before resizing the root node with PREEMPT_NONE configs; the value was
+ * obtained experimentally, aiming to avoid visible slowdown.
+ */
+#define SYNC_PAGES 128
+
+#define HALVE_THRESHOLD 25
+#define INFLATE_THRESHOLD 50
+#define HALVE_THRESHOLD_ROOT 15
+#define INFLATE_THRESHOLD_ROOT 30

struct node {
unsigned long parent;
@@ -166,13 +178,6 @@ static struct tnode *halve(struct trie *
static struct tnode *tnode_free_head;
static size_t tnode_free_size;

-/*
- * synchronize_rcu after call_rcu for that many pages; it should be especially
- * useful before resizing the root node with PREEMPT_NONE configs; the value was
- * obtained experimentally, aiming to avoid visible slowdown.
- */
-static const int sync_pages = 128;
-
static struct kmem_cache *fn_alias_kmem __read_mostly;
static struct kmem_cache *trie_leaf_kmem __read_mostly;

@@ -218,7 +223,7 @@ static inline int tnode_child_length(con

static inline t_key mask_pfx(t_key k, unsigned short l)
{
- return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l);
+ return (l == 0) ? 0 : k >> (KEYLENGTH - l) << (KEYLENGTH - l);
}

static inline t_key tkey_extract_bits(t_key a, int offset, int bits)
@@ -249,7 +254,7 @@ static inline int tkey_mismatch(t_key a,

if (!diff)
return 0;
- while ((diff << i) >> (KEYLENGTH-1) == 0)
+ while ((diff << i) >> (KEYLENGTH - 1) == 0)
i++;
return i;
}
@@ -322,11 +327,6 @@ static inline void check_tnode(const str
WARN_ON(tn && tn->pos+tn->bits > 32);
}

-static const int halve_threshold = 25;
-static const int inflate_threshold = 50;
-static const int halve_threshold_root = 15;
-static const int inflate_threshold_root = 30;
-
static void __alias_free_mem(struct rcu_head *head)
{
struct fib_alias *fa = container_of(head, struct fib_alias, rcu);
@@ -414,7 +414,7 @@ static void tnode_free_flush(void)
tnode_free(tn);
}

- if (tnode_free_size >= PAGE_SIZE * sync_pages) {
+ if (tnode_free_size >= PAGE_SIZE * SYNC_PAGES) {
tnode_free_size = 0;
synchronize_rcu();
}
@@ -432,7 +432,7 @@ static struct leaf *leaf_new(void)

static struct leaf_info *leaf_info_new(int plen)
{
- struct leaf_info *li = kmalloc(sizeof(struct leaf_info), GFP_KERNEL);
+ struct leaf_info *li = kmalloc(sizeof(struct leaf_info), GFP_KERNEL);
if (li) {
li->plen = plen;
INIT_LIST_HEAD(&li->falh);
@@ -451,7 +451,7 @@ static struct tnode *tnode_new(t_key key
tn->bits = bits;
tn->key = key;
tn->full_children = 0;
- tn->empty_children = 1<<bits;
+ tn->empty_children = 1 << bits;
}

pr_debug("AT %p s=%u %lu\n", tn, (unsigned int) sizeof(struct tnode),
@@ -489,7 +489,7 @@ static void tnode_put_child_reorg(struct
struct node *chi = tn->child[i];
int isfull;

- BUG_ON(i >= 1<<tn->bits);
+ BUG_ON(i >= 1 << tn->bits);

/* update emptyChildren */
if (n == NULL && chi != NULL)
@@ -526,7 +526,7 @@ static struct node *resize(struct trie *
return NULL;

pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
- tn, inflate_threshold, halve_threshold);
+ tn, INFLATE_THRESHOLD, HALVE_THRESHOLD);

/* No children */
if (tn->empty_children == tnode_child_length(tn)) {
@@ -604,13 +604,12 @@ static struct node *resize(struct trie *

/* Keep root node larger */

- if (!node_parent((struct node*) tn)) {
- inflate_threshold_use = inflate_threshold_root;
- halve_threshold_use = halve_threshold_root;
- }
- else {
- inflate_threshold_use = inflate_threshold;
- halve_threshold_use = halve_threshold;
+ if (!node_parent((struct node *) tn)) {
+ inflate_threshold_use = INFLATE_THRESHOLD_ROOT;
+ halve_threshold_use = HALVE_THRESHOLD_ROOT;
+ } else {
+ inflate_threshold_use = INFLATE_THRESHOLD;
+ halve_threshold_use = HALVE_THRESHOLD;
}

max_work = MAX_WORK;
@@ -634,7 +633,7 @@ static struct node *resize(struct trie *
check_tnode(tn);

/* Return if at least one inflate is run */
- if( max_work != MAX_WORK)
+ if (max_work != MAX_WORK)
return (struct node *) tn;

/*
@@ -643,7 +642,7 @@ static struct node *resize(struct trie *
*/

max_work = MAX_WORK;
- while (tn->bits > 1 && max_work-- &&
+ while (tn->bits > 1 && max_work-- &&
100 * (tnode_child_length(tn) - tn->empty_children) <
halve_threshold_use * tnode_child_length(tn)) {

@@ -710,12 +709,12 @@ static struct tnode *inflate(struct trie
struct tnode *left, *right;
t_key m = ~0U << (KEYLENGTH - 1) >> inode->pos;

- left = tnode_new(inode->key&(~m), inode->pos + 1,
+ left = tnode_new(inode->key & (~m), inode->pos + 1,
inode->bits - 1);
if (!left)
goto nomem;

- right = tnode_new(inode->key|m, inode->pos + 1,
+ right = tnode_new(inode->key | m, inode->pos + 1,
inode->bits - 1);

if (!right) {
@@ -723,8 +722,8 @@ static struct tnode *inflate(struct trie
goto nomem;
}

- put_child(t, tn, 2*i, (struct node *) left);
- put_child(t, tn, 2*i+1, (struct node *) right);
+ put_child(t, tn, 2 * i, (struct node *) left);
+ put_child(t, tn, 2 * i + 1, (struct node *) right);
}
}

@@ -745,9 +744,9 @@ static struct tnode *inflate(struct trie
if (tkey_extract_bits(node->key,
oldtnode->pos + oldtnode->bits,
1) == 0)
- put_child(t, tn, 2*i, node);
+ put_child(t, tn, 2 * i, node);
else
- put_child(t, tn, 2*i+1, node);
+ put_child(t, tn, 2 * i + 1, node);
continue;
}

@@ -755,8 +754,8 @@ static struct tnode *inflate(struct trie
inode = (struct tnode *) node;

if (inode->bits == 1) {
- put_child(t, tn, 2*i, inode->child[0]);
- put_child(t, tn, 2*i+1, inode->child[1]);
+ put_child(t, tn, 2 * i, inode->child[0]);
+ put_child(t, tn, 2 * i + 1, inode->child[1]);

tnode_free_safe(inode);
continue;
@@ -785,13 +784,13 @@ static struct tnode *inflate(struct trie
* bit to zero.
*/

- left = (struct tnode *) tnode_get_child(tn, 2*i);
- put_child(t, tn, 2*i, NULL);
+ left = (struct tnode *) tnode_get_child(tn, 2 * i);
+ put_child(t, tn, 2 * i, NULL);

BUG_ON(!left);

- right = (struct tnode *) tnode_get_child(tn, 2*i+1);
- put_child(t, tn, 2*i+1, NULL);
+ right = (struct tnode *) tnode_get_child(tn, 2 * i + 1);
+ put_child(t, tn, 2 * i + 1, NULL);

BUG_ON(!right);

@@ -800,8 +799,8 @@ static struct tnode *inflate(struct trie
put_child(t, left, j, inode->child[j]);
put_child(t, right, j, inode->child[j + size]);
}
- put_child(t, tn, 2*i, resize(t, left));
- put_child(t, tn, 2*i+1, resize(t, right));
+ put_child(t, tn, 2 * i, resize(t, left));
+ put_child(t, tn, 2 * i + 1, resize(t, right));

tnode_free_safe(inode);
}
@@ -845,7 +844,7 @@ static struct tnode *halve(struct trie *

for (i = 0; i < olen; i += 2) {
left = tnode_get_child(oldtnode, i);
- right = tnode_get_child(oldtnode, i+1);
+ right = tnode_get_child(oldtnode, i + 1);

/* Two nonempty children */
if (left && right) {
@@ -856,7 +855,7 @@ static struct tnode *halve(struct trie *
if (!newn)
goto nomem;

- put_child(t, tn, i/2, (struct node *)newn);
+ put_child(t, tn, i / 2, (struct node *)newn);
}

}
@@ -865,27 +864,27 @@ static struct tnode *halve(struct trie *
struct tnode *newBinNode;

left = tnode_get_child(oldtnode, i);
- right = tnode_get_child(oldtnode, i+1);
+ right = tnode_get_child(oldtnode, i + 1);

/* At least one of the children is empty */
if (left == NULL) {
if (right == NULL) /* Both are empty */
continue;
- put_child(t, tn, i/2, right);
+ put_child(t, tn, i / 2, right);
continue;
}

if (right == NULL) {
- put_child(t, tn, i/2, left);
+ put_child(t, tn, i / 2, left);
continue;
}

/* Two nonempty children */
- newBinNode = (struct tnode *) tnode_get_child(tn, i/2);
- put_child(t, tn, i/2, NULL);
+ newBinNode = (struct tnode *) tnode_get_child(tn, i / 2);
+ put_child(t, tn, i / 2, NULL);
put_child(t, newBinNode, 0, left);
put_child(t, newBinNode, 1, right);
- put_child(t, tn, i/2, resize(t, newBinNode));
+ put_child(t, tn, i / 2, resize(t, newBinNode));
}
tnode_free_safe(oldtnode);
return tn;
@@ -1147,7 +1146,7 @@ static struct list_head *fib_insert_node

missbit = tkey_extract_bits(key, newpos, 1);
put_child(t, tn, missbit, (struct node *)l);
- put_child(t, tn, 1-missbit, n);
+ put_child(t, tn, 1 - missbit, n);

if (tp) {
cindex = tkey_extract_bits(key, tp->pos, tp->bits);
@@ -1324,8 +1323,7 @@ static int fn_trie_insert(struct fib_tab
}
}

- list_add_tail_rcu(&new_fa->fa_list,
- (fa ? &fa->fa_list : fa_head));
+ list_add_tail_rcu(&new_fa->fa_list, (fa ? &fa->fa_list : fa_head));

rt_cache_flush(cfg->fc_nlinfo.nl_net, -1);
rtmsg_fib(RTM_NEWROUTE, htonl(key), new_fa, plen, tb->tb_id,
@@ -1463,9 +1461,9 @@ static int fn_trie_lookup(struct fib_tab
/* NOTA BENE: Checking only skipped bits
for the new node here */

- if (current_prefix_length < pos+bits) {
+ if (current_prefix_length < pos + bits) {
if (tkey_extract_bits(cn->key, current_prefix_length,
- cn->pos - current_prefix_length)
+ cn->pos - current_prefix_length)
|| !(cn->child[0]))
goto backtrace;
}
@@ -1504,7 +1502,7 @@ static int fn_trie_lookup(struct fib_tab

node_prefix = mask_pfx(cn->key, cn->pos);
key_prefix = mask_pfx(key, cn->pos);
- pref_mismatch = key_prefix^node_prefix;
+ pref_mismatch = key_prefix ^ node_prefix;
mp = 0;

/*
@@ -1513,11 +1511,12 @@ static int fn_trie_lookup(struct fib_tab
* state.directly.
*/
if (pref_mismatch) {
- while (!(pref_mismatch & (1<<(KEYLENGTH-1)))) {
+ while (!(pref_mismatch & (1 << (KEYLENGTH - 1)))) {
mp++;
pref_mismatch = pref_mismatch << 1;
}
- key_prefix = tkey_extract_bits(cn->key, mp, cn->pos-mp);
+ key_prefix = tkey_extract_bits(cn->key, mp,
+ cn->pos - mp);

if (key_prefix != 0)
goto backtrace;
@@ -1526,7 +1525,7 @@ static int fn_trie_lookup(struct fib_tab
current_prefix_length = mp;
}

- pn = (struct tnode *)n; /* Descend */
+ pn = (struct tnode *) n; /* Descend */
chopped_off = 0;
continue;

@@ -1535,7 +1534,7 @@ backtrace:

/* As zero don't change the child key (cindex) */
while ((chopped_off <= pn->bits)
- && !(cindex & (1<<(chopped_off-1))))
+ && !(cindex & (1 << (chopped_off - 1))))
chopped_off++;

/* Decrease current_... with bits chopped off */
@@ -1549,7 +1548,7 @@ backtrace:
*/

if (chopped_off <= pn->bits) {
- cindex &= ~(1 << (chopped_off-1));
+ cindex &= ~(1 << (chopped_off - 1));
} else {
struct tnode *parent = node_parent_rcu((struct node *) pn);
if (!parent)
@@ -1743,7 +1742,7 @@ static struct leaf *leaf_walk_rcu(struct

/* Node empty, walk back up to parent */
c = (struct node *) p;
- } while ( (p = node_parent_rcu(c)) != NULL);
+ } while ((p = node_parent_rcu(c)) != NULL);

return NULL; /* Root of trie */
}
@@ -1868,7 +1867,7 @@ static void fn_trie_select_default(struc
}

if (!fib_detect_death(fi, order, &last_resort, &last_idx,
- tb->tb_default)) {
+ tb->tb_default)) {
fib_result_assign(res, fi);
tb->tb_default = order;
goto out;
@@ -1986,7 +1985,7 @@ static int fn_trie_dump(struct fib_table
++count;
l = trie_nextleaf(l);
memset(&cb->args[4], 0,
- sizeof(cb->args) - 4*sizeof(cb->args[0]));
+ sizeof(cb->args) - 4 * sizeof(cb->args[0]));
}
cb->args[3] = count;
rcu_read_unlock();
@@ -2059,7 +2058,7 @@ static struct node *fib_trie_get_next(st
pr_debug("get_next iter={node=%p index=%d depth=%d}\n",
iter->tnode, iter->index, iter->depth);
rescan:
- while (cindex < (1<<tn->bits)) {
+ while (cindex < (1 << tn->bits)) {
struct node *n = tnode_get_child_rcu(tn, cindex);

if (n) {
@@ -2145,7 +2144,7 @@ static void trie_collect_stats(struct tr
if (tn->bits < MAX_STAT_DEPTH)
s->nodesizes[tn->bits]++;

- for (i = 0; i < (1<<tn->bits); i++)
+ for (i = 0; i < (1 << tn->bits); i++)
if (!tn->child[i])
s->nullpointers++;
}
@@ -2161,7 +2160,7 @@ static void trie_show_stats(struct seq_f
unsigned i, max, pointers, bytes, avdepth;

if (stat->leaves)
- avdepth = stat->totdepth*100 / stat->leaves;
+ avdepth = stat->totdepth * 100 / stat->leaves;
else
avdepth = 0;

@@ -2179,14 +2178,14 @@ static void trie_show_stats(struct seq_f
bytes += sizeof(struct tnode) * stat->tnodes;

max = MAX_STAT_DEPTH;
- while (max > 0 && stat->nodesizes[max-1] == 0)
+ while (max > 0 && stat->nodesizes[max - 1] == 0)
max--;

pointers = 0;
for (i = 1; i <= max; i++)
if (stat->nodesizes[i] != 0) {
seq_printf(seq, " %u: %u", i, stat->nodesizes[i]);
- pointers += (1<<i) * stat->nodesizes[i];
+ pointers += (1 << i) * stat->nodesizes[i];
}
seq_putc(seq, '\n');
seq_printf(seq, "\tPointers: %u\n", pointers);
@@ -2324,7 +2323,7 @@ static void *fib_trie_seq_next(struct se

/* walk rest of this hash chain */
h = tb->tb_id & (FIB_TABLE_HASHSZ - 1);
- while ( (tb_node = rcu_dereference(tb->tb_hlist.next)) ) {
+ while ((tb_node = rcu_dereference(tb->tb_hlist.next))) {
tb = hlist_entry(tb_node, struct fib_table, tb_hlist);
n = fib_trie_get_first(iter, (struct trie *) tb->tb_data);
if (n)
@@ -2355,7 +2354,8 @@ static void fib_trie_seq_stop(struct seq

static void seq_indent(struct seq_file *seq, int n)
{
- while (n-- > 0) seq_puts(seq, " ");
+ while (n-- > 0)
+ seq_puts(seq, " ");
}

static inline const char *rtn_scope(char *buf, size_t len, enum rt_scope_t s)
@@ -2408,7 +2408,7 @@ static int fib_trie_seq_show(struct seq_
struct tnode *tn = (struct tnode *) n;
__be32 prf = htonl(mask_pfx(tn->key, tn->pos));

- seq_indent(seq, iter->depth-1);
+ seq_indent(seq, iter->depth - 1);
seq_printf(seq, " +-- %pI4/%d %d %d %d\n",
&prf, tn->pos, tn->bits, tn->full_children,
tn->empty_children);
@@ -2428,7 +2428,7 @@ static int fib_trie_seq_show(struct seq_
list_for_each_entry_rcu(fa, &li->falh, fa_list) {
char buf1[32], buf2[32];

- seq_indent(seq, iter->depth+1);
+ seq_indent(seq, iter->depth + 1);
seq_printf(seq, " /%d %s %s", li->plen,
rtn_scope(buf1, sizeof(buf1),
fa->fa_scope),
@@ -2478,8 +2478,10 @@ static struct leaf *fib_route_get_idx(st
struct trie *t = iter->main_trie;

/* use cache location of last found key */
- if (iter->pos > 0 && pos >= iter->pos && (l = fib_find_node(t, iter->key)))
- pos -= iter->pos;
+ if (iter->pos > 0 && pos >= iter->pos)
+ l = fib_find_node(t, iter->key);
+ if (l)
+ pos -= iter->pos;
else {
iter->pos = 0;
l = trie_firstleaf(t);
@@ -2546,7 +2548,8 @@ static void fib_route_seq_stop(struct se
static unsigned fib_flag_trans(int type, __be32 mask, const struct fib_info *fi)
{
static unsigned type2flags[RTN_MAX + 1] = {
- [7] = RTF_REJECT, [8] = RTF_REJECT,
+ [7] = RTF_REJECT,
+ [8] = RTF_REJECT,
};
unsigned flags = type2flags[type];

@@ -2561,7 +2564,7 @@ static unsigned fib_flag_trans(int type,
/*
* This outputs /proc/net/route.
* The format of the file is not supposed to be changed
- * and needs to be same as fib_hash output to avoid breaking
+ * and needs to be same as fib_hash output to avoid breaking
* legacy utilities
*/
static int fib_route_seq_show(struct seq_file *seq, void *v)