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batman-adv: Replace bitarray operations with bitmap

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bitarray.c consists mostly of functionality that is already available as part
of the standard kernel API. batman-adv could use architecture optimized code
and reduce the binary size by switching to the standard functions.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
This commit is contained in:
Sven Eckelmann 2012-02-04 17:34:52 +01:00 • committed by Antonio Quartulli
parent c1faead333
commit 0079d2cef1
6 changed files with 41 additions and 130 deletions
Download patch file Download diff file Expand all files Collapse all files

118
net/batman-adv/bitarray.c
View file

@ -24,100 +24,13 @@
#include <linux/bitops.h>
/* returns true if the corresponding bit in the given seq_bits indicates true
* and curr_seqno is within range of last_seqno */
int get_bit_status(const unsigned long *seq_bits, uint32_t last_seqno,
uint32_t curr_seqno)
{
int32_t diff, word_offset, word_num;
diff = last_seqno - curr_seqno;
if (diff < 0 || diff >= TQ_LOCAL_WINDOW_SIZE) {
return 0;
} else {
/* which word */
word_num = (last_seqno - curr_seqno) / WORD_BIT_SIZE;
/* which position in the selected word */
word_offset = (last_seqno - curr_seqno) % WORD_BIT_SIZE;
if (test_bit(word_offset, &seq_bits[word_num]))
return 1;
else
return 0;
}
}
/* turn corresponding bit on, so we can remember that we got the packet */
void bit_mark(unsigned long *seq_bits, int32_t n)
{
int32_t word_offset, word_num;
/* if too old, just drop it */
if (n < 0 || n >= TQ_LOCAL_WINDOW_SIZE)
return;
/* which word */
word_num = n / WORD_BIT_SIZE;
/* which position in the selected word */
word_offset = n % WORD_BIT_SIZE;
set_bit(word_offset, &seq_bits[word_num]); /* turn the position on */
}
/* shift the packet array by n places. */
static void bit_shift(unsigned long *seq_bits, int32_t n)
static void bat_bitmap_shift_left(unsigned long *seq_bits, int32_t n)
{
int32_t word_offset, word_num;
int32_t i;
if (n <= 0 || n >= TQ_LOCAL_WINDOW_SIZE)
return;
word_offset = n % WORD_BIT_SIZE;/* shift how much inside each word */
word_num = n / WORD_BIT_SIZE; /* shift over how much (full) words */
for (i = NUM_WORDS - 1; i > word_num; i--) {
/* going from old to new, so we don't overwrite the data we copy
* from.
*
* left is high, right is low: FEDC BA98 7654 3210
* ^^ ^^
* vvvv
* ^^^^ = from, vvvvv =to, we'd have word_num==1 and
* word_offset==WORD_BIT_SIZE/2 ????? in this example.
* (=24 bits)
*
* our desired output would be: 9876 5432 1000 0000
* */
seq_bits[i] =
(seq_bits[i - word_num] << word_offset) +
/* take the lower port from the left half, shift it left
* to its final position */
(seq_bits[i - word_num - 1] >>
(WORD_BIT_SIZE-word_offset));
/* and the upper part of the right half and shift it left to
* its position */
/* for our example that would be: word[0] = 9800 + 0076 =
* 9876 */
}
/* now for our last word, i==word_num, we only have its "left" half.
* that's the 1000 word in our example.*/
seq_bits[i] = (seq_bits[i - word_num] << word_offset);
/* pad the rest with 0, if there is anything */
i--;
for (; i >= 0; i--)
seq_bits[i] = 0;
}
static void bit_reset_window(unsigned long *seq_bits)
{
int i;
for (i = 0; i < NUM_WORDS; i++)
seq_bits[i] = 0;
bitmap_shift_left(seq_bits, seq_bits, n, TQ_LOCAL_WINDOW_SIZE);
}
@ -137,7 +50,7 @@ int bit_get_packet(void *priv, unsigned long *seq_bits,
if ((seq_num_diff <= 0) && (seq_num_diff > -TQ_LOCAL_WINDOW_SIZE)) {
if (set_mark)
bit_mark(seq_bits, -seq_num_diff);
bat_set_bit(seq_bits, -seq_num_diff);
return 0;
}
@ -145,10 +58,10 @@ int bit_get_packet(void *priv, unsigned long *seq_bits,
* set the mark if required */
if ((seq_num_diff > 0) && (seq_num_diff < TQ_LOCAL_WINDOW_SIZE)) {
bit_shift(seq_bits, seq_num_diff);
bat_bitmap_shift_left(seq_bits, seq_num_diff);
if (set_mark)
bit_mark(seq_bits, 0);
bat_set_bit(seq_bits, 0);
return 1;
}
@ -159,9 +72,9 @@ int bit_get_packet(void *priv, unsigned long *seq_bits,
bat_dbg(DBG_BATMAN, bat_priv,
"We missed a lot of packets (%i) !\n",
seq_num_diff - 1);
bit_reset_window(seq_bits);
bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE);
if (set_mark)
bit_mark(seq_bits, 0);
bat_set_bit(seq_bits, 0);
return 1;
}
@ -176,9 +89,9 @@ int bit_get_packet(void *priv, unsigned long *seq_bits,
bat_dbg(DBG_BATMAN, bat_priv,
"Other host probably restarted!\n");
bit_reset_window(seq_bits);
bitmap_zero(seq_bits, TQ_LOCAL_WINDOW_SIZE);
if (set_mark)
bit_mark(seq_bits, 0);
bat_set_bit(seq_bits, 0);
return 1;
}
@ -186,16 +99,3 @@ int bit_get_packet(void *priv, unsigned long *seq_bits,
/* never reached */
return 0;
}
/* count the hamming weight, how many good packets did we receive? just count
* the 1's.
*/
int bit_packet_count(const unsigned long *seq_bits)
{
int i, hamming = 0;
for (i = 0; i < NUM_WORDS; i++)
hamming += hweight_long(seq_bits[i]);
return hamming;
}