batman-adv: Replace bitarray operations with bitmap

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>

6 files changed, 41 insertions, 130 deletions

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index a6d5d63fb6ad..fab1071f601e 100644
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -850,9 +850,9 @@ static int bat_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
         hlist_for_each_entry_rcu(tmp_neigh_node, node,
                                  &orig_node->neigh_list, list) {
 
-                is_duplicate |= get_bit_status(tmp_neigh_node->real_bits,
-                                               orig_node->last_real_seqno,
-                                               batman_ogm_packet->seqno);
+                is_duplicate |= bat_test_bit(tmp_neigh_node->real_bits,
+                                             orig_node->last_real_seqno,
+                                             batman_ogm_packet->seqno);
 
                 if (compare_eth(tmp_neigh_node->addr, ethhdr->h_source) &&
                     (tmp_neigh_node->if_incoming == if_incoming))
@@ -866,7 +866,8 @@ static int bat_iv_ogm_update_seqnos(const struct ethhdr *ethhdr,
                                               seq_diff, set_mark);
 
                 tmp_neigh_node->real_packet_count =
-                        bit_packet_count(tmp_neigh_node->real_bits);
+                        bitmap_weight(tmp_neigh_node->real_bits,
+                                      TQ_LOCAL_WINDOW_SIZE);
         }
         rcu_read_unlock();
 
@@ -998,11 +999,11 @@ static void bat_iv_ogm_process(const struct ethhdr *ethhdr,
 
                         spin_lock_bh(&orig_neigh_node->ogm_cnt_lock);
                         word = &(orig_neigh_node->bcast_own[offset]);
-                        bit_mark(word,
-                                 if_incoming_seqno -
+                        bat_set_bit(word,
+                                    if_incoming_seqno -
                                                 batman_ogm_packet->seqno - 2);
                         orig_neigh_node->bcast_own_sum[if_incoming->if_num] =
-                                bit_packet_count(word);
+                                bitmap_weight(word, TQ_LOCAL_WINDOW_SIZE);
                         spin_unlock_bh(&orig_neigh_node->ogm_cnt_lock);
                 }
 
diff --git a/net/batman-adv/bitarray.c b/net/batman-adv/bitarray.c
index 6d0aa216b232..07ae6e1b8aca 100644
--- a/net/batman-adv/bitarray.c
+++ b/net/batman-adv/bitarray.c
@@ -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;
-}
diff --git a/net/batman-adv/bitarray.h b/net/batman-adv/bitarray.h
index c6135728a680..1835c15cda41 100644
--- a/net/batman-adv/bitarray.h
+++ b/net/batman-adv/bitarray.h
@@ -22,23 +22,33 @@
 #ifndef _NET_BATMAN_ADV_BITARRAY_H_
 #define _NET_BATMAN_ADV_BITARRAY_H_
 
-#define WORD_BIT_SIZE (sizeof(unsigned long) * 8)
-
 /* 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);
+static inline int bat_test_bit(const unsigned long *seq_bits,
+                               uint32_t last_seqno, uint32_t curr_seqno)
+{
+        int32_t diff;
+
+        diff = last_seqno - curr_seqno;
+        if (diff < 0 || diff >= TQ_LOCAL_WINDOW_SIZE)
+                return 0;
+        else
+                return  test_bit(diff, seq_bits);
+}
 
 /* turn corresponding bit on, so we can remember that we got the packet */
-void bit_mark(unsigned long *seq_bits, int32_t n);
+static inline void bat_set_bit(unsigned long *seq_bits, int32_t n)
+{
+        /* if too old, just drop it */
+        if (n < 0 || n >= TQ_LOCAL_WINDOW_SIZE)
+                return;
 
+        set_bit(n, seq_bits); /* turn the position on */
+}
 
 /* receive and process one packet, returns 1 if received seq_num is considered
  * new, 0 if old  */
 int bit_get_packet(void *priv, unsigned long *seq_bits,
                    int32_t seq_num_diff, int set_mark);
 
-/* count the hamming weight, how many good packets did we receive? */
-int bit_packet_count(const unsigned long *seq_bits);
-
 #endif /* _NET_BATMAN_ADV_BITARRAY_H_ */
diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h
index 94fa1c2393a6..0a20a19197aa 100644
--- a/net/batman-adv/main.h
+++ b/net/batman-adv/main.h
@@ -65,7 +65,7 @@
 
 #define NULL_IFINDEX 0 /* dummy ifindex used to avoid iface checks */
 
-#define NUM_WORDS (TQ_LOCAL_WINDOW_SIZE / WORD_BIT_SIZE)
+#define NUM_WORDS BITS_TO_LONGS(TQ_LOCAL_WINDOW_SIZE)
 
 #define LOG_BUF_LEN 8192          /* has to be a power of 2 */
 
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 7f8e15899417..b0370e3c59e8 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -52,7 +52,7 @@ void slide_own_bcast_window(struct hard_iface *hard_iface)
 
                         bit_get_packet(bat_priv, word, 1, 0);
                         orig_node->bcast_own_sum[hard_iface->if_num] =
-                                bit_packet_count(word);
+                                bitmap_weight(word, TQ_LOCAL_WINDOW_SIZE);
                         spin_unlock_bh(&orig_node->ogm_cnt_lock);
                 }
                 rcu_read_unlock();
@@ -1047,8 +1047,8 @@ int recv_bcast_packet(struct sk_buff *skb, struct hard_iface *recv_if)
         spin_lock_bh(&orig_node->bcast_seqno_lock);
 
         /* check whether the packet is a duplicate */
-        if (get_bit_status(orig_node->bcast_bits, orig_node->last_bcast_seqno,
-                           ntohl(bcast_packet->seqno)))
+        if (bat_test_bit(orig_node->bcast_bits, orig_node->last_bcast_seqno,
+                         ntohl(bcast_packet->seqno)))
                 goto spin_unlock;
 
         seq_diff = ntohl(bcast_packet->seqno) - orig_node->last_bcast_seqno;
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index 302efb523475..24c8a31a3d91 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -90,7 +90,7 @@ struct orig_node {
         bool tt_poss_change;
         uint32_t last_real_seqno;
         uint8_t last_ttl;
-        unsigned long bcast_bits[NUM_WORDS];
+        DECLARE_BITMAP(bcast_bits, TQ_LOCAL_WINDOW_SIZE);
         uint32_t last_bcast_seqno;
         struct hlist_head neigh_list;
         struct list_head frag_list;
@@ -132,7 +132,7 @@ struct neigh_node {
         uint8_t last_ttl;
         struct list_head bonding_list;
         unsigned long last_valid;
-        unsigned long real_bits[NUM_WORDS];
+        DECLARE_BITMAP(real_bits, TQ_LOCAL_WINDOW_SIZE);
         atomic_t refcount;
         struct rcu_head rcu;
         struct orig_node *orig_node;