include: introduce bitmap API

Add a new bitmap_t that represents an array-based bitmap.
Implement alloc/free and various functions for bitmap operations.
Add div_round_up helper macro for computing the number of longs
that a given bitmap should be.

Signed-off-by: Connor Davis <[email protected]>

common/bitmap.c

@@ -0,0 +1,59 @@
+/*
+ * Copyright © 2021 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <bitmap.h>
+#include <mm/slab.h>
+
+bitmap_t *bitmap_alloc(unsigned int nbits) {
+    bitmap_t *map;
+
+    if (0 == nbits || UINT_MAX == nbits)
+        return NULL;
+
+    map = kzalloc(sizeof(*map));
+    if (NULL == map)
+        return NULL;
+
+    map->word = kzalloc(BITS_TO_LONGS(nbits) * __SIZEOF_LONG__);
+    if (NULL == map->word) {
+        kfree(map);
+        return NULL;
+    }
+
+    map->nbits = nbits;
+
+    return map;
+}
+
+void bitmap_free(bitmap_t *map) {
+    if (NULL == map)
+        return;
+
+    if (map->word) {
+        kfree(map->word);
+        map->word = NULL;
+    }
+
+    kfree(map);
+}

include/bitmap.h

@@ -0,0 +1,104 @@
+/*
+ * Copyright © 2021 Amazon.com, Inc. or its affiliates.
+ * All Rights Reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef KTF_BITMAP_H
+#define KTF_BITMAP_H
+
+#include <lib.h>
+
+#define BITS_PER_LONG        (__SIZEOF_LONG__ * 8)
+#define BITS_TO_LONGS(nbits) div_round_up(nbits, BITS_PER_LONG)
+
+typedef struct {
+    unsigned long *word;
+    unsigned int nbits;
+} bitmap_t;
+
+bitmap_t *bitmap_alloc(unsigned int nbits);
+void bitmap_free(bitmap_t *map);
+
+static inline unsigned int bitmap_find_first_set(const bitmap_t *map) {
+    if (NULL == map || NULL == map->word)
+        return UINT_MAX;
+
+    for (unsigned int i = 0; i < BITS_TO_LONGS(map->nbits); i++) {
+        unsigned int ret = __builtin_ffsl(map->word[i]);
+        if (0 == ret)
+            continue;
+
+        return i * BITS_PER_LONG + ret - 1;
+    }
+
+    return UINT_MAX;
+}
+
+static inline unsigned int bitmap_find_first_clear(const bitmap_t *map) {
+    if (NULL == map || NULL == map->word)
+        return UINT_MAX;
+
+    for (unsigned int i = 0; i < BITS_TO_LONGS(map->nbits); i++) {
+        unsigned int ret = __builtin_ffsl(~map->word[i]);
+        if (0 == ret)
+            continue;
+
+        return i * BITS_PER_LONG + ret - 1;
+    }
+
+    return UINT_MAX;
+}
+
+static inline bool bitmap_test_bit(const bitmap_t *map, unsigned int bit) {
+    unsigned int i;
+
+    if (NULL == map || NULL == map->word || bit >= map->nbits)
+        return false;
+
+    i = bit / BITS_PER_LONG;
+
+    return (map->word[i] & (1UL << (bit % BITS_PER_LONG))) != 0;
+}
+
+static inline void bitmap_set_bit(bitmap_t *map, unsigned int bit) {
+    unsigned int i;
+
+    if (NULL == map || NULL == map->word || bit >= map->nbits)
+        return;
+
+    i = bit / BITS_PER_LONG;
+
+    map->word[i] |= (1UL << (bit % BITS_PER_LONG));
+}
+
+static inline void bitmap_clear_bit(bitmap_t *map, unsigned int bit) {
+    unsigned int i;
+
+    if (NULL == map || NULL == map->word || bit >= map->nbits)
+        return;
+
+    i = bit / BITS_PER_LONG;
+
+    map->word[i] &= ~(1UL << (bit % BITS_PER_LONG));
+}
+
+#endif /* KTF_BITMAP_H */

include/lib.h

@@ -45,6 +45,8 @@
         _a > _b ? _a : _b;                                                               \
     })
 
+#define div_round_up(n, d) ((((n) + (d)) - 1) / (d))
+
 static inline unsigned int log2(unsigned int value) {
     return value == 0 ? 0 : (31 - __builtin_clz(value));
 }