axmap: ensure that overlaps are handled strictly sequential

[fio.git] / lib / axmap.c

diff --git a/lib/axmap.c b/lib/axmap.c
index 2ee3a2563f818b04ec0edd0400fee7287d7800f9..c29597f80e78748043b63db3756463596c164646 100644 (file)
--- a/lib/axmap.c
+++ b/lib/axmap.c
@@ -102,7 +102,7 @@ struct axmap *axmap_new(unsigned long nr_bits)
        }
 
        axmap->nr_levels = levels;
-       axmap->levels = malloc(axmap->nr_levels * sizeof(struct axmap_level));
+       axmap->levels = calloc(axmap->nr_levels, sizeof(struct axmap_level));
        axmap->nr_bits = nr_bits;
 
        for (i = 0; i < axmap->nr_levels; i++) {
@@ -184,6 +184,9 @@ static bool axmap_clear_fn(struct axmap_level *al, unsigned long offset,
 void axmap_clear(struct axmap *axmap, uint64_t bit_nr)
 {
        axmap_handler(axmap, bit_nr, axmap_clear_fn, NULL);
+
+       if (bit_nr < axmap->first_free)
+               axmap->first_free = bit_nr;
 }
 
 struct axmap_set_data {
@@ -191,7 +194,7 @@ struct axmap_set_data {
        unsigned int set_bits;
 };
 
-static unsigned long bit_masks[] = {
+static const unsigned long bit_masks[] = {
        0x0000000000000000, 0x0000000000000001, 0x0000000000000003, 0x0000000000000007,
        0x000000000000000f, 0x000000000000001f, 0x000000000000003f, 0x000000000000007f,
        0x00000000000000ff, 0x00000000000001ff, 0x00000000000003ff, 0x00000000000007ff,
@@ -231,17 +234,18 @@ static bool axmap_set_fn(struct axmap_level *al, unsigned long offset,
        if (overlap == mask)
                return true;
 
-       while (overlap) {
-               unsigned long clear_mask = ~(1UL << ffz(~overlap));
+       if (overlap) {
+               const int __bit = ffz(~overlap);
+
+               if (__bit == bit)
+                       return true;
 
-               mask &= clear_mask;
-               overlap &= clear_mask;
-               nr_bits--;
+               nr_bits = __bit - bit;
+               mask = bit_masks[nr_bits] << bit;
        }
 
        assert(mask);
        assert(!(al->map[offset] & mask));
-               
        al->map[offset] |= mask;
 
        if (!al->level)
@@ -372,10 +376,9 @@ static uint64_t axmap_find_first_free(struct axmap *axmap, unsigned int level,
 
 static uint64_t axmap_first_free(struct axmap *axmap)
 {
-       if (firstfree_valid(axmap))
-               return axmap->first_free;
+       if (!firstfree_valid(axmap))
+               axmap->first_free = axmap_find_first_free(axmap, axmap->nr_levels - 1, 0);
 
-       axmap->first_free = axmap_find_first_free(axmap, axmap->nr_levels - 1, 0);
        return axmap->first_free;
 }