Revert "axmap: fix deadlock"

[fio.git] / lib / axmap.c

diff --git a/lib/axmap.c b/lib/axmap.c
index eeb32d42a6085e096bdde44fc39f057d9853b8da..e847a387bc6b8ab984ca4ca4162183ef37b6dd0f 100644 (file)
--- a/lib/axmap.c
+++ b/lib/axmap.c
@@ -5,7 +5,7 @@
  * nothing to do with anything remotely narcissistic.
  *
  * A set bit at layer N indicates a full word at layer N-1, and so forth. As
- * the bitmap becomes progressively more full, checking for existance
+ * the bitmap becomes progressively more full, checking for existence
  * becomes cheaper (since fewer layers are walked, making it a lot more
  * cache friendly) and locating the next free space likewise.
  *
@@ -23,6 +23,7 @@
 #include "../arch/arch.h"
 #include "axmap.h"
 #include "../smalloc.h"
+#include "../mutex.h"
 #include "../minmax.h"
 
 #if BITS_PER_LONG == 64
@@ -33,7 +34,7 @@
 #error "Number of arch bits unknown"
 #endif
 
-#define BLOCKS_PER_UNIT                (1UL << UNIT_SHIFT)
+#define BLOCKS_PER_UNIT                (1U << UNIT_SHIFT)
 #define BLOCKS_PER_UNIT_MASK   (BLOCKS_PER_UNIT - 1)
 
 #define firstfree_valid(b)     ((b)->first_free != (uint64_t) -1)
@@ -45,6 +46,7 @@ struct axmap_level {
 };
 
 struct axmap {
+       struct fio_mutex lock;
        unsigned int nr_levels;
        struct axmap_level *levels;
        uint64_t first_free;
@@ -63,6 +65,8 @@ void axmap_reset(struct axmap *axmap)
 {
        int i;
 
+       fio_mutex_down(&axmap->lock);
+
        for (i = 0; i < axmap->nr_levels; i++) {
                struct axmap_level *al = &axmap->levels[i];
 
@@ -70,6 +74,7 @@ void axmap_reset(struct axmap *axmap)
        }
 
        axmap->first_free = 0;
+       fio_mutex_up(&axmap->lock);
 }
 
 void axmap_free(struct axmap *axmap)
@@ -83,6 +88,7 @@ void axmap_free(struct axmap *axmap)
                sfree(axmap->levels[i].map);
 
        sfree(axmap->levels);
+       __fio_mutex_remove(&axmap->lock);
        sfree(axmap);
 }
 
@@ -95,6 +101,8 @@ struct axmap *axmap_new(unsigned long nr_bits)
        if (!axmap)
                return NULL;
 
+       __fio_mutex_init(&axmap->lock, FIO_MUTEX_UNLOCKED);
+
        levels = 1;
        i = (nr_bits + BLOCKS_PER_UNIT - 1) >> UNIT_SHIFT;
        while (i > 1) {
@@ -126,6 +134,8 @@ err:
                        sfree(axmap->levels[i].map);
 
        sfree(axmap->levels);
+       __fio_mutex_remove(&axmap->lock);
+       sfree(axmap);
        return NULL;
 }
 
@@ -189,7 +199,6 @@ void axmap_clear(struct axmap *axmap, uint64_t bit_nr)
 struct axmap_set_data {
        unsigned int nr_bits;
        unsigned int set_bits;
-       unsigned int fail_ok;
 };
 
 static unsigned long bit_masks[] = {
@@ -229,10 +238,8 @@ static int axmap_set_fn(struct axmap_level *al, unsigned long offset,
         * Mask off any potential overlap, only sets contig regions
         */
        overlap = al->map[offset] & mask;
-       if (overlap == mask) {
-               assert(data->fail_ok);
+       if (overlap == mask)
                return 1;
-       }
 
        while (overlap) {
                unsigned long clear_mask = ~(1UL << ffz(~overlap));
@@ -273,14 +280,14 @@ static void __axmap_set(struct axmap *axmap, uint64_t bit_nr,
                axmap_handler(axmap, bit_nr, axmap_set_fn, data);
                set_bits += data->set_bits;
 
-               if (data->set_bits != (BLOCKS_PER_UNIT - nr_bits))
+               if (!data->set_bits ||
+                   data->set_bits != (BLOCKS_PER_UNIT - nr_bits))
                        break;
 
                nr_bits -= data->set_bits;
                bit_nr += data->set_bits;
 
                data->nr_bits = nr_bits;
-               data->fail_ok = 1;
        }
 
        data->set_bits = set_bits;
@@ -290,15 +297,34 @@ void axmap_set(struct axmap *axmap, uint64_t bit_nr)
 {
        struct axmap_set_data data = { .nr_bits = 1, };
 
+       fio_mutex_down(&axmap->lock);
        __axmap_set(axmap, bit_nr, &data);
+       fio_mutex_up(&axmap->lock);
 }
 
 unsigned int axmap_set_nr(struct axmap *axmap, uint64_t bit_nr, unsigned int nr_bits)
 {
-       struct axmap_set_data data = { .nr_bits = nr_bits, };
+       unsigned int set_bits = 0;
 
-       __axmap_set(axmap, bit_nr, &data);
-       return data.set_bits;
+       do {
+               struct axmap_set_data data = { .nr_bits = nr_bits, };
+               unsigned int max_bits, this_set;
+
+               max_bits = BLOCKS_PER_UNIT - (bit_nr & BLOCKS_PER_UNIT_MASK);
+               if (max_bits < nr_bits)
+                       data.nr_bits = max_bits;
+
+               this_set = data.nr_bits;
+               __axmap_set(axmap, bit_nr, &data);
+               set_bits += data.set_bits;
+               if (data.set_bits != this_set)
+                       break;
+
+               nr_bits -= data.set_bits;
+               bit_nr += data.set_bits;
+       } while (nr_bits);
+
+       return set_bits;
 }
 
 static int axmap_isset_fn(struct axmap_level *al, unsigned long offset,
@@ -309,8 +335,14 @@ static int axmap_isset_fn(struct axmap_level *al, unsigned long offset,
 
 int axmap_isset(struct axmap *axmap, uint64_t bit_nr)
 {
-       if (bit_nr <= axmap->nr_bits)
-               return axmap_handler_topdown(axmap, bit_nr, axmap_isset_fn, NULL);
+       if (bit_nr <= axmap->nr_bits) {
+               int ret;
+
+               fio_mutex_down(&axmap->lock);
+               ret = axmap_handler_topdown(axmap, bit_nr, axmap_isset_fn, NULL);
+               fio_mutex_up(&axmap->lock);
+               return ret;
+       }
 
        return 0;
 }
@@ -357,11 +389,17 @@ static uint64_t axmap_find_first_free(struct axmap *axmap, unsigned int level,
 
 uint64_t axmap_first_free(struct axmap *axmap)
 {
+       uint64_t ret;
+
        if (firstfree_valid(axmap))
                return axmap->first_free;
 
-       axmap->first_free = axmap_find_first_free(axmap, axmap->nr_levels - 1, 0);
-       return axmap->first_free;
+       fio_mutex_down(&axmap->lock);
+       ret = axmap_find_first_free(axmap, axmap->nr_levels - 1, 0);
+       axmap->first_free = ret;
+       fio_mutex_up(&axmap->lock);
+
+       return ret;
 }
 
 struct axmap_next_free_data {
@@ -397,11 +435,17 @@ uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr)
        struct axmap_next_free_data data = { .level = -1U, .bit = bit_nr, };
        uint64_t ret;
 
-       if (firstfree_valid(axmap) && bit_nr < axmap->first_free)
-               return axmap->first_free;
+       fio_mutex_down(&axmap->lock);
 
-       if (!axmap_handler(axmap, bit_nr, axmap_next_free_fn, &data))
-               return axmap_first_free(axmap);
+       if (firstfree_valid(axmap) && bit_nr < axmap->first_free) {
+               ret = axmap->first_free;
+               goto done;
+       }
+
+       if (!axmap_handler(axmap, bit_nr, axmap_next_free_fn, &data)) {
+               ret = axmap_first_free(axmap);
+               goto done;
+       }
 
        assert(data.level != -1U);
 
@@ -411,8 +455,12 @@ uint64_t axmap_next_free(struct axmap *axmap, uint64_t bit_nr)
         * find the first free one, the map is practically full.
         */
        ret = axmap_find_first_free(axmap, data.level, data.offset);
-       if (ret != -1ULL)
+       if (ret != -1ULL) {
+done:
+               fio_mutex_up(&axmap->lock);
                return ret;
+       }
 
-       return axmap_first_free(axmap);
+       ret = axmap_first_free(axmap);
+       goto done;
 }