From: "Charles (Chas) Williams" <ch...@att.com>

index2 is used inconsistently, both as an array offset and as a bit
offset.  Fix usage to be consistent as a bit offset.  Additonally,
offset1 needs to be shifted with the size of the array1 slab entries,
not the cache line sizes.  __rte_bitmap_scan_read() needs to examine
the current array2 slab bit by bit to find the next set bit.

The unit tests for rte_bitmap_scan() aren't correct.  If a slab isn't
empty, there is no reason to expect rte_bitmap_scan() to advance to
the next slab.  Change the slab magic values so that rte_bitmap_scan()
will advance on reading a bit from each slab and verify it is the bit
position we expect.

Fixes: de3cfa2c9823a ("sched: initial import")

Signed-off-by: Chas Williams <ch...@att.com>
---
 lib/librte_eal/common/include/rte_bitmap.h | 31 +++++++++++++++---------------
 test/test/test_bitmap.c                    | 12 ++++++------
 2 files changed, 22 insertions(+), 21 deletions(-)

diff --git a/lib/librte_eal/common/include/rte_bitmap.h 
b/lib/librte_eal/common/include/rte_bitmap.h
index 7d4935f..27084d9 100644
--- a/lib/librte_eal/common/include/rte_bitmap.h
+++ b/lib/librte_eal/common/include/rte_bitmap.h
@@ -94,7 +94,8 @@ __rte_bitmap_mask1_get(struct rte_bitmap *bmp)
 static inline void
 __rte_bitmap_index2_set(struct rte_bitmap *bmp)
 {
-       bmp->index2 = (((bmp->index1 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2) + 
bmp->offset1) << RTE_BITMAP_CL_SLAB_SIZE_LOG2);
+       bmp->index2 = ((bmp->index1 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2) +
+                      bmp->offset1) << RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
 }
 
 #if RTE_BITMAP_OPTIMIZATIONS
@@ -172,7 +173,6 @@ __rte_bitmap_scan_init(struct rte_bitmap *bmp)
        bmp->index1 = bmp->array1_size - 1;
        bmp->offset1 = RTE_BITMAP_SLAB_BIT_SIZE - 1;
        __rte_bitmap_index2_set(bmp);
-       bmp->index2 += RTE_BITMAP_CL_SLAB_SIZE;
 
        bmp->go2 = 0;
 }
@@ -338,7 +338,8 @@ rte_bitmap_set(struct rte_bitmap *bmp, uint32_t pos)
        index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
        offset2 = pos & RTE_BITMAP_SLAB_BIT_MASK;
        index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + 
RTE_BITMAP_CL_BIT_SIZE_LOG2);
-       offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & 
RTE_BITMAP_SLAB_BIT_MASK;
+       offset1 = (pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2) &
+                                               RTE_BITMAP_SLAB_BIT_MASK;
        slab2 = bmp->array2 + index2;
        slab1 = bmp->array1 + index1;
 
@@ -365,7 +366,8 @@ rte_bitmap_set_slab(struct rte_bitmap *bmp, uint32_t pos, 
uint64_t slab)
        /* Set bits in array2 slab and set bit in array1 slab */
        index2 = pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
        index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + 
RTE_BITMAP_CL_BIT_SIZE_LOG2);
-       offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & 
RTE_BITMAP_SLAB_BIT_MASK;
+       offset1 = (pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2) &
+                                               RTE_BITMAP_SLAB_BIT_MASK;
        slab2 = bmp->array2 + index2;
        slab1 = bmp->array1 + index1;
 
@@ -422,7 +424,8 @@ rte_bitmap_clear(struct rte_bitmap *bmp, uint32_t pos)
 
        /* The array2 cache line is all-zeros, so clear bit in array1 slab */
        index1 = pos >> (RTE_BITMAP_SLAB_BIT_SIZE_LOG2 + 
RTE_BITMAP_CL_BIT_SIZE_LOG2);
-       offset1 = (pos >> RTE_BITMAP_CL_BIT_SIZE_LOG2) & 
RTE_BITMAP_SLAB_BIT_MASK;
+       offset1 = (pos >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2) &
+                                               RTE_BITMAP_SLAB_BIT_MASK;
        slab1 = bmp->array1 + index1;
        *slab1 &= ~(1lu << offset1);
 
@@ -471,15 +474,14 @@ __rte_bitmap_scan_read(struct rte_bitmap *bmp, uint32_t 
*pos, uint64_t *slab)
 {
        uint64_t *slab2;
 
-       slab2 = bmp->array2 + bmp->index2;
-       for ( ; bmp->go2 ; bmp->index2 ++, slab2 ++, bmp->go2 = bmp->index2 & 
RTE_BITMAP_CL_SLAB_MASK) {
-               if (*slab2) {
-                       *pos = bmp->index2 << RTE_BITMAP_SLAB_BIT_SIZE_LOG2;
-                       *slab = *slab2;
+       slab2 = bmp->array2 + (bmp->index2 >> RTE_BITMAP_SLAB_BIT_SIZE_LOG2);
+       for ( ; bmp->go2 ; bmp->index2++,
+                          bmp->go2 = bmp->index2 & RTE_BITMAP_SLAB_BIT_MASK) {
+               uint32_t offset2 = bmp->index2 & RTE_BITMAP_SLAB_BIT_MASK;
 
-                       bmp->index2 ++;
-                       slab2 ++;
-                       bmp->go2 = bmp->index2 & RTE_BITMAP_CL_SLAB_MASK;
+               if (*slab2 & (1lu << offset2)) {
+                       *pos = bmp->index2++;
+                       *slab = *slab2;
                        return 1;
                }
        }
@@ -518,8 +520,7 @@ rte_bitmap_scan(struct rte_bitmap *bmp, uint32_t *pos, 
uint64_t *slab)
        /* Look for non-empty array2 line */
        if (__rte_bitmap_scan_search(bmp)) {
                __rte_bitmap_scan_read_init(bmp);
-               __rte_bitmap_scan_read(bmp, pos, slab);
-               return 1;
+               return __rte_bitmap_scan_read(bmp, pos, slab);
        }
 
        /* Empty bitmap */
diff --git a/test/test/test_bitmap.c b/test/test/test_bitmap.c
index f498c02..ffbbc02 100644
--- a/test/test/test_bitmap.c
+++ b/test/test/test_bitmap.c
@@ -17,8 +17,8 @@ static int
 test_bitmap_scan_operations(struct rte_bitmap *bmp)
 {
        uint32_t pos = 0;
-       uint64_t slab1_magic = 0xBADC0FFEEBADF00D;
-       uint64_t slab2_magic = 0xFEEDDEADDEADF00D;
+       uint64_t slab1_magic = 0x80; /* pos = 7 */
+       uint64_t slab2_magic = 0x08; /* pos = 67 */
        uint64_t out_slab = 0;
 
        rte_bitmap_reset(bmp);
@@ -26,7 +26,7 @@ test_bitmap_scan_operations(struct rte_bitmap *bmp)
        rte_bitmap_set_slab(bmp, pos, slab1_magic);
        rte_bitmap_set_slab(bmp, pos + RTE_BITMAP_SLAB_BIT_SIZE, slab2_magic);
 
-       if (!rte_bitmap_scan(bmp, &pos, &out_slab)) {
+       if (!rte_bitmap_scan(bmp, &pos, &out_slab) || pos != 7) {
                printf("Failed to get slab from bitmap.\n");
                return TEST_FAILED;
        }
@@ -36,7 +36,7 @@ test_bitmap_scan_operations(struct rte_bitmap *bmp)
                return TEST_FAILED;
        }
 
-       if (!rte_bitmap_scan(bmp, &pos, &out_slab)) {
+       if (!rte_bitmap_scan(bmp, &pos, &out_slab) || pos != 67) {
                printf("Failed to get slab from bitmap.\n");
                return TEST_FAILED;
        }
@@ -47,7 +47,7 @@ test_bitmap_scan_operations(struct rte_bitmap *bmp)
        }
 
        /* Wrap around */
-       if (!rte_bitmap_scan(bmp, &pos, &out_slab)) {
+       if (!rte_bitmap_scan(bmp, &pos, &out_slab) || pos != 7) {
                printf("Failed to get slab from bitmap.\n");
                return TEST_FAILED;
        }
@@ -60,7 +60,7 @@ test_bitmap_scan_operations(struct rte_bitmap *bmp)
        /* Scan reset check. */
        __rte_bitmap_scan_init(bmp);
 
-       if (!rte_bitmap_scan(bmp, &pos, &out_slab)) {
+       if (!rte_bitmap_scan(bmp, &pos, &out_slab) || pos != 7) {
                printf("Failed to get slab from bitmap.\n");
                return TEST_FAILED;
        }
-- 
2.9.5

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