From 300ff68e30f51846d0a226ee33a5878364303158 Mon Sep 17 00:00:00 2001

From: John Snow <jsnow@redhat.com>

Date: Wed, 6 Feb 2019 22:12:23 +0100

Subject: [PATCH 13/33] hbitmap: Add @advance param to hbitmap_iter_next()

RH-Author: John Snow <jsnow@redhat.com>

Message-id: <20190206221243.7407-4-jsnow@redhat.com>

Patchwork-id: 84260

O-Subject: [RHEL-7.7 qemu-kvm-rhev PATCH v2 03/23] hbitmap: Add @advance param to hbitmap_iter_next()

Bugzilla: 1658343

RH-Acked-by: Thomas Huth <thuth@redhat.com>

RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

From: Max Reitz <mreitz@redhat.com>

This new parameter allows the caller to just query the next dirty

position without moving the iterator.

Signed-off-by: Max Reitz <mreitz@redhat.com>

Reviewed-by: Fam Zheng <famz@redhat.com>

Reviewed-by: John Snow <jsnow@redhat.com>

Message-id: 20180613181823.13618-8-mreitz@redhat.com

Signed-off-by: Max Reitz <mreitz@redhat.com>

(cherry picked from commit a33fbb4f8b64226becf502a123733776ce319b24)

Signed-off-by: John Snow <jsnow@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>

---

 block/backup.c         |  2 +-

 block/dirty-bitmap.c   |  2 +-

 include/qemu/hbitmap.h |  5 ++++-

 tests/test-hbitmap.c   | 26 +++++++++++++-------------

 util/hbitmap.c         | 10 +++++++---

 5 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/block/backup.c b/block/backup.c

index 524e0ff..ac17db6 100644

--- a/block/backup.c

+++ b/block/backup.c

@@ -409,7 +409,7 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job)

     HBitmapIter hbi;

     hbitmap_iter_init(&hbi, job->copy_bitmap, 0);

-    while ((cluster = hbitmap_iter_next(&hbi)) != -1) {

+    while ((cluster = hbitmap_iter_next(&hbi, true)) != -1) {

         do {

             if (yield_and_check(job)) {

                 return 0;

diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c

index cd39afd..f4a4cb7 100644

--- a/block/dirty-bitmap.c

+++ b/block/dirty-bitmap.c

@@ -525,7 +525,7 @@ void bdrv_dirty_iter_free(BdrvDirtyBitmapIter *iter)

 int64_t bdrv_dirty_iter_next(BdrvDirtyBitmapIter *iter)

 {

-    return hbitmap_iter_next(&iter->hbi);

+    return hbitmap_iter_next(&iter->hbi, true);

 }

 /* Called within bdrv_dirty_bitmap_lock..unlock */

diff --git a/include/qemu/hbitmap.h b/include/qemu/hbitmap.h

index 6b6490e..ddca52c 100644

--- a/include/qemu/hbitmap.h

+++ b/include/qemu/hbitmap.h

@@ -324,11 +324,14 @@ void hbitmap_free_meta(HBitmap *hb);

 /**

  * hbitmap_iter_next:

  * @hbi: HBitmapIter to operate on.

+ * @advance: If true, advance the iterator.  Otherwise, the next call

+ *           of this function will return the same result (if that

+ *           position is still dirty).

  *

  * Return the next bit that is set in @hbi's associated HBitmap,

  * or -1 if all remaining bits are zero.

  */

-int64_t hbitmap_iter_next(HBitmapIter *hbi);

+int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance);

 /**

  * hbitmap_iter_next_word:

diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c

index f29631f..f2158f7 100644

--- a/tests/test-hbitmap.c

+++ b/tests/test-hbitmap.c

@@ -46,7 +46,7 @@ static void hbitmap_test_check(TestHBitmapData *data,

     i = first;

     for (;;) {

-        next = hbitmap_iter_next(&hbi;;

+        next = hbitmap_iter_next(&hbi, true);

         if (next < 0) {

             next = data->size;

         }

@@ -435,25 +435,25 @@ static void test_hbitmap_iter_granularity(TestHBitmapData *data,

     /* Note that hbitmap_test_check has to be invoked manually in this test.  */

     hbitmap_test_init(data, 131072 << 7, 7);

     hbitmap_iter_init(&hbi, data->hb, 0);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);

     hbitmap_test_set(data, ((L2 + L1 + 1) << 7) + 8, 8);

     hbitmap_iter_init(&hbi, data->hb, 0);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);

     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);

     hbitmap_test_set(data, (131072 << 7) - 8, 8);

     hbitmap_iter_init(&hbi, data->hb, 0);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, (L2 + L1 + 1) << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, (L2 + L1 + 1) << 7);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);

     hbitmap_iter_init(&hbi, data->hb, (L2 + L1 + 2) << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), ==, 131071 << 7);

-    g_assert_cmpint(hbitmap_iter_next(&hbi), <, 0);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), ==, 131071 << 7);

+    g_assert_cmpint(hbitmap_iter_next(&hbi, true), <, 0);

 }

 static void hbitmap_test_set_boundary_bits(TestHBitmapData *data, ssize_t diff)

@@ -893,7 +893,7 @@ static void test_hbitmap_serialize_zeroes(TestHBitmapData *data,

     for (i = 0; i < num_positions; i++) {

         hbitmap_deserialize_zeroes(data->hb, positions[i], min_l1, true);

         hbitmap_iter_init(&iter, data->hb, 0);

-        next = hbitmap_iter_next(&iter);

+        next = hbitmap_iter_next(&iter, true);

         if (i == num_positions - 1) {

             g_assert_cmpint(next, ==, -1);

         } else {

@@ -919,10 +919,10 @@ static void test_hbitmap_iter_and_reset(TestHBitmapData *data,

     hbitmap_iter_init(&hbi, data->hb, BITS_PER_LONG - 1);

-    hbitmap_iter_next(&hbi;;

+    hbitmap_iter_next(&hbi, true);

     hbitmap_reset_all(data->hb);

-    hbitmap_iter_next(&hbi;;

+    hbitmap_iter_next(&hbi, true);

 }

 static void test_hbitmap_next_zero_check(TestHBitmapData *data, int64_t start)

diff --git a/util/hbitmap.c b/util/hbitmap.c

index 58a2c93..bcd3040 100644

--- a/util/hbitmap.c

+++ b/util/hbitmap.c

@@ -141,7 +141,7 @@ unsigned long hbitmap_iter_skip_words(HBitmapIter *hbi)

     return cur;

 }

-int64_t hbitmap_iter_next(HBitmapIter *hbi)

+int64_t hbitmap_iter_next(HBitmapIter *hbi, bool advance)

 {

     unsigned long cur = hbi->cur[HBITMAP_LEVELS - 1] &

             hbi->hb->levels[HBITMAP_LEVELS - 1][hbi->pos];

@@ -154,8 +154,12 @@ int64_t hbitmap_iter_next(HBitmapIter *hbi)

         }

     }

-    /* The next call will resume work from the next bit.  */

-    hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);

+    if (advance) {

+        /* The next call will resume work from the next bit.  */

+        hbi->cur[HBITMAP_LEVELS - 1] = cur & (cur - 1);

+    } else {

+        hbi->cur[HBITMAP_LEVELS - 1] = cur;

+    }

     item = ((uint64_t)hbi->pos << BITS_PER_LEVEL) + ctzl(cur);

     return item << hbi->granularity;

-- 

1.8.3.1