[PULL 20/35] block: Add blk_[co_]preadv_part()

[Hanna Reitz]

From: Alberto Faria <afaria@redhat.com>

Implement blk_preadv_part() using generated_co_wrapper.

Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-9-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
---
 block/coroutines.h                |  5 -----
 include/sysemu/block-backend-io.h |  7 +++++++
 block/block-backend.c             | 30 +++++++++++++++++++++++-------
 tests/unit/test-block-iothread.c  | 19 +++++++++++++++++++
 4 files changed, 49 insertions(+), 12 deletions(-)

diff --git a/block/coroutines.h b/block/coroutines.h
index 443ef2f2e6..85423f8db6 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -63,11 +63,6 @@ nbd_co_do_establish_connection(BlockDriverState *bs, bool 
blocking,
                                Error **errp);
 
 
-int coroutine_fn
-blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
-                 QEMUIOVector *qiov, BdrvRequestFlags flags);
-
-
 int coroutine_fn
 blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
                        QEMUIOVector *qiov, size_t qiov_offset,
diff --git a/include/sysemu/block-backend-io.h 
b/include/sysemu/block-backend-io.h
index cbf4422ea1..877274a999 100644
--- a/include/sysemu/block-backend-io.h
+++ b/include/sysemu/block-backend-io.h
@@ -107,6 +107,13 @@ int generated_co_wrapper blk_pread(BlockBackend *blk, 
int64_t offset,
 int generated_co_wrapper blk_pwrite(BlockBackend *blk, int64_t offset,
                                     int64_t bytes, const void *buf,
                                     BdrvRequestFlags flags);
+int generated_co_wrapper blk_preadv_part(BlockBackend *blk, int64_t offset,
+                                         int64_t bytes, QEMUIOVector *qiov,
+                                         size_t qiov_offset,
+                                         BdrvRequestFlags flags);
+int coroutine_fn blk_co_preadv_part(BlockBackend *blk, int64_t offset,
+                                    int64_t bytes, QEMUIOVector *qiov,
+                                    size_t qiov_offset, BdrvRequestFlags 
flags);
 int generated_co_wrapper blk_preadv(BlockBackend *blk, int64_t offset,
                                     int64_t bytes, QEMUIOVector *qiov,
                                     BdrvRequestFlags flags);
diff --git a/block/block-backend.c b/block/block-backend.c
index 4d6c18bc39..49db3f63fb 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1280,9 +1280,10 @@ static void coroutine_fn 
blk_wait_while_drained(BlockBackend *blk)
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-int coroutine_fn
-blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
-                 QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn
+blk_co_do_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes,
+                      QEMUIOVector *qiov, size_t qiov_offset,
+                      BdrvRequestFlags flags)
 {
     int ret;
     BlockDriverState *bs;
@@ -1307,7 +1308,8 @@ blk_co_do_preadv(BlockBackend *blk, int64_t offset, 
int64_t bytes,
                 bytes, false);
     }
 
-    ret = bdrv_co_preadv(blk->root, offset, bytes, qiov, flags);
+    ret = bdrv_co_preadv_part(blk->root, offset, bytes, qiov, qiov_offset,
+                              flags);
     bdrv_dec_in_flight(bs);
     return ret;
 }
@@ -1320,7 +1322,21 @@ int coroutine_fn blk_co_preadv(BlockBackend *blk, 
int64_t offset,
     IO_OR_GS_CODE();
 
     blk_inc_in_flight(blk);
-    ret = blk_co_do_preadv(blk, offset, bytes, qiov, flags);
+    ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, 0, flags);
+    blk_dec_in_flight(blk);
+
+    return ret;
+}
+
+int coroutine_fn blk_co_preadv_part(BlockBackend *blk, int64_t offset,
+                                    int64_t bytes, QEMUIOVector *qiov,
+                                    size_t qiov_offset, BdrvRequestFlags flags)
+{
+    int ret;
+    IO_OR_GS_CODE();
+
+    blk_inc_in_flight(blk);
+    ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, qiov_offset, flags);
     blk_dec_in_flight(blk);
 
     return ret;
@@ -1537,8 +1553,8 @@ static void blk_aio_read_entry(void *opaque)
     QEMUIOVector *qiov = rwco->iobuf;
 
     assert(qiov->size == acb->bytes);
-    rwco->ret = blk_co_do_preadv(rwco->blk, rwco->offset, acb->bytes,
-                                 qiov, rwco->flags);
+    rwco->ret = blk_co_do_preadv_part(rwco->blk, rwco->offset, acb->bytes, 
qiov,
+                                      0, rwco->flags);
     blk_aio_complete(acb);
 }
 
diff --git a/tests/unit/test-block-iothread.c b/tests/unit/test-block-iothread.c
index b9c5da3a87..2fa1248445 100644
--- a/tests/unit/test-block-iothread.c
+++ b/tests/unit/test-block-iothread.c
@@ -168,6 +168,21 @@ static void test_sync_op_blk_pwritev(BlockBackend *blk)
     g_assert_cmpint(ret, ==, -EIO);
 }
 
+static void test_sync_op_blk_preadv_part(BlockBackend *blk)
+{
+    uint8_t buf[512];
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, sizeof(buf));
+    int ret;
+
+    /* Success */
+    ret = blk_preadv_part(blk, 0, sizeof(buf), &qiov, 0, 0);
+    g_assert_cmpint(ret, ==, 0);
+
+    /* Early error: Negative offset */
+    ret = blk_preadv_part(blk, -2, sizeof(buf), &qiov, 0, 0);
+    g_assert_cmpint(ret, ==, -EIO);
+}
+
 static void test_sync_op_load_vmstate(BdrvChild *c)
 {
     uint8_t buf[512];
@@ -339,6 +354,10 @@ const SyncOpTest sync_op_tests[] = {
         .name   = "/sync-op/pwritev",
         .fn     = NULL,
         .blkfn  = test_sync_op_blk_pwritev,
+    }, {
+        .name   = "/sync-op/preadv_part",
+        .fn     = NULL,
+        .blkfn  = test_sync_op_blk_preadv_part,
     }, {
         .name   = "/sync-op/load_vmstate",
         .fn     = test_sync_op_load_vmstate,
-- 
2.35.3