[PATCH v2 1/3] block: Add bdrv_co_get_lba_status

[Lin Ma <lma@suse.com>]

The get lba status wrapper based on the bdrv_block_status. The following
patches will add GET LBA STATUS 16 support for scsi emulation layer.

Signed-off-by: Lin Ma <lma@suse.com>
---
 block/io.c                | 43 +++++++++++++++++++++++++++++++++++++++
 include/block/block_int.h |  5 +++++
 2 files changed, 48 insertions(+)

diff --git a/block/io.c b/block/io.c
index df8f2a98d4..2064016b19 100644
--- a/block/io.c
+++ b/block/io.c
@@ -2208,6 +2208,49 @@ int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
                            BDRV_REQ_ZERO_WRITE | flags);
 }
 
+int coroutine_fn
+bdrv_co_get_lba_status(BdrvChild *child, int64_t offset, int64_t bytes,
+                       uint32_t *num_blocks, uint32_t *is_deallocated)
+{
+    BlockDriverState *bs = child->bs;
+    int ret = 0;
+    int64_t target_size, count = 0;
+    bool first = true;
+    uint8_t wanted_bit1 = 0;
+
+    target_size = bdrv_getlength(bs);
+    if (target_size < 0) {
+        return -EIO;
+    }
+
+    if (offset < 0 || bytes < 0) {
+        return -EIO;
+    }
+
+    for ( ; offset <= target_size - bytes; offset += count) {
+        ret = bdrv_block_status(bs, offset, bytes, &count, NULL, NULL);
+        if (ret < 0) {
+            goto out;
+        }
+        if (first) {
+            if (ret & BDRV_BLOCK_ZERO) {
+                wanted_bit1 = BDRV_BLOCK_ZERO >> 1;
+                *is_deallocated = 1;
+            } else {
+                wanted_bit1 = 0;
+            }
+            first = false;
+        }
+        if ((ret & BDRV_BLOCK_ZERO) >> 1 == wanted_bit1) {
+            (*num_blocks)++;
+        } else {
+            break;
+        }
+    }
+out:
+    return ret;
+}
+
 /*
  * Flush ALL BDSes regardless of if they are reachable via a BlkBackend or not.
  */
diff --git a/include/block/block_int.h b/include/block/block_int.h
index 791de6a59c..43f90591b9 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -1296,6 +1296,11 @@ int coroutine_fn bdrv_co_block_status_from_backing(BlockDriverState *bs,
                                                    int64_t *pnum,
                                                    int64_t *map,
                                                    BlockDriverState **file);
+int coroutine_fn bdrv_co_get_lba_status(BdrvChild *child,
+                                        int64_t offset,
+                                        int64_t bytes,
+                                        uint32_t *num_blocks,
+                                        uint32_t *is_deallocated);
 const char *bdrv_get_parent_name(const BlockDriverState *bs);
 void blk_dev_change_media_cb(BlockBackend *blk, bool load, Error **errp);
 bool blk_dev_has_removable_media(BlockBackend *blk);
-- 
2.26.0