block: use int64_t instead of uint64_t in driver read handlers

We are generally moving to int64_t for both offset and bytes parameters
on all io paths.

Main motivation is realization of 64-bit write_zeroes operation for
fast zeroing large disk chunks, up to the whole disk.

We chose signed type, to be consistent with off_t (which is signed) and
with possibility for signed return type (where negative value means
error).

So, convert driver read handlers parameters which are already 64bit to
signed type.

While being here, convert also flags parameter to be BdrvRequestFlags.

Now let's consider all callers. Simple

  git grep '\->bdrv_\(aio\|co\)_preadv\(_part\)\?'

shows that's there three callers of driver function:

 bdrv_driver_preadv() in block/io.c, passes int64_t, checked by
   bdrv_check_qiov_request() to be non-negative.

 qcow2_load_vmstate() does bdrv_check_qiov_request().

 do_perform_cow_read() has uint64_t argument. And a lot of things in
 qcow2 driver are uint64_t, so converting it is big job. But we must
 not work with requests that don't satisfy bdrv_check_qiov_request(),
 so let's just assert it here.

Still, the functions may be called directly, not only by drv->...
Let's check:

git grep '\.bdrv_\(aio\|co\)_preadv\(_part\)\?\s*=' | \
awk '{print $4}' | sed 's/,//' | sed 's/&//' | sort | uniq | \
while read func; do git grep "$func(" | \
grep -v "$func(BlockDriverState"; done

The only one such caller:

    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, &data, 1);
    ...
    ret = bdrv_replace_test_co_preadv(bs, 0, 1, &qiov, 0);

in tests/unit/test-bdrv-drain.c, and it's OK obviously.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20210903102807.27127-4-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: fix typos]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 10 insertions, 10 deletions

diff --git a/block/raw-format.c b/block/raw-format.c
index c26f493688..a5728e7b0c 100644
--- a/block/raw-format.c
+++ b/block/raw-format.c
@@ -181,8 +181,8 @@ static void raw_reopen_abort(BDRVReopenState *state)
 }
 
 /* Check and adjust the offset, against 'offset' and 'size' options. */
-static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
-                                    uint64_t bytes, bool is_write)
+static inline int raw_adjust_offset(BlockDriverState *bs, int64_t *offset,
+                                    int64_t bytes, bool is_write)
 {
     BDRVRawState *s = bs->opaque;
 
@@ -201,9 +201,9 @@ static inline int raw_adjust_offset(BlockDriverState *bs, uint64_t *offset,
     return 0;
 }
 
-static int coroutine_fn raw_co_preadv(BlockDriverState *bs, uint64_t offset,
-                                      uint64_t bytes, QEMUIOVector *qiov,
-                                      int flags)
+static int coroutine_fn raw_co_preadv(BlockDriverState *bs, int64_t offset,
+                                      int64_t bytes, QEMUIOVector *qiov,
+                                      BdrvRequestFlags flags)
 {
     int ret;
 
@@ -259,7 +259,7 @@ static int coroutine_fn raw_co_pwritev(BlockDriverState *bs, uint64_t offset,
         qiov = &local_qiov;
     }
 
-    ret = raw_adjust_offset(bs, &offset, bytes, true);
+    ret = raw_adjust_offset(bs, (int64_t *)&offset, bytes, true);
     if (ret) {
         goto fail;
     }
@@ -294,7 +294,7 @@ static int coroutine_fn raw_co_pwrite_zeroes(BlockDriverState *bs,
 {
     int ret;
 
-    ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
+    ret = raw_adjust_offset(bs, &offset, bytes, true);
     if (ret) {
         return ret;
     }
@@ -306,7 +306,7 @@ static int coroutine_fn raw_co_pdiscard(BlockDriverState *bs,
 {
     int ret;
 
-    ret = raw_adjust_offset(bs, (uint64_t *)&offset, bytes, true);
+    ret = raw_adjust_offset(bs, &offset, bytes, true);
     if (ret) {
         return ret;
     }
@@ -541,7 +541,7 @@ static int coroutine_fn raw_co_copy_range_from(BlockDriverState *bs,
 {
     int ret;
 
-    ret = raw_adjust_offset(bs, &src_offset, bytes, false);
+    ret = raw_adjust_offset(bs, (int64_t *)&src_offset, bytes, false);
     if (ret) {
         return ret;
     }
@@ -560,7 +560,7 @@ static int coroutine_fn raw_co_copy_range_to(BlockDriverState *bs,
 {
     int ret;
 
-    ret = raw_adjust_offset(bs, &dst_offset, bytes, true);
+    ret = raw_adjust_offset(bs, (int64_t *)&dst_offset, bytes, true);
     if (ret) {
         return ret;
     }