block/io: support int64_t bytes in read/write wrappers

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).

Now, since bdrv_co_preadv_part() and bdrv_co_pwritev_part() have been
updated, update all their wrappers.

For all of them type of 'bytes' is widening, so callers are safe. We
have update request_fn in blkverify.c simultaneously. Still it's just a
pointer to one of bdrv_co_pwritev() or bdrv_co_preadv(), and type is
widening for callers of the request_fn anyway.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-16-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: grammar tweak]
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 6 insertions, 5 deletions

diff --git a/include/block/block.h b/include/block/block.h
index 81fcaad5ac..5f28d0d33f 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -392,12 +392,13 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state,
 void bdrv_reopen_commit(BDRVReopenState *reopen_state);
 void bdrv_reopen_abort(BDRVReopenState *reopen_state);
 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
-                       int bytes, BdrvRequestFlags flags);
+                       int64_t bytes, BdrvRequestFlags flags);
 int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
-int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes);
-int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes);
+int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int64_t bytes);
+int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf,
+                int64_t bytes);
 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
-                     const void *buf, int count);
+                     const void *buf, int64_t bytes);
 /*
  * Efficiently zero a region of the disk image.  Note that this is a regular
  * I/O request like read or write and should have a reasonable size.  This
@@ -405,7 +406,7 @@ int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
  * because it may allocate memory for the entire region.
  */
 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
-                                       int bytes, BdrvRequestFlags flags);
+                                       int64_t bytes, BdrvRequestFlags flags);
 BlockDriverState *bdrv_find_backing_image(BlockDriverState *bs,
     const char *backing_file);
 void bdrv_refresh_filename(BlockDriverState *bs);