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, 8 insertions, 7 deletions

diff --git a/block/io.c b/block/io.c
index 7b6b0027bc..8817c84966 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1005,7 +1005,7 @@ static int bdrv_check_request32(int64_t offset, int64_t bytes,
 }
 
 int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
-                       int bytes, BdrvRequestFlags flags)
+                       int64_t bytes, BdrvRequestFlags flags)
 {
     return bdrv_pwritev(child, offset, bytes, NULL,
                         BDRV_REQ_ZERO_WRITE | flags);
@@ -1053,7 +1053,7 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags)
 }
 
 /* See bdrv_pwrite() for the return codes */
-int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
+int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int64_t bytes)
 {
     int ret;
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
@@ -1073,7 +1073,8 @@ int bdrv_pread(BdrvChild *child, int64_t offset, void *buf, int bytes)
   -EINVAL      Invalid offset or number of bytes
   -EACCES      Trying to write a read-only device
 */
-int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes)
+int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf,
+                int64_t bytes)
 {
     int ret;
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
@@ -1094,7 +1095,7 @@ int bdrv_pwrite(BdrvChild *child, int64_t offset, const void *buf, int bytes)
  * Returns 0 on success, -errno in error cases.
  */
 int bdrv_pwrite_sync(BdrvChild *child, int64_t offset,
-                     const void *buf, int count)
+                     const void *buf, int64_t count)
 {
     int ret;
 
@@ -1759,7 +1760,7 @@ static int bdrv_pad_request(BlockDriverState *bs,
 }
 
 int coroutine_fn bdrv_co_preadv(BdrvChild *child,
-    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+    int64_t offset, int64_t bytes, QEMUIOVector *qiov,
     BdrvRequestFlags flags)
 {
     return bdrv_co_preadv_part(child, offset, bytes, qiov, 0, flags);
@@ -2186,7 +2187,7 @@ out:
  * Handle a write request in coroutine context
  */
 int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
-    int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
+    int64_t offset, int64_t bytes, QEMUIOVector *qiov,
     BdrvRequestFlags flags)
 {
     return bdrv_co_pwritev_part(child, offset, bytes, qiov, 0, flags);
@@ -2279,7 +2280,7 @@ out:
 }
 
 int coroutine_fn bdrv_co_pwrite_zeroes(BdrvChild *child, int64_t offset,
-                                       int bytes, BdrvRequestFlags flags)
+                                       int64_t bytes, BdrvRequestFlags flags)
 {
     trace_bdrv_co_pwrite_zeroes(child->bs, offset, bytes, flags);