[PULL 11/15] block-backend: convert blk_aio_ functions to int64_t bytes paramter

[Eric Blake <eblake@redhat.com>]

From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

1. Convert bytes in BlkAioEmAIOCB:
  aio->bytes is only passed to already int64_t interfaces, and set in
  blk_aio_prwv, which is updated here.

2. For all updated functions the parameter type becomes wider so callers
   are safe.

3. In blk_aio_prwv we only store bytes to BlkAioEmAIOCB, which is
   updated here.

4. Other updated functions are wrappers on blk_aio_prwv.

Note that blk_aio_preadv and blk_aio_pwritev become safer: before this
commit, it's theoretically possible to pass qiov with size exceeding
INT_MAX, which than converted to int argument of blk_aio_prwv. Now it's
converted to int64_t which is a lot better. Still add assertions.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20211006131718.214235-11-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
[eblake: tweak assertion and grammar]
Signed-off-by: Eric Blake <eblake@redhat.com>
---
 include/sysemu/block-backend.h |  4 ++--
 block/block-backend.c          | 13 ++++++++-----
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index 9ccf9f1a8025..b5409a6b4553 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -157,7 +157,7 @@ static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
 int blk_pwrite_zeroes(BlockBackend *blk, int64_t offset,
                       int64_t bytes, BdrvRequestFlags flags);
 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                  int bytes, BdrvRequestFlags flags,
+                                  int64_t bytes, BdrvRequestFlags flags,
                                   BlockCompletionFunc *cb, void *opaque);
 int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags);
 int blk_pread(BlockBackend *blk, int64_t offset, void *buf, int bytes);
@@ -174,7 +174,7 @@ BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
                             BlockCompletionFunc *cb, void *opaque);
 BlockAIOCB *blk_aio_flush(BlockBackend *blk,
                           BlockCompletionFunc *cb, void *opaque);
-BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int bytes,
+BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes,
                              BlockCompletionFunc *cb, void *opaque);
 void blk_aio_cancel(BlockAIOCB *acb);
 void blk_aio_cancel_async(BlockAIOCB *acb);
diff --git a/block/block-backend.c b/block/block-backend.c
index 0746be89842b..c889d0f97c45 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1380,7 +1380,7 @@ BlockAIOCB *blk_abort_aio_request(BlockBackend *blk,
 typedef struct BlkAioEmAIOCB {
     BlockAIOCB common;
     BlkRwCo rwco;
-    int bytes;
+    int64_t bytes;
     bool has_returned;
 } BlkAioEmAIOCB;

@@ -1412,7 +1412,8 @@ static void blk_aio_complete_bh(void *opaque)
     blk_aio_complete(acb);
 }

-static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset, int bytes,
+static BlockAIOCB *blk_aio_prwv(BlockBackend *blk, int64_t offset,
+                                int64_t bytes,
                                 void *iobuf, CoroutineEntry co_entry,
                                 BdrvRequestFlags flags,
                                 BlockCompletionFunc *cb, void *opaque)
@@ -1469,10 +1470,10 @@ static void blk_aio_write_entry(void *opaque)
 }

 BlockAIOCB *blk_aio_pwrite_zeroes(BlockBackend *blk, int64_t offset,
-                                  int count, BdrvRequestFlags flags,
+                                  int64_t bytes, BdrvRequestFlags flags,
                                   BlockCompletionFunc *cb, void *opaque)
 {
-    return blk_aio_prwv(blk, offset, count, NULL, blk_aio_write_entry,
+    return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_write_entry,
                         flags | BDRV_REQ_ZERO_WRITE, cb, opaque);
 }

@@ -1530,6 +1531,7 @@ BlockAIOCB *blk_aio_preadv(BlockBackend *blk, int64_t offset,
                            QEMUIOVector *qiov, BdrvRequestFlags flags,
                            BlockCompletionFunc *cb, void *opaque)
 {
+    assert((uint64_t)qiov->size <= INT64_MAX);
     return blk_aio_prwv(blk, offset, qiov->size, qiov,
                         blk_aio_read_entry, flags, cb, opaque);
 }
@@ -1538,6 +1540,7 @@ BlockAIOCB *blk_aio_pwritev(BlockBackend *blk, int64_t offset,
                             QEMUIOVector *qiov, BdrvRequestFlags flags,
                             BlockCompletionFunc *cb, void *opaque)
 {
+    assert(qiov->size <= INT64_MAX);
     return blk_aio_prwv(blk, offset, qiov->size, qiov,
                         blk_aio_write_entry, flags, cb, opaque);
 }
@@ -1618,7 +1621,7 @@ static void blk_aio_pdiscard_entry(void *opaque)
 }

 BlockAIOCB *blk_aio_pdiscard(BlockBackend *blk,
-                             int64_t offset, int bytes,
+                             int64_t offset, int64_t bytes,
                              BlockCompletionFunc *cb, void *opaque)
 {
     return blk_aio_prwv(blk, offset, bytes, NULL, blk_aio_pdiscard_entry, 0,
-- 
2.31.1