[PATCH 14/12] block-backend: update blk_co_pwrite() and blk_co_pread() wrappers

Vladimir Sementsov-Ogievskiy posted 12 patches 4 years, 4 months ago
Maintainers: Cleber Rosa <crosa@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Hanna Reitz <hreitz@redhat.com>, Eduardo Habkost <ehabkost@redhat.com>
[PATCH 14/12] block-backend: update blk_co_pwrite() and blk_co_pread() wrappers
Posted by Vladimir Sementsov-Ogievskiy 4 years, 4 months ago
Make bytes argument int64_t to be consistent with modern block-layer.
Callers should be OK with it as type becomes wider.

What is inside functions?

- Conversion from int64_t to size_t. Still, we
can't have a buffer larger than SIZE_MAX, therefore bytes should not be
larger than SIZE_MAX as well. Add and assertion.

- Passing to blk_co_pwritev() / blk_co_preadv() which already has
  int64_t bytes argument.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 include/sysemu/block-backend.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/include/sysemu/block-backend.h b/include/sysemu/block-backend.h
index f3227098fc..53c9b3271b 100644
--- a/include/sysemu/block-backend.h
+++ b/include/sysemu/block-backend.h
@@ -137,20 +137,24 @@ int coroutine_fn blk_co_pwritev(BlockBackend *blk, int64_t offset,
                                BdrvRequestFlags flags);
 
 static inline int coroutine_fn blk_co_pread(BlockBackend *blk, int64_t offset,
-                                            unsigned int bytes, void *buf,
+                                            int64_t bytes, void *buf,
                                             BdrvRequestFlags flags)
 {
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
 
+    assert(bytes <= SIZE_MAX);
+
     return blk_co_preadv(blk, offset, bytes, &qiov, flags);
 }
 
 static inline int coroutine_fn blk_co_pwrite(BlockBackend *blk, int64_t offset,
-                                             unsigned int bytes, void *buf,
+                                             int64_t bytes, void *buf,
                                              BdrvRequestFlags flags)
 {
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
 
+    assert(bytes <= SIZE_MAX);
+
     return blk_co_pwritev(blk, offset, bytes, &qiov, flags);
 }
 
-- 
2.31.1


Re: [PATCH 14/12] block-backend: update blk_co_pwrite() and blk_co_pread() wrappers
Posted by Eric Blake 4 years, 4 months ago
On Thu, Oct 07, 2021 at 07:52:43PM +0200, Vladimir Sementsov-Ogievskiy wrote:
> Make bytes argument int64_t to be consistent with modern block-layer.
> Callers should be OK with it as type becomes wider.
> 
> What is inside functions?
> 
> - Conversion from int64_t to size_t. Still, we
> can't have a buffer larger than SIZE_MAX, therefore bytes should not be
> larger than SIZE_MAX as well. Add and assertion.

s/and/an/

> 
> - Passing to blk_co_pwritev() / blk_co_preadv() which already has
>   int64_t bytes argument.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  include/sysemu/block-backend.h | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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