Re: [sheepdog] [PATCH v3 02/17] block: use int64_t as bytes type in tracked requests

[Eric Blake]

On 4/30/20 6:10 AM, Vladimir Sementsov-Ogievskiy wrote:

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 tracked requests now.

Series: 64bit-block-status
Signed-off-by: Vladimir Sementsov-Ogievskiy 
Reviewed-by: Stefan Hajnoczi 
Reviewed-by: Eric Blake 
---



  static void tracked_request_begin(BdrvTrackedRequest *req,
BlockDriverState *bs,
int64_t offset,
-  uint64_t bytes,
+  int64_t bytes,
enum BdrvTrackedRequestType type)
  {
-assert(bytes <= INT64_MAX && offset <= INT64_MAX - bytes);
+assert(offset >= 0 && bytes >= 0 &&
+   bytes <= INT64_MAX && offset <= INT64_MAX - bytes);


'bytes <= INT64_MAX' was previously a real runtime check, but is now a 
tautology and therefore a dead branch; a picky compiler might complain. 
This assert could be compressed to:


assert(offset >= 0 && (uint64_t) bytes <= INT64_MAX - offset);

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.   +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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[sheepdog] [PATCH v3 02/17] block: use int64_t as bytes type in tracked requests

[Vladimir Sementsov-Ogievskiy]

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 tracked requests now.

Series: 64bit-block-status
Signed-off-by: Vladimir Sementsov-Ogievskiy 
Reviewed-by: Stefan Hajnoczi 
Reviewed-by: Eric Blake 
---
 include/block/block_int.h |  4 ++--
 block/io.c| 11 ++-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/block/block_int.h b/include/block/block_int.h
index 4c3587ea19..c8daba608b 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -70,12 +70,12 @@ enum BdrvTrackedRequestType {
 typedef struct BdrvTrackedRequest {
 BlockDriverState *bs;
 int64_t offset;
-uint64_t bytes;
+int64_t bytes;
 enum BdrvTrackedRequestType type;
 
 bool serialising;
 int64_t overlap_offset;
-uint64_t overlap_bytes;
+int64_t overlap_bytes;
 
 QLIST_ENTRY(BdrvTrackedRequest) list;
 Coroutine *co; /* owner, used for deadlock detection */
diff --git a/block/io.c b/block/io.c
index cd5374e6c7..20ebf3c536 100644
--- a/block/io.c
+++ b/block/io.c
@@ -692,10 +692,11 @@ static void tracked_request_end(BdrvTrackedRequest *req)
 static void tracked_request_begin(BdrvTrackedRequest *req,
   BlockDriverState *bs,
   int64_t offset,
-  uint64_t bytes,
+  int64_t bytes,
   enum BdrvTrackedRequestType type)
 {
-assert(bytes <= INT64_MAX && offset <= INT64_MAX - bytes);
+assert(offset >= 0 && bytes >= 0 &&
+   bytes <= INT64_MAX && offset <= INT64_MAX - bytes);
 
 *req = (BdrvTrackedRequest){
 .bs = bs,
@@ -716,7 +717,7 @@ static void tracked_request_begin(BdrvTrackedRequest *req,
 }
 
 static bool tracked_request_overlaps(BdrvTrackedRequest *req,
- int64_t offset, uint64_t bytes)
+ int64_t offset, int64_t bytes)
 {
 /*    */
 if (offset >= req->overlap_offset + req->overlap_bytes) {
@@ -773,8 +774,8 @@ bool bdrv_mark_request_serialising(BdrvTrackedRequest *req, 
uint64_t align)
 {
 BlockDriverState *bs = req->bs;
 int64_t overlap_offset = req->offset & ~(align - 1);
-uint64_t overlap_bytes = ROUND_UP(req->offset + req->bytes, align)
-   - overlap_offset;
+int64_t overlap_bytes =
+ROUND_UP(req->offset + req->bytes, align) - overlap_offset;
 bool waited;
 
 qemu_co_mutex_lock(>reqs_lock);
-- 
2.21.0

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