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block/io: support int64_t bytes in bdrv_co_p{read,write}v_part()

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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, prepare bdrv_co_preadv_part() and bdrv_co_pwritev_part() and their
remaining dependencies now.

bdrv_pad_request() is updated simultaneously, as pointer to bytes passed
to it both from bdrv_co_pwritev_part() and bdrv_co_preadv_part().

So, all callers of bdrv_pad_request() are updated to pass 64bit bytes.
bdrv_pad_request() is already good for 64bit requests, add
corresponding assertion.

Look at bdrv_co_preadv_part() and bdrv_co_pwritev_part().
Type is widening, so callers are safe. Let's look inside the functions.

In bdrv_co_preadv_part() and bdrv_aligned_pwritev() we only pass bytes
to other already int64_t interfaces (and some obviously safe
calculations), it's OK.

In bdrv_co_do_zero_pwritev() aligned_bytes may become large now, still
it's passed to bdrv_aligned_pwritev which supports int64_t bytes.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-Id: <20201211183934.169161-15-vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2020-12-11 21:39:32 +03:00 • committed by Eric Blake
parent 8b0c5d7659
commit 37e9403ea8
3 changed files with 12 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

4
include/block/block_int.h
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@ -1035,13 +1035,13 @@ int coroutine_fn bdrv_co_preadv(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
int64_t offset, unsigned int bytes,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
BdrvRequestFlags flags);
int coroutine_fn bdrv_co_pwritev_part(BdrvChild *child,
int64_t offset, unsigned int bytes,
int64_t offset, int64_t bytes,
QEMUIOVector *qiov, size_t qiov_offset, BdrvRequestFlags flags);
static inline int coroutine_fn bdrv_co_pread(BdrvChild *child,