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| author | Eric Blake <eblake@redhat.com> | 2016-06-23 16:37:12 -0600 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2016-07-05 16:46:25 +0200 |
| commit | 24ce9a20260713e86377cfa78fb8699335759f4f (patch) | |
| tree | 9896792aec32b6b6153778828641071f8e1c238d /block | |
| parent | efaf4781a995aacd22b1dd521b14e4644bafae14 (diff) | |
| download | qemu-24ce9a20260713e86377cfa78fb8699335759f4f.tar.gz qemu-24ce9a20260713e86377cfa78fb8699335759f4f.tar.bz2 qemu-24ce9a20260713e86377cfa78fb8699335759f4f.zip | |
block: Give nonzero result to blk_get_max_transfer_length()
Making all callers special-case 0 as unlimited is awkward,
and we DO have a hard maximum of BDRV_REQUEST_MAX_SECTORS given
our current block layer API limits.
In the case of scsi, this means that we now always advertise a
limit to the guest, even in cases where the underlying layers
previously use 0 for no inherent limit beyond the block layer.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/block-backend.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/block/block-backend.c b/block/block-backend.c index 34500e6080..1fb070b4e4 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1303,15 +1303,16 @@ int blk_get_flags(BlockBackend *blk) } } +/* Returns the maximum transfer length, in sectors; guaranteed nonzero */ int blk_get_max_transfer_length(BlockBackend *blk) { BlockDriverState *bs = blk_bs(blk); + int max = 0; if (bs) { - return bs->bl.max_transfer_length; - } else { - return 0; + max = bs->bl.max_transfer_length; } + return MIN_NON_ZERO(max, BDRV_REQUEST_MAX_SECTORS); } int blk_get_max_iov(BlockBackend *blk) |