diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2015-07-09 10:56:44 +0100 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2015-12-22 16:01:07 +0800 |
| commit | bd44feb754bdb1354f9813ca5dfe883f3d058193 (patch) | |
| tree | 4a827ef93d32907b0bd9fdd3ff1cb4dcbb89bc3e /block/io.c | |
| parent | 49cffbc6079c27432b4635d5d03ce14a249d86e2 (diff) | |
block: add BlockLimits.max_iov field
The maximum number of struct iovec elements depends on the
BlockDriverState. The raw-posix and iSCSI protocols have a maximum of
IOV_MAX but others could have different values.
Cc: Peter Lieven <pl@kamp.de>
Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/io.c')
| -rw-r--r-- | block/io.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/block/io.c b/block/io.c index 841f5b503f..42050a0598 100644 --- a/block/io.c +++ b/block/io.c @@ -166,9 +166,13 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) bs->bl.max_transfer_length = bs->file->bs->bl.max_transfer_length; bs->bl.min_mem_alignment = bs->file->bs->bl.min_mem_alignment; bs->bl.opt_mem_alignment = bs->file->bs->bl.opt_mem_alignment; + bs->bl.max_iov = bs->file->bs->bl.max_iov; } else { bs->bl.min_mem_alignment = 512; bs->bl.opt_mem_alignment = getpagesize(); + + /* Safe default since most protocols use readv()/writev()/etc */ + bs->bl.max_iov = IOV_MAX; } if (bs->backing) { @@ -189,6 +193,9 @@ void bdrv_refresh_limits(BlockDriverState *bs, Error **errp) bs->bl.min_mem_alignment = MAX(bs->bl.min_mem_alignment, bs->backing->bs->bl.min_mem_alignment); + bs->bl.max_iov = + MIN(bs->bl.max_iov, + bs->backing->bs->bl.max_iov); } /* Then let the driver override it */ |