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| author | Eric Blake <eblake@redhat.com> | 2016-06-23 16:37:08 -0600 |
|---|---|---|
| committer | Michael Roth <mdroth@linux.vnet.ibm.com> | 2016-08-05 14:34:45 -0500 |
| commit | ab2aac59e8cc7172800864a28f2386d780a08016 (patch) | |
| tree | 59740130fcec47229a7eb2f121953685c508b6a9 | |
| parent | e19b9ad27ca65bbb8743fda22e4815dfa311f4e2 (diff) | |
| download | qemu-ab2aac59e8cc7172800864a28f2386d780a08016.tar.gz | |
nbd: Allow larger requests
The NBD layer was breaking up request at a limit of 2040 sectors
(just under 1M) to cater to old qemu-nbd. But the server limit
was raised to 32M in commit 2d8214885 to match the kernel, more
than three years ago; and the upstream NBD Protocol is proposing
documentation that without any explicit communication to state
otherwise, a client should be able to safely assume that a 32M
transaction will work. It is time to rely on the larger sizing,
and any downstream distro that cares about maximum
interoperability to older qemu-nbd servers can just tweak the
value of #define NBD_MAX_SECTORS.
Signed-off-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
(cherry picked from commit 476b923c32ece0e268580776aaf1fab4ab4459a8)
Conflicts:
include/block/nbd.h
* removed context dependency on 943cec86
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
| -rw-r--r-- | block/nbd-client.c | 4 | ||||
| -rw-r--r-- | include/block/nbd.h | 1 |
2 files changed, 1 insertions, 4 deletions
diff --git a/block/nbd-client.c b/block/nbd-client.c index 878e879ace..6f6df468fa 100644 --- a/block/nbd-client.c +++ b/block/nbd-client.c @@ -269,10 +269,6 @@ static int nbd_co_writev_1(BlockDriverState *bs, int64_t sector_num, return -reply.error; } -/* qemu-nbd has a limit of slightly less than 1M per request. Try to - * remain aligned to 4K. */ -#define NBD_MAX_SECTORS 2040 - int nbd_client_co_readv(BlockDriverState *bs, int64_t sector_num, int nb_sectors, QEMUIOVector *qiov) { diff --git a/include/block/nbd.h b/include/block/nbd.h index b86a976984..36dde24e51 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -76,6 +76,7 @@ enum { /* Maximum size of a single READ/WRITE data buffer */ #define NBD_MAX_BUFFER_SIZE (32 * 1024 * 1024) +#define NBD_MAX_SECTORS (NBD_MAX_BUFFER_SIZE / BDRV_SECTOR_SIZE) ssize_t nbd_wr_syncv(QIOChannel *ioc, struct iovec *iov, |