From 476b923c32ece0e268580776aaf1fab4ab4459a8 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Thu, 23 Jun 2016 16:37:08 -0600 Subject: 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 Reviewed-by: Kevin Wolf Acked-by: Paolo Bonzini Cc: qemu-stable@nongnu.org Reviewed-by: Fam Zheng Reviewed-by: Stefan Hajnoczi Signed-off-by: Kevin Wolf --- include/block/nbd.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/block/nbd.h') diff --git a/include/block/nbd.h b/include/block/nbd.h index df1f804..eeda3eb 100644 --- a/include/block/nbd.h +++ b/include/block/nbd.h @@ -77,6 +77,8 @@ 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) + /* Maximum size of an export name. The NBD spec requires 256 and * suggests that servers support up to 4096, but we stick to only the * required size so that we can stack-allocate the names, and because -- cgit v1.1