From 01ef8185b809af9d287e1a03a3f9d8ea8231118a Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 14 Apr 2021 19:51:48 +0200 Subject: scsi-generic: pass max_segments via max_iov field in BlockLimits I/O to a disk via read/write is not limited by the number of segments allowed by the host adapter; the kernel can split requests if needed, and the limit imposed by the host adapter can be very low (256k or so) to avoid that SG_IO returns EINVAL if memory is heavily fragmented. Since this value is only interesting for SG_IO-based I/O, do not include it in the max_transfer and only take it into account when patching the block limits VPD page in the scsi-generic device. Signed-off-by: Paolo Bonzini Reviewed-by: Max Reitz --- block/file-posix.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'block/file-posix.c') diff --git a/block/file-posix.c b/block/file-posix.c index b8dc19ce1a..6db690baf2 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -1237,8 +1237,7 @@ static void raw_refresh_limits(BlockDriverState *bs, Error **errp) ret = sg_get_max_segments(s->fd); if (ret > 0) { - bs->bl.max_transfer = MIN(bs->bl.max_transfer, - ret * qemu_real_host_page_size); + bs->bl.max_iov = ret; } } -- cgit v1.2.3