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authorPaolo Bonzini <pbonzini@redhat.com>2021-04-14 19:51:48 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2021-06-25 10:54:12 +0200
commit01ef8185b809af9d287e1a03a3f9d8ea8231118a (patch)
tree3310b456ff028325cfe6b5e7bb286ab1c57ecc68 /block
parent8ad5ab6148dca8aad297c134c09c84b0b92d45ed (diff)
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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 <pbonzini@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/file-posix.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/block/file-posix.c b/block/file-posix.c
index b8dc19c..6db690b 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;
}
}