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Diffstat (limited to 'qemu/hw/block/xen_blkif.h')
-rw-r--r--qemu/hw/block/xen_blkif.h12
1 files changed, 8 insertions, 4 deletions
diff --git a/qemu/hw/block/xen_blkif.h b/qemu/hw/block/xen_blkif.h
index 711b69274..c68487cb3 100644
--- a/qemu/hw/block/xen_blkif.h
+++ b/qemu/hw/block/xen_blkif.h
@@ -85,8 +85,10 @@ static inline void blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_reque
d->nr_sectors = s->nr_sectors;
return;
}
- if (n > src->nr_segments)
- n = src->nr_segments;
+ /* prevent the compiler from optimizing the code and using src->nr_segments instead */
+ barrier();
+ if (n > dst->nr_segments)
+ n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->seg[i] = src->seg[i];
}
@@ -106,8 +108,10 @@ static inline void blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_reque
d->nr_sectors = s->nr_sectors;
return;
}
- if (n > src->nr_segments)
- n = src->nr_segments;
+ /* prevent the compiler from optimizing the code and using src->nr_segments instead */
+ barrier();
+ if (n > dst->nr_segments)
+ n = dst->nr_segments;
for (i = 0; i < n; i++)
dst->seg[i] = src->seg[i];
}