When Linux is using 64K page granularity, every page will be slipt in
multiple non-contiguous 4K MFN (page granularity of Xen).
I'm not sure how to handle efficiently the check to know whether we can
merge 2 biovec with a such case. So for now, always says that biovec are
not mergeable.
Signed-off-by: Julien Grall <julien.gr...@citrix.com>
Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Cc: Boris Ostrovsky <boris.ostrov...@oracle.com>
Cc: David Vrabel <david.vra...@citrix.com>
---
Changes in v2:
- Remove the workaround and check if the Linux page granularity
is the same as Xen or not
---
drivers/xen/biomerge.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c
index 0edb91c..571567c 100644
--- a/drivers/xen/biomerge.c
+++ b/drivers/xen/biomerge.c
@@ -6,10 +6,17 @@
bool xen_biovec_phys_mergeable(const struct bio_vec *vec1,
const struct bio_vec *vec2)
{
+#if XEN_PAGE_SIZE == PAGE_SIZE
unsigned long mfn1 = pfn_to_mfn(page_to_pfn(vec1->bv_page));
unsigned long mfn2 = pfn_to_mfn(page_to_pfn(vec2->bv_page));
return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) &&
((mfn1 == mfn2) || ((mfn1+1) == mfn2));
+#else
+ /* XXX: bio_vec are not mergeable when using different page size in
+ * Xen and Linux
+ */
+ return 0;
+#endif
}
EXPORT_SYMBOL(xen_biovec_phys_mergeable);
--
2.1.4
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