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authorJulien Grall <julien.grall@citrix.com>2015-10-13 19:50:12 +0300
committerDavid Vrabel <david.vrabel@citrix.com>2015-10-23 16:20:46 +0300
commitf73314b28148f9ee9f89a0ae961c8fb36e3269fa (patch)
tree723535d3e14456d2c36d75ebfb97774f74998407
parent9cce2914e2b21339dca12c91dc9f35790366cc4c (diff)
downloadlinux-f73314b28148f9ee9f89a0ae961c8fb36e3269fa.tar.xz
xen/grant-table: Add an helper to iterate over a specific number of grants
With the 64KB page granularity support on ARM64, a Linux page may be split accross multiple grant. Currently we have the helper gnttab_foreach_grant_in_grant to break a Linux page based on an offset and a len, but it doesn't fit when we only have a number of grants in hand. Introduce a new helper which take an array of Linux page and a number of grant and will figure out the address of each grant. Signed-off-by: Julien Grall <julien.grall@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
-rw-r--r--drivers/xen/grant-table.c22
-rw-r--r--include/xen/grant_table.h6
2 files changed, 28 insertions, 0 deletions
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 72d633962095..c49f79ed58c5 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -802,6 +802,28 @@ void gnttab_foreach_grant_in_range(struct page *page,
}
EXPORT_SYMBOL_GPL(gnttab_foreach_grant_in_range);
+void gnttab_foreach_grant(struct page **pages,
+ unsigned int nr_grefs,
+ xen_grant_fn_t fn,
+ void *data)
+{
+ unsigned int goffset = 0;
+ unsigned long xen_pfn = 0;
+ unsigned int i;
+
+ for (i = 0; i < nr_grefs; i++) {
+ if ((i % XEN_PFN_PER_PAGE) == 0) {
+ xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]);
+ goffset = 0;
+ }
+
+ fn(pfn_to_gfn(xen_pfn), goffset, XEN_PAGE_SIZE, data);
+
+ goffset += XEN_PAGE_SIZE;
+ xen_pfn++;
+ }
+}
+
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count)
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index e17a4b381a16..34b1379f9777 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -264,6 +264,12 @@ static inline void gnttab_for_one_grant(struct page *page, unsigned int offset,
gnttab_foreach_grant_in_range(page, offset, len, fn, data);
}
+/* Get @nr_grefs grants from an array of page and call fn for each grant */
+void gnttab_foreach_grant(struct page **pages,
+ unsigned int nr_grefs,
+ xen_grant_fn_t fn,
+ void *data);
+
/* Get the number of grant in a specified region
*
* start: Offset from the beginning of the first page