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| author | Julien Grall <julien.grall@citrix.com> | 2015-10-13 19:50:12 +0300 |
|---|---|---|
| committer | David Vrabel <david.vrabel@citrix.com> | 2015-10-23 16:20:46 +0300 |
| commit | f73314b28148f9ee9f89a0ae961c8fb36e3269fa (patch) | |
| tree | 723535d3e14456d2c36d75ebfb97774f74998407 | |
| parent | 9cce2914e2b21339dca12c91dc9f35790366cc4c (diff) | |
| download | linux-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.c | 22 | ||||
| -rw-r--r-- | include/xen/grant_table.h | 6 |
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 |