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authorZoltan Kiss <zoltan.kiss@citrix.com>2014-01-23 21:23:44 +0000
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2014-01-31 09:48:32 -0500
commit08ece5bb2312b4510b161a6ef6682f37f4eac8a1 (patch)
treed331f6b82ca8f0346afdf54bc793fb10c4bdaec8 /drivers/xen/gntdev.c
parent47c542050d306e50f09512eb6339dbf2fc02fddd (diff)
downloadop-kernel-dev-08ece5bb2312b4510b161a6ef6682f37f4eac8a1.zip
op-kernel-dev-08ece5bb2312b4510b161a6ef6682f37f4eac8a1.tar.gz
xen/grant-table: Avoid m2p_override during mapping
The grant mapping API does m2p_override unnecessarily: only gntdev needs it, for blkback and future netback patches it just cause a lock contention, as those pages never go to userspace. Therefore this series does the following: - the original functions were renamed to __gnttab_[un]map_refs, with a new parameter m2p_override - based on m2p_override either they follow the original behaviour, or just set the private flag and call set_phys_to_machine - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with m2p_override false - a new function gnttab_[un]map_refs_userspace provides the old behaviour It also removes a stray space from page.h and change ret to 0 if XENFEAT_auto_translated_physmap, as that is the only possible return value there. v2: - move the storing of the old mfn in page->index to gnttab_map_refs - move the function header update to a separate patch v3: - a new approach to retain old behaviour where it needed - squash the patches into one v4: - move out the common bits from m2p* functions, and pass pfn/mfn as parameter - clear page->private before doing anything with the page, so m2p_find_override won't race with this v5: - change return value handling in __gnttab_[un]map_refs - remove a stray space in page.h - add detail why ret = 0 now at some places v6: - don't pass pfn to m2p* functions, just get it locally Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> Suggested-by: David Vrabel <david.vrabel@citrix.com> Acked-by: David Vrabel <david.vrabel@citrix.com> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/xen/gntdev.c')
-rw-r--r--drivers/xen/gntdev.c13
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 073b4a1..34a2704 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -284,8 +284,10 @@ static int map_grant_pages(struct grant_map *map)
}
pr_debug("map %d+%d\n", map->index, map->count);
- err = gnttab_map_refs(map->map_ops, use_ptemod ? map->kmap_ops : NULL,
- map->pages, map->count);
+ err = gnttab_map_refs_userspace(map->map_ops,
+ use_ptemod ? map->kmap_ops : NULL,
+ map->pages,
+ map->count);
if (err)
return err;
@@ -315,9 +317,10 @@ static int __unmap_grant_pages(struct grant_map *map, int offset, int pages)
}
}
- err = gnttab_unmap_refs(map->unmap_ops + offset,
- use_ptemod ? map->kmap_ops + offset : NULL, map->pages + offset,
- pages);
+ err = gnttab_unmap_refs_userspace(map->unmap_ops + offset,
+ use_ptemod ? map->kmap_ops + offset : NULL,
+ map->pages + offset,
+ pages);
if (err)
return err;
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