[PATCH v6 04/11] swiotlb: Map the buffer if it was unmapped by XPFO

Tycho Andersen
2017-09-07T17:37:13Z

From: Juerg Haefliger <juerg.haefliger@canonical.com>

v6: * guard against lookup_xpfo() returning NULL

CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Juerg Haefliger <juerg.haefliger@canonical.com>
Signed-off-by: Tycho Andersen <tycho@docker.com>
---
include/linux/xpfo.h | 4 ++++
lib/swiotlb.c | 3 ++-
mm/xpfo.c | 15 +++++++++++++++
3 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/linux/xpfo.h b/include/linux/xpfo.h
index 442c58ee930e..04590d1dcefa 100644
--- a/include/linux/xpfo.h
+++ b/include/linux/xpfo.h
@@ -30,6 +30,8 @@ void xpfo_kunmap(void *kaddr, struct page *page);
void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp);
void xpfo_free_pages(struct page *page, int order);

+bool xpfo_page_is_unmapped(struct page *page);
+
#else /* !CONFIG_XPFO */

static inline void xpfo_kmap(void *kaddr, struct page *page) { }
@@ -37,6 +39,8 @@ static inline void xpfo_kunmap(void *kaddr, struct page *page) { }
static inline void xpfo_alloc_pages(struct page *page, int order, gfp_t gfp) { }
static inline void xpfo_free_pages(struct page *page, int order) { }

+static inline bool xpfo_page_is_unmapped(struct page *page) { return false; }
+
#endif /* CONFIG_XPFO */

#endif /* _LINUX_XPFO_H */
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index a8d74a733a38..d4fee5ca2d9e 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -420,8 +420,9 @@ static void swiotlb_bounce(phys_addr_t orig_addr, phys_addr_t tlb_addr,
{
unsigned long pfn = PFN_DOWN(orig_addr);
unsigned char *vaddr = phys_to_virt(tlb_addr);
+ struct page *page = pfn_to_page(pfn);

- if (PageHighMem(pfn_to_page(pfn))) {
+ if (PageHighMem(page) || xpfo_page_is_unmapped(page)) {
/* The buffer does not have a mapping. Map it in and copy */
unsigned int offset = orig_addr & ~PAGE_MASK;
char *buffer;
diff --git a/mm/xpfo.c b/mm/xpfo.c
index bff24afcaa2e..cdbcbac582d5 100644
--- a/mm/xpfo.c
+++ b/mm/xpfo.c
@@ -220,3 +220,18 @@ void xpfo_kunmap(void *kaddr, struct page *page)
spin_unlock(&xpfo->maplock);
}
EXPORT_SYMBOL(xpfo_kunmap);
+
+bool xpfo_page_is_unmapped(struct page *page)
+{
+ struct xpfo *xpfo;
+
+ if (!static_branch_unlikely(&xpfo_inited))
+ return false;
+
+ xpfo = lookup_xpfo(page);
+ if (unlikely(!xpfo) && !xpfo->inited)
+ return false;
+
+ return test_bit(XPFO_PAGE_UNMAPPED, &xpfo->flags);
+}
+EXPORT_SYMBOL(xpfo_page_is_unmapped);
--
2.11.0