From: Juerg Haefliger <juerg.haefli...@canonical.com>
XPFO can unmap a bounce buffer. Check for this and map it back in if
needed.
Signed-off-by: Juerg Haefliger <juerg.haefli...@canonical.com>
Signed-off-by: Tycho Andersen <ty...@tycho.ws>
Signed-off-by: Khalid Aziz <khalid.a...@oracle.com>
Cc: Khalid Aziz <kha...@gonehiking.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
---
v9: * Added a generic check for whether a page is mapped or not (suggested
by Chris Hellwig)
v6: * guard against lookup_xpfo() returning NULL
include/linux/highmem.h | 7 +++++++
kernel/dma/swiotlb.c | 3 ++-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 59a1a5fa598d..cf21f023dff4 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -77,6 +77,13 @@ static inline struct page *kmap_to_page(void *addr)
}
static inline unsigned long totalhigh_pages(void) { return 0UL; }
+static inline bool page_is_unmapped(struct page *page)
+{
+ if (PageHighMem(page) || PageXpfoUnmapped(page))
+ return true;
+ else
+ return false;
+}
#endif /* CONFIG_HIGHMEM */
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 1fb6fd68b9c7..90a1a3709b55 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -392,8 +392,9 @@ 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 (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;
--
2.17.1
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