Merge branch 'stable/xen-swiotlb.bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb-2.6

* 'stable/xen-swiotlb.bugfix' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb-2.6:
  swiotlb: Export swioltb_nr_tbl and utilize it as appropiate.

drivers/xen/swiotlb-xen.c

@@ -147,9 +147,15 @@ void __init xen_swiotlb_init(int verbose)
 {
 	unsigned long bytes;
 	int rc;
+	unsigned long nr_tbl;
 
-	xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+	nr_tbl = swioltb_nr_tbl();
-	xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+	if (nr_tbl)
+		xen_io_tlb_nslabs = nr_tbl;
+	else {
+		xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
+		xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
+	}
 
 	bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
 

include/linux/swiotlb.h

@@ -24,6 +24,7 @@ extern int swiotlb_force;
 
 extern void swiotlb_init(int verbose);
 extern void swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
+extern unsigned long swioltb_nr_tbl(void);
 
 /*
  * Enumeration for sync targets

lib/swiotlb.c

@@ -110,6 +110,11 @@ setup_io_tlb_npages(char *str)
 __setup("swiotlb=", setup_io_tlb_npages);
 /* make io_tlb_overflow tunable too? */
 
+unsigned long swioltb_nr_tbl(void)
+{
+	return io_tlb_nslabs;
+}
+
 /* Note that this doesn't work with highmem page */
 static dma_addr_t swiotlb_virt_to_bus(struct device *hwdev,
 				      volatile void *address)