xen-swiotlb: remove xen_set_nslabs

The xen_set_nslabs function is a little weird, as it has just one
caller, that caller passes a global variable as the argument,
which is then overriden in the function and a derivative of it
returned.  Just add a cpp symbol for the default size using a readable
constant and open code the remaining three lines in the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c
index e99f061..5352655 100644 (file)
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -138,16 +138,6 @@ xen_swiotlb_fixup(void *buf, size_t size, unsigned long nslabs)
        } while (i < nslabs);
        return 0;
 }
-static unsigned long xen_set_nslabs(unsigned long nr_tbl)
-{
-       if (!nr_tbl) {
-               xen_io_tlb_nslabs = (64 * 1024 * 1024 >> IO_TLB_SHIFT);
-               xen_io_tlb_nslabs = ALIGN(xen_io_tlb_nslabs, IO_TLB_SEGSIZE);
-       } else
-               xen_io_tlb_nslabs = nr_tbl;
-
-       return xen_io_tlb_nslabs << IO_TLB_SHIFT;
-}
 
 enum xen_swiotlb_err {
        XEN_SWIOTLB_UNKNOWN = 0,
@@ -170,6 +160,9 @@ static const char *xen_swiotlb_error(enum xen_swiotlb_err err)
        }
        return "";
 }
+
+#define DEFAULT_NSLABS         ALIGN(SZ_64M >> IO_TLB_SHIFT, IO_TLB_SEGSIZE)
+
 int __ref xen_swiotlb_init(int verbose, bool early)
 {
        unsigned long bytes, order;
@@ -179,8 +172,10 @@ int __ref xen_swiotlb_init(int verbose, bool early)
 
        xen_io_tlb_nslabs = swiotlb_nr_tbl();
 retry:
-       bytes = xen_set_nslabs(xen_io_tlb_nslabs);
-       order = get_order(xen_io_tlb_nslabs << IO_TLB_SHIFT);
+       if (!xen_io_tlb_nslabs)
+               xen_io_tlb_nslabs = DEFAULT_NSLABS;
+       bytes = xen_io_tlb_nslabs << IO_TLB_SHIFT;
+       order = get_order(bytes);
 
        /*
         * IO TLB memory already allocated. Just use it.