swiotlb: lift the double initialization protection from xen-swiotlb

Lift the double initialization protection from xen-swiotlb to the core
code to avoid exposing too many swiotlb internals.  Also upgrade the
check to a warning as it should not happen.

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 1a31ddf..060eeb0 100644 (file)
--- a/drivers/xen/swiotlb-xen.c
+++ b/drivers/xen/swiotlb-xen.c
@@ -173,12 +173,6 @@ retry:
        order = get_order(bytes);
 
        /*
-        * IO TLB memory already allocated. Just use it.
-        */
-       if (io_tlb_start != 0)
-               goto end;
-
-       /*
         * Get IO TLB memory from any location.
         */
        if (early) {
@@ -232,7 +226,6 @@ retry:
        } else
                rc = swiotlb_late_init_with_tbl(start, nslabs);
 
-end:
        if (!rc)
                swiotlb_set_max_segment(PAGE_SIZE);
 

diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index 5fe8781..35e24f0 100644 (file)
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -229,6 +229,10 @@ int __init swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose)
        unsigned long i, bytes;
        size_t alloc_size;
 
+       /* protect against double initialization */
+       if (WARN_ON_ONCE(io_tlb_start))
+               return -ENOMEM;
+
        bytes = nslabs << IO_TLB_SHIFT;
 
        io_tlb_nslabs = nslabs;
@@ -367,6 +371,10 @@ swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs)
 {
        unsigned long i, bytes;
 
+       /* protect against double initialization */
+       if (WARN_ON_ONCE(io_tlb_start))
+               return -ENOMEM;
+
        bytes = nslabs << IO_TLB_SHIFT;
 
        io_tlb_nslabs = nslabs;