From 7f966d394d6630313e02679de1875f67978f8bdd Mon Sep 17 00:00:00 2001 From: Thadeu Lima de Souza Cascardo Date: Fri, 28 Dec 2012 09:08:51 +0000 Subject: [PATCH] powerpc/iommu: Prevent false TCE leak message When a device DMA window includes the address 0, it's reserved in the TCE bitmap to avoid returning that address to drivers. When the device is removed, the bitmap is checked for any mappings not removed by the driver, indicating a possible DMA mapping leak. Since the reserved address is not cleared, a message is printed, warning of such a leak. Check for the reservation, and clear it before checking for any other standing mappings. Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/iommu.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index c862fd716fe3..31c4fdc6859c 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -717,6 +717,13 @@ void iommu_free_table(struct iommu_table *tbl, const char *node_name) return; } + /* + * In case we have reserved the first bit, we should not emit + * the warning below. + */ + if (tbl->it_offset == 0) + clear_bit(0, tbl->it_map); + /* verify that table contains no entries */ if (!bitmap_empty(tbl->it_map, tbl->it_size)) pr_warn("%s: Unexpected TCEs for %s\n", __func__, node_name);