[Patch Part1 V2 17/20] iommu/vt-d: fix wrong return value of dmar_table_init()

From: Jiang Liu
Date: Thu Dec 05 2013 - 22:21:36 EST


If dmar_table_init() fails to detect DMAR table on the first call,
it will return wrong result on following calls because it always
sets dmar_table_initialized no matter if succeeds or fails to
detect DMAR table.

Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
---
drivers/iommu/dmar.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index a9d9d0f..b6b8a7f5 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -472,24 +472,23 @@ int __init dmar_table_init(void)
static int dmar_table_initialized;
int ret;

- if (dmar_table_initialized)
- return 0;
-
- dmar_table_initialized = 1;
-
- ret = parse_dmar_table();
- if (ret) {
- if (ret != -ENODEV)
- pr_info("parse DMAR table failure.\n");
- return ret;
- }
+ if (dmar_table_initialized == 0) {
+ ret = parse_dmar_table();
+ if (ret < 0) {
+ if (ret != -ENODEV)
+ pr_info("parse DMAR table failure.\n");
+ } else if (list_empty(&dmar_drhd_units)) {
+ pr_info("No DMAR devices found\n");
+ ret = -ENODEV;
+ }

- if (list_empty(&dmar_drhd_units)) {
- pr_info("No DMAR devices found\n");
- return -ENODEV;
+ if (ret < 0)
+ dmar_table_initialized = ret;
+ else
+ dmar_table_initialized = 1;
}

- return 0;
+ return dmar_table_initialized < 0 ? dmar_table_initialized : 0;
}

static void warn_invalid_dmar(u64 addr, const char *message)
--
1.7.10.4

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