iommu/sva: Fix signedness bug in iommu_sva_alloc_pasid()

The ida_alloc_range() function returns negative error codes on error.
On success it returns values in the min to max range (inclusive).  It
never returns more then INT_MAX even if "max" is higher.  It never
returns values in the 0 to (min - 1) range.

The bug is that "min" is an unsigned int so negative error codes will
be promoted to high positive values errors treated as success.

Fixes: 1a14bf0fc7ed ("iommu/sva: Use GFP_KERNEL for pasid allocation")
Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/6b32095d-7491-4ebb-a850-12e96209eaaf@kili.mountain
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index 3ebd4b6586b3eee2e99b885b2606b1cb8f076a41..05c0fb2acbc447f94ed3209adbdc893d1b334583 100644 (file)
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -34,8 +34,9 @@ static int iommu_sva_alloc_pasid(struct mm_struct *mm, ioasid_t min, ioasid_t ma
        }
 
        ret = ida_alloc_range(&iommu_global_pasid_ida, min, max, GFP_KERNEL);
-       if (ret < min)
+       if (ret < 0)
                goto out;
+
        mm->pasid = ret;
        ret = 0;
 out: