[PATCH v18 11/15] IB/mlx4: untag user pointers in mlx4_get_umem_mr

Andrey Konovalov
2019-06-24T14:32:56Z

This patch is a part of a series that extends kernel ABI to allow to pass
tagged user pointers (with the top byte set to something else other than
0x00) as syscall arguments.

mlx4_get_umem_mr() uses provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in this function.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
drivers/infiniband/hw/mlx4/mr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index 355205a28544..13d9f917f249 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -378,6 +378,7 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start,
* again
*/
if (!ib_access_writable(access_flags)) {
+ unsigned long untagged_start = untagged_addr(start);
struct vm_area_struct *vma;

down_read(&current->mm->mmap_sem);
@@ -386,9 +387,9 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start,
* cover the memory, but for now it requires a single vma to
* entirely cover the MR to support RO mappings.
*/
- vma = find_vma(current->mm, start);
- if (vma && vma->vm_end >= start + length &&
- vma->vm_start <= start) {
+ vma = find_vma(current->mm, untagged_start);
+ if (vma && vma->vm_end >= untagged_start + length &&
+ vma->vm_start <= untagged_start) {
if (vma->vm_flags & VM_WRITE)
access_flags |= IB_ACCESS_LOCAL_WRITE;
} else {
--
2.22.0.410.gd8fdbe21b5-goog