From: Andrey Konovalov <andreyknvl@google.com>
Date: Tue, 23 Jul 2019 19:58:48 +0200
Subject: RDMA/mlx4: Untag user pointers in mlx4_get_umem_mr
Patch-mainline: v5.4-rc1
Git-commit: ecc53f8a3c097d13f4b6793855e0bd30a63a5c3a
References: jsc#SLE-8461
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.
Link: https://lore.kernel.org/r/7969018013a67ddbbf784ac7afeea5a57b1e2bcb.1563904656.git.andreyknvl@google.com
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
drivers/infiniband/hw/mlx4/mr.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -377,6 +377,7 @@ static struct ib_umem *mlx4_get_umem_mr(
* again
*/
if (!ib_access_writable(access_flags)) {
+ unsigned long untagged_start = untagged_addr(start);
struct vm_area_struct *vma;
down_read(¤t->mm->mmap_sem);
@@ -385,9 +386,9 @@ static struct ib_umem *mlx4_get_umem_mr(
* 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 {