1 files changed, 42 insertions, 8 deletions

diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index e80a7f764a74..1587cedee13e 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -131,6 +131,40 @@ out:
 	return err;
 }
 
+static struct ib_umem *mlx4_get_umem_mr(struct ib_ucontext *context, u64 start,
+					u64 length, u64 virt_addr,
+					int access_flags)
+{
+	/*
+	 * Force registering the memory as writable if the underlying pages
+	 * are writable.  This is so rereg can change the access permissions
+	 * from readable to writable without having to run through ib_umem_get
+	 * again
+	 */
+	if (!ib_access_writable(access_flags)) {
+		struct vm_area_struct *vma;
+
+		down_read(&current->mm->mmap_sem);
+		/*
+		 * FIXME: Ideally this would iterate over all the vmas that
+		 * 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) {
+			if (vma->vm_flags & VM_WRITE)
+				access_flags |= IB_ACCESS_LOCAL_WRITE;
+		} else {
+			access_flags |= IB_ACCESS_LOCAL_WRITE;
+		}
+
+		up_read(&current->mm->mmap_sem);
+	}
+
+	return ib_umem_get(context, start, length, access_flags, 0);
+}
+
 struct ib_mr *mlx4_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 				  u64 virt_addr, int access_flags,
 				  struct ib_udata *udata)
@@ -145,10 +179,8 @@ struct ib_mr *mlx4_ib_reg_user_mr(struct ib_pd *pd, u64 start, u64 length,
 	if (!mr)
 		return ERR_PTR(-ENOMEM);
 
-	/* Force registering the memory as writable. */
-	/* Used for memory re-registeration. HCA protects the access */
-	mr->umem = ib_umem_get(pd->uobject->context, start, length,
-			       access_flags | IB_ACCESS_LOCAL_WRITE, 0);
+	mr->umem = mlx4_get_umem_mr(pd->uobject->context, start, length,
+				    virt_addr, access_flags);
 	if (IS_ERR(mr->umem)) {
 		err = PTR_ERR(mr->umem);
 		goto err_free;
@@ -215,6 +247,9 @@ int mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags,
 	}
 
 	if (flags & IB_MR_REREG_ACCESS) {
+		if (ib_access_writable(mr_access_flags) && !mmr->umem->writable)
+			return -EPERM;
+
 		err = mlx4_mr_hw_change_access(dev->dev, *pmpt_entry,
 					       convert_access(mr_access_flags));
 
@@ -228,10 +263,9 @@ int mlx4_ib_rereg_user_mr(struct ib_mr *mr, int flags,
 
 		mlx4_mr_rereg_mem_cleanup(dev->dev, &mmr->mmr);
 		ib_umem_release(mmr->umem);
-		mmr->umem = ib_umem_get(mr->uobject->context, start, length,
-					mr_access_flags |
-					IB_ACCESS_LOCAL_WRITE,
-					0);
+		mmr->umem =
+			mlx4_get_umem_mr(mr->uobject->context, start, length,
+					 virt_addr, mr_access_flags);
 		if (IS_ERR(mmr->umem)) {
 			err = PTR_ERR(mmr->umem);
 			/* Prevent mlx4_ib_dereg_mr from free'ing invalid pointer */