Merge branch 'odp_fixes' into rdma.git for-next

Jason Gunthorpe says:

====================
This is a collection of general cleanups for ODP to clarify some of the
flows around umem creation and use of the interval tree.
====================

The branch is based on v5.3-rc5 due to dependencies

* odp_fixes:
  RDMA/mlx5: Use odp instead of mr->umem in pagefault_mr
  RDMA/mlx5: Use ib_umem_start instead of umem.address
  RDMA/core: Make invalidate_range a device operation
  RDMA/odp: Use kvcalloc for the dma_list and page_list
  RDMA/odp: Check for overflow when computing the umem_odp end
  RDMA/odp: Provide ib_umem_odp_release() to undo the allocs
  RDMA/odp: Split creating a umem_odp from ib_umem_get
  RDMA/odp: Make the three ways to create a umem_odp clear
  RMDA/odp: Consolidate umem_odp initialization
  RDMA/odp: Make it clearer when a umem is an implicit ODP umem
  RDMA/odp: Iterate over the whole rbtree directly
  RDMA/odp: Use the common interval tree library instead of generic
  RDMA/mlx5: Fix MR npages calculation for IB_ACCESS_HUGETLB

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/fs/open.c b/fs/open.c
index b5b80469b93d..a59abe3c669a 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -374,6 +374,25 @@ long do_faccessat(int dfd, const char __user *filename, int mode)
 				override_cred->cap_permitted;
 	}
 
+	/*
+	 * The new set of credentials can *only* be used in
+	 * task-synchronous circumstances, and does not need
+	 * RCU freeing, unless somebody then takes a separate
+	 * reference to it.
+	 *
+	 * NOTE! This is _only_ true because this credential
+	 * is used purely for override_creds() that installs
+	 * it as the subjective cred. Other threads will be
+	 * accessing ->real_cred, not the subjective cred.
+	 *
+	 * If somebody _does_ make a copy of this (using the
+	 * 'get_current_cred()' function), that will clear the
+	 * non_rcu field, because now that other user may be
+	 * expecting RCU freeing. But normal thread-synchronous
+	 * cred accesses will keep things non-RCY.
+	 */
+	override_cred->non_rcu = 1;
+
 	old_cred = override_creds(override_cred);
 retry:
 	res = user_path_at(dfd, filename, lookup_flags, &path);