IB: Put rlimit accounting struct in struct ib_umem
When memory pinned with ib_umem_get() is released, ib_umem_release()
needs to subtract the amount of memory being unpinned from
mm->locked_vm. However, ib_umem_release() may be called with
mm->mmap_sem already held for writing if the memory is being released
as part of an munmap() call, so it is sometimes necessary to defer
this accounting into a workqueue.
However, the work struct used to defer this accounting is dynamically
allocated before it is queued, so there is the possibility of failing
that allocation. If the allocation fails, then ib_umem_release has no
choice except to bail out and leave the process with a permanently
elevated locked_vm.
Fix this by allocating the structure to defer accounting as part of
the original struct ib_umem, so there's no possibility of failing a
later allocation if creating the struct ib_umem and pinning memory
succeeds.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/include/rdma/ib_umem.h b/include/rdma/ib_umem.h
index 06307f7..b3a36f7 100644
--- a/include/rdma/ib_umem.h
+++ b/include/rdma/ib_umem.h
@@ -45,6 +45,9 @@
int page_size;
int writable;
struct list_head chunk_list;
+ struct work_struct work;
+ struct mm_struct *mm;
+ unsigned long diff;
};
struct ib_umem_chunk {
