IB/core: Make testing MR flags for writability a static inline function

BugLink: https://bugs.launchpad.net/bugs/1792174

commit 08bb558a upstream.

Make the MR writability flags check, which is performed in umem.c,
a static inline function in file ib_verbs.h

This allows the function to be used by low-level infiniband drivers.

Cc: <stable@vger.kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/infiniband/core/umem.c

@@ -122,16 +122,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 	umem->address   = addr;
 	umem->page_size = PAGE_SIZE;
 	umem->pid       = get_task_pid(current, PIDTYPE_PID);
-	/*
-	 * We ask for writable memory if any of the following
-	 * access flags are set.  "Local write" and "remote write"
-	 * obviously require write access.  "Remote atomic" can do
-	 * things like fetch and add, which will modify memory, and
-	 * "MW bind" can change permissions by binding a window.
-	 */
-	umem->writable  = !!(access &
-		(IB_ACCESS_LOCAL_WRITE   | IB_ACCESS_REMOTE_WRITE |
-		 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
+	umem->writable   = ib_access_writable(access);
 
 	if (access & IB_ACCESS_ON_DEMAND) {
 		put_pid(umem->pid);

include/rdma/ib_verbs.h

@@ -3007,6 +3007,20 @@ static inline int ib_check_mr_access(int flags)
 	return 0;
 }
 
+static inline bool ib_access_writable(int access_flags)
+{
+	/*
+	 * We have writable memory backing the MR if any of the following
+	 * access flags are set.  "Local write" and "remote write" obviously
+	 * require write access.  "Remote atomic" can do things like fetch and
+	 * add, which will modify memory, and "MW bind" can change permissions
+	 * by binding a window.
+	 */
+	return access_flags &
+		(IB_ACCESS_LOCAL_WRITE   | IB_ACCESS_REMOTE_WRITE |
+		 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND);
+}
+
 /**
  * ib_check_mr_status: lightweight check of MR status.
  *     This routine may provide status checks on a selected