linuxkpi: Add mmap_lock.h

This contain mmap_read_lock, mmap_read_unlock and mmap_write_lock_killable
which are abstraction around down_read, up_read and down_write_killable.
Note that in Linux 5.8 mmap_sem was renamed to mmap_lock.
We might want to do the same at some point but some drivers still uses
the old mmap locking API.

Reviewed by:	bz
MFC after:	2 weeks
Sponsored by:	Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D34297

(cherry picked from commit 995c3b88d485b9b64ab94efe270d424b2526ade7)

diff --git a/sys/compat/linuxkpi/common/include/linux/mm.h b/sys/compat/linuxkpi/common/include/linux/mm.h
index b8fa59f8dd5b15419085fc9afef86007d6cebd45..4d4c189e29391fe1debd682df9116415e50d520d 100644 (file)
--- a/sys/compat/linuxkpi/common/include/linux/mm.h
+++ b/sys/compat/linuxkpi/common/include/linux/mm.h
@@ -39,6 +39,7 @@
 #include <linux/mm_types.h>
 #include <linux/pfn.h>
 #include <linux/list.h>
+#include <linux/mmap_lock.h>
 
 #include <asm/pgtable.h>
 

diff --git a/sys/compat/linuxkpi/common/include/linux/mm_types.h b/sys/compat/linuxkpi/common/include/linux/mm_types.h
index a59c1e535b45db8e9860674c5cbd496f6361fe79..2a7b33d15054a1bcdfaf3fc946ae68e0b76f2338 100644 (file)
--- a/sys/compat/linuxkpi/common/include/linux/mm_types.h
+++ b/sys/compat/linuxkpi/common/include/linux/mm_types.h
@@ -45,6 +45,7 @@ struct mm_struct {
        atomic_t mm_count;
        atomic_t mm_users;
        size_t pinned_vm;
+       /* Renamed to mmap_lock in v5.8 */
        struct rw_semaphore mmap_sem;
 };
 

diff --git a/sys/compat/linuxkpi/common/include/linux/mmap_lock.h b/sys/compat/linuxkpi/common/include/linux/mmap_lock.h
new file mode 100644 (file)
index 0000000..de6b2a0
--- /dev/null
+++ b/sys/compat/linuxkpi/common/include/linux/mmap_lock.h
@@ -0,0 +1,54 @@
+/*-
+ * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#ifndef _LINUXKPI_LINUX_MMAP_LOCK_H_
+#define        _LINUXKPI_LINUX_MMAP_LOCK_H_
+
+#include <linux/mm_types.h>
+#include <linux/rwsem.h>
+
+static inline void
+mmap_read_lock(struct mm_struct *mm)
+{
+
+       down_read(&mm->mmap_sem);
+}
+
+static inline void
+mmap_read_unlock(struct mm_struct *mm)
+{
+
+       up_read(&mm->mmap_sem);
+}
+
+static inline void
+mmap_write_lock_killable(struct mm_struct *mm)
+{
+
+       down_write_killable(&mm->mmap_sem);
+}
+
+#endif /* _LINUXKPI_LINUX_MMAP_LOCK_H_ */