[PATCH 14/62] xarray: Add the xa_lock to the radix_tree_root

Matthew Wilcox
2017-11-22T21:32:06Z

This results in no change in structure size on 64-bit x86 as it fits in
the padding between the gfp_t and the void *.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
---
fs/f2fs/gc.c | 2 +-
include/linux/idr.h | 12 ++++++------
include/linux/radix-tree.h | 7 +++++--
include/linux/xarray.h | 34 ++++++++++++++++++++++++++++++++++
kernel/pid.c | 2 +-
tools/include/linux/spinlock.h | 1 +
6 files changed, 48 insertions(+), 10 deletions(-)
create mode 100644 include/linux/xarray.h

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5d5bba462f26..2cf52b92db5c 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -991,7 +991,7 @@ int f2fs_gc(struct f2fs_sb_info *sbi, bool sync,
unsigned int init_segno = segno;
struct gc_inode_list gc_list = {
.ilist = LIST_HEAD_INIT(gc_list.ilist),
- .iroot = RADIX_TREE_INIT(GFP_NOFS),
+ .iroot = RADIX_TREE_INIT(gc_list.iroot, GFP_NOFS),
};

trace_f2fs_gc_begin(sbi->sb, sync, background,
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 87ae635fcee6..3c3346441cbc 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -29,11 +29,11 @@ struct idr {
/* Set the IDR flag and the IDR_FREE tag */
#define IDR_RT_MARKER ((__force gfp_t)(3 << __GFP_BITS_SHIFT))

-#define IDR_INIT \
+#define IDR_INIT(name) \
{ \
- .idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER) \
+ .idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER) \
}
-#define DEFINE_IDR(name) struct idr name = IDR_INIT
+#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)

/**
* DOC: idr sync
@@ -166,10 +166,10 @@ struct ida {
struct radix_tree_root ida_rt;
};

-#define IDA_INIT { \
- .ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT), \
+#define IDA_INIT(name) { \
+ .ida_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER | GFP_NOWAIT), \
}
-#define DEFINE_IDA(name) struct ida name = IDA_INIT
+#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)

int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index fc55ff31eca7..b4d60295decd 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -109,20 +109,23 @@ struct radix_tree_node {
#define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT + 1)

struct radix_tree_root {
+ spinlock_t xa_lock;
gfp_t gfp_mask;
struct radix_tree_node __rcu *rnode;
};

-#define RADIX_TREE_INIT(mask) { \
+#define RADIX_TREE_INIT(name, mask) { \
+ .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \
.gfp_mask = (mask), \
.rnode = NULL, \
}

#define RADIX_TREE(name, mask) \
- struct radix_tree_root name = RADIX_TREE_INIT(mask)
+ struct radix_tree_root name = RADIX_TREE_INIT(name, mask)

#define INIT_RADIX_TREE(root, mask) \
do { \
+ (root)->xa_lock = __SPIN_LOCK_UNLOCKED(root.xa_lock); \
(root)->gfp_mask = (mask); \
(root)->rnode = NULL; \
} while (0)
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
new file mode 100644
index 000000000000..a5a933925b85
--- /dev/null
+++ b/include/linux/xarray.h
@@ -0,0 +1,34 @@
+#ifndef _LINUX_XARRAY_H
+#define _LINUX_XARRAY_H
+/*
+ * eXtensible Arrays
+ * Copyright (c) 2017 Microsoft Corporation
+ * Author: Matthew Wilcox <mawilcox@microsoft.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/spinlock.h>
+
+#define xa_trylock(xa) spin_trylock(&(xa)->xa_lock)
+#define xa_lock(xa) spin_lock(&(xa)->xa_lock)
+#define xa_unlock(xa) spin_unlock(&(xa)->xa_lock)
+#define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock)
+#define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock)
+#define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock)
+#define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock)
+#define xa_lock_irqsave(xa, flags) \
+ spin_lock_irqsave(&(xa)->xa_lock, flags)
+#define xa_unlock_irqrestore(xa, flags) \
+ spin_unlock_irqrestore(&(xa)->xa_lock, flags)
+#define xa_lock_held(xa) lockdep_is_held(&(xa)->xa_lock)
+
+#endif /* _LINUX_XARRAY_H */
diff --git a/kernel/pid.c b/kernel/pid.c
index aae5f3307c35..1df901f32b54 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -58,7 +58,7 @@ int pid_max_max = PID_MAX_LIMIT;
*/
struct pid_namespace init_pid_ns = {
.kref = KREF_INIT(2),
- .idr = IDR_INIT,
+ .idr = IDR_INIT(init_pid_ns.idr),
.pid_allocated = PIDNS_ADDING,
.level = 0,
.child_reaper = &init_task,
diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h
index 4ed569fcb139..b21b586b9854 100644
--- a/tools/include/linux/spinlock.h
+++ b/tools/include/linux/spinlock.h
@@ -7,6 +7,7 @@

#define spinlock_t pthread_mutex_t
#define DEFINE_SPINLOCK(x) pthread_mutex_t x = PTHREAD_MUTEX_INITIALIZER;
+#define __SPIN_LOCK_UNLOCKED(x) (pthread_mutex_t)PTHREAD_MUTEX_INITIALIZER

#define spin_lock_irqsave(x, f) (void)f, pthread_mutex_lock(x)
#define spin_unlock_irqrestore(x, f) (void)f, pthread_mutex_unlock(x)
--
2.15.0