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From e4caae8cd260d60e1239f6bb9163fae545360e90 Mon Sep 17 00:00:00 2001
Message-Id: <e4caae8cd260d60e1239f6bb9163fae545360e90.1601675152.git.zanussi@kernel.org>
In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 14 Sep 2016 14:35:49 +0200
Subject: [PATCH 189/333] fs/dcache: use swait_queue instead of waitqueue
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
__d_lookup_done() invokes wake_up_all() while holding a hlist_bl_lock()
which disables preemption. As a workaround convert it to swait.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
fs/cifs/readdir.c | 2 +-
fs/dcache.c | 27 +++++++++++++++------------
fs/fuse/dir.c | 2 +-
fs/namei.c | 4 ++--
fs/nfs/dir.c | 4 ++--
fs/nfs/unlink.c | 4 ++--
fs/proc/base.c | 2 +-
fs/proc/proc_sysctl.c | 2 +-
include/linux/dcache.h | 4 ++--
include/linux/nfs_xdr.h | 2 +-
kernel/sched/swait.c | 1 +
11 files changed, 29 insertions(+), 25 deletions(-)
diff --git a/fs/cifs/readdir.c b/fs/cifs/readdir.c
index 3925a7bfc74d..33f7723fb83e 100644
--- a/fs/cifs/readdir.c
+++ b/fs/cifs/readdir.c
@@ -80,7 +80,7 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
struct inode *inode;
struct super_block *sb = parent->d_sb;
struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
diff --git a/fs/dcache.c b/fs/dcache.c
index dcde8ffe384c..b2a00f3ff7df 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2421,21 +2421,24 @@ static inline void end_dir_add(struct inode *dir, unsigned n)
static void d_wait_lookup(struct dentry *dentry)
{
- if (d_in_lookup(dentry)) {
- DECLARE_WAITQUEUE(wait, current);
- add_wait_queue(dentry->d_wait, &wait);
- do {
- set_current_state(TASK_UNINTERRUPTIBLE);
- spin_unlock(&dentry->d_lock);
- schedule();
- spin_lock(&dentry->d_lock);
- } while (d_in_lookup(dentry));
- }
+ struct swait_queue __wait;
+
+ if (!d_in_lookup(dentry))
+ return;
+
+ INIT_LIST_HEAD(&__wait.task_list);
+ do {
+ prepare_to_swait_exclusive(dentry->d_wait, &__wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock(&dentry->d_lock);
+ schedule();
+ spin_lock(&dentry->d_lock);
+ } while (d_in_lookup(dentry));
+ finish_swait(dentry->d_wait, &__wait);
}
struct dentry *d_alloc_parallel(struct dentry *parent,
const struct qstr *name,
- wait_queue_head_t *wq)
+ struct swait_queue_head *wq)
{
unsigned int hash = name->hash;
struct hlist_bl_head *b = in_lookup_hash(parent, hash);
@@ -2550,7 +2553,7 @@ void __d_lookup_done(struct dentry *dentry)
hlist_bl_lock(b);
dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
__hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
- wake_up_all(dentry->d_wait);
+ swake_up_all(dentry->d_wait);
dentry->d_wait = NULL;
hlist_bl_unlock(b);
INIT_HLIST_NODE(&dentry->d_u.d_alias);
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c
index 6244345a5745..7ee10b7cc808 100644
--- a/fs/fuse/dir.c
+++ b/fs/fuse/dir.c
@@ -1213,7 +1213,7 @@ static int fuse_direntplus_link(struct file *file,
struct inode *dir = d_inode(parent);
struct fuse_conn *fc;
struct inode *inode;
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
if (!o->nodeid) {
/*
diff --git a/fs/namei.c b/fs/namei.c
index 327844fedf3d..5114c8111807 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1646,7 +1646,7 @@ static struct dentry *__lookup_slow(const struct qstr *name,
{
struct dentry *dentry, *old;
struct inode *inode = dir->d_inode;
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
/* Don't go there if it's already dead */
if (unlikely(IS_DEADDIR(inode)))
@@ -3136,7 +3136,7 @@ static int lookup_open(struct nameidata *nd, struct path *path,
struct dentry *dentry;
int error, create_error = 0;
umode_t mode = op->mode;
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
if (unlikely(IS_DEADDIR(dir_inode)))
return -ENOENT;
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index c60b20884c45..7e653c14c7ed 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -457,7 +457,7 @@ static
void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
{
struct qstr filename = QSTR_INIT(entry->name, entry->len);
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
struct dentry *dentry;
struct dentry *alias;
struct inode *dir = d_inode(parent);
@@ -1516,7 +1516,7 @@ int nfs_atomic_open(struct inode *dir, struct dentry *dentry,
struct file *file, unsigned open_flags,
umode_t mode)
{
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
struct nfs_open_context *ctx;
struct dentry *res;
struct iattr attr = { .ia_valid = ATTR_OPEN };
diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index ce9100b5604d..839bfa76f41e 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -13,7 +13,7 @@
#include <linux/sunrpc/clnt.h>
#include <linux/nfs_fs.h>
#include <linux/sched.h>
-#include <linux/wait.h>
+#include <linux/swait.h>
#include <linux/namei.h>
#include <linux/fsnotify.h>
@@ -206,7 +206,7 @@ nfs_async_unlink(struct dentry *dentry, const struct qstr *name)
goto out_free_name;
}
data->res.dir_attr = &data->dir_attr;
- init_waitqueue_head(&data->wq);
+ init_swait_queue_head(&data->wq);
status = -EBUSY;
spin_lock(&dentry->d_lock);
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 3b9b726b1a6c..a45d4d640f01 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1890,7 +1890,7 @@ bool proc_fill_cache(struct file *file, struct dir_context *ctx,
child = d_hash_and_lookup(dir, &qname);
if (!child) {
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
child = d_alloc_parallel(dir, &qname, &wq);
if (IS_ERR(child))
goto end_instantiate;
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index c95f32b83a94..75f500cb7e74 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -681,7 +681,7 @@ static bool proc_sys_fill_cache(struct file *file,
child = d_lookup(dir, &qname);
if (!child) {
- DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+ DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
child = d_alloc_parallel(dir, &qname, &wq);
if (IS_ERR(child))
return false;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 0880baefd85f..8b4d6c8c1f7f 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -105,7 +105,7 @@ struct dentry {
union {
struct list_head d_lru; /* LRU list */
- wait_queue_head_t *d_wait; /* in-lookup ones only */
+ struct swait_queue_head *d_wait; /* in-lookup ones only */
};
struct list_head d_child; /* child of parent list */
struct list_head d_subdirs; /* our children */
@@ -236,7 +236,7 @@ extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
extern struct dentry * d_alloc_anon(struct super_block *);
extern struct dentry * d_alloc_pseudo(struct super_block *, const struct qstr *);
extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
- wait_queue_head_t *);
+ struct swait_queue_head *);
extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
diff --git a/include/linux/nfs_xdr.h b/include/linux/nfs_xdr.h
index cab24a127feb..73b0d19ef0d9 100644
--- a/include/linux/nfs_xdr.h
+++ b/include/linux/nfs_xdr.h
@@ -1549,7 +1549,7 @@ struct nfs_unlinkdata {
struct nfs_removeargs args;
struct nfs_removeres res;
struct dentry *dentry;
- wait_queue_head_t wq;
+ struct swait_queue_head wq;
struct rpc_cred *cred;
struct nfs_fattr dir_attr;
long timeout;
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c
index c7cb30cdd1b7..119a56d7f739 100644
--- a/kernel/sched/swait.c
+++ b/kernel/sched/swait.c
@@ -70,6 +70,7 @@ void swake_up_all(struct swait_queue_head *q)
struct swait_queue *curr;
LIST_HEAD(tmp);
+ WARN_ON(irqs_disabled());
raw_spin_lock_irq(&q->lock);
list_splice_init(&q->task_list, &tmp);
while (!list_empty(&tmp)) {
--
2.17.1
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