From: Sebastian Andrzej Siewior Date: Wed, 14 Sep 2016 14:35:49 +0200 Subject: [PATCH 189/353] fs/dcache: use swait_queue instead of waitqueue Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=61d4045b9c6beeffcdd2c05d35c3214d65c595ed __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 --- 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 1ae163d54925..6e1c0b4c04f4 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -2423,21 +2423,24 @@ 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); @@ -2552,7 +2555,7 @@ 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 6098e0c7f87b..9ce28840684a 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1234,7 +1234,7 @@ 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 9e8fca598acc..277508fc3cbc 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 4999bd148491..d8376dae3f7d 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); @@ -1519,7 +1519,7 @@ 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 #include #include -#include +#include #include #include @@ -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 e3f10c110b74..accc230079bb 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1889,7 +1889,7 @@ 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 7c62a526506c..499f67bf01e6 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -682,7 +682,7 @@ 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 02b1b40fea5b..50cbde278301 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)) {