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-rw-r--r--include/linux/cgroup.h4
-rw-r--r--include/linux/compiler.h4
-rw-r--r--include/linux/cred.h2
-rw-r--r--include/linux/fdtable.h6
-rw-r--r--include/linux/fs.h2
-rw-r--r--include/linux/genhd.h6
-rw-r--r--include/linux/hardirq.h2
-rw-r--r--include/linux/idr.h4
-rw-r--r--include/linux/init_task.h14
-rw-r--r--include/linux/input.h2
-rw-r--r--include/linux/iocontext.h2
-rw-r--r--include/linux/key.h3
-rw-r--r--include/linux/kvm_host.h2
-rw-r--r--include/linux/mm_types.h2
-rw-r--r--include/linux/nfs_fs.h2
-rw-r--r--include/linux/notifier.h10
-rw-r--r--include/linux/radix-tree.h4
-rw-r--r--include/linux/rculist.h62
-rw-r--r--include/linux/rculist_nulls.h16
-rw-r--r--include/linux/rcupdate.h482
-rw-r--r--include/linux/rcutiny.h104
-rw-r--r--include/linux/rcutree.h57
-rw-r--r--include/linux/sched.h16
-rw-r--r--include/linux/srcu.h34
-rw-r--r--include/linux/sunrpc/auth_gss.h4
25 files changed, 516 insertions, 330 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ed3e92e41c6e..3cb7d04308cd 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -75,7 +75,7 @@ struct cgroup_subsys_state {
unsigned long flags;
/* ID for this css, if possible */
- struct css_id *id;
+ struct css_id __rcu *id;
};
/* bits in struct cgroup_subsys_state flags field */
@@ -205,7 +205,7 @@ struct cgroup {
struct list_head children; /* my children */
struct cgroup *parent; /* my parent */
- struct dentry *dentry; /* cgroup fs entry, RCU protected */
+ struct dentry __rcu *dentry; /* cgroup fs entry, RCU protected */
/* Private pointers for each registered subsystem */
struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index c1a62c56a660..320d6c94ff84 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -16,7 +16,11 @@
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
# define __percpu __attribute__((noderef, address_space(3)))
+#ifdef CONFIG_SPARSE_RCU_POINTER
+# define __rcu __attribute__((noderef, address_space(4)))
+#else
# define __rcu
+#endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 4d2c39573f36..4aaeab376446 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -84,7 +84,7 @@ struct thread_group_cred {
atomic_t usage;
pid_t tgid; /* thread group process ID */
spinlock_t lock;
- struct key *session_keyring; /* keyring inherited over fork */
+ struct key __rcu *session_keyring; /* keyring inherited over fork */
struct key *process_keyring; /* keyring private to this process */
struct rcu_head rcu; /* RCU deletion hook */
};
diff --git a/include/linux/fdtable.h b/include/linux/fdtable.h
index f59ed297b661..133c0ba25e30 100644
--- a/include/linux/fdtable.h
+++ b/include/linux/fdtable.h
@@ -31,7 +31,7 @@ struct embedded_fd_set {
struct fdtable {
unsigned int max_fds;
- struct file ** fd; /* current fd array */
+ struct file __rcu **fd; /* current fd array */
fd_set *close_on_exec;
fd_set *open_fds;
struct rcu_head rcu;
@@ -46,7 +46,7 @@ struct files_struct {
* read mostly part
*/
atomic_t count;
- struct fdtable *fdt;
+ struct fdtable __rcu *fdt;
struct fdtable fdtab;
/*
* written part on a separate cache line in SMP
@@ -55,7 +55,7 @@ struct files_struct {
int next_fd;
struct embedded_fd_set close_on_exec_init;
struct embedded_fd_set open_fds_init;
- struct file * fd_array[NR_OPEN_DEFAULT];
+ struct file __rcu * fd_array[NR_OPEN_DEFAULT];
};
#define rcu_dereference_check_fdtable(files, fdtfd) \
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 76041b614758..aa3dc8d20436 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1380,7 +1380,7 @@ struct super_block {
* Saved mount options for lazy filesystems using
* generic_show_options()
*/
- char *s_options;
+ char __rcu *s_options;
};
extern struct timespec current_fs_time(struct super_block *sb);
diff --git a/include/linux/genhd.h b/include/linux/genhd.h
index 5f2f4c4d8fb0..af3f06b41dc1 100644
--- a/include/linux/genhd.h
+++ b/include/linux/genhd.h
@@ -129,8 +129,8 @@ struct blk_scsi_cmd_filter {
struct disk_part_tbl {
struct rcu_head rcu_head;
int len;
- struct hd_struct *last_lookup;
- struct hd_struct *part[];
+ struct hd_struct __rcu *last_lookup;
+ struct hd_struct __rcu *part[];
};
struct gendisk {
@@ -149,7 +149,7 @@ struct gendisk {
* non-critical accesses use RCU. Always access through
* helpers.
*/
- struct disk_part_tbl *part_tbl;
+ struct disk_part_tbl __rcu *part_tbl;
struct hd_struct part0;
const struct block_device_operations *fops;
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index d5b387669dab..1f4517d55b19 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -139,7 +139,7 @@ static inline void account_system_vtime(struct task_struct *tsk)
#endif
#if defined(CONFIG_NO_HZ)
-#if defined(CONFIG_TINY_RCU)
+#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
extern void rcu_enter_nohz(void);
extern void rcu_exit_nohz(void);
diff --git a/include/linux/idr.h b/include/linux/idr.h
index e968db71e33a..cdb715e58e3e 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -50,14 +50,14 @@
struct idr_layer {
unsigned long bitmap; /* A zero bit means "space here" */
- struct idr_layer *ary[1<<IDR_BITS];
+ struct idr_layer __rcu *ary[1<<IDR_BITS];
int count; /* When zero, we can release it */
int layer; /* distance from leaf */
struct rcu_head rcu_head;
};
struct idr {
- struct idr_layer *top;
+ struct idr_layer __rcu *top;
struct idr_layer *id_free;
int layers; /* only valid without concurrent changes */
int id_free_cnt;
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 1f43fa56f600..2fea6c8ef6ba 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -82,11 +82,17 @@ extern struct group_info init_groups;
# define CAP_INIT_BSET CAP_FULL_SET
#ifdef CONFIG_TREE_PREEMPT_RCU
+#define INIT_TASK_RCU_TREE_PREEMPT() \
+ .rcu_blocked_node = NULL,
+#else
+#define INIT_TASK_RCU_TREE_PREEMPT(tsk)
+#endif
+#ifdef CONFIG_PREEMPT_RCU
#define INIT_TASK_RCU_PREEMPT(tsk) \
.rcu_read_lock_nesting = 0, \
.rcu_read_unlock_special = 0, \
- .rcu_blocked_node = NULL, \
- .rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry),
+ .rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \
+ INIT_TASK_RCU_TREE_PREEMPT()
#else
#define INIT_TASK_RCU_PREEMPT(tsk)
#endif
@@ -137,8 +143,8 @@ extern struct cred init_cred;
.children = LIST_HEAD_INIT(tsk.children), \
.sibling = LIST_HEAD_INIT(tsk.sibling), \
.group_leader = &tsk, \
- .real_cred = &init_cred, \
- .cred = &init_cred, \
+ RCU_INIT_POINTER(.real_cred, &init_cred), \
+ RCU_INIT_POINTER(.cred, &init_cred), \
.cred_guard_mutex = \
__MUTEX_INITIALIZER(tsk.cred_guard_mutex), \
.comm = "swapper", \
diff --git a/include/linux/input.h b/include/linux/input.h
index 896a92227bc4..d6ae1761be97 100644
--- a/include/linux/input.h
+++ b/include/linux/input.h
@@ -1196,7 +1196,7 @@ struct input_dev {
int (*flush)(struct input_dev *dev, struct file *file);
int (*event)(struct input_dev *dev, unsigned int type, unsigned int code, int value);
- struct input_handle *grab;
+ struct input_handle __rcu *grab;
spinlock_t event_lock;
struct mutex mutex;
diff --git a/include/linux/iocontext.h b/include/linux/iocontext.h
index 64d529133031..3e70b21884a9 100644
--- a/include/linux/iocontext.h
+++ b/include/linux/iocontext.h
@@ -53,7 +53,7 @@ struct io_context {
struct radix_tree_root radix_root;
struct hlist_head cic_list;
- void *ioc_data;
+ void __rcu *ioc_data;
};
static inline struct io_context *ioc_task_link(struct io_context *ioc)
diff --git a/include/linux/key.h b/include/linux/key.h
index cd50dfa1d4c2..3db0adce1fda 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -178,8 +178,9 @@ struct key {
*/
union {
unsigned long value;
+ void __rcu *rcudata;
void *data;
- struct keyring_list *subscriptions;
+ struct keyring_list __rcu *subscriptions;
} payload;
};
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index c13cc48697aa..ac740b26eb10 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -205,7 +205,7 @@ struct kvm {
struct mutex irq_lock;
#ifdef CONFIG_HAVE_KVM_IRQCHIP
- struct kvm_irq_routing_table *irq_routing;
+ struct kvm_irq_routing_table __rcu *irq_routing;
struct hlist_head mask_notifier_list;
struct hlist_head irq_ack_notifier_list;
#endif
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index ee7e258627f9..cb57d657ce4d 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -299,7 +299,7 @@ struct mm_struct {
* new_owner->mm == mm
* new_owner->alloc_lock is held
*/
- struct task_struct *owner;
+ struct task_struct __rcu *owner;
#endif
#ifdef CONFIG_PROC_FS
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 508f8cf6da37..d0edf7d823ae 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -185,7 +185,7 @@ struct nfs_inode {
struct nfs4_cached_acl *nfs4_acl;
/* NFSv4 state */
struct list_head open_states;
- struct nfs_delegation *delegation;
+ struct nfs_delegation __rcu *delegation;
fmode_t delegation_state;
struct rw_semaphore rwsem;
#endif /* CONFIG_NFS_V4*/
diff --git a/include/linux/notifier.h b/include/linux/notifier.h
index b2f1a4d83550..2026f9e1ceb8 100644
--- a/include/linux/notifier.h
+++ b/include/linux/notifier.h
@@ -49,28 +49,28 @@
struct notifier_block {
int (*notifier_call)(struct notifier_block *, unsigned long, void *);
- struct notifier_block *next;
+ struct notifier_block __rcu *next;
int priority;
};
struct atomic_notifier_head {
spinlock_t lock;
- struct notifier_block *head;
+ struct notifier_block __rcu *head;
};
struct blocking_notifier_head {
struct rw_semaphore rwsem;
- struct notifier_block *head;
+ struct notifier_block __rcu *head;
};
struct raw_notifier_head {
- struct notifier_block *head;
+ struct notifier_block __rcu *head;
};
struct srcu_notifier_head {
struct mutex mutex;
struct srcu_struct srcu;
- struct notifier_block *head;
+ struct notifier_block __rcu *head;
};
#define ATOMIC_INIT_NOTIFIER_HEAD(name) do { \
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 634b8e674ac5..a39cbed9ee17 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -47,6 +47,8 @@ static inline void *radix_tree_indirect_to_ptr(void *ptr)
{
return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR);
}
+#define radix_tree_indirect_to_ptr(ptr) \
+ radix_tree_indirect_to_ptr((void __force *)(ptr))
static inline int radix_tree_is_indirect_ptr(void *ptr)
{
@@ -61,7 +63,7 @@ static inline int radix_tree_is_indirect_ptr(void *ptr)
struct radix_tree_root {
unsigned int height;
gfp_t gfp_mask;
- struct radix_tree_node *rnode;
+ struct radix_tree_node __rcu *rnode;
};
#define RADIX_TREE_INIT(mask) { \
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 4ec3b38ce9c5..f31ef61f1c65 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -10,6 +10,21 @@
#include <linux/rcupdate.h>
/*
+ * Why is there no list_empty_rcu()? Because list_empty() serves this
+ * purpose. The list_empty() function fetches the RCU-protected pointer
+ * and compares it to the address of the list head, but neither dereferences
+ * this pointer itself nor provides this pointer to the caller. Therefore,
+ * it is not necessary to use rcu_dereference(), so that list_empty() can
+ * be used anywhere you would want to use a list_empty_rcu().
+ */
+
+/*
+ * return the ->next pointer of a list_head in an rcu safe
+ * way, we must not access it directly
+ */
+#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next)))
+
+/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
@@ -20,7 +35,7 @@ static inline void __list_add_rcu(struct list_head *new,
{
new->next = next;
new->prev = prev;
- rcu_assign_pointer(prev->next, new);
+ rcu_assign_pointer(list_next_rcu(prev), new);
next->prev = new;
}
@@ -138,7 +153,7 @@ static inline void list_replace_rcu(struct list_head *old,
{
new->next = old->next;
new->prev = old->prev;
- rcu_assign_pointer(new->prev->next, new);
+ rcu_assign_pointer(list_next_rcu(new->prev), new);
new->next->prev = new;
old->prev = LIST_POISON2;
}
@@ -193,7 +208,7 @@ static inline void list_splice_init_rcu(struct list_head *list,
*/
last->next = at;
- rcu_assign_pointer(head->next, first);
+ rcu_assign_pointer(list_next_rcu(head), first);
first->prev = head;
at->prev = last;
}
@@ -208,7 +223,9 @@ static inline void list_splice_init_rcu(struct list_head *list,
* primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
*/
#define list_entry_rcu(ptr, type, member) \
- container_of(rcu_dereference_raw(ptr), type, member)
+ ({typeof (*ptr) __rcu *__ptr = (typeof (*ptr) __rcu __force *)ptr; \
+ container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \
+ })
/**
* list_first_entry_rcu - get the first element from a list
@@ -225,9 +242,9 @@ static inline void list_splice_init_rcu(struct list_head *list,
list_entry_rcu((ptr)->next, type, member)
#define __list_for_each_rcu(pos, head) \
- for (pos = rcu_dereference_raw((head)->next); \
+ for (pos = rcu_dereference_raw(list_next_rcu(head)); \
pos != (head); \
- pos = rcu_dereference_raw(pos->next))
+ pos = rcu_dereference_raw(list_next_rcu((pos)))
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
@@ -257,9 +274,9 @@ static inline void list_splice_init_rcu(struct list_head *list,
* as long as the traversal is guarded by rcu_read_lock().
*/
#define list_for_each_continue_rcu(pos, head) \
- for ((pos) = rcu_dereference_raw((pos)->next); \
+ for ((pos) = rcu_dereference_raw(list_next_rcu(pos)); \
prefetch((pos)->next), (pos) != (head); \
- (pos) = rcu_dereference_raw((pos)->next))
+ (pos) = rcu_dereference_raw(list_next_rcu(pos)))
/**
* list_for_each_entry_continue_rcu - continue iteration over list of given type
@@ -314,12 +331,19 @@ static inline void hlist_replace_rcu(struct hlist_node *old,
new->next = next;
new->pprev = old->pprev;
- rcu_assign_pointer(*new->pprev, new);
+ rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new);
if (next)
new->next->pprev = &new->next;
old->pprev = LIST_POISON2;
}
+/*
+ * return the first or the next element in an RCU protected hlist
+ */
+#define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first)))
+#define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next)))
+#define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev)))
+
/**
* hlist_add_head_rcu
* @n: the element to add to the hash list.
@@ -346,7 +370,7 @@ static inline void hlist_add_head_rcu(struct hlist_node *n,
n->next = first;
n->pprev = &h->first;
- rcu_assign_pointer(h->first, n);
+ rcu_assign_pointer(hlist_first_rcu(h), n);
if (first)
first->pprev = &n->next;
}
@@ -374,7 +398,7 @@ static inline void hlist_add_before_rcu(struct hlist_node *n,
{
n->pprev = next->pprev;
n->next = next;
- rcu_assign_pointer(*(n->pprev), n);
+ rcu_assign_pointer(hlist_pprev_rcu(n), n);
next->pprev = &n->next;
}
@@ -401,15 +425,15 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
{
n->next = prev->next;
n->pprev = &prev->next;
- rcu_assign_pointer(prev->next, n);
+ rcu_assign_pointer(hlist_next_rcu(prev), n);
if (n->next)
n->next->pprev = &n->next;
}
-#define __hlist_for_each_rcu(pos, head) \
- for (pos = rcu_dereference((head)->first); \
- pos && ({ prefetch(pos->next); 1; }); \
- pos = rcu_dereference(pos->next))
+#define __hlist_for_each_rcu(pos, head) \
+ for (pos = rcu_dereference(hlist_first_rcu(head)); \
+ pos && ({ prefetch(pos->next); 1; }); \
+ pos = rcu_dereference(hlist_next_rcu(pos)))
/**
* hlist_for_each_entry_rcu - iterate over rcu list of given type
@@ -422,11 +446,11 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
* as long as the traversal is guarded by rcu_read_lock().
*/
-#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = rcu_dereference_raw((head)->first); \
+#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
+ for (pos = rcu_dereference_raw(hlist_first_rcu(head)); \
pos && ({ prefetch(pos->next); 1; }) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \
- pos = rcu_dereference_raw(pos->next))
+ pos = rcu_dereference_raw(hlist_next_rcu(pos)))
/**
* hlist_for_each_entry_rcu_bh - iterate over rcu list of given type
diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
index b70ffe53cb9f..2ae13714828b 100644
--- a/include/linux/rculist_nulls.h
+++ b/include/linux/rculist_nulls.h
@@ -37,6 +37,12 @@ static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n)
}
}
+#define hlist_nulls_first_rcu(head) \
+ (*((struct hlist_nulls_node __rcu __force **)&(head)->first))
+
+#define hlist_nulls_next_rcu(node) \
+ (*((struct hlist_nulls_node __rcu __force **)&(node)->next))
+
/**
* hlist_nulls_del_rcu - deletes entry from hash list without re-initialization
* @n: the element to delete from the hash list.
@@ -88,7 +94,7 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
n->next = first;
n->pprev = &h->first;
- rcu_assign_pointer(h->first, n);
+ rcu_assign_pointer(hlist_nulls_first_rcu(h), n);
if (!is_a_nulls(first))
first->pprev = &n->next;
}
@@ -100,11 +106,11 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
* @member: the name of the hlist_nulls_node within the struct.
*
*/
-#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \
- for (pos = rcu_dereference_raw((head)->first); \
- (!is_a_nulls(pos)) && \
+#define hlist_nulls_for_each_entry_rcu(tpos, pos, head, member) \
+ for (pos = rcu_dereference_raw(hlist_nulls_first_rcu(head)); \
+ (!is_a_nulls(pos)) && \
({ tpos = hlist_nulls_entry(pos, typeof(*tpos), member); 1; }); \
- pos = rcu_dereference_raw(pos->next))
+ pos = rcu_dereference_raw(hlist_nulls_next_rcu(pos)))
#endif
#endif
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 9fbc54a2585d..89414d67d961 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -41,11 +41,15 @@
#include <linux/lockdep.h>
#include <linux/completion.h>
#include <linux/debugobjects.h>
+#include <linux/compiler.h>
#ifdef CONFIG_RCU_TORTURE_TEST
extern int rcutorture_runnable; /* for sysctl */
#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
+#define ULONG_CMP_GE(a, b) (ULONG_MAX / 2 >= (a) - (b))
+#define ULONG_CMP_LT(a, b) (ULONG_MAX / 2 < (a) - (b))
+
/**
* struct rcu_head - callback structure for use with RCU
* @next: next update requests in a list
@@ -57,29 +61,94 @@ struct rcu_head {
};
/* Exported common interfaces */
-extern void rcu_barrier(void);
+extern void call_rcu_sched(struct rcu_head *head,
+ void (*func)(struct rcu_head *rcu));
+extern void synchronize_sched(void);
extern void rcu_barrier_bh(void);
extern void rcu_barrier_sched(void);
extern void synchronize_sched_expedited(void);
extern int sched_expedited_torture_stats(char *page);
+static inline void __rcu_read_lock_bh(void)
+{
+ local_bh_disable();
+}
+
+static inline void __rcu_read_unlock_bh(void)
+{
+ local_bh_enable();
+}
+
+#ifdef CONFIG_PREEMPT_RCU
+
+extern void __rcu_read_lock(void);
+extern void __rcu_read_unlock(void);
+void synchronize_rcu(void);
+
+/*
+ * Defined as a macro as it is a very low level header included from
+ * areas that don't even know about current. This gives the rcu_read_lock()
+ * nesting depth, but makes sense only if CONFIG_PREEMPT_RCU -- in other
+ * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
+ */
+#define rcu_preempt_depth() (current->rcu_read_lock_nesting)
+
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+
+static inline void __rcu_read_lock(void)
+{
+ preempt_disable();
+}
+
+static inline void __rcu_read_unlock(void)
+{
+ preempt_enable();
+}
+
+static inline void synchronize_rcu(void)
+{
+ synchronize_sched();
+}
+
+static inline int rcu_preempt_depth(void)
+{
+ return 0;
+}
+
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
/* Internal to kernel */
extern void rcu_init(void);
+extern void rcu_sched_qs(int cpu);
+extern void rcu_bh_qs(int cpu);
+extern void rcu_check_callbacks(int cpu, int user);
+struct notifier_block;
+
+#ifdef CONFIG_NO_HZ
+
+extern void rcu_enter_nohz(void);
+extern void rcu_exit_nohz(void);
+
+#else /* #ifdef CONFIG_NO_HZ */
+
+static inline void rcu_enter_nohz(void)
+{
+}
+
+static inline void rcu_exit_nohz(void)
+{
+}
+
+#endif /* #else #ifdef CONFIG_NO_HZ */
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
#include <linux/rcutree.h>
-#elif defined(CONFIG_TINY_RCU)
+#elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU)
#include <linux/rcutiny.h>
#else
#error "Unknown RCU implementation specified to kernel configuration"
#endif
-#define RCU_HEAD_INIT { .next = NULL, .func = NULL }
-#define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
-#define INIT_RCU_HEAD(ptr) do { \
- (ptr)->next = NULL; (ptr)->func = NULL; \
-} while (0)
-
/*
* init_rcu_head_on_stack()/destroy_rcu_head_on_stack() are needed for dynamic
* initialization and destruction of rcu_head on the stack. rcu_head structures
@@ -120,14 +189,15 @@ extern struct lockdep_map rcu_sched_lock_map;
extern int debug_lockdep_rcu_enabled(void);
/**
- * rcu_read_lock_held - might we be in RCU read-side critical section?
+ * rcu_read_lock_held() - might we be in RCU read-side critical section?
*
* If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an RCU
* read-side critical section. In absence of CONFIG_DEBUG_LOCK_ALLOC,
* this assumes we are in an RCU read-side critical section unless it can
- * prove otherwise.
+ * prove otherwise. This is useful for debug checks in functions that
+ * require that they be called within an RCU read-side critical section.
*
- * Check debug_lockdep_rcu_enabled() to prevent false positives during boot
+ * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
* and while lockdep is disabled.
*/
static inline int rcu_read_lock_held(void)
@@ -144,14 +214,16 @@ static inline int rcu_read_lock_held(void)
extern int rcu_read_lock_bh_held(void);
/**
- * rcu_read_lock_sched_held - might we be in RCU-sched read-side critical section?
+ * rcu_read_lock_sched_held() - might we be in RCU-sched read-side critical section?
*
* If CONFIG_DEBUG_LOCK_ALLOC is selected, returns nonzero iff in an
* RCU-sched read-side critical section. In absence of
* CONFIG_DEBUG_LOCK_ALLOC, this assumes we are in an RCU-sched read-side
* critical section unless it can prove otherwise. Note that disabling
* of preemption (including disabling irqs) counts as an RCU-sched
- * read-side critical section.
+ * read-side critical section. This is useful for debug checks in functions
+ * that required that they be called within an RCU-sched read-side
+ * critical section.
*
* Check debug_lockdep_rcu_enabled() to prevent false positives during boot
* and while lockdep is disabled.
@@ -211,7 +283,11 @@ static inline int rcu_read_lock_sched_held(void)
extern int rcu_my_thread_group_empty(void);
-#define __do_rcu_dereference_check(c) \
+/**
+ * rcu_lockdep_assert - emit lockdep splat if specified condition not met
+ * @c: condition to check
+ */
+#define rcu_lockdep_assert(c) \
do { \
static bool __warned; \
if (debug_lockdep_rcu_enabled() && !__warned && !(c)) { \
@@ -220,41 +296,155 @@ extern int rcu_my_thread_group_empty(void);
} \
} while (0)
+#else /* #ifdef CONFIG_PROVE_RCU */
+
+#define rcu_lockdep_assert(c) do { } while (0)
+
+#endif /* #else #ifdef CONFIG_PROVE_RCU */
+
+/*
+ * Helper functions for rcu_dereference_check(), rcu_dereference_protected()
+ * and rcu_assign_pointer(). Some of these could be folded into their
+ * callers, but they are left separate in order to ease introduction of
+ * multiple flavors of pointers to match the multiple flavors of RCU
+ * (e.g., __rcu_bh, * __rcu_sched, and __srcu), should this make sense in
+ * the future.
+ */
+#define __rcu_access_pointer(p, space) \
+ ({ \
+ typeof(*p) *_________p1 = (typeof(*p)*__force )ACCESS_ONCE(p); \
+ (void) (((typeof (*p) space *)p) == p); \
+ ((typeof(*p) __force __kernel *)(_________p1)); \
+ })
+#define __rcu_dereference_check(p, c, space) \
+ ({ \
+ typeof(*p) *_________p1 = (typeof(*p)*__force )ACCESS_ONCE(p); \
+ rcu_lockdep_assert(c); \
+ (void) (((typeof (*p) space *)p) == p); \
+ smp_read_barrier_depends(); \
+ ((typeof(*p) __force __kernel *)(_________p1)); \
+ })
+#define __rcu_dereference_protected(p, c, space) \
+ ({ \
+ rcu_lockdep_assert(c); \
+ (void) (((typeof (*p) space *)p) == p); \
+ ((typeof(*p) __force __kernel *)(p)); \
+ })
+
+#define __rcu_dereference_index_check(p, c) \
+ ({ \
+ typeof(p) _________p1 = ACCESS_ONCE(p); \
+ rcu_lockdep_assert(c); \
+ smp_read_barrier_depends(); \
+ (_________p1); \
+ })
+#define __rcu_assign_pointer(p, v, space) \
+ ({ \
+ if (!__builtin_constant_p(v) || \
+ ((v) != NULL)) \
+ smp_wmb(); \
+ (p) = (typeof(*v) __force space *)(v); \
+ })
+
+
/**
- * rcu_dereference_check - rcu_dereference with debug checking
+ * rcu_access_pointer() - fetch RCU pointer with no dereferencing
+ * @p: The pointer to read
+ *
+ * Return the value of the specified RCU-protected pointer, but omit the
+ * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful
+ * when the value of this pointer is accessed, but the pointer is not
+ * dereferenced, for example, when testing an RCU-protected pointer against
+ * NULL. Although rcu_access_pointer() may also be used in cases where
+ * update-side locks prevent the value of the pointer from changing, you
+ * should instead use rcu_dereference_protected() for this use case.
+ */
+#define rcu_access_pointer(p) __rcu_access_pointer((p), __rcu)
+
+/**
+ * rcu_dereference_check() - rcu_dereference with debug checking
* @p: The pointer to read, prior to dereferencing
* @c: The conditions under which the dereference will take place
*
* Do an rcu_dereference(), but check that the conditions under which the
- * dereference will take place are correct. Typically the conditions indicate
- * the various locking conditions that should be held at that point. The check
- * should return true if the conditions are satisfied.
+ * dereference will take place are correct. Typically the conditions
+ * indicate the various locking conditions that should be held at that
+ * point. The check should return true if the conditions are satisfied.
+ * An implicit check for being in an RCU read-side critical section
+ * (rcu_read_lock()) is included.
*
* For example:
*
- * bar = rcu_dereference_check(foo->bar, rcu_read_lock_held() ||
- * lockdep_is_held(&foo->lock));
+ * bar = rcu_dereference_check(foo->bar, lockdep_is_held(&foo->lock));
*
* could be used to indicate to lockdep that foo->bar may only be dereferenced
- * if either the RCU read lock is held, or that the lock required to replace
+ * if either rcu_read_lock() is held, or that the lock required to replace
* the bar struct at foo->bar is held.
*
* Note that the list of conditions may also include indications of when a lock
* need not be held, for example during initialisation or destruction of the
* target struct:
*
- * bar = rcu_dereference_check(foo->bar, rcu_read_lock_held() ||
- * lockdep_is_held(&foo->lock) ||
+ * bar = rcu_dereference_check(foo->bar, lockdep_is_held(&foo->lock) ||
* atomic_read(&foo->usage) == 0);
+ *
+ * Inserts memory barriers on architectures that require them
+ * (currently only the Alpha), prevents the compiler from refetching
+ * (and from merging fetches), and, more importantly, documents exactly
+ * which pointers are protected by RCU and checks that the pointer is
+ * annotated as __rcu.
*/
#define rcu_dereference_check(p, c) \
- ({ \
- __do_rcu_dereference_check(c); \
- rcu_dereference_raw(p); \
- })
+ __rcu_dereference_check((p), rcu_read_lock_held() || (c), __rcu)
/**
- * rcu_dereference_protected - fetch RCU pointer when updates prevented
+ * rcu_dereference_bh_check() - rcu_dereference_bh with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * This is the RCU-bh counterpart to rcu_dereference_check().
+ */
+#define rcu_dereference_bh_check(p, c) \
+ __rcu_dereference_check((p), rcu_read_lock_bh_held() || (c), __rcu)
+
+/**
+ * rcu_dereference_sched_check() - rcu_dereference_sched with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * This is the RCU-sched counterpart to rcu_dereference_check().
+ */
+#define rcu_dereference_sched_check(p, c) \
+ __rcu_dereference_check((p), rcu_read_lock_sched_held() || (c), \
+ __rcu)
+
+#define rcu_dereference_raw(p) rcu_dereference_check(p, 1) /*@@@ needed? @@@*/
+
+/**
+ * rcu_dereference_index_check() - rcu_dereference for indices with debug checking
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * Similar to rcu_dereference_check(), but omits the sparse checking.
+ * This allows rcu_dereference_index_check() to be used on integers,
+ * which can then be used as array indices. Attempting to use
+ * rcu_dereference_check() on an integer will give compiler warnings
+ * because the sparse address-space mechanism relies on dereferencing
+ * the RCU-protected pointer. Dereferencing integers is not something
+ * that even gcc will put up with.
+ *
+ * Note that this function does not implicitly check for RCU read-side
+ * critical sections. If this function gains lots of uses, it might
+ * make sense to provide versions for each flavor of RCU, but it does
+ * not make sense as of early 2010.
+ */
+#define rcu_dereference_index_check(p, c) \
+ __rcu_dereference_index_check((p), (c))
+
+/**
+ * rcu_dereference_protected() - fetch RCU pointer when updates prevented
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
*
* Return the value of the specified RCU-protected pointer, but omit
* both the smp_read_barrier_depends() and the ACCESS_ONCE(). This
@@ -263,35 +453,61 @@ extern int rcu_my_thread_group_empty(void);
* prevent the compiler from repeating this reference or combining it
* with other references, so it should not be used without protection
* of appropriate locks.
+ *
+ * This function is only for update-side use. Using this function
+ * when protected only by rcu_read_lock() will result in infrequent
+ * but very ugly failures.
*/
#define rcu_dereference_protected(p, c) \
- ({ \
- __do_rcu_dereference_check(c); \
- (p); \
- })
+ __rcu_dereference_protected((p), (c), __rcu)
-#else /* #ifdef CONFIG_PROVE_RCU */
+/**
+ * rcu_dereference_bh_protected() - fetch RCU-bh pointer when updates prevented
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * This is the RCU-bh counterpart to rcu_dereference_protected().
+ */
+#define rcu_dereference_bh_protected(p, c) \
+ __rcu_dereference_protected((p), (c), __rcu)
-#define rcu_dereference_check(p, c) rcu_dereference_raw(p)
-#define rcu_dereference_protected(p, c) (p)
+/**
+ * rcu_dereference_sched_protected() - fetch RCU-sched pointer when updates prevented
+ * @p: The pointer to read, prior to dereferencing
+ * @c: The conditions under which the dereference will take place
+ *
+ * This is the RCU-sched counterpart to rcu_dereference_protected().
+ */
+#define rcu_dereference_sched_protected(p, c) \
+ __rcu_dereference_protected((p), (c), __rcu)
-#endif /* #else #ifdef CONFIG_PROVE_RCU */
/**
- * rcu_access_pointer - fetch RCU pointer with no dereferencing
+ * rcu_dereference() - fetch RCU-protected pointer for dereferencing
+ * @p: The pointer to read, prior to dereferencing
*
- * Return the value of the specified RCU-protected pointer, but omit the
- * smp_read_barrier_depends() and keep the ACCESS_ONCE(). This is useful
- * when the value of this pointer is accessed, but the pointer is not
- * dereferenced, for example, when testing an RCU-protected pointer against
- * NULL. This may also be used in cases where update-side locks prevent
- * the value of the pointer from changing, but rcu_dereference_protected()
- * is a lighter-weight primitive for this use case.
+ * This is a simple wrapper around rcu_dereference_check().
+ */
+#define rcu_dereference(p) rcu_dereference_check(p, 0)
+
+/**
+ * rcu_dereference_bh() - fetch an RCU-bh-protected pointer for dereferencing
+ * @p: The pointer to read, prior to dereferencing
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define rcu_dereference_bh(p) rcu_dereference_bh_check(p, 0)
+
+/**
+ * rcu_dereference_sched() - fetch RCU-sched-protected pointer for dereferencing
+ * @p: The pointer to read, prior to dereferencing
+ *
+ * Makes rcu_dereference_check() do the dirty work.
*/
-#define rcu_access_pointer(p) ACCESS_ONCE(p)
+#define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0)
/**
- * rcu_read_lock - mark the beginning of an RCU read-side critical section.
+ * rcu_read_lock() - mark the beginning of an RCU read-side critical section
*
* When synchronize_rcu() is invoked on one CPU while other CPUs
* are within RCU read-side critical sections, then the
@@ -302,7 +518,7 @@ extern int rcu_my_thread_group_empty(void);
* until after the all the other CPUs exit their critical sections.
*
* Note, however, that RCU callbacks are permitted to run concurrently
- * with RCU read-side critical sections. One way that this can happen
+ * with new RCU read-side critical sections. One way that this can happen
* is via the following sequence of events: (1) CPU 0 enters an RCU
* read-side critical section, (2) CPU 1 invokes call_rcu() to register
* an RCU callback, (3) CPU 0 exits the RCU read-side critical section,
@@ -317,7 +533,20 @@ extern int rcu_my_thread_group_empty(void);
* will be deferred until the outermost RCU read-side critical section
* completes.
*
- * It is illegal to block while in an RCU read-side critical section.
+ * You can avoid reading and understanding the next paragraph by
+ * following this rule: don't put anything in an rcu_read_lock() RCU
+ * read-side critical section that would block in a !PREEMPT kernel.
+ * But if you want the full story, read on!
+ *
+ * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), it
+ * is illegal to block while in an RCU read-side critical section. In
+ * preemptible RCU implementations (TREE_PREEMPT_RCU and TINY_PREEMPT_RCU)
+ * in CONFIG_PREEMPT kernel builds, RCU read-side critical sections may
+ * be preempted, but explicit blocking is illegal. Finally, in preemptible
+ * RCU implementations in real-time (CONFIG_PREEMPT_RT) kernel builds,
+ * RCU read-side critical sections may be preempted and they may also
+ * block, but only when acquiring spinlocks that are subject to priority
+ * inheritance.
*/
static inline void rcu_read_lock(void)
{
@@ -337,7 +566,7 @@ static inline void rcu_read_lock(void)
*/
/**
- * rcu_read_unlock - marks the end of an RCU read-side critical section.
+ * rcu_read_unlock() - marks the end of an RCU read-side critical section.
*
* See rcu_read_lock() for more information.
*/
@@ -349,15 +578,16 @@ static inline void rcu_read_unlock(void)
}
/**
- * rcu_read_lock_bh - mark the beginning of a softirq-only RCU critical section
+ * rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
*
* This is equivalent of rcu_read_lock(), but to be used when updates
- * are being done using call_rcu_bh(). Since call_rcu_bh() callbacks
- * consider completion of a softirq handler to be a quiescent state,
- * a process in RCU read-side critical section must be protected by
- * disabling softirqs. Read-side critical sections in interrupt context
- * can use just rcu_read_lock().
- *
+ * are being done using call_rcu_bh() or synchronize_rcu_bh(). Since
+ * both call_rcu_bh() and synchronize_rcu_bh() consider completion of a
+ * softirq handler to be a quiescent state, a process in RCU read-side
+ * critical section must be protected by disabling softirqs. Read-side
+ * critical sections in interrupt context can use just rcu_read_lock(),
+ * though this should at least be commented to avoid confusing people
+ * reading the code.
*/
static inline void rcu_read_lock_bh(void)
{
@@ -379,13 +609,12 @@ static inline void rcu_read_unlock_bh(void)
}
/**
- * rcu_read_lock_sched - mark the beginning of a RCU-classic critical section
+ * rcu_read_lock_sched() - mark the beginning of a RCU-sched critical section
*
- * Should be used with either
- * - synchronize_sched()
- * or
- * - call_rcu_sched() and rcu_barrier_sched()
- * on the write-side to insure proper synchronization.
+ * This is equivalent of rcu_read_lock(), but to be used when updates
+ * are being done using call_rcu_sched() or synchronize_rcu_sched().
+ * Read-side critical sections can also be introduced by anything that
+ * disables preemption, including local_irq_disable() and friends.
*/
static inline void rcu_read_lock_sched(void)
{
@@ -420,54 +649,14 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
preempt_enable_notrace();
}
-
-/**
- * rcu_dereference_raw - fetch an RCU-protected pointer
- *
- * The caller must be within some flavor of RCU read-side critical
- * section, or must be otherwise preventing the pointer from changing,
- * for example, by holding an appropriate lock. This pointer may later
- * be safely dereferenced. It is the caller's responsibility to have
- * done the right thing, as this primitive does no checking of any kind.
- *
- * Inserts memory barriers on architectures that require them
- * (currently only the Alpha), and, more importantly, documents
- * exactly which pointers are protected by RCU.
- */
-#define rcu_dereference_raw(p) ({ \
- typeof(p) _________p1 = ACCESS_ONCE(p); \
- smp_read_barrier_depends(); \
- (_________p1); \
- })
-
-/**
- * rcu_dereference - fetch an RCU-protected pointer, checking for RCU
- *
- * Makes rcu_dereference_check() do the dirty work.
- */
-#define rcu_dereference(p) \
- rcu_dereference_check(p, rcu_read_lock_held())
-
/**
- * rcu_dereference_bh - fetch an RCU-protected pointer, checking for RCU-bh
+ * rcu_assign_pointer() - assign to RCU-protected pointer
+ * @p: pointer to assign to
+ * @v: value to assign (publish)
*
- * Makes rcu_dereference_check() do the dirty work.
- */
-#define rcu_dereference_bh(p) \
- rcu_dereference_check(p, rcu_read_lock_bh_held())
-
-/**
- * rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched
- *
- * Makes rcu_dereference_check() do the dirty work.
- */
-#define rcu_dereference_sched(p) \
- rcu_dereference_check(p, rcu_read_lock_sched_held())
-
-/**
- * rcu_assign_pointer - assign (publicize) a pointer to a newly
- * initialized structure that will be dereferenced by RCU read-side
- * critical sections. Returns the value assigned.
+ * Assigns the specified value to the specified RCU-protected
+ * pointer, ensuring that any concurrent RCU readers will see
+ * any prior initialization. Returns the value assigned.
*
* Inserts memory barriers on architectures that require them
* (pretty much all of them other than x86), and also prevents
@@ -476,14 +665,17 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* call documents which pointers will be dereferenced by RCU read-side
* code.
*/
-
#define rcu_assign_pointer(p, v) \
- ({ \
- if (!__builtin_constant_p(v) || \
- ((v) != NULL)) \
- smp_wmb(); \
- (p) = (v); \
- })
+ __rcu_assign_pointer((p), (v), __rcu)
+
+/**
+ * RCU_INIT_POINTER() - initialize an RCU protected pointer
+ *
+ * Initialize an RCU-protected pointer in such a way to avoid RCU-lockdep
+ * splats.
+ */
+#define RCU_INIT_POINTER(p, v) \
+ p = (typeof(*v) __force __rcu *)(v)
/* Infrastructure to implement the synchronize_() primitives. */
@@ -494,26 +686,37 @@ struct rcu_synchronize {
extern void wakeme_after_rcu(struct rcu_head *head);
+#ifdef CONFIG_PREEMPT_RCU
+
/**
- * call_rcu - Queue an RCU callback for invocation after a grace period.
+ * call_rcu() - Queue an RCU callback for invocation after a grace period.
* @head: structure to be used for queueing the RCU updates.
- * @func: actual update function to be invoked after the grace period
+ * @func: actual callback function to be invoked after the grace period
*
- * The update function will be invoked some time after a full grace
- * period elapses, in other words after all currently executing RCU
- * read-side critical sections have completed. RCU read-side critical
+ * The callback function will be invoked some time after a full grace
+ * period elapses, in other words after all pre-existing RCU read-side
+ * critical sections have completed. However, the callback function
+ * might well execute concurrently with RCU read-side critical sections
+ * that started after call_rcu() was invoked. RCU read-side critical
* sections are delimited by rcu_read_lock() and rcu_read_unlock(),
* and may be nested.
*/
extern void call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *head));
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+
+/* In classic RCU, call_rcu() is just call_rcu_sched(). */
+#define call_rcu call_rcu_sched
+
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+
/**
- * call_rcu_bh - Queue an RCU for invocation after a quicker grace period.
+ * call_rcu_bh() - Queue an RCU for invocation after a quicker grace period.
* @head: structure to be used for queueing the RCU updates.
- * @func: actual update function to be invoked after the grace period
+ * @func: actual callback function to be invoked after the grace period
*
- * The update function will be invoked some time after a full grace
+ * The callback function will be invoked some time after a full grace
* period elapses, in other words after all currently executing RCU
* read-side critical sections have completed. call_rcu_bh() assumes
* that the read-side critical sections end on completion of a softirq
@@ -566,37 +769,4 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head)
}
#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
-#ifndef CONFIG_PROVE_RCU
-#define __do_rcu_dereference_check(c) do { } while (0)
-#endif /* #ifdef CONFIG_PROVE_RCU */
-
-#define __rcu_dereference_index_check(p, c) \
- ({ \
- typeof(p) _________p1 = ACCESS_ONCE(p); \
- __do_rcu_dereference_check(c); \
- smp_read_barrier_depends(); \
- (_________p1); \
- })
-
-/**
- * rcu_dereference_index_check() - rcu_dereference for indices with debug checking
- * @p: The pointer to read, prior to dereferencing
- * @c: The conditions under which the dereference will take place
- *
- * Similar to rcu_dereference_check(), but omits the sparse checking.
- * This allows rcu_dereference_index_check() to be used on integers,
- * which can then be used as array indices. Attempting to use
- * rcu_dereference_check() on an integer will give compiler warnings
- * because the sparse address-space mechanism relies on dereferencing
- * the RCU-protected pointer. Dereferencing integers is not something
- * that even gcc will put up with.
- *
- * Note that this function does not implicitly check for RCU read-side
- * critical sections. If this function gains lots of uses, it might
- * make sense to provide versions for each flavor of RCU, but it does
- * not make sense as of early 2010.
- */
-#define rcu_dereference_index_check(p, c) \
- __rcu_dereference_index_check((p), (c))
-
#endif /* __LINUX_RCUPDATE_H */
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index e2e893144a84..13877cb93a60 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -27,103 +27,101 @@
#include <linux/cache.h>
-void rcu_sched_qs(int cpu);
-void rcu_bh_qs(int cpu);
-static inline void rcu_note_context_switch(int cpu)
-{
- rcu_sched_qs(cpu);
-}
+#define rcu_init_sched() do { } while (0)
-#define __rcu_read_lock() preempt_disable()
-#define __rcu_read_unlock() preempt_enable()
-#define __rcu_read_lock_bh() local_bh_disable()
-#define __rcu_read_unlock_bh() local_bh_enable()
-#define call_rcu_sched call_rcu
+#ifdef CONFIG_TINY_RCU
-#define rcu_init_sched() do { } while (0)
-extern void rcu_check_callbacks(int cpu, int user);
+static inline void synchronize_rcu_expedited(void)
+{
+ synchronize_sched(); /* Only one CPU, so pretty fast anyway!!! */
+}
-static inline int rcu_needs_cpu(int cpu)
+static inline void rcu_barrier(void)
{
- return 0;
+ rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */
}
-/*
- * Return the number of grace periods.
- */
-static inline long rcu_batches_completed(void)
+#else /* #ifdef CONFIG_TINY_RCU */
+
+void rcu_barrier(void);
+void synchronize_rcu_expedited(void);
+
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+static inline void synchronize_rcu_bh(void)
{
- return 0;
+ synchronize_sched();
}
-/*
- * Return the number of bottom-half grace periods.
- */
-static inline long rcu_batches_completed_bh(void)
+static inline void synchronize_rcu_bh_expedited(void)
{
- return 0;
+ synchronize_sched();
}
-static inline void rcu_force_quiescent_state(void)
+#ifdef CONFIG_TINY_RCU
+
+static inline void rcu_preempt_note_context_switch(void)
{
}
-static inline void rcu_bh_force_quiescent_state(void)
+static inline void exit_rcu(void)
{
}
-static inline void rcu_sched_force_quiescent_state(void)
+static inline int rcu_needs_cpu(int cpu)
{
+ return 0;
}
-extern void synchronize_sched(void);
+#else /* #ifdef CONFIG_TINY_RCU */
+
+void rcu_preempt_note_context_switch(void);
+extern void exit_rcu(void);
+int rcu_preempt_needs_cpu(void);
-static inline void synchronize_rcu(void)
+static inline int rcu_needs_cpu(int cpu)
{
- synchronize_sched();
+ return rcu_preempt_needs_cpu();
}
-static inline void synchronize_rcu_bh(void)
+#endif /* #else #ifdef CONFIG_TINY_RCU */
+
+static inline void rcu_note_context_switch(int cpu)
{
- synchronize_sched();
+ rcu_sched_qs(cpu);
+ rcu_preempt_note_context_switch();
}
-static inline void synchronize_rcu_expedited(void)
+/*
+ * Return the number of grace periods.
+ */
+static inline long rcu_batches_completed(void)
{
- synchronize_sched();
+ return 0;
}
-static inline void synchronize_rcu_bh_expedited(void)
+/*
+ * Return the number of bottom-half grace periods.
+ */
+static inline long rcu_batches_completed_bh(void)
{
- synchronize_sched();
+ return 0;
}
-struct notifier_block;
-
-#ifdef CONFIG_NO_HZ
-
-extern void rcu_enter_nohz(void);
-extern void rcu_exit_nohz(void);
-
-#else /* #ifdef CONFIG_NO_HZ */
-
-static inline void rcu_enter_nohz(void)
+static inline void rcu_force_quiescent_state(void)
{
}
-static inline void rcu_exit_nohz(void)
+static inline void rcu_bh_force_quiescent_state(void)
{
}
-#endif /* #else #ifdef CONFIG_NO_HZ */
-
-static inline void exit_rcu(void)
+static inline void rcu_sched_force_quiescent_state(void)
{
}
-static inline int rcu_preempt_depth(void)
+static inline void rcu_cpu_stall_reset(void)
{
- return 0;
}
#ifdef CONFIG_DEBUG_LOCK_ALLOC
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index c0ed1c056f29..95518e628794 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -30,64 +30,23 @@
#ifndef __LINUX_RCUTREE_H
#define __LINUX_RCUTREE_H
-struct notifier_block;
-
-extern void rcu_sched_qs(int cpu);
-extern void rcu_bh_qs(int cpu);
extern void rcu_note_context_switch(int cpu);
extern int rcu_needs_cpu(int cpu);
+extern void rcu_cpu_stall_reset(void);
#ifdef CONFIG_TREE_PREEMPT_RCU
-extern void __rcu_read_lock(void);
-extern void __rcu_read_unlock(void);
-extern void synchronize_rcu(void);
extern void exit_rcu(void);
-/*
- * Defined as macro as it is a very low level header
- * included from areas that don't even know about current
- */
-#define rcu_preempt_depth() (current->rcu_read_lock_nesting)
-
#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-static inline void __rcu_read_lock(void)
-{
- preempt_disable();
-}
-
-static inline void __rcu_read_unlock(void)
-{
- preempt_enable();
-}
-
-#define synchronize_rcu synchronize_sched
-
static inline void exit_rcu(void)
{
}
-static inline int rcu_preempt_depth(void)
-{
- return 0;
-}
-
#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
-static inline void __rcu_read_lock_bh(void)
-{
- local_bh_disable();
-}
-static inline void __rcu_read_unlock_bh(void)
-{
- local_bh_enable();
-}
-
-extern void call_rcu_sched(struct rcu_head *head,
- void (*func)(struct rcu_head *rcu));
extern void synchronize_rcu_bh(void);
-extern void synchronize_sched(void);
extern void synchronize_rcu_expedited(void);
static inline void synchronize_rcu_bh_expedited(void)
@@ -95,7 +54,7 @@ static inline void synchronize_rcu_bh_expedited(void)
synchronize_sched_expedited();
}
-extern void rcu_check_callbacks(int cpu, int user);
+extern void rcu_barrier(void);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
@@ -104,18 +63,6 @@ extern void rcu_force_quiescent_state(void);
extern void rcu_bh_force_quiescent_state(void);
extern void rcu_sched_force_quiescent_state(void);
-#ifdef CONFIG_NO_HZ
-void rcu_enter_nohz(void);
-void rcu_exit_nohz(void);
-#else /* CONFIG_NO_HZ */
-static inline void rcu_enter_nohz(void)
-{
-}
-static inline void rcu_exit_nohz(void)
-{
-}
-#endif /* CONFIG_NO_HZ */
-
/* A context switch is a grace period for RCU-sched and RCU-bh. */
static inline int rcu_blocking_is_gp(void)
{
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1e2a6db2d7dd..e18473f0eb78 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1202,11 +1202,13 @@ struct task_struct {
unsigned int policy;
cpumask_t cpus_allowed;
-#ifdef CONFIG_TREE_PREEMPT_RCU
+#ifdef CONFIG_PREEMPT_RCU
int rcu_read_lock_nesting;
char rcu_read_unlock_special;
- struct rcu_node *rcu_blocked_node;
struct list_head rcu_node_entry;
+#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#ifdef CONFIG_TREE_PREEMPT_RCU
+ struct rcu_node *rcu_blocked_node;
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
@@ -1288,9 +1290,9 @@ struct task_struct {
struct list_head cpu_timers[3];
/* process credentials */
- const struct cred *real_cred; /* objective and real subjective task
+ const struct cred __rcu *real_cred; /* objective and real subjective task
* credentials (COW) */
- const struct cred *cred; /* effective (overridable) subjective task
+ const struct cred __rcu *cred; /* effective (overridable) subjective task
* credentials (COW) */
struct mutex cred_guard_mutex; /* guard against foreign influences on
* credential calculations
@@ -1418,7 +1420,7 @@ struct task_struct {
#endif
#ifdef CONFIG_CGROUPS
/* Control Group info protected by css_set_lock */
- struct css_set *cgroups;
+ struct css_set __rcu *cgroups;
/* cg_list protected by css_set_lock and tsk->alloc_lock */
struct list_head cg_list;
#endif
@@ -1740,7 +1742,7 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
#define tsk_used_math(p) ((p)->flags & PF_USED_MATH)
#define used_math() tsk_used_math(current)
-#ifdef CONFIG_TREE_PREEMPT_RCU
+#ifdef CONFIG_PREEMPT_RCU
#define RCU_READ_UNLOCK_BLOCKED (1 << 0) /* blocked while in RCU read-side. */
#define RCU_READ_UNLOCK_NEED_QS (1 << 1) /* RCU core needs CPU response. */
@@ -1749,7 +1751,9 @@ static inline void rcu_copy_process(struct task_struct *p)
{
p->rcu_read_lock_nesting = 0;
p->rcu_read_unlock_special = 0;
+#ifdef CONFIG_TREE_PREEMPT_RCU
p->rcu_blocked_node = NULL;
+#endif
INIT_LIST_HEAD(&p->rcu_node_entry);
}
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 4d5d2f546dbf..58971e891f48 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -108,19 +108,43 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/**
- * srcu_dereference - fetch SRCU-protected pointer with checking
+ * srcu_dereference_check - fetch SRCU-protected pointer for later dereferencing
+ * @p: the pointer to fetch and protect for later dereferencing
+ * @sp: pointer to the srcu_struct, which is used to check that we
+ * really are in an SRCU read-side critical section.
+ * @c: condition to check for update-side use
*
- * Makes rcu_dereference_check() do the dirty work.
+ * If PROVE_RCU is enabled, invoking this outside of an RCU read-side
+ * critical section will result in an RCU-lockdep splat, unless @c evaluates
+ * to 1. The @c argument will normally be a logical expression containing
+ * lockdep_is_held() calls.
*/
-#define srcu_dereference(p, sp) \
- rcu_dereference_check(p, srcu_read_lock_held(sp))
+#define srcu_dereference_check(p, sp, c) \
+ __rcu_dereference_check((p), srcu_read_lock_held(sp) || (c), __rcu)
+
+/**
+ * srcu_dereference - fetch SRCU-protected pointer for later dereferencing
+ * @p: the pointer to fetch and protect for later dereferencing
+ * @sp: pointer to the srcu_struct, which is used to check that we
+ * really are in an SRCU read-side critical section.
+ *
+ * Makes rcu_dereference_check() do the dirty work. If PROVE_RCU
+ * is enabled, invoking this outside of an RCU read-side critical
+ * section will result in an RCU-lockdep splat.
+ */
+#define srcu_dereference(p, sp) srcu_dereference_check((p), (sp), 0)
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
* @sp: srcu_struct in which to register the new reader.
*
* Enter an SRCU read-side critical section. Note that SRCU read-side
- * critical sections may be nested.
+ * critical sections may be nested. However, it is illegal to
+ * call anything that waits on an SRCU grace period for the same
+ * srcu_struct, whether directly or indirectly. Please note that
+ * one way to indirectly wait on an SRCU grace period is to acquire
+ * a mutex that is held elsewhere while calling synchronize_srcu() or
+ * synchronize_srcu_expedited().
*/
static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
{
diff --git a/include/linux/sunrpc/auth_gss.h b/include/linux/sunrpc/auth_gss.h
index 671538d25bc1..8eee9dbbfe7a 100644
--- a/include/linux/sunrpc/auth_gss.h
+++ b/include/linux/sunrpc/auth_gss.h
@@ -69,7 +69,7 @@ struct gss_cl_ctx {
enum rpc_gss_proc gc_proc;
u32 gc_seq;
spinlock_t gc_seq_lock;
- struct gss_ctx *gc_gss_ctx;
+ struct gss_ctx __rcu *gc_gss_ctx;
struct xdr_netobj gc_wire_ctx;
u32 gc_win;
unsigned long gc_expiry;
@@ -80,7 +80,7 @@ struct gss_upcall_msg;
struct gss_cred {
struct rpc_cred gc_base;
enum rpc_gss_svc gc_service;
- struct gss_cl_ctx *gc_ctx;
+ struct gss_cl_ctx __rcu *gc_ctx;
struct gss_upcall_msg *gc_upcall;
unsigned long gc_upcall_timestamp;
unsigned char gc_machine_cred : 1;
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-16 04:54:33 +0000