#include <linux/rcupdate.h>
#include <linux/workqueue.h>
+#include <asm/unistd.h>
+
#include "util.h"
/**
if(size > IPCMNI)
size = IPCMNI;
- ids->size = size;
ids->in_use = 0;
ids->max_id = -1;
ids->seq = 0;
ids->seq_max = seq_limit;
}
- ids->entries = ipc_rcu_alloc(sizeof(struct ipc_id)*size);
+ ids->entries = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*size +
+ sizeof(struct ipc_id_ary));
if(ids->entries == NULL) {
printk(KERN_ERR "ipc_init_ids() failed, ipc service disabled.\n");
- ids->size = 0;
+ size = 0;
+ ids->entries = &ids->nullentry;
}
- for(i=0;i<ids->size;i++)
- ids->entries[i].p = NULL;
+ ids->entries->size = size;
+ for(i=0;i<size;i++)
+ ids->entries->p[i] = NULL;
}
/**
int max_id = ids->max_id;
/*
- * read_barrier_depends is not needed here
+ * rcu_dereference() is not needed here
* since ipc_ids.sem is held
*/
for (id = 0; id <= max_id; id++) {
- p = ids->entries[id].p;
- if(p==NULL)
+ p = ids->entries->p[id];
+ if (p==NULL)
+ continue;
+ if (!vx_check(p->xid, VX_IDENT))
continue;
if (key == p->key)
return id;
*/
static int grow_ary(struct ipc_ids* ids, int newsize)
{
- struct ipc_id* new;
- struct ipc_id* old;
+ struct ipc_id_ary* new;
+ struct ipc_id_ary* old;
int i;
+ int size = ids->entries->size;
if(newsize > IPCMNI)
newsize = IPCMNI;
- if(newsize <= ids->size)
+ if(newsize <= size)
return newsize;
- new = ipc_rcu_alloc(sizeof(struct ipc_id)*newsize);
+ new = ipc_rcu_alloc(sizeof(struct kern_ipc_perm *)*newsize +
+ sizeof(struct ipc_id_ary));
if(new == NULL)
- return ids->size;
- memcpy(new, ids->entries, sizeof(struct ipc_id)*ids->size);
- for(i=ids->size;i<newsize;i++) {
- new[i].p = NULL;
+ return size;
+ new->size = newsize;
+ memcpy(new->p, ids->entries->p, sizeof(struct kern_ipc_perm *)*size +
+ sizeof(struct ipc_id_ary));
+ for(i=size;i<newsize;i++) {
+ new->p[i] = NULL;
}
old = ids->entries;
- i = ids->size;
/*
- * before setting the ids->entries to the new array, there must be a
- * smp_wmb() to make sure the memcpyed contents of the new array are
- * visible before the new array becomes visible.
+ * Use rcu_assign_pointer() to make sure the memcpyed contents
+ * of the new array are visible before the new array becomes visible.
*/
- smp_wmb(); /* prevent seeing new array uninitialized. */
- ids->entries = new;
- smp_wmb(); /* prevent indexing into old array based on new size. */
- ids->size = newsize;
+ rcu_assign_pointer(ids->entries, new);
- ipc_rcu_free(old, sizeof(struct ipc_id)*i);
- return ids->size;
+ ipc_rcu_putref(old);
+ return newsize;
}
/**
size = grow_ary(ids,size);
/*
- * read_barrier_depends() is not needed here since
+ * rcu_dereference()() is not needed here since
* ipc_ids.sem is held
*/
for (id = 0; id < size; id++) {
- if(ids->entries[id].p == NULL)
+ if(ids->entries->p[id] == NULL)
goto found;
}
return -1;
if(ids->seq > ids->seq_max)
ids->seq = 0;
- new->lock = SPIN_LOCK_UNLOCKED;
+ spin_lock_init(&new->lock);
new->deleted = 0;
rcu_read_lock();
spin_lock(&new->lock);
- ids->entries[id].p = new;
+ ids->entries->p[id] = new;
return id;
}
{
struct kern_ipc_perm* p;
int lid = id % SEQ_MULTIPLIER;
- if(lid >= ids->size)
+ if(lid >= ids->entries->size)
BUG();
/*
- * do not need a read_barrier_depends() here to force ordering
+ * do not need a rcu_dereference()() here to force ordering
* on Alpha, since the ipc_ids.sem is held.
*/
- p = ids->entries[lid].p;
- ids->entries[lid].p = NULL;
+ p = ids->entries->p[lid];
+ ids->entries->p[lid] = NULL;
if(p==NULL)
BUG();
ids->in_use--;
lid--;
if(lid == -1)
break;
- } while (ids->entries[lid].p == NULL);
+ } while (ids->entries->p[lid] == NULL);
ids->max_id = lid;
}
p->deleted = 1;
kfree(ptr);
}
-struct ipc_rcu_kmalloc
+/*
+ * rcu allocations:
+ * There are three headers that are prepended to the actual allocation:
+ * - during use: ipc_rcu_hdr.
+ * - during the rcu grace period: ipc_rcu_grace.
+ * - [only if vmalloc]: ipc_rcu_sched.
+ * Their lifetime doesn't overlap, thus the headers share the same memory.
+ * Unlike a normal union, they are right-aligned, thus some container_of
+ * forward/backward casting is necessary:
+ */
+struct ipc_rcu_hdr
+{
+ int refcount;
+ int is_vmalloc;
+ void *data[0];
+};
+
+
+struct ipc_rcu_grace
{
struct rcu_head rcu;
/* "void *" makes sure alignment of following data is sane. */
void *data[0];
};
-struct ipc_rcu_vmalloc
+struct ipc_rcu_sched
{
- struct rcu_head rcu;
struct work_struct work;
/* "void *" makes sure alignment of following data is sane. */
void *data[0];
};
+#define HDRLEN_KMALLOC (sizeof(struct ipc_rcu_grace) > sizeof(struct ipc_rcu_hdr) ? \
+ sizeof(struct ipc_rcu_grace) : sizeof(struct ipc_rcu_hdr))
+#define HDRLEN_VMALLOC (sizeof(struct ipc_rcu_sched) > HDRLEN_KMALLOC ? \
+ sizeof(struct ipc_rcu_sched) : HDRLEN_KMALLOC)
+
static inline int rcu_use_vmalloc(int size)
{
/* Too big for a single page? */
- if (sizeof(struct ipc_rcu_kmalloc) + size > PAGE_SIZE)
+ if (HDRLEN_KMALLOC + size > PAGE_SIZE)
return 1;
return 0;
}
* workqueue if necessary (for vmalloc).
*/
if (rcu_use_vmalloc(size)) {
- out = vmalloc(sizeof(struct ipc_rcu_vmalloc) + size);
- if (out) out += sizeof(struct ipc_rcu_vmalloc);
+ out = vmalloc(HDRLEN_VMALLOC + size);
+ if (out) {
+ out += HDRLEN_VMALLOC;
+ container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 1;
+ container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
+ }
} else {
- out = kmalloc(sizeof(struct ipc_rcu_kmalloc)+size, GFP_KERNEL);
- if (out) out += sizeof(struct ipc_rcu_kmalloc);
+ out = kmalloc(HDRLEN_KMALLOC + size, GFP_KERNEL);
+ if (out) {
+ out += HDRLEN_KMALLOC;
+ container_of(out, struct ipc_rcu_hdr, data)->is_vmalloc = 0;
+ container_of(out, struct ipc_rcu_hdr, data)->refcount = 1;
+ }
}
return out;
}
+void ipc_rcu_getref(void *ptr)
+{
+ container_of(ptr, struct ipc_rcu_hdr, data)->refcount++;
+}
+
/**
* ipc_schedule_free - free ipc + rcu space
*
* Since RCU callback function is called in bh,
* we need to defer the vfree to schedule_work
*/
-static void ipc_schedule_free(void* arg)
+static void ipc_schedule_free(struct rcu_head *head)
{
- struct ipc_rcu_vmalloc *free = arg;
+ struct ipc_rcu_grace *grace =
+ container_of(head, struct ipc_rcu_grace, rcu);
+ struct ipc_rcu_sched *sched =
+ container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]);
- INIT_WORK(&free->work, vfree, free);
- schedule_work(&free->work);
+ INIT_WORK(&sched->work, vfree, sched);
+ schedule_work(&sched->work);
}
-void ipc_rcu_free(void* ptr, int size)
+/**
+ * ipc_immediate_free - free ipc + rcu space
+ *
+ * Free from the RCU callback context
+ *
+ */
+static void ipc_immediate_free(struct rcu_head *head)
{
- if (rcu_use_vmalloc(size)) {
- struct ipc_rcu_vmalloc *free;
- free = ptr - sizeof(*free);
- call_rcu(&free->rcu, ipc_schedule_free, free);
+ struct ipc_rcu_grace *free =
+ container_of(head, struct ipc_rcu_grace, rcu);
+ kfree(free);
+}
+
+void ipc_rcu_putref(void *ptr)
+{
+ if (--container_of(ptr, struct ipc_rcu_hdr, data)->refcount > 0)
+ return;
+
+ if (container_of(ptr, struct ipc_rcu_hdr, data)->is_vmalloc) {
+ call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
+ ipc_schedule_free);
} else {
- struct ipc_rcu_kmalloc *free;
- free = ptr - sizeof(*free);
- /* kfree takes a "const void *" so gcc warns. So we cast. */
- call_rcu(&free->rcu, (void (*)(void *))kfree, free);
+ call_rcu(&container_of(ptr, struct ipc_rcu_grace, data)->rcu,
+ ipc_immediate_free);
}
-
}
/**
{ /* flag will most probably be 0 or S_...UGO from <linux/stat.h> */
int requested_mode, granted_mode;
+ if (!vx_check(ipcp->xid, VX_ADMIN|VX_IDENT)) /* maybe just VX_IDENT? */
+ return -1;
requested_mode = (flag >> 6) | (flag >> 3) | flag;
granted_mode = ipcp->mode;
if (current->euid == ipcp->cuid || current->euid == ipcp->uid)
{
struct kern_ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
- if(lid >= ids->size)
+ if(lid >= ids->entries->size)
return NULL;
- out = ids->entries[lid].p;
+ out = ids->entries->p[lid];
return out;
}
{
struct kern_ipc_perm* out;
int lid = id % SEQ_MULTIPLIER;
- struct ipc_id* entries;
+ struct ipc_id_ary* entries;
rcu_read_lock();
- if(lid >= ids->size) {
+ entries = rcu_dereference(ids->entries);
+ if(lid >= entries->size) {
rcu_read_unlock();
return NULL;
}
-
- /*
- * Note: The following two read barriers are corresponding
- * to the two write barriers in grow_ary(). They guarantee
- * the writes are seen in the same order on the read side.
- * smp_rmb() has effect on all CPUs. read_barrier_depends()
- * is used if there are data dependency between two reads, and
- * has effect only on Alpha.
- */
- smp_rmb(); /* prevent indexing old array with new size */
- entries = ids->entries;
- read_barrier_depends(); /*prevent seeing new array unitialized */
- out = entries[lid].p;
+ out = entries->p[lid];
if(out == NULL) {
rcu_read_unlock();
return NULL;
return out;
}
+void ipc_lock_by_ptr(struct kern_ipc_perm *perm)
+{
+ rcu_read_lock();
+ spin_lock(&perm->lock);
+}
+
void ipc_unlock(struct kern_ipc_perm* perm)
{
spin_unlock(&perm->lock);
return 0;
}
-#if !defined(__ia64__) && !defined(__x86_64__) && !defined(__hppa__)
+#ifdef __ARCH_WANT_IPC_PARSE_VERSION
+
/**
* ipc_parse_version - IPC call version
}
}
-#endif /* __ia64__ */
+#endif /* __ARCH_WANT_IPC_PARSE_VERSION */
git://git.onelab.eu / linux-2.6.git / blobdiff