forked from luck/tmp_suning_uos_patched
ipc: merge ipc_rcu and kern_ipc_perm
ipc has two management structures that exist for every id: - struct kern_ipc_perm, it contains e.g. the permissions. - struct ipc_rcu, it contains the rcu head for rcu handling and the refcount. The patch merges both structures. As a bonus, we may save one cacheline, because both structures are cacheline aligned. In addition, it reduces the number of casts, instead most codepaths can use container_of. To simplify code, the ipc_rcu_alloc initializes the allocation to 0. [manfred@colorfullife.com: really include the memset() into ipc_alloc_rcu()] Link: http://lkml.kernel.org/r/564f8612-0601-b267-514f-a9f650ec9b32@colorfullife.com Link: http://lkml.kernel.org/r/20170525185107.12869-3-manfred@colorfullife.com Signed-off-by: Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Manfred Spraul
Linus Torvalds
parent
1a23395672
commit
dba4cdd39e
|
|
@ -20,6 +20,9 @@ struct kern_ipc_perm {
|
|||
umode_t mode;
|
||||
unsigned long seq;
|
||||
void *security;
|
||||
|
||||
struct rcu_head rcu;
|
||||
atomic_t refcount;
|
||||
} ____cacheline_aligned_in_smp;
|
||||
|
||||
#endif /* _LINUX_IPC_H */
|
||||
|
|
|
|||
19
ipc/msg.c
19
ipc/msg.c
|
|
@ -97,8 +97,8 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
|
|||
|
||||
static void msg_rcu_free(struct rcu_head *head)
|
||||
{
|
||||
struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
|
||||
struct msg_queue *msq = ipc_rcu_to_struct(p);
|
||||
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
|
||||
struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
|
||||
|
||||
security_msg_queue_free(msq);
|
||||
ipc_rcu_free(head);
|
||||
|
|
@ -118,7 +118,10 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
key_t key = params->key;
|
||||
int msgflg = params->flg;
|
||||
|
||||
msq = ipc_rcu_alloc(sizeof(*msq));
|
||||
BUILD_BUG_ON(offsetof(struct msg_queue, q_perm) != 0);
|
||||
|
||||
msq = container_of(ipc_rcu_alloc(sizeof(*msq)), struct msg_queue,
|
||||
q_perm);
|
||||
if (!msq)
|
||||
return -ENOMEM;
|
||||
|
||||
|
|
@ -128,7 +131,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
msq->q_perm.security = NULL;
|
||||
retval = security_msg_queue_alloc(msq);
|
||||
if (retval) {
|
||||
ipc_rcu_putref(msq, ipc_rcu_free);
|
||||
ipc_rcu_putref(&msq->q_perm, ipc_rcu_free);
|
||||
return retval;
|
||||
}
|
||||
|
||||
|
|
@ -144,7 +147,7 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
/* ipc_addid() locks msq upon success. */
|
||||
id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
|
||||
if (id < 0) {
|
||||
ipc_rcu_putref(msq, msg_rcu_free);
|
||||
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
|
||||
return id;
|
||||
}
|
||||
|
||||
|
|
@ -249,7 +252,7 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
|
|||
free_msg(msg);
|
||||
}
|
||||
atomic_sub(msq->q_cbytes, &ns->msg_bytes);
|
||||
ipc_rcu_putref(msq, msg_rcu_free);
|
||||
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -688,7 +691,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
|
|||
/* enqueue the sender and prepare to block */
|
||||
ss_add(msq, &s, msgsz);
|
||||
|
||||
if (!ipc_rcu_getref(msq)) {
|
||||
if (!ipc_rcu_getref(&msq->q_perm)) {
|
||||
err = -EIDRM;
|
||||
goto out_unlock0;
|
||||
}
|
||||
|
|
@ -700,7 +703,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext,
|
|||
rcu_read_lock();
|
||||
ipc_lock_object(&msq->q_perm);
|
||||
|
||||
ipc_rcu_putref(msq, msg_rcu_free);
|
||||
ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
|
||||
/* raced with RMID? */
|
||||
if (!ipc_valid_object(&msq->q_perm)) {
|
||||
err = -EIDRM;
|
||||
|
|
|
|||
34
ipc/sem.c
34
ipc/sem.c
|
|
@ -260,8 +260,8 @@ static void merge_queues(struct sem_array *sma)
|
|||
|
||||
static void sem_rcu_free(struct rcu_head *head)
|
||||
{
|
||||
struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
|
||||
struct sem_array *sma = ipc_rcu_to_struct(p);
|
||||
struct kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
|
||||
struct sem_array *sma = container_of(p, struct sem_array, sem_perm);
|
||||
|
||||
security_sem_free(sma);
|
||||
ipc_rcu_free(head);
|
||||
|
|
@ -438,7 +438,7 @@ static inline struct sem_array *sem_obtain_object_check(struct ipc_namespace *ns
|
|||
static inline void sem_lock_and_putref(struct sem_array *sma)
|
||||
{
|
||||
sem_lock(sma, NULL, -1);
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
}
|
||||
|
||||
static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
|
||||
|
|
@ -469,20 +469,20 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
if (ns->used_sems + nsems > ns->sc_semmns)
|
||||
return -ENOSPC;
|
||||
|
||||
BUILD_BUG_ON(offsetof(struct sem_array, sem_perm) != 0);
|
||||
|
||||
size = sizeof(*sma) + nsems * sizeof(sma->sems[0]);
|
||||
sma = ipc_rcu_alloc(size);
|
||||
sma = container_of(ipc_rcu_alloc(size), struct sem_array, sem_perm);
|
||||
if (!sma)
|
||||
return -ENOMEM;
|
||||
|
||||
memset(sma, 0, size);
|
||||
|
||||
sma->sem_perm.mode = (semflg & S_IRWXUGO);
|
||||
sma->sem_perm.key = key;
|
||||
|
||||
sma->sem_perm.security = NULL;
|
||||
retval = security_sem_alloc(sma);
|
||||
if (retval) {
|
||||
ipc_rcu_putref(sma, ipc_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, ipc_rcu_free);
|
||||
return retval;
|
||||
}
|
||||
|
||||
|
|
@ -502,7 +502,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
|
||||
id = ipc_addid(&sem_ids(ns), &sma->sem_perm, ns->sc_semmni);
|
||||
if (id < 0) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
return id;
|
||||
}
|
||||
ns->used_sems += nsems;
|
||||
|
|
@ -1122,7 +1122,7 @@ static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
|
|||
|
||||
wake_up_q(&wake_q);
|
||||
ns->used_sems -= sma->sem_nsems;
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
}
|
||||
|
||||
static unsigned long copy_semid_to_user(void __user *buf, struct semid64_ds *in, int version)
|
||||
|
|
@ -1362,7 +1362,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
|
|||
goto out_unlock;
|
||||
}
|
||||
if (nsems > SEMMSL_FAST) {
|
||||
if (!ipc_rcu_getref(sma)) {
|
||||
if (!ipc_rcu_getref(&sma->sem_perm)) {
|
||||
err = -EIDRM;
|
||||
goto out_unlock;
|
||||
}
|
||||
|
|
@ -1370,7 +1370,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
|
|||
rcu_read_unlock();
|
||||
sem_io = ipc_alloc(sizeof(ushort)*nsems);
|
||||
if (sem_io == NULL) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
return -ENOMEM;
|
||||
}
|
||||
|
||||
|
|
@ -1395,7 +1395,7 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
|
|||
int i;
|
||||
struct sem_undo *un;
|
||||
|
||||
if (!ipc_rcu_getref(sma)) {
|
||||
if (!ipc_rcu_getref(&sma->sem_perm)) {
|
||||
err = -EIDRM;
|
||||
goto out_rcu_wakeup;
|
||||
}
|
||||
|
|
@ -1404,20 +1404,20 @@ static int semctl_main(struct ipc_namespace *ns, int semid, int semnum,
|
|||
if (nsems > SEMMSL_FAST) {
|
||||
sem_io = ipc_alloc(sizeof(ushort)*nsems);
|
||||
if (sem_io == NULL) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
return -ENOMEM;
|
||||
}
|
||||
}
|
||||
|
||||
if (copy_from_user(sem_io, p, nsems*sizeof(ushort))) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
err = -EFAULT;
|
||||
goto out_free;
|
||||
}
|
||||
|
||||
for (i = 0; i < nsems; i++) {
|
||||
if (sem_io[i] > SEMVMX) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
err = -ERANGE;
|
||||
goto out_free;
|
||||
}
|
||||
|
|
@ -1699,7 +1699,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
|
|||
}
|
||||
|
||||
nsems = sma->sem_nsems;
|
||||
if (!ipc_rcu_getref(sma)) {
|
||||
if (!ipc_rcu_getref(&sma->sem_perm)) {
|
||||
rcu_read_unlock();
|
||||
un = ERR_PTR(-EIDRM);
|
||||
goto out;
|
||||
|
|
@ -1709,7 +1709,7 @@ static struct sem_undo *find_alloc_undo(struct ipc_namespace *ns, int semid)
|
|||
/* step 2: allocate new undo structure */
|
||||
new = kzalloc(sizeof(struct sem_undo) + sizeof(short)*nsems, GFP_KERNEL);
|
||||
if (!new) {
|
||||
ipc_rcu_putref(sma, sem_rcu_free);
|
||||
ipc_rcu_putref(&sma->sem_perm, sem_rcu_free);
|
||||
return ERR_PTR(-ENOMEM);
|
||||
}
|
||||
|
||||
|
|
|
|||
18
ipc/shm.c
18
ipc/shm.c
|
|
@ -174,9 +174,10 @@ static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
|
|||
|
||||
static void shm_rcu_free(struct rcu_head *head)
|
||||
{
|
||||
struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
|
||||
struct shmid_kernel *shp = ipc_rcu_to_struct(p);
|
||||
|
||||
struct kern_ipc_perm *ptr = container_of(head, struct kern_ipc_perm,
|
||||
rcu);
|
||||
struct shmid_kernel *shp = container_of(ptr, struct shmid_kernel,
|
||||
shm_perm);
|
||||
security_shm_free(shp);
|
||||
ipc_rcu_free(head);
|
||||
}
|
||||
|
|
@ -241,7 +242,7 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
|
|||
user_shm_unlock(i_size_read(file_inode(shm_file)),
|
||||
shp->mlock_user);
|
||||
fput(shm_file);
|
||||
ipc_rcu_putref(shp, shm_rcu_free);
|
||||
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
@ -542,7 +543,10 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
ns->shm_tot + numpages > ns->shm_ctlall)
|
||||
return -ENOSPC;
|
||||
|
||||
shp = ipc_rcu_alloc(sizeof(*shp));
|
||||
BUILD_BUG_ON(offsetof(struct shmid_kernel, shm_perm) != 0);
|
||||
|
||||
shp = container_of(ipc_rcu_alloc(sizeof(*shp)), struct shmid_kernel,
|
||||
shm_perm);
|
||||
if (!shp)
|
||||
return -ENOMEM;
|
||||
|
||||
|
|
@ -553,7 +557,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
shp->shm_perm.security = NULL;
|
||||
error = security_shm_alloc(shp);
|
||||
if (error) {
|
||||
ipc_rcu_putref(shp, ipc_rcu_free);
|
||||
ipc_rcu_putref(&shp->shm_perm, ipc_rcu_free);
|
||||
return error;
|
||||
}
|
||||
|
||||
|
|
@ -624,7 +628,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
|
|||
user_shm_unlock(size, shp->mlock_user);
|
||||
fput(file);
|
||||
no_file:
|
||||
ipc_rcu_putref(shp, shm_rcu_free);
|
||||
ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
|
||||
return error;
|
||||
}
|
||||
|
||||
|
|
|
|||
35
ipc/util.c
35
ipc/util.c
|
|
@ -418,46 +418,45 @@ void ipc_free(void *ptr)
|
|||
}
|
||||
|
||||
/**
|
||||
* ipc_rcu_alloc - allocate ipc and rcu space
|
||||
* ipc_rcu_alloc - allocate ipc space
|
||||
* @size: size desired
|
||||
*
|
||||
* Allocate memory for the rcu header structure + the object.
|
||||
* Returns the pointer to the object or NULL upon failure.
|
||||
* Allocate memory for an ipc object.
|
||||
* The first member must be struct kern_ipc_perm.
|
||||
*/
|
||||
void *ipc_rcu_alloc(int size)
|
||||
struct kern_ipc_perm *ipc_rcu_alloc(int size)
|
||||
{
|
||||
/*
|
||||
* We prepend the allocation with the rcu struct
|
||||
*/
|
||||
struct ipc_rcu *out = ipc_alloc(sizeof(struct ipc_rcu) + size);
|
||||
struct kern_ipc_perm *out = ipc_alloc(size);
|
||||
if (unlikely(!out))
|
||||
return NULL;
|
||||
|
||||
memset(out, 0, size);
|
||||
atomic_set(&out->refcount, 1);
|
||||
return out + 1;
|
||||
return out;
|
||||
}
|
||||
|
||||
int ipc_rcu_getref(void *ptr)
|
||||
int ipc_rcu_getref(struct kern_ipc_perm *ptr)
|
||||
{
|
||||
struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
|
||||
|
||||
return atomic_inc_not_zero(&p->refcount);
|
||||
return atomic_inc_not_zero(&ptr->refcount);
|
||||
}
|
||||
|
||||
void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head))
|
||||
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
|
||||
void (*func)(struct rcu_head *head))
|
||||
{
|
||||
struct ipc_rcu *p = ((struct ipc_rcu *)ptr) - 1;
|
||||
|
||||
if (!atomic_dec_and_test(&p->refcount))
|
||||
if (!atomic_dec_and_test(&ptr->refcount))
|
||||
return;
|
||||
|
||||
call_rcu(&p->rcu, func);
|
||||
call_rcu(&ptr->rcu, func);
|
||||
}
|
||||
|
||||
void ipc_rcu_free(struct rcu_head *head)
|
||||
void ipc_rcu_free(struct rcu_head *h)
|
||||
{
|
||||
struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
|
||||
struct kern_ipc_perm *ptr = container_of(h, struct kern_ipc_perm, rcu);
|
||||
|
||||
kvfree(p);
|
||||
kvfree(ptr);
|
||||
}
|
||||
|
||||
/**
|
||||
|
|
|
|||
18
ipc/util.h
18
ipc/util.h
|
|
@ -47,13 +47,6 @@ static inline void msg_exit_ns(struct ipc_namespace *ns) { }
|
|||
static inline void shm_exit_ns(struct ipc_namespace *ns) { }
|
||||
#endif
|
||||
|
||||
struct ipc_rcu {
|
||||
struct rcu_head rcu;
|
||||
atomic_t refcount;
|
||||
} ____cacheline_aligned_in_smp;
|
||||
|
||||
#define ipc_rcu_to_struct(p) ((void *)(p+1))
|
||||
|
||||
/*
|
||||
* Structure that holds the parameters needed by the ipc operations
|
||||
* (see after)
|
||||
|
|
@ -125,11 +118,14 @@ void ipc_free(void *ptr);
|
|||
* Objects are reference counted, they start with reference count 1.
|
||||
* getref increases the refcount, the putref call that reduces the recount
|
||||
* to 0 schedules the rcu destruction. Caller must guarantee locking.
|
||||
*
|
||||
* struct kern_ipc_perm must be the first member in the allocated structure.
|
||||
*/
|
||||
void *ipc_rcu_alloc(int size);
|
||||
int ipc_rcu_getref(void *ptr);
|
||||
void ipc_rcu_putref(void *ptr, void (*func)(struct rcu_head *head));
|
||||
void ipc_rcu_free(struct rcu_head *head);
|
||||
struct kern_ipc_perm *ipc_rcu_alloc(int size);
|
||||
int ipc_rcu_getref(struct kern_ipc_perm *ptr);
|
||||
void ipc_rcu_putref(struct kern_ipc_perm *ptr,
|
||||
void (*func)(struct rcu_head *head));
|
||||
void ipc_rcu_free(struct rcu_head *h);
|
||||
|
||||
struct kern_ipc_perm *ipc_lock(struct ipc_ids *, int);
|
||||
struct kern_ipc_perm *ipc_obtain_object_idr(struct ipc_ids *ids, int id);
|
||||
|
|
|
|||
Loading…
Reference in New Issue
Block a user