ipc: unify the syscalls code

This patch introduces a change into the sys_msgget(), sys_semget() and
sys_shmget() routines: they now share a common code, which is better for
maintainability.

Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 27 insertions, 46 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
index dcc333239683..d20cc25c5bdf 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -68,8 +68,7 @@ static struct ipc_ids init_shm_ids;
 #define shm_buildid(ns, id, seq)        \
         ipc_buildid(&shm_ids(ns), id, seq)
 
-static int newseg (struct ipc_namespace *ns, key_t key,
-                int shmflg, size_t size);
+static int newseg(struct ipc_namespace *, struct ipc_params *);
 static void shm_open(struct vm_area_struct *vma);
 static void shm_close(struct vm_area_struct *vma);
 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
@@ -341,8 +340,11 @@ static struct vm_operations_struct shm_vm_ops = {
 #endif
 };
 
-static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
+static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 {
+        key_t key = params->key;
+        int shmflg = params->flg;
+        size_t size = params->u.size;
         int error;
         struct shmid_kernel *shp;
         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
@@ -423,57 +425,36 @@ no_file:
         return error;
 }
 
+static inline int shm_security(void *shp, int shmflg)
+{
+        return security_shm_associate((struct shmid_kernel *) shp, shmflg);
+}
+
+static inline int shm_more_checks(void *shp, struct ipc_params *params)
+{
+        if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size)
+                return -EINVAL;
+
+        return 0;
+}
+
 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
 {
-        struct shmid_kernel *shp;
-        int err;
         struct ipc_namespace *ns;
+        struct ipc_ops shm_ops;
+        struct ipc_params shm_params;
 
         ns = current->nsproxy->ipc_ns;
 
-        err = idr_pre_get(&shm_ids(ns).ipcs_idr, GFP_KERNEL);
+        shm_ops.getnew = newseg;
+        shm_ops.associate = shm_security;
+        shm_ops.more_checks = shm_more_checks;
 
-        if (key == IPC_PRIVATE) {
-                if (!err)
-                        err = -ENOMEM;
-                else {
-                        mutex_lock(&shm_ids(ns).mutex);
-                        err = newseg(ns, key, shmflg, size);
-                        mutex_unlock(&shm_ids(ns).mutex);
-                }
-        } else {
-                mutex_lock(&shm_ids(ns).mutex);
-                shp = (struct shmid_kernel *) ipc_findkey(&shm_ids(ns), key);
-                if (shp == NULL) {
-                        if (!(shmflg & IPC_CREAT))
-                                err = -ENOENT;
-                        else if (!err)
-                                err = -ENOMEM;
-                        else
-                                err = newseg(ns, key, shmflg, size);
-                } else {
-                        /* shp has been locked by ipc_findkey() */
-
-                        if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL))
-                                err = -EEXIST;
-                        else {
-                                if (shp->shm_segsz < size)
-                                        err = -EINVAL;
-                                else if (ipcperms(&shp->shm_perm, shmflg))
-                                        err = -EACCES;
-                                else {
-                                        err = security_shm_associate(shp,
-                                                                shmflg);
-                                        if (!err)
-                                                err = shp->shm_perm.id;
-                                }
-                        }
-                        shm_unlock(shp);
-                }
-                mutex_unlock(&shm_ids(ns).mutex);
-        }
+        shm_params.key = key;
+        shm_params.flg = shmflg;
+        shm_params.u.size = size;
 
-        return err;
+        return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
 }
 
 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)