2.6.24

 ipc

diff --git a/ipc/shm.c b/ipc/shm.c
index a86a3a5..3818fae 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -35,7 +35,7 @@
 #include <linux/capability.h>
 #include <linux/ptrace.h>
 #include <linux/seq_file.h>
-#include <linux/mutex.h>
+#include <linux/rwsem.h>
 #include <linux/nsproxy.h>
 #include <linux/mount.h>
 
@@ -59,17 +59,11 @@ static struct ipc_ids init_shm_ids;
 
 #define shm_ids(ns)   (*((ns)->ids[IPC_SHM_IDS]))
 
-#define shm_lock(ns, id)      \
-   ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
 #define shm_unlock(shp)         \
    ipc_unlock(&(shp)->shm_perm)
-#define shm_get(ns, id)         \
-   ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
-#define shm_buildid(ns, id, seq)   \
-   ipc_buildid(&shm_ids(ns), id, seq)
+#define shm_buildid(id, seq)   ipc_buildid(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);
@@ -84,9 +78,13 @@ static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
    ns->shm_ctlall = SHMALL;
    ns->shm_ctlmni = SHMMNI;
    ns->shm_tot = 0;
-   ipc_init_ids(ids, 1);
+   ipc_init_ids(ids);
 }
 
+/*
+ * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
+ * Only shm_ids.rw_mutex remains locked on exit.
+ */
 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 {
    if (shp->shm_nattch){
@@ -112,20 +110,24 @@ int shm_init_ns(struct ipc_namespace *ns)
 
 void shm_exit_ns(struct ipc_namespace *ns)
 {
-   int i;
    struct shmid_kernel *shp;
+   int next_id;
+   int total, in_use;
+
+   down_write(&shm_ids(ns).rw_mutex);
 
-   mutex_lock(&shm_ids(ns).mutex);
-   for (i = 0; i <= shm_ids(ns).max_id; i++) {
-      shp = shm_lock(ns, i);
+   in_use = shm_ids(ns).in_use;
+
+   for (total = 0, next_id = 0; total < in_use; next_id++) {
+      shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
       if (shp == NULL)
          continue;
-
+      ipc_lock_by_ptr(&shp->shm_perm);
       do_shm_rmid(ns, shp);
+      total++;
    }
-   mutex_unlock(&shm_ids(ns).mutex);
+   up_write(&shm_ids(ns).rw_mutex);
 
-   ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
    kfree(ns->ids[IPC_SHM_IDS]);
    ns->ids[IPC_SHM_IDS] = NULL;
 }
@@ -138,17 +140,49 @@ void __init shm_init (void)
             IPC_SHM_IDS, sysvipc_shm_proc_show);
 }
 
-static inline int shm_checkid(struct ipc_namespace *ns,
-      struct shmid_kernel *s, int id)
+/*
+ * shm_lock_(check_)down routines are called in the paths where the rw_mutex
+ * is held to protect access to the idr tree.
+ */
+static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
+                  int id)
 {
-   if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
-      return -EIDRM;
-   return 0;
+   struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
+
+   return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline struct shmid_kernel *shm_lock_check_down(
+                  struct ipc_namespace *ns,
+                  int id)
+{
+   struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
+
+   return container_of(ipcp, struct shmid_kernel, shm_perm);
 }
 
-static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
+/*
+ * shm_lock_(check_) routines are called in the paths where the rw_mutex
+ * is not held.
+ */
+static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 {
-   return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
+   struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
+
+   return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
+                  int id)
+{
+   struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
+
+   return container_of(ipcp, struct shmid_kernel, shm_perm);
+}
+
+static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
+{
+   ipc_rmid(&shm_ids(ns), &s->shm_perm);
 }
 
 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
@@ -166,9 +200,9 @@ static void shm_open(struct vm_area_struct *vma)
    struct shmid_kernel *shp;
 
    shp = shm_lock(sfd->ns, sfd->id);
-   BUG_ON(!shp);
+   BUG_ON(IS_ERR(shp));
    shp->shm_atim = get_seconds();
-   shp->shm_lprid = current->tgid;
+   shp->shm_lprid = task_tgid_vnr(current);
    shp->shm_nattch++;
    shm_unlock(shp);
 }
@@ -176,15 +210,16 @@ static void shm_open(struct vm_area_struct *vma)
 /*
  * shm_destroy - free the struct shmid_kernel
  *
+ * @ns: namespace
  * @shp: struct to free
  *
- * It has to be called with shp and shm_ids.mutex locked,
+ * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
  * but returns with shp unlocked and freed.
  */
 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 {
    ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
-   shm_rmid(ns, shp->id);
+   shm_rmid(ns, shp);
    shm_unlock(shp);
    if (!is_file_hugepages(shp->shm_file))
       shmem_lock(shp->shm_file, 0, shp->mlock_user);
@@ -209,11 +244,11 @@ static void shm_close(struct vm_area_struct *vma)
    struct shmid_kernel *shp;
    struct ipc_namespace *ns = sfd->ns;
 
-   mutex_lock(&shm_ids(ns).mutex);
+   down_write(&shm_ids(ns).rw_mutex);
    /* remove from the list of attaches of the shm segment */
-   shp = shm_lock(ns, sfd->id);
-   BUG_ON(!shp);
-   shp->shm_lprid = current->tgid;
+   shp = shm_lock_down(ns, sfd->id);
+   BUG_ON(IS_ERR(shp));
+   shp->shm_lprid = task_tgid_vnr(current);
    shp->shm_dtim = get_seconds();
    shp->shm_nattch--;
    if(shp->shm_nattch == 0 &&
@@ -221,7 +256,7 @@ static void shm_close(struct vm_area_struct *vma)
       shm_destroy(ns, shp);
    else
       shm_unlock(shp);
-   mutex_unlock(&shm_ids(ns).mutex);
+   up_write(&shm_ids(ns).rw_mutex);
 }
 
 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -233,7 +268,7 @@ static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 }
 
 #ifdef CONFIG_NUMA
-int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
+static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
 {
    struct file *file = vma->vm_file;
    struct shm_file_data *sfd = shm_file_data(file);
@@ -243,7 +278,8 @@ int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
    return err;
 }
 
-struct mempolicy *shm_get_policy(struct vm_area_struct *vma, unsigned long addr)
+static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
+               unsigned long addr)
 {
    struct file *file = vma->vm_file;
    struct shm_file_data *sfd = shm_file_data(file);
@@ -336,8 +372,19 @@ static struct vm_operations_struct shm_vm_ops = {
 #endif
 };
 
-static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
+/**
+ * newseg - Create a new shared memory segment
+ * @ns: namespace
+ * @params: ptr to the structure that contains key, size and shmflg
+ *
+ * Called with shm_ids.rw_mutex held as a writer.
+ */
+
+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;
@@ -386,28 +433,30 @@ static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
    if (IS_ERR(file))
       goto no_file;
 
-   error = -ENOSPC;
    id = shm_addid(ns, shp);
-   if(id == -1) 
+   if (id < 0) {
+      error = id;
       goto no_id;
+   }
 
-   shp->shm_cprid = current->tgid;
+   shp->shm_cprid = task_tgid_vnr(current);
    shp->shm_lprid = 0;
    shp->shm_atim = shp->shm_dtim = 0;
    shp->shm_ctim = get_seconds();
    shp->shm_segsz = size;
    shp->shm_nattch = 0;
-   shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
+   shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
    shp->shm_file = file;
    /*
     * shmid gets reported as "inode#" in /proc/pid/maps.
     * proc-ps tools use this. Changing this will break them.
     */
-   file->f_dentry->d_inode->i_ino = shp->id;
+   file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
 
    ns->shm_tot += numpages;
+   error = shp->shm_perm.id;
    shm_unlock(shp);
-   return shp->id;
+   return error;
 
 no_id:
    fput(file);
@@ -417,42 +466,49 @@ no_file:
    return error;
 }
 
-asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
+/*
+ * Called with shm_ids.rw_mutex and ipcp locked.
+ */
+static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
 {
    struct shmid_kernel *shp;
-   int err, id = 0;
+
+   shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+   return security_shm_associate(shp, shmflg);
+}
+
+/*
+ * Called with shm_ids.rw_mutex and ipcp locked.
+ */
+static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
+            struct ipc_params *params)
+{
+   struct shmid_kernel *shp;
+
+   shp = container_of(ipcp, struct shmid_kernel, shm_perm);
+   if (shp->shm_segsz < params->u.size)
+      return -EINVAL;
+
+   return 0;
+}
+
+asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
+{
    struct ipc_namespace *ns;
+   struct ipc_ops shm_ops;
+   struct ipc_params shm_params;
 
    ns = current->nsproxy->ipc_ns;
 
-   mutex_lock(&shm_ids(ns).mutex);
-   if (key == IPC_PRIVATE) {
-      err = newseg(ns, key, shmflg, size);
-   } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
-      if (!(shmflg & IPC_CREAT))
-         err = -ENOENT;
-      else
-         err = newseg(ns, key, shmflg, size);
-   } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
-      err = -EEXIST;
-   } else {
-      shp = shm_lock(ns, id);
-      BUG_ON(shp==NULL);
-      if (shp->shm_segsz < size)
-         err = -EINVAL;
-      else if (ipcperms(&shp->shm_perm, shmflg))
-         err = -EACCES;
-      else {
-         int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
-         err = security_shm_associate(shp, shmflg);
-         if (!err)
-            err = shmid;
-      }
-      shm_unlock(shp);
-   }
-   mutex_unlock(&shm_ids(ns).mutex);
+   shm_ops.getnew = newseg;
+   shm_ops.associate = shm_security;
+   shm_ops.more_checks = shm_more_checks;
 
-   return err;
+   shm_params.key = key;
+   shm_params.flg = shmflg;
+   shm_params.u.size = size;
+
+   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)
@@ -546,20 +602,26 @@ static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminf
    }
 }
 
+/*
+ * Called with shm_ids.rw_mutex held as a reader
+ */
 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
       unsigned long *swp)
 {
-   int i;
+   int next_id;
+   int total, in_use;
 
    *rss = 0;
    *swp = 0;
 
-   for (i = 0; i <= shm_ids(ns).max_id; i++) {
+   in_use = shm_ids(ns).in_use;
+
+   for (total = 0, next_id = 0; total < in_use; next_id++) {
       struct shmid_kernel *shp;
       struct inode *inode;
 
-      shp = shm_get(ns, i);
-      if(!shp)
+      shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
+      if (shp == NULL)
          continue;
 
       inode = shp->shm_file->f_path.dentry->d_inode;
@@ -574,6 +636,8 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
          *swp += info->swapped;
          spin_unlock(&info->lock);
       }
+
+      total++;
    }
 }
 
@@ -609,8 +673,11 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
       shminfo.shmmin = SHMMIN;
       if(copy_shminfo_to_user (buf, &shminfo, version))
          return -EFAULT;
-      /* reading a integer is always atomic */
-      err= shm_ids(ns).max_id;
+
+      down_read(&shm_ids(ns).rw_mutex);
+      err = ipc_get_maxid(&shm_ids(ns));
+      up_read(&shm_ids(ns).rw_mutex);
+
       if(err<0)
          err = 0;
       goto out;
@@ -624,14 +691,14 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
          return err;
 
       memset(&shm_info,0,sizeof(shm_info));
-      mutex_lock(&shm_ids(ns).mutex);
+      down_read(&shm_ids(ns).rw_mutex);
       shm_info.used_ids = shm_ids(ns).in_use;
       shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
       shm_info.shm_tot = ns->shm_tot;
       shm_info.swap_attempts = 0;
       shm_info.swap_successes = 0;
-      err = shm_ids(ns).max_id;
-      mutex_unlock(&shm_ids(ns).mutex);
+      err = ipc_get_maxid(&shm_ids(ns));
+      up_read(&shm_ids(ns).rw_mutex);
       if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
          err = -EFAULT;
          goto out;
@@ -645,20 +712,25 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
    {
       struct shmid64_ds tbuf;
       int result;
-      memset(&tbuf, 0, sizeof(tbuf));
-      shp = shm_lock(ns, shmid);
-      if(shp==NULL) {
-         err = -EINVAL;
+
+      if (!buf) {
+         err = -EFAULT;
          goto out;
-      } else if(cmd==SHM_STAT) {
-         err = -EINVAL;
-         if (shmid > shm_ids(ns).max_id)
-            goto out_unlock;
-         result = shm_buildid(ns, shmid, shp->shm_perm.seq);
+      }
+
+      if (cmd == SHM_STAT) {
+         shp = shm_lock(ns, shmid);
+         if (IS_ERR(shp)) {
+            err = PTR_ERR(shp);
+            goto out;
+         }
+         result = shp->shm_perm.id;
       } else {
-         err = shm_checkid(ns, shp,shmid);
-         if(err)
-            goto out_unlock;
+         shp = shm_lock_check(ns, shmid);
+         if (IS_ERR(shp)) {
+            err = PTR_ERR(shp);
+            goto out;
+         }
          result = 0;
       }
       err=-EACCES;
@@ -667,6 +739,7 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
       err = security_shm_shmctl(shp, cmd);
       if (err)
          goto out_unlock;
+      memset(&tbuf, 0, sizeof(tbuf));
       kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
       tbuf.shm_segsz   = shp->shm_segsz;
       tbuf.shm_atime   = shp->shm_atim;
@@ -685,14 +758,11 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
    case SHM_LOCK:
    case SHM_UNLOCK:
    {
-      shp = shm_lock(ns, shmid);
-      if(shp==NULL) {
-         err = -EINVAL;
+      shp = shm_lock_check(ns, shmid);
+      if (IS_ERR(shp)) {
+         err = PTR_ERR(shp);
          goto out;
       }
-      err = shm_checkid(ns, shp,shmid);
-      if(err)
-         goto out_unlock;
 
       err = audit_ipc_obj(&(shp->shm_perm));
       if (err)
@@ -741,14 +811,12 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
        *   Instead we set a destroyed flag, and then blow
        *   the name away when the usage hits zero.
        */
-      mutex_lock(&shm_ids(ns).mutex);
-      shp = shm_lock(ns, shmid);
-      err = -EINVAL;
-      if (shp == NULL) 
+      down_write(&shm_ids(ns).rw_mutex);
+      shp = shm_lock_check_down(ns, shmid);
+      if (IS_ERR(shp)) {
+         err = PTR_ERR(shp);
          goto out_up;
-      err = shm_checkid(ns, shp, shmid);
-      if(err)
-         goto out_unlock_up;
+      }
 
       err = audit_ipc_obj(&(shp->shm_perm));
       if (err)
@@ -766,24 +834,27 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
          goto out_unlock_up;
 
       do_shm_rmid(ns, shp);
-      mutex_unlock(&shm_ids(ns).mutex);
+      up_write(&shm_ids(ns).rw_mutex);
       goto out;
    }
 
    case IPC_SET:
    {
+      if (!buf) {
+         err = -EFAULT;
+         goto out;
+      }
+
       if (copy_shmid_from_user (&setbuf, buf, version)) {
          err = -EFAULT;
          goto out;
       }
-      mutex_lock(&shm_ids(ns).mutex);
-      shp = shm_lock(ns, shmid);
-      err=-EINVAL;
-      if(shp==NULL)
+      down_write(&shm_ids(ns).rw_mutex);
+      shp = shm_lock_check_down(ns, shmid);
+      if (IS_ERR(shp)) {
+         err = PTR_ERR(shp);
          goto out_up;
-      err = shm_checkid(ns, shp,shmid);
-      if(err)
-         goto out_unlock_up;
+      }
       err = audit_ipc_obj(&(shp->shm_perm));
       if (err)
          goto out_unlock_up;
@@ -818,7 +889,7 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
 out_unlock_up:
    shm_unlock(shp);
 out_up:
-   mutex_unlock(&shm_ids(ns).mutex);
+   up_write(&shm_ids(ns).rw_mutex);
    goto out;
 out_unlock:
    shm_unlock(shp);
@@ -889,13 +960,11 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
     * additional creator id...
     */
    ns = current->nsproxy->ipc_ns;
-   shp = shm_lock(ns, shmid);
-   if(shp == NULL)
+   shp = shm_lock_check(ns, shmid);
+   if (IS_ERR(shp)) {
+      err = PTR_ERR(shp);
       goto out;
-
-   err = shm_checkid(ns, shp,shmid);
-   if (err)
-      goto out_unlock;
+   }
 
    err = -EACCES;
    if (ipcperms(&shp->shm_perm, acc_mode))
@@ -906,7 +975,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
       goto out_unlock;
 
    path.dentry = dget(shp->shm_file->f_path.dentry);
-   path.mnt    = mntget(shp->shm_file->f_path.mnt);
+   path.mnt    = shp->shm_file->f_path.mnt;
    shp->shm_nattch++;
    size = i_size_read(path.dentry->d_inode);
    shm_unlock(shp);
@@ -914,19 +983,17 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
    err = -ENOMEM;
    sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
    if (!sfd)
-      goto out_put_path;
+      goto out_put_dentry;
 
    err = -ENOMEM;
-   file = get_empty_filp();
+
+   file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
    if (!file)
       goto out_free;
 
-   file->f_op = &shm_file_operations;
    file->private_data = sfd;
-   file->f_path = path;
    file->f_mapping = shp->shm_file->f_mapping;
-   file->f_mode = f_mode;
-   sfd->id = shp->id;
+   sfd->id = shp->shm_perm.id;
    sfd->ns = get_ipc_ns(ns);
    sfd->file = shp->shm_file;
    sfd->vm_ops = NULL;
@@ -956,16 +1023,16 @@ invalid:
    fput(file);
 
 out_nattch:
-   mutex_lock(&shm_ids(ns).mutex);
-   shp = shm_lock(ns, shmid);
-   BUG_ON(!shp);
+   down_write(&shm_ids(ns).rw_mutex);
+   shp = shm_lock_down(ns, shmid);
+   BUG_ON(IS_ERR(shp));
    shp->shm_nattch--;
    if(shp->shm_nattch == 0 &&
       shp->shm_perm.mode & SHM_DEST)
       shm_destroy(ns, shp);
    else
       shm_unlock(shp);
-   mutex_unlock(&shm_ids(ns).mutex);
+   up_write(&shm_ids(ns).rw_mutex);
 
 out:
    return err;
@@ -976,9 +1043,8 @@ out_unlock:
 
 out_free:
    kfree(sfd);
-out_put_path:
+out_put_dentry:
    dput(path.dentry);
-   mntput(path.mnt);
    goto out_nattch;
 }
 
@@ -1096,7 +1162,7 @@ static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
       format = BIG_STRING;
    return seq_printf(s, format,
            shp->shm_perm.key,
-           shp->id,
+           shp->shm_perm.id,
            shp->shm_perm.mode,
            shp->shm_segsz,
            shp->shm_cprid,