1 files changed, 71 insertions, 39 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index 8e7e135d0817..0276c30401a0 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -59,7 +59,6 @@
 #include <linux/taskstats_kern.h>
 #include <linux/random.h>
 #include <linux/tty.h>
-#include <linux/proc_fs.h>
 #include <linux/blkdev.h>
 #include <linux/fs_struct.h>
 #include <linux/magic.h>
@@ -485,20 +484,6 @@ static void mm_init_aio(struct mm_struct *mm)
 #endif
 }
 
-int mm_init_cpumask(struct mm_struct *mm, struct mm_struct *oldmm)
-{
-#ifdef CONFIG_CPUMASK_OFFSTACK
-        if (!alloc_cpumask_var(&mm->cpu_vm_mask_var, GFP_KERNEL))
-                return -ENOMEM;
-
-        if (oldmm)
-                cpumask_copy(mm_cpumask(mm), mm_cpumask(oldmm));
-        else
-                memset(mm_cpumask(mm), 0, cpumask_size());
-#endif
-        return 0;
-}
-
 static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p)
 {
         atomic_set(&mm->mm_users, 1);
@@ -539,17 +524,8 @@ struct mm_struct * mm_alloc(void)
                 return NULL;
 
         memset(mm, 0, sizeof(*mm));
-        mm = mm_init(mm, current);
-        if (!mm)
-                return NULL;
-
-        if (mm_init_cpumask(mm, NULL)) {
-                mm_free_pgd(mm);
-                free_mm(mm);
-                return NULL;
-        }
-
-        return mm;
+        mm_init_cpumask(mm);
+        return mm_init(mm, current);
 }
 
 /*
@@ -560,7 +536,6 @@ struct mm_struct * mm_alloc(void)
 void __mmdrop(struct mm_struct *mm)
 {
         BUG_ON(mm == &init_mm);
-        free_cpumask_var(mm->cpu_vm_mask_var);
         mm_free_pgd(mm);
         destroy_context(mm);
         mmu_notifier_mm_destroy(mm);
@@ -597,6 +572,57 @@ void mmput(struct mm_struct *mm)
 }
 EXPORT_SYMBOL_GPL(mmput);
 
+/*
+ * We added or removed a vma mapping the executable. The vmas are only mapped
+ * during exec and are not mapped with the mmap system call.
+ * Callers must hold down_write() on the mm's mmap_sem for these
+ */
+void added_exe_file_vma(struct mm_struct *mm)
+{
+        mm->num_exe_file_vmas++;
+}
+
+void removed_exe_file_vma(struct mm_struct *mm)
+{
+        mm->num_exe_file_vmas--;
+        if ((mm->num_exe_file_vmas == 0) && mm->exe_file){
+                fput(mm->exe_file);
+                mm->exe_file = NULL;
+        }
+
+}
+
+void set_mm_exe_file(struct mm_struct *mm, struct file *new_exe_file)
+{
+        if (new_exe_file)
+                get_file(new_exe_file);
+        if (mm->exe_file)
+                fput(mm->exe_file);
+        mm->exe_file = new_exe_file;
+        mm->num_exe_file_vmas = 0;
+}
+
+struct file *get_mm_exe_file(struct mm_struct *mm)
+{
+        struct file *exe_file;
+
+        /* We need mmap_sem to protect against races with removal of
+         * VM_EXECUTABLE vmas */
+        down_read(&mm->mmap_sem);
+        exe_file = mm->exe_file;
+        if (exe_file)
+                get_file(exe_file);
+        up_read(&mm->mmap_sem);
+        return exe_file;
+}
+
+static void dup_mm_exe_file(struct mm_struct *oldmm, struct mm_struct *newmm)
+{
+        /* It's safe to write the exe_file pointer without exe_file_lock because
+         * this is called during fork when the task is not yet in /proc */
+        newmm->exe_file = get_mm_exe_file(oldmm);
+}
+
 /**
  * get_task_mm - acquire a reference to the task's mm
  *
@@ -703,6 +729,7 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
                 goto fail_nomem;
 
         memcpy(mm, oldmm, sizeof(*mm));
+        mm_init_cpumask(mm);
 
         /* Initializing for Swap token stuff */
         mm->token_priority = 0;
@@ -715,9 +742,6 @@ struct mm_struct *dup_mm(struct task_struct *tsk)
         if (!mm_init(mm, tsk))
                 goto fail_nomem;
 
-        if (mm_init_cpumask(mm, oldmm))
-                goto fail_nocpumask;
-
         if (init_new_context(tsk, mm))
                 goto fail_nocontext;
 
@@ -744,9 +768,6 @@ fail_nomem:
         return NULL;
 
 fail_nocontext:
-        free_cpumask_var(mm->cpu_vm_mask_var);
-
-fail_nocpumask:
         /*
          * If init_new_context() failed, we cannot use mmput() to free the mm
          * because it calls destroy_context()
@@ -957,6 +978,10 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
         tty_audit_fork(sig);
         sched_autogroup_fork(sig);
 
+#ifdef CONFIG_CGROUPS
+        init_rwsem(&sig->threadgroup_fork_lock);
+#endif
+
         sig->oom_adj = current->signal->oom_adj;
         sig->oom_score_adj = current->signal->oom_score_adj;
         sig->oom_score_adj_min = current->signal->oom_score_adj_min;
@@ -1138,6 +1163,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         monotonic_to_bootbased(&p->real_start_time);
         p->io_context = NULL;
         p->audit_context = NULL;
+        if (clone_flags & CLONE_THREAD)
+                threadgroup_fork_read_lock(current);
         cgroup_fork(p);
 #ifdef CONFIG_NUMA
         p->mempolicy = mpol_dup(p->mempolicy);
@@ -1223,12 +1250,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         if (clone_flags & CLONE_THREAD)
                 p->tgid = current->tgid;
 
-        if (current->nsproxy != p->nsproxy) {
-                retval = ns_cgroup_clone(p, pid);
-                if (retval)
-                        goto bad_fork_free_pid;
-        }
-
         p->set_child_tid = (clone_flags & CLONE_CHILD_SETTID) ? child_tidptr : NULL;
         /*
          * Clear TID on mm_release()?
@@ -1342,6 +1363,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
         write_unlock_irq(&tasklist_lock);
         proc_fork_connector(p);
         cgroup_post_fork(p);
+        if (clone_flags & CLONE_THREAD)
+                threadgroup_fork_read_unlock(current);
         perf_event_fork(p);
         return p;
 
@@ -1380,6 +1403,8 @@ bad_fork_cleanup_policy:
         mpol_put(p->mempolicy);
 bad_fork_cleanup_cgroup:
 #endif
+        if (clone_flags & CLONE_THREAD)
+                threadgroup_fork_read_unlock(current);
         cgroup_exit(p, cgroup_callbacks_done);
         delayacct_tsk_free(p);
         module_put(task_thread_info(p)->exec_domain->module);
@@ -1537,6 +1562,13 @@ void __init proc_caches_init(void)
         fs_cachep = kmem_cache_create("fs_cache",
                         sizeof(struct fs_struct), 0,
                         SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);
+        /*
+         * FIXME! The "sizeof(struct mm_struct)" currently includes the
+         * whole struct cpumask for the OFFSTACK case. We could change
+         * this to *only* allocate as much of it as required by the
+         * maximum number of CPU's we can ever have.  The cpumask_allocation
+         * is at the end of the structure, exactly for that reason.
+         */
         mm_cachep = kmem_cache_create("mm_struct",
                         sizeof(struct mm_struct), ARCH_MIN_MMSTRUCT_ALIGN,
                         SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_NOTRACK, NULL);