Merge with master.kernel.org:/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

1 files changed, 22 insertions, 11 deletions

diff --git a/kernel/fork.c b/kernel/fork.c
index f42a17f88699..cdef6cea8900 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -194,6 +194,7 @@ static inline int dup_mmap(struct mm_struct * mm, struct mm_struct * oldmm)
         mm->mmap = NULL;
         mm->mmap_cache = NULL;
         mm->free_area_cache = oldmm->mmap_base;
+        mm->cached_hole_size = ~0UL;
         mm->map_count = 0;
         set_mm_counter(mm, rss, 0);
         set_mm_counter(mm, anon_rss, 0);
@@ -249,8 +250,9 @@ static inline int dup_mmap(struct mm_struct * mm, struct mm_struct * oldmm)
 
                 /*
                  * Link in the new vma and copy the page table entries:
-                 * link in first so that swapoff can see swap entries,
-                 * and try_to_unmap_one's find_vma find the new vma.
+                 * link in first so that swapoff can see swap entries.
+                 * Note that, exceptionally, here the vma is inserted
+                 * without holding mm->mmap_sem.
                  */
                 spin_lock(&mm->page_table_lock);
                 *pprev = tmp;
@@ -322,6 +324,7 @@ static struct mm_struct * mm_init(struct mm_struct * mm)
         mm->ioctx_list = NULL;
         mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm);
         mm->free_area_cache = TASK_UNMAPPED_BASE;
+        mm->cached_hole_size = ~0UL;
 
         if (likely(!mm_alloc_pgd(mm))) {
                 mm->def_flags = 0;
@@ -1000,9 +1003,6 @@ static task_t *copy_process(unsigned long clone_flags,
         p->pdeath_signal = 0;
         p->exit_state = 0;
 
-        /* Perform scheduler related setup */
-        sched_fork(p);
-
         /*
          * Ok, make it visible to the rest of the system.
          * We dont wake it up yet.
@@ -1011,18 +1011,24 @@ static task_t *copy_process(unsigned long clone_flags,
         INIT_LIST_HEAD(&p->ptrace_children);
         INIT_LIST_HEAD(&p->ptrace_list);
 
+        /* Perform scheduler related setup. Assign this task to a CPU. */
+        sched_fork(p, clone_flags);
+
         /* Need tasklist lock for parent etc handling! */
         write_lock_irq(&tasklist_lock);
 
         /*
-         * The task hasn't been attached yet, so cpus_allowed mask cannot
-         * have changed. The cpus_allowed mask of the parent may have
-         * changed after it was copied first time, and it may then move to
-         * another CPU - so we re-copy it here and set the child's CPU to
-         * the parent's CPU. This avoids alot of nasty races.
+         * The task hasn't been attached yet, so its cpus_allowed mask will
+         * not be changed, nor will its assigned CPU.
+         *
+         * The cpus_allowed mask of the parent may have changed after it was
+         * copied first time - so re-copy it here, then check the child's CPU
+         * to ensure it is on a valid CPU (and if not, just force it back to
+         * parent's CPU). This avoids alot of nasty races.
          */
         p->cpus_allowed = current->cpus_allowed;
-        set_task_cpu(p, smp_processor_id());
+        if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed)))
+                set_task_cpu(p, smp_processor_id());
 
         /*
          * Check for pending SIGKILL! The new thread should not be allowed
@@ -1084,6 +1090,11 @@ static task_t *copy_process(unsigned long clone_flags,
                 spin_unlock(&current->sighand->siglock);
         }
 
+        /*
+         * inherit ioprio
+         */
+        p->ioprio = current->ioprio;
+
         SET_LINKS(p);
         if (unlikely(p->ptrace & PT_PTRACED))
                 __ptrace_link(p, current->parent);