diff options
| -rw-r--r-- | arch/arc/kernel/smp.c | 2 | ||||
| -rw-r--r-- | arch/blackfin/mach-common/smp.c | 2 | ||||
| -rw-r--r-- | arch/frv/mm/mmu-context.c | 2 | ||||
| -rw-r--r-- | arch/metag/kernel/smp.c | 2 | ||||
| -rw-r--r-- | arch/sh/kernel/smp.c | 2 | ||||
| -rw-r--r-- | arch/xtensa/kernel/smp.c | 2 | ||||
| -rw-r--r-- | include/linux/sched.h | 21 | ||||
| -rw-r--r-- | kernel/fork.c | 4 | ||||
| -rw-r--r-- | mm/swapfile.c | 10 | ||||
| -rw-r--r-- | virt/kvm/async_pf.c | 2 |
10 files changed, 35 insertions, 14 deletions
diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index 695624181682..b8e8d3944481 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -139,7 +139,7 @@ void start_kernel_secondary(void) /* MMU, Caches, Vector Table, Interrupts etc */ setup_processor(); - atomic_inc(&mm->mm_users); + mmget(mm); mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); diff --git a/arch/blackfin/mach-common/smp.c b/arch/blackfin/mach-common/smp.c index bc5617ef7128..a2e6db2ce811 100644 --- a/arch/blackfin/mach-common/smp.c +++ b/arch/blackfin/mach-common/smp.c @@ -307,7 +307,7 @@ void secondary_start_kernel(void) local_irq_disable(); /* Attach the new idle task to the global mm. */ - atomic_inc(&mm->mm_users); + mmget(mm); mmgrab(mm); current->active_mm = mm; diff --git a/arch/frv/mm/mmu-context.c b/arch/frv/mm/mmu-context.c index 81757d55a5b5..3473bde77f56 100644 --- a/arch/frv/mm/mmu-context.c +++ b/arch/frv/mm/mmu-context.c @@ -188,7 +188,7 @@ int cxn_pin_by_pid(pid_t pid) task_lock(tsk); if (tsk->mm) { mm = tsk->mm; - atomic_inc(&mm->mm_users); + mmget(mm); ret = 0; } task_unlock(tsk); diff --git a/arch/metag/kernel/smp.c b/arch/metag/kernel/smp.c index af9cff547a19..c622293254e4 100644 --- a/arch/metag/kernel/smp.c +++ b/arch/metag/kernel/smp.c @@ -344,7 +344,7 @@ asmlinkage void secondary_start_kernel(void) * All kernel threads share the same mm context; grab a * reference and switch to it. */ - atomic_inc(&mm->mm_users); + mmget(mm); mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c index ee379c699c08..edc4769b047e 100644 --- a/arch/sh/kernel/smp.c +++ b/arch/sh/kernel/smp.c @@ -179,7 +179,7 @@ asmlinkage void start_secondary(void) enable_mmu(); mmgrab(mm); - atomic_inc(&mm->mm_users); + mmget(mm); current->active_mm = mm; #ifdef CONFIG_MMU enter_lazy_tlb(mm, current); diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c index 9bf5cea3bae4..fcea72019df7 100644 --- a/arch/xtensa/kernel/smp.c +++ b/arch/xtensa/kernel/smp.c @@ -135,7 +135,7 @@ void secondary_start_kernel(void) /* All kernel threads share the same mm context. */ - atomic_inc(&mm->mm_users); + mmget(mm); mmgrab(mm); current->active_mm = mm; cpumask_set_cpu(cpu, mm_cpumask(mm)); diff --git a/include/linux/sched.h b/include/linux/sched.h index 7cfa5546c840..4a28deb5f210 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2948,6 +2948,27 @@ static inline void mmdrop_async(struct mm_struct *mm) } } +/** + * mmget() - Pin the address space associated with a &struct mm_struct. + * @mm: The address space to pin. + * + * Make sure that the address space of the given &struct mm_struct doesn't + * go away. This does not protect against parts of the address space being + * modified or freed, however. + * + * Never use this function to pin this address space for an + * unbounded/indefinite amount of time. + * + * Use mmput() to release the reference acquired by mmget(). + * + * See also <Documentation/vm/active_mm.txt> for an in-depth explanation + * of &mm_struct.mm_count vs &mm_struct.mm_users. + */ +static inline void mmget(struct mm_struct *mm) +{ + atomic_inc(&mm->mm_users); +} + static inline bool mmget_not_zero(struct mm_struct *mm) { return atomic_inc_not_zero(&mm->mm_users); diff --git a/kernel/fork.c b/kernel/fork.c index 348fe73155bc..246bf9aaf9df 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1000,7 +1000,7 @@ struct mm_struct *get_task_mm(struct task_struct *task) if (task->flags & PF_KTHREAD) mm = NULL; else - atomic_inc(&mm->mm_users); + mmget(mm); } task_unlock(task); return mm; @@ -1188,7 +1188,7 @@ static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) vmacache_flush(tsk); if (clone_flags & CLONE_VM) { - atomic_inc(&oldmm->mm_users); + mmget(oldmm); mm = oldmm; goto good_mm; } diff --git a/mm/swapfile.c b/mm/swapfile.c index 2cac12cc9abe..7a0713b76668 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1671,7 +1671,7 @@ int try_to_unuse(unsigned int type, bool frontswap, * that. */ start_mm = &init_mm; - atomic_inc(&init_mm.mm_users); + mmget(&init_mm); /* * Keep on scanning until all entries have gone. Usually, @@ -1720,7 +1720,7 @@ int try_to_unuse(unsigned int type, bool frontswap, if (atomic_read(&start_mm->mm_users) == 1) { mmput(start_mm); start_mm = &init_mm; - atomic_inc(&init_mm.mm_users); + mmget(&init_mm); } /* @@ -1757,8 +1757,8 @@ int try_to_unuse(unsigned int type, bool frontswap, struct mm_struct *prev_mm = start_mm; struct mm_struct *mm; - atomic_inc(&new_start_mm->mm_users); - atomic_inc(&prev_mm->mm_users); + mmget(new_start_mm); + mmget(prev_mm); spin_lock(&mmlist_lock); while (swap_count(*swap_map) && !retval && (p = p->next) != &start_mm->mmlist) { @@ -1781,7 +1781,7 @@ int try_to_unuse(unsigned int type, bool frontswap, if (set_start_mm && *swap_map < swcount) { mmput(new_start_mm); - atomic_inc(&mm->mm_users); + mmget(mm); new_start_mm = mm; set_start_mm = 0; } diff --git a/virt/kvm/async_pf.c b/virt/kvm/async_pf.c index 3815e940fbea..2366177172f6 100644 --- a/virt/kvm/async_pf.c +++ b/virt/kvm/async_pf.c @@ -204,7 +204,7 @@ int kvm_setup_async_pf(struct kvm_vcpu *vcpu, gva_t gva, unsigned long hva, work->addr = hva; work->arch = *arch; work->mm = current->mm; - atomic_inc(&work->mm->mm_users); + mmget(work->mm); kvm_get_kvm(work->vcpu->kvm); /* this can't really happen otherwise gfn_to_pfn_async |