From 6b6482bbf64ef6f6dbc8b52f7a7cf88a0498bd51 Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:27:48 -0700 Subject: mempolicy: remove the "task" arg of vma_policy_mof() and simplify it 1. vma_policy_mof(task) is simply not safe unless task == current, it can race with do_exit()->mpol_put(). Remove this arg and update its single caller. 2. vma can not be NULL, remove this check and simplify the code. Signed-off-by: Oleg Nesterov Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Hugh Dickins Cc: Andi Kleen Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mempolicy.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/mempolicy.h') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index f230a978e6ba..5e4bfcedd2ce 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -136,7 +136,7 @@ struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, struct mempolicy *get_vma_policy(struct task_struct *tsk, struct vm_area_struct *vma, unsigned long addr); -bool vma_policy_mof(struct task_struct *task, struct vm_area_struct *vma); +bool vma_policy_mof(struct vm_area_struct *vma); extern void numa_default_policy(void); extern void numa_policy_init(void); -- cgit v1.2.3 From 74d2c3a05cc6c1eef2d7236a9919036ed85ddaaf Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:27:50 -0700 Subject: mempolicy: introduce __get_vma_policy(), export get_task_policy() Extract the code which looks for vma's policy from get_vma_policy() into the new helper, __get_vma_policy(). Export get_task_policy(). Signed-off-by: Oleg Nesterov Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Hugh Dickins Cc: Andi Kleen Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mempolicy.h | 3 +++ mm/mempolicy.c | 44 ++++++++++++++++++++++++++------------------ 2 files changed, 29 insertions(+), 18 deletions(-) (limited to 'include/linux/mempolicy.h') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 5e4bfcedd2ce..e1abe249892a 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -134,6 +134,9 @@ void mpol_free_shared_policy(struct shared_policy *p); struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, unsigned long idx); +struct mempolicy *get_task_policy(struct task_struct *p); +struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, + unsigned long addr); struct mempolicy *get_vma_policy(struct task_struct *tsk, struct vm_area_struct *vma, unsigned long addr); bool vma_policy_mof(struct vm_area_struct *vma); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ad27bbc757bf..4378c334e89b 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -123,7 +123,7 @@ static struct mempolicy default_policy = { static struct mempolicy preferred_node_policy[MAX_NUMNODES]; -static struct mempolicy *get_task_policy(struct task_struct *p) +struct mempolicy *get_task_policy(struct task_struct *p) { struct mempolicy *pol = p->mempolicy; int node; @@ -1603,23 +1603,8 @@ COMPAT_SYSCALL_DEFINE6(mbind, compat_ulong_t, start, compat_ulong_t, len, #endif -/* - * get_vma_policy(@task, @vma, @addr) - * @task: task for fallback if vma policy == default - * @vma: virtual memory area whose policy is sought - * @addr: address in @vma for shared policy lookup - * - * Returns effective policy for a VMA at specified address. - * Falls back to @task or system default policy, as necessary. - * Current or other task's task mempolicy and non-shared vma policies must be - * protected by task_lock(task) by the caller. - * Shared policies [those marked as MPOL_F_SHARED] require an extra reference - * count--added by the get_policy() vm_op, as appropriate--to protect against - * freeing by another task. It is the caller's responsibility to free the - * extra reference for shared policies. - */ -struct mempolicy *get_vma_policy(struct task_struct *task, - struct vm_area_struct *vma, unsigned long addr) +struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, + unsigned long addr) { struct mempolicy *pol = NULL; @@ -1640,6 +1625,29 @@ struct mempolicy *get_vma_policy(struct task_struct *task, } } + return pol; +} + +/* + * get_vma_policy(@task, @vma, @addr) + * @task: task for fallback if vma policy == default + * @vma: virtual memory area whose policy is sought + * @addr: address in @vma for shared policy lookup + * + * Returns effective policy for a VMA at specified address. + * Falls back to @task or system default policy, as necessary. + * Current or other task's task mempolicy and non-shared vma policies must be + * protected by task_lock(task) by the caller. + * Shared policies [those marked as MPOL_F_SHARED] require an extra reference + * count--added by the get_policy() vm_op, as appropriate--to protect against + * freeing by another task. It is the caller's responsibility to free the + * extra reference for shared policies. + */ +struct mempolicy *get_vma_policy(struct task_struct *task, + struct vm_area_struct *vma, unsigned long addr) +{ + struct mempolicy *pol = __get_vma_policy(vma, addr); + if (!pol) pol = get_task_policy(task); -- cgit v1.2.3 From dd6eecb917938c1b7e505a83df307b3476e7c8bd Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Thu, 9 Oct 2014 15:27:57 -0700 Subject: mempolicy: unexport get_vma_policy() and remove its "task" arg - get_vma_policy(task) is not safe if task != current, remove this argument. - get_vma_policy() no longer has callers outside of mempolicy.c, make it static. Signed-off-by: Oleg Nesterov Cc: KAMEZAWA Hiroyuki Cc: David Rientjes Cc: KOSAKI Motohiro Cc: Alexander Viro Cc: Cyrill Gorcunov Cc: "Eric W. Biederman" Cc: "Kirill A. Shutemov" Cc: Peter Zijlstra Cc: Hugh Dickins Cc: Andi Kleen Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mempolicy.h | 2 -- mm/mempolicy.c | 19 ++++++++----------- 2 files changed, 8 insertions(+), 13 deletions(-) (limited to 'include/linux/mempolicy.h') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index e1abe249892a..3d385c81c153 100644 --- a/include/linux/mempolicy.h +++ b/include/linux/mempolicy.h @@ -137,8 +137,6 @@ struct mempolicy *mpol_shared_policy_lookup(struct shared_policy *sp, struct mempolicy *get_task_policy(struct task_struct *p); struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, unsigned long addr); -struct mempolicy *get_vma_policy(struct task_struct *tsk, - struct vm_area_struct *vma, unsigned long addr); bool vma_policy_mof(struct vm_area_struct *vma); extern void numa_default_policy(void); diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 9695a9a3ab90..008fb32936eb 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1616,27 +1616,24 @@ struct mempolicy *__get_vma_policy(struct vm_area_struct *vma, } /* - * get_vma_policy(@task, @vma, @addr) - * @task: task for fallback if vma policy == default + * get_vma_policy(@vma, @addr) * @vma: virtual memory area whose policy is sought * @addr: address in @vma for shared policy lookup * * Returns effective policy for a VMA at specified address. - * Falls back to @task or system default policy, as necessary. - * Current or other task's task mempolicy and non-shared vma policies must be - * protected by task_lock(task) by the caller. + * Falls back to current->mempolicy or system default policy, as necessary. * Shared policies [those marked as MPOL_F_SHARED] require an extra reference * count--added by the get_policy() vm_op, as appropriate--to protect against * freeing by another task. It is the caller's responsibility to free the * extra reference for shared policies. */ -struct mempolicy *get_vma_policy(struct task_struct *task, - struct vm_area_struct *vma, unsigned long addr) +static struct mempolicy *get_vma_policy(struct vm_area_struct *vma, + unsigned long addr) { struct mempolicy *pol = __get_vma_policy(vma, addr); if (!pol) - pol = get_task_policy(task); + pol = get_task_policy(current); return pol; } @@ -1864,7 +1861,7 @@ struct zonelist *huge_zonelist(struct vm_area_struct *vma, unsigned long addr, { struct zonelist *zl; - *mpol = get_vma_policy(current, vma, addr); + *mpol = get_vma_policy(vma, addr); *nodemask = NULL; /* assume !MPOL_BIND */ if (unlikely((*mpol)->mode == MPOL_INTERLEAVE)) { @@ -2019,7 +2016,7 @@ alloc_pages_vma(gfp_t gfp, int order, struct vm_area_struct *vma, unsigned int cpuset_mems_cookie; retry_cpuset: - pol = get_vma_policy(current, vma, addr); + pol = get_vma_policy(vma, addr); cpuset_mems_cookie = read_mems_allowed_begin(); if (unlikely(pol->mode == MPOL_INTERLEAVE)) { @@ -2285,7 +2282,7 @@ int mpol_misplaced(struct page *page, struct vm_area_struct *vma, unsigned long BUG_ON(!vma); - pol = get_vma_policy(current, vma, addr); + pol = get_vma_policy(vma, addr); if (!(pol->flags & MPOL_F_MOF)) goto out; -- cgit v1.2.3