From: NeilBrown Date: Fri, 7 Apr 2017 00:03:26 +0000 (+1000) Subject: sched/core: Remove 'task' parameter and rename tsk_restore_flags() to current_restore... X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=717a94b5fc7092afebe9c93791f29b2d8e5d297a;p=linux.git sched/core: Remove 'task' parameter and rename tsk_restore_flags() to current_restore_flags() It is not safe for one thread to modify the ->flags of another thread as there is no locking that can protect the update. So tsk_restore_flags(), which takes a task pointer and modifies the flags, is an invitation to do the wrong thing. All current users pass "current" as the task, so no developers have accepted that invitation. It would be best to ensure it remains that way. So rename tsk_restore_flags() to current_restore_flags() and don't pass in a task_struct pointer. Always operate on current->flags. Signed-off-by: NeilBrown Cc: Linus Torvalds Cc: Mel Gorman Cc: Michal Hocko Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar --- diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index d8a23561b4cb4..3c9052bf23279 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -244,7 +244,7 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send, *sent += result; } while (msg_data_left(&msg)); - tsk_restore_flags(current, pflags, PF_MEMALLOC); + current_restore_flags(pflags, PF_MEMALLOC); return result; } diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c index 4228aba1f654e..bbea8eac9abb7 100644 --- a/drivers/scsi/iscsi_tcp.c +++ b/drivers/scsi/iscsi_tcp.c @@ -387,7 +387,7 @@ static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task) rc = 0; } - tsk_restore_flags(current, pflags, PF_MEMALLOC); + current_restore_flags(pflags, PF_MEMALLOC); return rc; } diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 19d50f600e8d4..9aaf6ca775699 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1004,7 +1004,7 @@ out_nfserr: else err = nfserrno(host_err); if (test_bit(RQ_LOCAL, &rqstp->rq_flags)) - tsk_restore_flags(current, pflags, PF_LESS_THROTTLE); + current_restore_flags(pflags, PF_LESS_THROTTLE); return err; } diff --git a/include/linux/sched.h b/include/linux/sched.h index d67eee84fd430..0978fb74e45a7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1286,10 +1286,10 @@ TASK_PFA_TEST(LMK_WAITING, lmk_waiting) TASK_PFA_SET(LMK_WAITING, lmk_waiting) static inline void -tsk_restore_flags(struct task_struct *task, unsigned long orig_flags, unsigned long flags) +current_restore_flags(unsigned long orig_flags, unsigned long flags) { - task->flags &= ~flags; - task->flags |= orig_flags & flags; + current->flags &= ~flags; + current->flags |= orig_flags & flags; } extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial); diff --git a/kernel/softirq.c b/kernel/softirq.c index 744fa611cae06..4e09821f9d9e8 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -309,7 +309,7 @@ restart: account_irq_exit_time(current); __local_bh_enable(SOFTIRQ_OFFSET); WARN_ON_ONCE(in_interrupt()); - tsk_restore_flags(current, old_flags, PF_MEMALLOC); + current_restore_flags(old_flags, PF_MEMALLOC); } asmlinkage __visible void do_softirq(void) diff --git a/net/core/dev.c b/net/core/dev.c index 7869ae3837ca7..e8a366387a99c 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4240,7 +4240,7 @@ static int __netif_receive_skb(struct sk_buff *skb) */ current->flags |= PF_MEMALLOC; ret = __netif_receive_skb_core(skb, true); - tsk_restore_flags(current, pflags, PF_MEMALLOC); + current_restore_flags(pflags, PF_MEMALLOC); } else ret = __netif_receive_skb_core(skb, false); diff --git a/net/core/sock.c b/net/core/sock.c index 2c4f574168fbd..b416a537bd0ac 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -325,7 +325,7 @@ int __sk_backlog_rcv(struct sock *sk, struct sk_buff *skb) current->flags |= PF_MEMALLOC; ret = sk->sk_backlog_rcv(sk, skb); - tsk_restore_flags(current, pflags, PF_MEMALLOC); + current_restore_flags(pflags, PF_MEMALLOC); return ret; }