diff options
Diffstat (limited to 'fs/userfaultfd.c')
| -rw-r--r-- | fs/userfaultfd.c | 62 |
1 files changed, 28 insertions, 34 deletions
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index 37df7c9eedb1..703c1c3faa6e 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -334,6 +334,30 @@ out: return ret; } +/* Should pair with userfaultfd_signal_pending() */ +static inline long userfaultfd_get_blocking_state(unsigned int flags) +{ + if (flags & FAULT_FLAG_INTERRUPTIBLE) + return TASK_INTERRUPTIBLE; + + if (flags & FAULT_FLAG_KILLABLE) + return TASK_KILLABLE; + + return TASK_UNINTERRUPTIBLE; +} + +/* Should pair with userfaultfd_get_blocking_state() */ +static inline bool userfaultfd_signal_pending(unsigned int flags) +{ + if (flags & FAULT_FLAG_INTERRUPTIBLE) + return signal_pending(current); + + if (flags & FAULT_FLAG_KILLABLE) + return fatal_signal_pending(current); + + return false; +} + /* * The locking rules involved in returning VM_FAULT_RETRY depending on * FAULT_FLAG_ALLOW_RETRY, FAULT_FLAG_RETRY_NOWAIT and @@ -355,7 +379,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) struct userfaultfd_ctx *ctx; struct userfaultfd_wait_queue uwq; vm_fault_t ret = VM_FAULT_SIGBUS; - bool must_wait, return_to_userland; + bool must_wait; long blocking_state; /* @@ -462,11 +486,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) uwq.ctx = ctx; uwq.waken = false; - return_to_userland = - (vmf->flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) == - (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE); - blocking_state = return_to_userland ? TASK_INTERRUPTIBLE : - TASK_KILLABLE; + blocking_state = userfaultfd_get_blocking_state(vmf->flags); spin_lock_irq(&ctx->fault_pending_wqh.lock); /* @@ -492,8 +512,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) up_read(&mm->mmap_sem); if (likely(must_wait && !READ_ONCE(ctx->released) && - (return_to_userland ? !signal_pending(current) : - !fatal_signal_pending(current)))) { + !userfaultfd_signal_pending(vmf->flags))) { wake_up_poll(&ctx->fd_wqh, EPOLLIN); schedule(); ret |= VM_FAULT_MAJOR; @@ -515,8 +534,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) set_current_state(blocking_state); if (READ_ONCE(uwq.waken) || READ_ONCE(ctx->released) || - (return_to_userland ? signal_pending(current) : - fatal_signal_pending(current))) + userfaultfd_signal_pending(vmf->flags)) break; schedule(); } @@ -524,30 +542,6 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason) __set_current_state(TASK_RUNNING); - if (return_to_userland) { - if (signal_pending(current) && - !fatal_signal_pending(current)) { - /* - * If we got a SIGSTOP or SIGCONT and this is - * a normal userland page fault, just let - * userland return so the signal will be - * handled and gdb debugging works. The page - * fault code immediately after we return from - * this function is going to release the - * mmap_sem and it's not depending on it - * (unlike gup would if we were not to return - * VM_FAULT_RETRY). - * - * If a fatal signal is pending we still take - * the streamlined VM_FAULT_RETRY failure path - * and there's no need to retake the mmap_sem - * in such case. - */ - down_read(&mm->mmap_sem); - ret = VM_FAULT_NOPAGE; - } - } - /* * Here we race with the list_del; list_add in * userfaultfd_ctx_read(), however because we don't ever run |