diff options
Diffstat (limited to 'fs/notify')
-rw-r--r-- | fs/notify/inotify/inotify.c | 2 | ||||
-rw-r--r-- | fs/notify/inotify/inotify_user.c | 135 |
2 files changed, 75 insertions, 62 deletions
diff --git a/fs/notify/inotify/inotify.c b/fs/notify/inotify/inotify.c index dae3f28f30d..331f2e88e28 100644 --- a/fs/notify/inotify/inotify.c +++ b/fs/notify/inotify/inotify.c @@ -156,7 +156,7 @@ static int inotify_handle_get_wd(struct inotify_handle *ih, int ret; do { - if (unlikely(!idr_pre_get(&ih->idr, GFP_KERNEL))) + if (unlikely(!idr_pre_get(&ih->idr, GFP_NOFS))) return -ENOSPC; ret = idr_get_new_above(&ih->idr, watch, ih->last_wd+1, &watch->wd); } while (ret == -EAGAIN); diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c index d53a1838d6e..bed766e435b 100644 --- a/fs/notify/inotify/inotify_user.c +++ b/fs/notify/inotify/inotify_user.c @@ -427,10 +427,61 @@ static unsigned int inotify_poll(struct file *file, poll_table *wait) return ret; } +/* + * Get an inotify_kernel_event if one exists and is small + * enough to fit in "count". Return an error pointer if + * not large enough. + * + * Called with the device ev_mutex held. + */ +static struct inotify_kernel_event *get_one_event(struct inotify_device *dev, + size_t count) +{ + size_t event_size = sizeof(struct inotify_event); + struct inotify_kernel_event *kevent; + + if (list_empty(&dev->events)) + return NULL; + + kevent = inotify_dev_get_event(dev); + if (kevent->name) + event_size += kevent->event.len; + + if (event_size > count) + return ERR_PTR(-EINVAL); + + remove_kevent(dev, kevent); + return kevent; +} + +/* + * Copy an event to user space, returning how much we copied. + * + * We already checked that the event size is smaller than the + * buffer we had in "get_one_event()" above. + */ +static ssize_t copy_event_to_user(struct inotify_kernel_event *kevent, + char __user *buf) +{ + size_t event_size = sizeof(struct inotify_event); + + if (copy_to_user(buf, &kevent->event, event_size)) + return -EFAULT; + + if (kevent->name) { + buf += event_size; + + if (copy_to_user(buf, kevent->name, kevent->event.len)) + return -EFAULT; + + event_size += kevent->event.len; + } + return event_size; +} + static ssize_t inotify_read(struct file *file, char __user *buf, size_t count, loff_t *pos) { - size_t event_size = sizeof (struct inotify_event); struct inotify_device *dev; char __user *start; int ret; @@ -440,81 +491,43 @@ static ssize_t inotify_read(struct file *file, char __user *buf, dev = file->private_data; while (1) { + struct inotify_kernel_event *kevent; prepare_to_wait(&dev->wq, &wait, TASK_INTERRUPTIBLE); mutex_lock(&dev->ev_mutex); - if (!list_empty(&dev->events)) { - ret = 0; - break; - } + kevent = get_one_event(dev, count); mutex_unlock(&dev->ev_mutex); - if (file->f_flags & O_NONBLOCK) { - ret = -EAGAIN; - break; - } - - if (signal_pending(current)) { - ret = -EINTR; - break; + if (kevent) { + ret = PTR_ERR(kevent); + if (IS_ERR(kevent)) + break; + ret = copy_event_to_user(kevent, buf); + free_kevent(kevent); + if (ret < 0) + break; + buf += ret; + count -= ret; + continue; } - schedule(); - } - - finish_wait(&dev->wq, &wait); - if (ret) - return ret; - - while (1) { - struct inotify_kernel_event *kevent; - - ret = buf - start; - if (list_empty(&dev->events)) + ret = -EAGAIN; + if (file->f_flags & O_NONBLOCK) break; - - kevent = inotify_dev_get_event(dev); - if (event_size + kevent->event.len > count) { - if (ret == 0 && count > 0) { - /* - * could not get a single event because we - * didn't have enough buffer space. - */ - ret = -EINVAL; - } + ret = -EINTR; + if (signal_pending(current)) break; - } - remove_kevent(dev, kevent); - /* - * Must perform the copy_to_user outside the mutex in order - * to avoid a lock order reversal with mmap_sem. - */ - mutex_unlock(&dev->ev_mutex); - - if (copy_to_user(buf, &kevent->event, event_size)) { - ret = -EFAULT; + if (start != buf) break; - } - buf += event_size; - count -= event_size; - - if (kevent->name) { - if (copy_to_user(buf, kevent->name, kevent->event.len)){ - ret = -EFAULT; - break; - } - buf += kevent->event.len; - count -= kevent->event.len; - } - - free_kevent(kevent); - mutex_lock(&dev->ev_mutex); + schedule(); } - mutex_unlock(&dev->ev_mutex); + finish_wait(&dev->wq, &wait); + if (start != buf && ret != -EFAULT) + ret = buf - start; return ret; } |