diff options
| -rw-r--r-- | Documentation/filesystems/Locking | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 13 | ||||
| -rw-r--r-- | fs/select.c | 23 | ||||
| -rw-r--r-- | include/linux/fs.h | 2 | ||||
| -rw-r--r-- | include/linux/poll.h | 12 |
5 files changed, 50 insertions, 7 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 220bba28f72b..6d227f9d7bd9 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -440,6 +440,8 @@ prototypes: ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); int (*iterate) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); + struct wait_queue_head * (*get_poll_head)(struct file *, __poll_t); + __poll_t (*poll_mask) (struct file *, __poll_t); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); int (*mmap) (struct file *, struct vm_area_struct *); @@ -470,7 +472,7 @@ prototypes: }; locking rules: - All may block. + All except for ->poll_mask may block. ->llseek() locking has moved from llseek to the individual llseek implementations. If your fs is not using generic_file_llseek, you @@ -498,6 +500,9 @@ in sys_read() and friends. the lease within the individual filesystem to record the result of the operation +->poll_mask can be called with or without the waitqueue lock for the waitqueue +returned from ->get_poll_head. + --------------------------- dquot_operations ------------------------------- prototypes: int (*write_dquot) (struct dquot *); diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index f608180ad59d..829a7b7857a4 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -857,6 +857,8 @@ struct file_operations { ssize_t (*write_iter) (struct kiocb *, struct iov_iter *); int (*iterate) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); + struct wait_queue_head * (*get_poll_head)(struct file *, __poll_t); + __poll_t (*poll_mask) (struct file *, __poll_t); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); int (*mmap) (struct file *, struct vm_area_struct *); @@ -901,6 +903,17 @@ otherwise noted. activity on this file and (optionally) go to sleep until there is activity. Called by the select(2) and poll(2) system calls + get_poll_head: Returns the struct wait_queue_head that callers can + wait on. Callers need to check the returned events using ->poll_mask + once woken. Can return NULL to indicate polling is not supported, + or any error code using the ERR_PTR convention to indicate that a + grave error occured and ->poll_mask shall not be called. + + poll_mask: return the mask of EPOLL* values describing the file descriptor + state. Called either before going to sleep on the waitqueue returned by + get_poll_head, or after it has been woken. If ->get_poll_head and + ->poll_mask are implemented ->poll does not need to be implement. + unlocked_ioctl: called by the ioctl(2) system call. compat_ioctl: called by the ioctl(2) system call when 32 bit system calls diff --git a/fs/select.c b/fs/select.c index e30def680b2e..bc3cc0f98896 100644 --- a/fs/select.c +++ b/fs/select.c @@ -34,6 +34,29 @@ #include <linux/uaccess.h> +__poll_t vfs_poll(struct file *file, struct poll_table_struct *pt) +{ + if (file->f_op->poll) { + return file->f_op->poll(file, pt); + } else if (file_has_poll_mask(file)) { + unsigned int events = poll_requested_events(pt); + struct wait_queue_head *head; + + if (pt && pt->_qproc) { + head = file->f_op->get_poll_head(file, events); + if (!head) + return DEFAULT_POLLMASK; + if (IS_ERR(head)) + return EPOLLERR; + pt->_qproc(file, head, pt); + } + + return file->f_op->poll_mask(file, events); + } else { + return DEFAULT_POLLMASK; + } +} +EXPORT_SYMBOL_GPL(vfs_poll); /* * Estimate expected accuracy in ns from a timeval. diff --git a/include/linux/fs.h b/include/linux/fs.h index 760d8da1b6c7..4b6045ebb2f2 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1711,6 +1711,8 @@ struct file_operations { int (*iterate) (struct file *, struct dir_context *); int (*iterate_shared) (struct file *, struct dir_context *); __poll_t (*poll) (struct file *, struct poll_table_struct *); + struct wait_queue_head * (*get_poll_head)(struct file *, __poll_t); + __poll_t (*poll_mask) (struct file *, __poll_t); long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long); long (*compat_ioctl) (struct file *, unsigned int, unsigned long); int (*mmap) (struct file *, struct vm_area_struct *); diff --git a/include/linux/poll.h b/include/linux/poll.h index 7e0fdcf905d2..fdf86b4cbc71 100644 --- a/include/linux/poll.h +++ b/include/linux/poll.h @@ -74,18 +74,18 @@ static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) pt->_key = ~(__poll_t)0; /* all events enabled */ } -static inline bool file_can_poll(struct file *file) +static inline bool file_has_poll_mask(struct file *file) { - return file->f_op->poll; + return file->f_op->get_poll_head && file->f_op->poll_mask; } -static inline __poll_t vfs_poll(struct file *file, struct poll_table_struct *pt) +static inline bool file_can_poll(struct file *file) { - if (unlikely(!file->f_op->poll)) - return DEFAULT_POLLMASK; - return file->f_op->poll(file, pt); + return file->f_op->poll || file_has_poll_mask(file); } +__poll_t vfs_poll(struct file *file, struct poll_table_struct *pt); + struct poll_table_entry { struct file *filp; __poll_t key; |