From 9965ed174e7d38896e5d2582159d8ef31ecd4cb5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 5 Mar 2018 07:26:05 -0800 Subject: [PATCH] fs: add new vfs_poll and file_can_poll helpers These abstract out calls to the poll method in preparation for changes in how we poll. Signed-off-by: Christoph Hellwig Reviewed-by: Greg Kroah-Hartman Reviewed-by: Darrick J. Wong --- drivers/staging/comedi/drivers/serial2002.c | 4 ++-- drivers/vfio/virqfd.c | 2 +- drivers/vhost/vhost.c | 2 +- fs/eventpoll.c | 5 ++--- fs/select.c | 23 +++++++-------------- include/linux/poll.h | 12 +++++++++++ mm/memcontrol.c | 2 +- net/9p/trans_fd.c | 18 ++++------------ virt/kvm/eventfd.c | 2 +- 9 files changed, 32 insertions(+), 38 deletions(-) diff --git a/drivers/staging/comedi/drivers/serial2002.c b/drivers/staging/comedi/drivers/serial2002.c index b3f3b4a201af..5471b2212a62 100644 --- a/drivers/staging/comedi/drivers/serial2002.c +++ b/drivers/staging/comedi/drivers/serial2002.c @@ -113,7 +113,7 @@ static void serial2002_tty_read_poll_wait(struct file *f, int timeout) long elapsed; __poll_t mask; - mask = f->f_op->poll(f, &table.pt); + mask = vfs_poll(f, &table.pt); if (mask & (EPOLLRDNORM | EPOLLRDBAND | EPOLLIN | EPOLLHUP | EPOLLERR)) { break; @@ -136,7 +136,7 @@ static int serial2002_tty_read(struct file *f, int timeout) result = -1; if (!IS_ERR(f)) { - if (f->f_op->poll) { + if (file_can_poll(f)) { serial2002_tty_read_poll_wait(f, timeout); if (kernel_read(f, &ch, 1, &pos) == 1) diff --git a/drivers/vfio/virqfd.c b/drivers/vfio/virqfd.c index 085700f1be10..2a1be859ee71 100644 --- a/drivers/vfio/virqfd.c +++ b/drivers/vfio/virqfd.c @@ -166,7 +166,7 @@ int vfio_virqfd_enable(void *opaque, init_waitqueue_func_entry(&virqfd->wait, virqfd_wakeup); init_poll_funcptr(&virqfd->pt, virqfd_ptable_queue_proc); - events = irqfd.file->f_op->poll(irqfd.file, &virqfd->pt); + events = vfs_poll(irqfd.file, &virqfd->pt); /* * Check if there was an event already pending on the eventfd diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index f3bd8e941224..f6022881f147 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -208,7 +208,7 @@ int vhost_poll_start(struct vhost_poll *poll, struct file *file) if (poll->wqh) return 0; - mask = file->f_op->poll(file, &poll->table); + mask = vfs_poll(file, &poll->table); if (mask) vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask)); if (mask & EPOLLERR) { diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 602ca4285b2e..67db22fe99c5 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -884,8 +884,7 @@ static __poll_t ep_item_poll(const struct epitem *epi, poll_table *pt, pt->_key = epi->event.events; if (!is_file_epoll(epi->ffd.file)) - return epi->ffd.file->f_op->poll(epi->ffd.file, pt) & - epi->event.events; + return vfs_poll(epi->ffd.file, pt) & epi->event.events; ep = epi->ffd.file->private_data; poll_wait(epi->ffd.file, &ep->poll_wait, pt); @@ -2025,7 +2024,7 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, /* The target file descriptor must support poll */ error = -EPERM; - if (!tf.file->f_op->poll) + if (!file_can_poll(tf.file)) goto error_tgt_fput; /* Check if EPOLLWAKEUP is allowed */ diff --git a/fs/select.c b/fs/select.c index 25da26253485..e30def680b2e 100644 --- a/fs/select.c +++ b/fs/select.c @@ -502,14 +502,10 @@ static int do_select(int n, fd_set_bits *fds, struct timespec64 *end_time) continue; f = fdget(i); if (f.file) { - const struct file_operations *f_op; - f_op = f.file->f_op; - mask = DEFAULT_POLLMASK; - if (f_op->poll) { - wait_key_set(wait, in, out, - bit, busy_flag); - mask = (*f_op->poll)(f.file, wait); - } + wait_key_set(wait, in, out, bit, + busy_flag); + mask = vfs_poll(f.file, wait); + fdput(f); if ((mask & POLLIN_SET) && (in & bit)) { res_in |= bit; @@ -825,13 +821,10 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait, /* userland u16 ->events contains POLL... bitmap */ filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP; - mask = DEFAULT_POLLMASK; - if (f.file->f_op->poll) { - pwait->_key = filter | busy_flag; - mask = f.file->f_op->poll(f.file, pwait); - if (mask & busy_flag) - *can_busy_poll = true; - } + pwait->_key = filter | busy_flag; + mask = vfs_poll(f.file, pwait); + if (mask & busy_flag) + *can_busy_poll = true; mask &= filter; /* Mask out unneeded events. */ fdput(f); diff --git a/include/linux/poll.h b/include/linux/poll.h index a3576da63377..7e0fdcf905d2 100644 --- a/include/linux/poll.h +++ b/include/linux/poll.h @@ -74,6 +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) +{ + return file->f_op->poll; +} + +static inline __poll_t vfs_poll(struct file *file, struct poll_table_struct *pt) +{ + if (unlikely(!file->f_op->poll)) + return DEFAULT_POLLMASK; + return file->f_op->poll(file, pt); +} + struct poll_table_entry { struct file *filp; __poll_t key; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2bd3df3d101a..1695f38630f1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3849,7 +3849,7 @@ static ssize_t memcg_write_event_control(struct kernfs_open_file *of, if (ret) goto out_put_css; - efile.file->f_op->poll(efile.file, &event->pt); + vfs_poll(efile.file, &event->pt); spin_lock(&memcg->event_list_lock); list_add(&event->list, &memcg->event_list); diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index 0cfba919d167..3811775692d0 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -231,7 +231,7 @@ static void p9_conn_cancel(struct p9_conn *m, int err) static __poll_t p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err) { - __poll_t ret, n; + __poll_t ret; struct p9_trans_fd *ts = NULL; if (client && client->status == Connected) @@ -243,19 +243,9 @@ p9_fd_poll(struct p9_client *client, struct poll_table_struct *pt, int *err) return EPOLLERR; } - if (!ts->rd->f_op->poll) - ret = DEFAULT_POLLMASK; - else - ret = ts->rd->f_op->poll(ts->rd, pt); - - if (ts->rd != ts->wr) { - if (!ts->wr->f_op->poll) - n = DEFAULT_POLLMASK; - else - n = ts->wr->f_op->poll(ts->wr, pt); - ret = (ret & ~EPOLLOUT) | (n & ~EPOLLIN); - } - + ret = vfs_poll(ts->rd, pt); + if (ts->rd != ts->wr) + ret = (ret & ~EPOLLOUT) | (vfs_poll(ts->wr, pt) & ~EPOLLIN); return ret; } diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c index 6e865e8b5b10..90d30fbe95ae 100644 --- a/virt/kvm/eventfd.c +++ b/virt/kvm/eventfd.c @@ -397,7 +397,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) * Check if there was an event already pending on the eventfd * before we registered, and trigger it as if we didn't miss it. */ - events = f.file->f_op->poll(f.file, &irqfd->pt); + events = vfs_poll(f.file, &irqfd->pt); if (events & EPOLLIN) schedule_work(&irqfd->inject);