There are 2 way of adding item to wait_queue, 1. add_wait_queue() 2. add_wait_queue_exclusive() and add_wait_queue_exclusive() is very useful API. unforunately, poll_wait_exclusive() against poll_wait() doesn't exist. it means there is no way that wake up only 1 process where polled. wake_up() is wake up all sleeping process by poll_wait(), not 1 process. this patch introduce poll_wait_exclusive() new API for allow wake up only 1 process. <usage example> unsigned int kosaki_poll(struct file *file, struct poll_table_struct *wait) { poll_wait_exclusive(file, &kosaki_wait_queue, wait); if (data_exist) return POLLIN | POLLRDNORM; return 0; } </usage example> Signed-off-by: Marcelo Tosatti <marcelo@xxxxxxxxx> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> --- fs/eventpoll.c | 7 +++++-- fs/select.c | 9 ++++++--- include/linux/poll.h | 13 +++++++++++-- 3 files changed, 22 insertions(+), 7 deletions(-) Index: b/fs/eventpoll.c =================================================================== --- a/fs/eventpoll.c 2008-01-23 19:22:19.000000000 +0900 +++ b/fs/eventpoll.c 2008-01-23 21:11:56.000000000 +0900 @@ -675,7 +675,7 @@ out_unlock: * target file wakeup lists. */ static void ep_ptable_queue_proc(struct file *file, wait_queue_head_t *whead, - poll_table *pt) + poll_table *pt, int exclusive) { struct epitem *epi = ep_item_from_epqueue(pt); struct eppoll_entry *pwq; @@ -684,7 +684,10 @@ static void ep_ptable_queue_proc(struct init_waitqueue_func_entry(&pwq->wait, ep_poll_callback); pwq->whead = whead; pwq->base = epi; - add_wait_queue(whead, &pwq->wait); + if (exclusive) + add_wait_queue_exclusive(whead, &pwq->wait); + else + add_wait_queue(whead, &pwq->wait); list_add_tail(&pwq->llink, &epi->pwqlist); epi->nwait++; } else { Index: b/fs/select.c =================================================================== --- a/fs/select.c 2008-01-23 19:22:22.000000000 +0900 +++ b/fs/select.c 2008-01-23 21:11:56.000000000 +0900 @@ -48,7 +48,7 @@ struct poll_table_page { * poll table. */ static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, - poll_table *p); + poll_table *p, int exclusive); void poll_initwait(struct poll_wqueues *pwq) { @@ -117,7 +117,7 @@ static struct poll_table_entry *poll_get /* Add a new entry */ static void __pollwait(struct file *filp, wait_queue_head_t *wait_address, - poll_table *p) + poll_table *p, int exclusive) { struct poll_table_entry *entry = poll_get_entry(p); if (!entry) @@ -126,7 +126,10 @@ static void __pollwait(struct file *filp entry->filp = filp; entry->wait_address = wait_address; init_waitqueue_entry(&entry->wait, current); - add_wait_queue(wait_address, &entry->wait); + if (exclusive) + add_wait_queue_exclusive(wait_address, &entry->wait); + else + add_wait_queue(wait_address, &entry->wait); } #define FDS_IN(fds, n) (fds->in + n) Index: b/include/linux/poll.h =================================================================== --- a/include/linux/poll.h 2008-01-23 19:22:55.000000000 +0900 +++ b/include/linux/poll.h 2008-02-03 20:28:27.000000000 +0900 @@ -28,7 +28,8 @@ struct poll_table_struct; /* * structures and helpers for f_op->poll implementations */ -typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, struct poll_table_struct *); +typedef void (*poll_queue_proc)(struct file *, wait_queue_head_t *, + struct poll_table_struct *, int); typedef struct poll_table_struct { poll_queue_proc qproc; @@ -37,7 +38,15 @@ typedef struct poll_table_struct { static inline void poll_wait(struct file * filp, wait_queue_head_t * wait_address, poll_table *p) { if (p && wait_address) - p->qproc(filp, wait_address, p); + p->qproc(filp, wait_address, p, 0); +} + +static inline void poll_wait_exclusive(struct file *filp, + wait_queue_head_t *wait_address, + poll_table *p) +{ + if (p && wait_address) + p->qproc(filp, wait_address, p, 1); } static inline void init_poll_funcptr(poll_table *pt, poll_queue_proc qproc) - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html