[PATCH 11/12] mm: add kiocb_wait_page_queue_init() helper

Jens Axboe
2020-05-24T19:22:43Z

Checks if the file supports it, and initializes the values that we need.
Caller passes in 'data' pointer, if any, and the callback function to
be used.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
include/linux/pagemap.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index d3e63c9c61ae..8b65420410ee 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -493,6 +493,27 @@ static inline int wake_page_match(struct wait_page_queue *wait_page,
return 1;
}

+static inline int kiocb_wait_page_queue_init(struct kiocb *kiocb,
+ struct wait_page_queue *wait,
+ wait_queue_func_t func,
+ void *data)
+{
+ /* Can't support async wakeup with polled IO */
+ if (kiocb->ki_flags & IOCB_HIPRI)
+ return -EINVAL;
+ if (kiocb->ki_filp->f_mode & FMODE_BUF_RASYNC) {
+ wait->wait.func = func;
+ wait->wait.private = data;
+ wait->wait.flags = 0;
+ INIT_LIST_HEAD(&wait->wait.entry);
+ kiocb->ki_flags |= IOCB_WAITQ;
+ kiocb->ki_waitq = wait;
+ return 0;
+ }
+
+ return -EOPNOTSUPP;
+}
+
extern void __lock_page(struct page *page);
extern int __lock_page_killable(struct page *page);
extern int __lock_page_async(struct page *page, struct wait_page_queue *wait);
--
2.26.2