From 8cfba76383e902acbed95092163052b1572f17a8 Mon Sep 17 00:00:00 2001 From: David Howells Date: Tue, 14 Jan 2020 17:07:11 +0000 Subject: pipe: Allow buffers to be marked read-whole-or-error for notifications Allow a buffer to be marked such that read() must return the entire buffer in one go or return ENOBUFS. Multiple buffers can be amalgamated into a single read, but a short read will occur if the next "whole" buffer won't fit. This is useful for watch queue notifications to make sure we don't split a notification across multiple reads, especially given that we need to fabricate an overrun record under some circumstances - and that isn't in the buffers. Signed-off-by: David Howells --- include/linux/pipe_fs_i.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 1d3eaa233f4a..eaff59a2f074 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -8,6 +8,7 @@ #define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ #define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ #define PIPE_BUF_FLAG_PACKET 0x08 /* read() as a packet */ +#define PIPE_BUF_FLAG_WHOLE 0x10 /* read() must return entire buffer or error */ /** * struct pipe_buffer - a linux kernel pipe buffer -- cgit v1.2.3