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From: Drew DeVault <sir@cmpwn.com>
To: io-uring@vger.kernel.org
Cc: Drew DeVault <sir@cmpwn.com>, "Jens Axboe" <axboe@kernel.dk>,
	"Pavel Begunkov" <asml.silence@gmail.com>
Subject: [PATCH v2] io_uring_enter(2): clarify OP_READ and OP_WRITE
Date: Sun, 23 May 2021 12:44:37 -0400	[thread overview]
Message-ID: <20210523164437.22784-1-sir@cmpwn.com> (raw)

These do not advance the internal file offset unless the offset is set
to -1, making them behave more like pread/pwrite than read/write.
---
 man/io_uring_enter.2 | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/man/io_uring_enter.2 b/man/io_uring_enter.2
index f898ffd..5b498e5 100644
--- a/man/io_uring_enter.2
+++ b/man/io_uring_enter.2
@@ -576,16 +576,24 @@ for the general description of the related system call. Available since 5.6.
 .TP
 .B IORING_OP_WRITE
 Issue the equivalent of a
-.BR read(2)
+.BR pread(2)
 or
-.BR write(2)
+.BR pwrite(2)
 system call.
 .I fd
 is the file descriptor to be operated on,
 .I addr
-contains the buffer in question, and
+contains the buffer in question,
 .I len
-contains the length of the IO operation. These are non-vectored versions of the
+contains the length of the IO operation, and
+.I offs
+contains the read or write offset. If
+.I offs
+is set to -1, the offset will use (and advance) the file position, like the
+.BR read(2)
+and
+.BR write(2)
+system calls. These are non-vectored versions of the
 .B IORING_OP_READV
 and
 .B IORING_OP_WRITEV
-- 
2.31.1


             reply	other threads:[~2021-05-23 16:44 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-23 16:44 Drew DeVault [this message]
2021-05-27 19:05 ` [PATCH v2] io_uring_enter(2): clarify OP_READ and OP_WRITE Jens Axboe

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