From: Drew DeVault <[email protected]>
To: [email protected]
Cc: Drew DeVault <[email protected]>, "Jens Axboe" <[email protected]>,
"Pavel Begunkov" <[email protected]>
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: <[email protected]> (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
next 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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