From f6b543fd03d347e8bf245cee4f2d54eb6ffd8fcb Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@kernel.dk>
Date: Thu, 21 Jul 2022 09:06:47 -0600
Subject: [PATCH] io_uring: ensure REQ_F_ISREG is set async offload
Git-commit: f6b543fd03d347e8bf245cee4f2d54eb6ffd8fcb
Patch-mainline: v6.0-rc1
References: git-fixes

If we're offloading requests directly to io-wq because IOSQE_ASYNC was
set in the sqe, we can miss hashing writes appropriately because we
haven't set REQ_F_ISREG yet. This can cause a performance regression
with buffered writes, as io-wq then no longer correctly serializes writes
to that file.

Ensure that we set the flags in io_prep_async_work(), which will cause
the io-wq work item to be hashed appropriately.

Fixes: 584b0180f0f4 ("io_uring: move read/write file prep state into actual opcode handler")
Link: https://lore.kernel.org/io-uring/20220608080054.GB22428@xsang-OptiPlex-9020/
Reported-by: kernel test robot <oliver.sang@intel.com>
Tested-by: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -1408,6 +1408,8 @@ const char *io_uring_get_opcode(u8 opcod
 	return "INVALID";
 }
 
+static unsigned int io_file_get_flags(struct file *file);
+
 struct sock *io_uring_get_socket(struct file *file)
 {
 #if defined(CONFIG_UNIX)
@@ -1967,6 +1969,9 @@ static void io_prep_async_work(struct io
 	if (req->flags & REQ_F_FORCE_ASYNC)
 		req->work.flags |= IO_WQ_WORK_CONCURRENT;
 
+	if (req->file && !io_req_ffs_set(req))
+		req->flags |= io_file_get_flags(req->file) << REQ_F_SUPPORT_NOWAIT_BIT;
+
 	if (req->flags & REQ_F_ISREG) {
 		if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
 			io_wq_hash_work(&req->work, file_inode(req->file));