From f3251183b298912e09297cb22614361c63122e82 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Tue, 23 Nov 2021 00:07:48 +0000
Subject: [PATCH] io_uring: clean __io_import_iovec()
Git-commit: f3251183b298912e09297cb22614361c63122e82
Patch-mainline: v5.17-rc1
References: bsc#1205205

Apparently, implicit 0 to NULL conversion with ERR_PTR is not
recommended and makes some tooling like Smatch to complain. Handle it
explicitly, compilers are perfectly capable to optimise it out.

Link: https://lore.kernel.org/all/20211108134937.GA2863@kili/
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/5c6ed369ad95075dab345df679f8677b8fe66656.1637524285.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Gabriel Krisman Bertazi <krisman@suse.de>
---
 fs/io_uring.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7ef2d0c1296f..a65fb9cd9db7 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3179,10 +3179,12 @@ static struct iovec *__io_import_iovec(int rw, struct io_kiocb *req,
 	size_t sqe_len;
 	ssize_t ret;
 
-	BUILD_BUG_ON(ERR_PTR(0) != NULL);
-
-	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED)
-		return ERR_PTR(io_import_fixed(req, rw, iter));
+	if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
+		ret = io_import_fixed(req, rw, iter);
+		if (ret)
+			return ERR_PTR(ret);
+		return NULL;
+	}
 
 	/* buffer index only valid with fixed read/write, or buffer select  */
 	if (unlikely(req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT)))
@@ -3200,15 +3202,18 @@ static struct iovec *__io_import_iovec(int rw, struct io_kiocb *req,
 		}
 
 		ret = import_single_range(rw, buf, sqe_len, s->fast_iov, iter);
-		return ERR_PTR(ret);
+		if (ret)
+			return ERR_PTR(ret);
+		return NULL;
 	}
 
 	iovec = s->fast_iov;
 	if (req->flags & REQ_F_BUFFER_SELECT) {
 		ret = io_iov_buffer_select(req, iovec, issue_flags);
-		if (!ret)
-			iov_iter_init(iter, rw, iovec, 1, iovec->iov_len);
-		return ERR_PTR(ret);
+		if (ret)
+			return ERR_PTR(ret);
+		iov_iter_init(iter, rw, iovec, 1, iovec->iov_len);
+		return NULL;
 	}
 
 	ret = __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, &iovec, iter,
-- 
2.35.3