[PATCH] net/9p: Fix iov_iter usage

[PATCH] net/9p: Fix iov_iter usage

[Andy Lutomirski]

Trying to use 9pfs causes QEMU to complain:

    qemu-system-x86_64: virtio: bogus descriptor or out of resources

This happens because 9p was broken by the iov_iter refactoring because
a ! got lost.  Put it back.  The offending hunk was:

diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 7728b0acde09..4d7d2070e9c8 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -322,7 +322,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
 	if (!iov_iter_count(data))
 		return 0;

-	if (!(data->type & ITER_KVEC)) {
+	if (iov_iter_is_kvec(data)) {

Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Fixes: 00e23707442a ("iov_iter: Use accessor function")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 net/9p/trans_virtio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index 91981970f542..b1d39cabf125 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -329,7 +329,7 @@ static int p9_get_mapped_pages(struct virtio_chan *chan,
 	if (!iov_iter_count(data))
 		return 0;
 
-	if (iov_iter_is_kvec(data)) {
+	if (!iov_iter_is_kvec(data)) {
 		int n;
 		/*
 		 * We allow only p9_max_pages pinned. We wait for the
-- 
2.17.2

Re: [PATCH] net/9p: Fix iov_iter usage

[Al Viro]

On Sat, Nov 03, 2018 at 08:04:28PM -0700, Andy Lutomirski wrote:
> Trying to use 9pfs causes QEMU to complain:

commit 2cbfdf4df58330f6cb493500387427dae1c5551d
Author: Marc Zyngier <marc.zyngier@arm.com>
Date:   Fri Nov 2 17:16:51 2018 +0000

    iov_iter: Fix 9p virtio breakage