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| author | Neeraj Upadhyay <neeraju@codeaurora.org> | 2021-06-25 06:25:02 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-03 11:09:27 +0300 |
| commit | c7ee4d22614e43ae1d633864b70ac075469ad27f (patch) | |
| tree | 7baf645270b6fccfd5706220883e7888368f1a3c | |
| parent | 6c074eaaf7855dfee8faa8a093940fff5e779ec3 (diff) | |
| download | linux-c7ee4d22614e43ae1d633864b70ac075469ad27f.tar.xz | |
vringh: Use wiov->used to check for read/write desc order
[ Upstream commit e74cfa91f42c50f7f649b0eca46aa049754ccdbd ]
As __vringh_iov() traverses a descriptor chain, it populates
each descriptor entry into either read or write vring iov
and increments that iov's ->used member. So, as we iterate
over a descriptor chain, at any point, (riov/wriov)->used
value gives the number of descriptor enteries available,
which are to be read or written by the device. As all read
iovs must precede the write iovs, wiov->used should be zero
when we are traversing a read descriptor. Current code checks
for wiov->i, to figure out whether any previous entry in the
current descriptor chain was a write descriptor. However,
iov->i is only incremented, when these vring iovs are consumed,
at a later point, and remain 0 in __vringh_iov(). So, correct
the check for read and write descriptor order, to use
wiov->used.
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Link: https://lore.kernel.org/r/1624591502-4827-1-git-send-email-neeraju@codeaurora.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/vhost/vringh.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index b7403ba8e7f7..0bd7e64331f0 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -341,7 +341,7 @@ __vringh_iov(struct vringh *vrh, u16 i, iov = wiov; else { iov = riov; - if (unlikely(wiov && wiov->i)) { + if (unlikely(wiov && wiov->used)) { vringh_bad("Readable desc %p after writable", &descs[i]); err = -EINVAL; |