linux-brain/drivers/vhost
Neeraj Upadhyay 73ba9e4ece 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>
2021-09-03 10:08:15 +02:00
..
Kconfig
Kconfig.vringh
Makefile
net.c vhost_net: fix ubuf refcount incorrectly when sendmsg fails 2021-01-12 20:16:16 +01:00
scsi.c vhost scsi: fix cmd completion race 2020-12-02 08:49:48 +01:00
test.c
test.h
vhost.c vhost: Fix the calculation in vhost_overflow() 2021-08-26 08:36:16 -04:00
vhost.h
vringh.c vringh: Use wiov->used to check for read/write desc order 2021-09-03 10:08:15 +02:00
vsock.c