[PATCH 5.7 323/393] net/tls: Fix kmap usage

[Greg Kroah-Hartman]

From: Ira Weiny <ira.we...@intel.com>

[ Upstream commit b06c19d9f827f6743122795570bfc0c72db482b0 ]

When MSG_OOB is specified to tls_device_sendpage() the mapped page is
never unmapped.

Hold off mapping the page until after the flags are checked and the page
is actually needed.

Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Ira Weiny <ira.we...@intel.com>
Reviewed-by: Jakub Kicinski <k...@kernel.org>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/tls/tls_device.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/tls/tls_device.c
+++ b/net/tls/tls_device.c
@@ -561,7 +561,7 @@ int tls_device_sendpage(struct sock *sk,
 {
        struct tls_context *tls_ctx = tls_get_ctx(sk);
        struct iov_iter msg_iter;
-       char *kaddr = kmap(page);
+       char *kaddr;
        struct kvec iov;
        int rc;
 
@@ -576,6 +576,7 @@ int tls_device_sendpage(struct sock *sk,
                goto out;
        }
 
+       kaddr = kmap(page);
        iov.iov_base = kaddr + offset;
        iov.iov_len = size;
        iov_iter_kvec(&msg_iter, WRITE, &iov, 1, size);