Bluetooth: Provide L2CAP ops callback for memcpy_fromiovec
The highly optimized TX path for L2CAP channels and its fragmentation
within the HCI ACL packets requires to copy data from user provided
IO vectors and also kernel provided memory buffers.
This patch allows channel clients to provide a memcpy_fromiovec callback
to keep this optimized behavior, but adapt it to kernel vs user memory
for the TX path. For all kernel internal L2CAP channels, a default
implementation is provided that can be referenced.
In case of A2MP, this fixes a long-standing issue with wrongly accessing
kernel memory as user memory.
This patch originally by Marcel Holtmann.
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 9251103..1ee6f00d7 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -602,6 +602,10 @@
struct sk_buff *(*alloc_skb) (struct l2cap_chan *chan,
unsigned long hdr_len,
unsigned long len, int nb);
+ int (*memcpy_fromiovec) (struct l2cap_chan *chan,
+ unsigned char *kdata,
+ struct iovec *iov,
+ int len);
};
struct l2cap_conn {
@@ -857,6 +861,31 @@
return 0;
}
+static inline int l2cap_chan_no_memcpy_fromiovec(struct l2cap_chan *chan,
+ unsigned char *kdata,
+ struct iovec *iov,
+ int len)
+{
+ /* Following is safe since for compiler definitions of kvec and
+ * iovec are identical, yielding the same in-core layout and alignment
+ */
+ struct kvec *vec = (struct kvec *)iov;
+
+ while (len > 0) {
+ if (vec->iov_len) {
+ int copy = min_t(unsigned int, len, vec->iov_len);
+ memcpy(kdata, vec->iov_base, copy);
+ len -= copy;
+ kdata += copy;
+ vec->iov_base += copy;
+ vec->iov_len -= copy;
+ }
+ vec++;
+ }
+
+ return 0;
+}
+
extern bool disable_ertm;
int l2cap_init_sockets(void);
diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 0fd8d1d..5dcade5 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -720,6 +720,7 @@
.resume = l2cap_chan_no_resume,
.set_shutdown = l2cap_chan_no_set_shutdown,
.get_sndtimeo = l2cap_chan_no_get_sndtimeo,
+ .memcpy_fromiovec = l2cap_chan_no_memcpy_fromiovec,
};
static struct l2cap_chan *a2mp_chan_open(struct l2cap_conn *conn, bool locked)
diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c
index ac24614..d0a5fde 100644
--- a/net/bluetooth/l2cap_core.c
+++ b/net/bluetooth/l2cap_core.c
@@ -2118,7 +2118,8 @@
struct sk_buff **frag;
int sent = 0;
- if (memcpy_fromiovec(skb_put(skb, count), msg->msg_iov, count))
+ if (chan->ops->memcpy_fromiovec(chan, skb_put(skb, count),
+ msg->msg_iov, count))
return -EFAULT;
sent += count;
@@ -2138,7 +2139,8 @@
*frag = tmp;
- if (memcpy_fromiovec(skb_put(*frag, count), msg->msg_iov, count))
+ if (chan->ops->memcpy_fromiovec(chan, skb_put(*frag, count),
+ msg->msg_iov, count))
return -EFAULT;
sent += count;
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index 55215eb..bf72886 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -1313,6 +1313,13 @@
return skb;
}
+static int l2cap_sock_memcpy_fromiovec_cb(struct l2cap_chan *chan,
+ unsigned char *kdata,
+ struct iovec *iov, int len)
+{
+ return memcpy_fromiovec(kdata, iov, len);
+}
+
static void l2cap_sock_ready_cb(struct l2cap_chan *chan)
{
struct sock *sk = chan->data;
@@ -1379,19 +1386,20 @@
}
static const struct l2cap_ops l2cap_chan_ops = {
- .name = "L2CAP Socket Interface",
- .new_connection = l2cap_sock_new_connection_cb,
- .recv = l2cap_sock_recv_cb,
- .close = l2cap_sock_close_cb,
- .teardown = l2cap_sock_teardown_cb,
- .state_change = l2cap_sock_state_change_cb,
- .ready = l2cap_sock_ready_cb,
- .defer = l2cap_sock_defer_cb,
- .resume = l2cap_sock_resume_cb,
- .suspend = l2cap_sock_suspend_cb,
- .set_shutdown = l2cap_sock_set_shutdown_cb,
- .get_sndtimeo = l2cap_sock_get_sndtimeo_cb,
- .alloc_skb = l2cap_sock_alloc_skb_cb,
+ .name = "L2CAP Socket Interface",
+ .new_connection = l2cap_sock_new_connection_cb,
+ .recv = l2cap_sock_recv_cb,
+ .close = l2cap_sock_close_cb,
+ .teardown = l2cap_sock_teardown_cb,
+ .state_change = l2cap_sock_state_change_cb,
+ .ready = l2cap_sock_ready_cb,
+ .defer = l2cap_sock_defer_cb,
+ .resume = l2cap_sock_resume_cb,
+ .suspend = l2cap_sock_suspend_cb,
+ .set_shutdown = l2cap_sock_set_shutdown_cb,
+ .get_sndtimeo = l2cap_sock_get_sndtimeo_cb,
+ .alloc_skb = l2cap_sock_alloc_skb_cb,
+ .memcpy_fromiovec = l2cap_sock_memcpy_fromiovec_cb,
};
static void l2cap_sock_destruct(struct sock *sk)