From 0498878b18993891f7b71c75b6adcb7c157501db Mon Sep 17 00:00:00 2001 From: Jukka Rissanen Date: Wed, 18 Jun 2014 16:37:07 +0300 Subject: [PATCH] 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 Signed-off-by: Marcel Holtmann --- include/net/bluetooth/l2cap.h | 29 +++++++++++++++++++++++++++++ net/bluetooth/a2mp.c | 1 + net/bluetooth/l2cap_core.c | 6 ++++-- net/bluetooth/l2cap_sock.c | 34 +++++++++++++++++++++------------- 4 files changed, 55 insertions(+), 15 deletions(-) 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 l2cap_ops { 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 @@ static inline long l2cap_chan_no_get_sndtimeo(struct l2cap_chan *chan) 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 @@ static const struct l2cap_ops a2mp_chan_ops = { .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 @@ static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan, 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 @@ static inline int l2cap_skbuff_fromiovec(struct l2cap_chan *chan, *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 @@ static struct sk_buff *l2cap_sock_alloc_skb_cb(struct l2cap_chan *chan, 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 void l2cap_sock_suspend_cb(struct l2cap_chan *chan) } 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) -- 2.7.4