netlink: mmaped netlink: ring setup
Add support for mmap'ed RX and TX ring setup and teardown based on the
af_packet.c code. The following patches will use this to add the real
mmap'ed receive and transmit functionality.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/Kconfig b/net/Kconfig
index 2ddc904..1a22216 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -23,6 +23,15 @@
if NET
+config NETLINK_MMAP
+ bool "Netlink: mmaped IO"
+ help
+ This option enables support for memory mapped netlink IO. This
+ reduces overhead by avoiding copying data between kernel- and
+ userspace.
+
+ If unsure, say N.
+
config WANT_COMPAT_NETLINK_MESSAGES
bool
help
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 58b9025..1d3c712 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -55,6 +55,7 @@
#include <linux/types.h>
#include <linux/audit.h>
#include <linux/mutex.h>
+#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/sock.h>
@@ -107,6 +108,234 @@
return &hash->table[jhash_1word(portid, hash->rnd) & hash->mask];
}
+#ifdef CONFIG_NETLINK_MMAP
+static __pure struct page *pgvec_to_page(const void *addr)
+{
+ if (is_vmalloc_addr(addr))
+ return vmalloc_to_page(addr);
+ else
+ return virt_to_page(addr);
+}
+
+static void free_pg_vec(void **pg_vec, unsigned int order, unsigned int len)
+{
+ unsigned int i;
+
+ for (i = 0; i < len; i++) {
+ if (pg_vec[i] != NULL) {
+ if (is_vmalloc_addr(pg_vec[i]))
+ vfree(pg_vec[i]);
+ else
+ free_pages((unsigned long)pg_vec[i], order);
+ }
+ }
+ kfree(pg_vec);
+}
+
+static void *alloc_one_pg_vec_page(unsigned long order)
+{
+ void *buffer;
+ gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO |
+ __GFP_NOWARN | __GFP_NORETRY;
+
+ buffer = (void *)__get_free_pages(gfp_flags, order);
+ if (buffer != NULL)
+ return buffer;
+
+ buffer = vzalloc((1 << order) * PAGE_SIZE);
+ if (buffer != NULL)
+ return buffer;
+
+ gfp_flags &= ~__GFP_NORETRY;
+ return (void *)__get_free_pages(gfp_flags, order);
+}
+
+static void **alloc_pg_vec(struct netlink_sock *nlk,
+ struct nl_mmap_req *req, unsigned int order)
+{
+ unsigned int block_nr = req->nm_block_nr;
+ unsigned int i;
+ void **pg_vec, *ptr;
+
+ pg_vec = kcalloc(block_nr, sizeof(void *), GFP_KERNEL);
+ if (pg_vec == NULL)
+ return NULL;
+
+ for (i = 0; i < block_nr; i++) {
+ pg_vec[i] = ptr = alloc_one_pg_vec_page(order);
+ if (pg_vec[i] == NULL)
+ goto err1;
+ }
+
+ return pg_vec;
+err1:
+ free_pg_vec(pg_vec, order, block_nr);
+ return NULL;
+}
+
+static int netlink_set_ring(struct sock *sk, struct nl_mmap_req *req,
+ bool closing, bool tx_ring)
+{
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct netlink_ring *ring;
+ struct sk_buff_head *queue;
+ void **pg_vec = NULL;
+ unsigned int order = 0;
+ int err;
+
+ ring = tx_ring ? &nlk->tx_ring : &nlk->rx_ring;
+ queue = tx_ring ? &sk->sk_write_queue : &sk->sk_receive_queue;
+
+ if (!closing) {
+ if (atomic_read(&nlk->mapped))
+ return -EBUSY;
+ if (atomic_read(&ring->pending))
+ return -EBUSY;
+ }
+
+ if (req->nm_block_nr) {
+ if (ring->pg_vec != NULL)
+ return -EBUSY;
+
+ if ((int)req->nm_block_size <= 0)
+ return -EINVAL;
+ if (!IS_ALIGNED(req->nm_block_size, PAGE_SIZE))
+ return -EINVAL;
+ if (req->nm_frame_size < NL_MMAP_HDRLEN)
+ return -EINVAL;
+ if (!IS_ALIGNED(req->nm_frame_size, NL_MMAP_MSG_ALIGNMENT))
+ return -EINVAL;
+
+ ring->frames_per_block = req->nm_block_size /
+ req->nm_frame_size;
+ if (ring->frames_per_block == 0)
+ return -EINVAL;
+ if (ring->frames_per_block * req->nm_block_nr !=
+ req->nm_frame_nr)
+ return -EINVAL;
+
+ order = get_order(req->nm_block_size);
+ pg_vec = alloc_pg_vec(nlk, req, order);
+ if (pg_vec == NULL)
+ return -ENOMEM;
+ } else {
+ if (req->nm_frame_nr)
+ return -EINVAL;
+ }
+
+ err = -EBUSY;
+ mutex_lock(&nlk->pg_vec_lock);
+ if (closing || atomic_read(&nlk->mapped) == 0) {
+ err = 0;
+ spin_lock_bh(&queue->lock);
+
+ ring->frame_max = req->nm_frame_nr - 1;
+ ring->head = 0;
+ ring->frame_size = req->nm_frame_size;
+ ring->pg_vec_pages = req->nm_block_size / PAGE_SIZE;
+
+ swap(ring->pg_vec_len, req->nm_block_nr);
+ swap(ring->pg_vec_order, order);
+ swap(ring->pg_vec, pg_vec);
+
+ __skb_queue_purge(queue);
+ spin_unlock_bh(&queue->lock);
+
+ WARN_ON(atomic_read(&nlk->mapped));
+ }
+ mutex_unlock(&nlk->pg_vec_lock);
+
+ if (pg_vec)
+ free_pg_vec(pg_vec, order, req->nm_block_nr);
+ return err;
+}
+
+static void netlink_mm_open(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct socket *sock = file->private_data;
+ struct sock *sk = sock->sk;
+
+ if (sk)
+ atomic_inc(&nlk_sk(sk)->mapped);
+}
+
+static void netlink_mm_close(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+ struct socket *sock = file->private_data;
+ struct sock *sk = sock->sk;
+
+ if (sk)
+ atomic_dec(&nlk_sk(sk)->mapped);
+}
+
+static const struct vm_operations_struct netlink_mmap_ops = {
+ .open = netlink_mm_open,
+ .close = netlink_mm_close,
+};
+
+static int netlink_mmap(struct file *file, struct socket *sock,
+ struct vm_area_struct *vma)
+{
+ struct sock *sk = sock->sk;
+ struct netlink_sock *nlk = nlk_sk(sk);
+ struct netlink_ring *ring;
+ unsigned long start, size, expected;
+ unsigned int i;
+ int err = -EINVAL;
+
+ if (vma->vm_pgoff)
+ return -EINVAL;
+
+ mutex_lock(&nlk->pg_vec_lock);
+
+ expected = 0;
+ for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
+ if (ring->pg_vec == NULL)
+ continue;
+ expected += ring->pg_vec_len * ring->pg_vec_pages * PAGE_SIZE;
+ }
+
+ if (expected == 0)
+ goto out;
+
+ size = vma->vm_end - vma->vm_start;
+ if (size != expected)
+ goto out;
+
+ start = vma->vm_start;
+ for (ring = &nlk->rx_ring; ring <= &nlk->tx_ring; ring++) {
+ if (ring->pg_vec == NULL)
+ continue;
+
+ for (i = 0; i < ring->pg_vec_len; i++) {
+ struct page *page;
+ void *kaddr = ring->pg_vec[i];
+ unsigned int pg_num;
+
+ for (pg_num = 0; pg_num < ring->pg_vec_pages; pg_num++) {
+ page = pgvec_to_page(kaddr);
+ err = vm_insert_page(vma, start, page);
+ if (err < 0)
+ goto out;
+ start += PAGE_SIZE;
+ kaddr += PAGE_SIZE;
+ }
+ }
+ }
+
+ atomic_inc(&nlk->mapped);
+ vma->vm_ops = &netlink_mmap_ops;
+ err = 0;
+out:
+ mutex_unlock(&nlk->pg_vec_lock);
+ return 0;
+}
+#else /* CONFIG_NETLINK_MMAP */
+#define netlink_mmap sock_no_mmap
+#endif /* CONFIG_NETLINK_MMAP */
+
static void netlink_destroy_callback(struct netlink_callback *cb)
{
kfree_skb(cb->skb);
@@ -146,6 +375,18 @@
}
skb_queue_purge(&sk->sk_receive_queue);
+#ifdef CONFIG_NETLINK_MMAP
+ if (1) {
+ struct nl_mmap_req req;
+
+ memset(&req, 0, sizeof(req));
+ if (nlk->rx_ring.pg_vec)
+ netlink_set_ring(sk, &req, true, false);
+ memset(&req, 0, sizeof(req));
+ if (nlk->tx_ring.pg_vec)
+ netlink_set_ring(sk, &req, true, true);
+ }
+#endif /* CONFIG_NETLINK_MMAP */
if (!sock_flag(sk, SOCK_DEAD)) {
printk(KERN_ERR "Freeing alive netlink socket %p\n", sk);
@@ -409,6 +650,9 @@
mutex_init(nlk->cb_mutex);
}
init_waitqueue_head(&nlk->wait);
+#ifdef CONFIG_NETLINK_MMAP
+ mutex_init(&nlk->pg_vec_lock);
+#endif
sk->sk_destruct = netlink_sock_destruct;
sk->sk_protocol = protocol;
@@ -1211,7 +1455,8 @@
if (level != SOL_NETLINK)
return -ENOPROTOOPT;
- if (optlen >= sizeof(int) &&
+ if (optname != NETLINK_RX_RING && optname != NETLINK_TX_RING &&
+ optlen >= sizeof(int) &&
get_user(val, (unsigned int __user *)optval))
return -EFAULT;
@@ -1260,6 +1505,25 @@
}
err = 0;
break;
+#ifdef CONFIG_NETLINK_MMAP
+ case NETLINK_RX_RING:
+ case NETLINK_TX_RING: {
+ struct nl_mmap_req req;
+
+ /* Rings might consume more memory than queue limits, require
+ * CAP_NET_ADMIN.
+ */
+ if (!capable(CAP_NET_ADMIN))
+ return -EPERM;
+ if (optlen < sizeof(req))
+ return -EINVAL;
+ if (copy_from_user(&req, optval, sizeof(req)))
+ return -EFAULT;
+ err = netlink_set_ring(sk, &req, false,
+ optname == NETLINK_TX_RING);
+ break;
+ }
+#endif /* CONFIG_NETLINK_MMAP */
default:
err = -ENOPROTOOPT;
}
@@ -2093,7 +2357,7 @@
.getsockopt = netlink_getsockopt,
.sendmsg = netlink_sendmsg,
.recvmsg = netlink_recvmsg,
- .mmap = sock_no_mmap,
+ .mmap = netlink_mmap,
.sendpage = sock_no_sendpage,
};
diff --git a/net/netlink/af_netlink.h b/net/netlink/af_netlink.h
index d9acb2a..ed85222 100644
--- a/net/netlink/af_netlink.h
+++ b/net/netlink/af_netlink.h
@@ -6,6 +6,20 @@
#define NLGRPSZ(x) (ALIGN(x, sizeof(unsigned long) * 8) / 8)
#define NLGRPLONGS(x) (NLGRPSZ(x)/sizeof(unsigned long))
+struct netlink_ring {
+ void **pg_vec;
+ unsigned int head;
+ unsigned int frames_per_block;
+ unsigned int frame_size;
+ unsigned int frame_max;
+
+ unsigned int pg_vec_order;
+ unsigned int pg_vec_pages;
+ unsigned int pg_vec_len;
+
+ atomic_t pending;
+};
+
struct netlink_sock {
/* struct sock has to be the first member of netlink_sock */
struct sock sk;
@@ -24,6 +38,12 @@
void (*netlink_rcv)(struct sk_buff *skb);
void (*netlink_bind)(int group);
struct module *module;
+#ifdef CONFIG_NETLINK_MMAP
+ struct mutex pg_vec_lock;
+ struct netlink_ring rx_ring;
+ struct netlink_ring tx_ring;
+ atomic_t mapped;
+#endif /* CONFIG_NETLINK_MMAP */
};
static inline struct netlink_sock *nlk_sk(struct sock *sk)