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Author: Neil Horman <nhorman@tuxdriver.com>
Date: Fri Dec 17 13:35:36 2010 -0500
Enhance AF_PACKET to support using non-contiguous memory when allocating ring
buffer space. This is a combined backport of the following commits from
net-next-2.6:
0e3125c755445664f00ad036e4fc2cd32fd52877
bbce5a59e4e0e6e1dbc85492caaf310ff6611309
0af55bb58f8fa7865004ac48d16affe125ac1b7f
920b8d913bd3d963d5c88bca160a272b71e0c95a
diff -up linux-2.6.34.x86_64/net/packet/af_packet.c.orig linux-2.6.34.x86_64/net/packet/af_packet.c
--- linux-2.6.34.x86_64/net/packet/af_packet.c.orig 2010-12-17 12:16:58.000000000 -0500
+++ linux-2.6.34.x86_64/net/packet/af_packet.c 2010-12-17 12:30:14.000000000 -0500
@@ -61,6 +61,7 @@
#include <linux/kernel.h>
#include <linux/kmod.h>
#include <linux/slab.h>
+#include <linux/vmalloc.h>
#include <net/net_namespace.h>
#include <net/ip.h>
#include <net/protocol.h>
@@ -161,8 +162,14 @@ struct packet_mreq_max {
static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
int closing, int tx_ring);
+#define PGV_FROM_VMALLOC 1
+struct pgv {
+ char *buffer;
+ unsigned char flags;
+};
+
struct packet_ring_buffer {
- char **pg_vec;
+ struct pgv *pg_vec;
unsigned int head;
unsigned int frames_per_block;
unsigned int frame_size;
@@ -214,6 +221,13 @@ struct packet_skb_cb {
#define PACKET_SKB_CB(__skb) ((struct packet_skb_cb *)((__skb)->cb))
+static inline struct page *pgv_to_page(void *addr)
+{
+ if (is_vmalloc_addr(addr))
+ return vmalloc_to_page(addr);
+ return virt_to_page(addr);
+}
+
static void __packet_set_status(struct packet_sock *po, void *frame, int status)
{
union {
@@ -226,11 +240,11 @@ static void __packet_set_status(struct p
switch (po->tp_version) {
case TPACKET_V1:
h.h1->tp_status = status;
- flush_dcache_page(virt_to_page(&h.h1->tp_status));
+ flush_dcache_page(pgv_to_page(&h.h1->tp_status));
break;
case TPACKET_V2:
h.h2->tp_status = status;
- flush_dcache_page(virt_to_page(&h.h2->tp_status));
+ flush_dcache_page(pgv_to_page(&h.h2->tp_status));
break;
default:
pr_err("TPACKET version not supported\n");
@@ -253,10 +267,10 @@ static int __packet_get_status(struct pa
h.raw = frame;
switch (po->tp_version) {
case TPACKET_V1:
- flush_dcache_page(virt_to_page(&h.h1->tp_status));
+ flush_dcache_page(pgv_to_page(&h.h1->tp_status));
return h.h1->tp_status;
case TPACKET_V2:
- flush_dcache_page(virt_to_page(&h.h2->tp_status));
+ flush_dcache_page(pgv_to_page(&h.h2->tp_status));
return h.h2->tp_status;
default:
pr_err("TPACKET version not supported\n");
@@ -280,7 +294,8 @@ static void *packet_lookup_frame(struct
pg_vec_pos = position / rb->frames_per_block;
frame_offset = position % rb->frames_per_block;
- h.raw = rb->pg_vec[pg_vec_pos] + (frame_offset * rb->frame_size);
+ h.raw = rb->pg_vec[pg_vec_pos].buffer +
+ (frame_offset * rb->frame_size);
if (status != __packet_get_status(po, h.raw))
return NULL;
@@ -771,15 +786,11 @@ static int tpacket_rcv(struct sk_buff *s
__packet_set_status(po, h.raw, status);
smp_mb();
{
- struct page *p_start, *p_end;
- u8 *h_end = h.raw + macoff + snaplen - 1;
+ u8 *start, *end;
- p_start = virt_to_page(h.raw);
- p_end = virt_to_page(h_end);
- while (p_start <= p_end) {
- flush_dcache_page(p_start);
- p_start++;
- }
+ end = (u8 *)PAGE_ALIGN((unsigned long)h.raw + macoff + snaplen);
+ for (start = h.raw; start < end; start += PAGE_SIZE)
+ flush_dcache_page(pgv_to_page(start));
}
sk->sk_data_ready(sk, 0);
@@ -886,7 +897,6 @@ static int tpacket_fill_skb(struct packe
}
err = -EFAULT;
- page = virt_to_page(data);
offset = offset_in_page(data);
len_max = PAGE_SIZE - offset;
len = ((to_write > len_max) ? len_max : to_write);
@@ -905,11 +915,11 @@ static int tpacket_fill_skb(struct packe
return -EFAULT;
}
+ page = pgv_to_page(data);
+ data += len;
flush_dcache_page(page);
get_page(page);
- skb_fill_page_desc(skb,
- nr_frags,
- page++, offset, len);
+ skb_fill_page_desc(skb, nr_frags, page, offset, len);
to_write -= len;
offset = 0;
len_max = PAGE_SIZE;
@@ -2230,37 +2240,76 @@ static const struct vm_operations_struct
.close = packet_mm_close,
};
-static void free_pg_vec(char **pg_vec, unsigned int order, unsigned int len)
+static void free_pg_vec(struct pgv *pg_vec, unsigned int order,
+ unsigned int len)
{
int i;
for (i = 0; i < len; i++) {
- if (likely(pg_vec[i]))
- free_pages((unsigned long) pg_vec[i], order);
+ if (likely(pg_vec[i].buffer)) {
+ if (pg_vec[i].flags & PGV_FROM_VMALLOC)
+ vfree(pg_vec[i].buffer);
+ else
+ free_pages((unsigned long)pg_vec[i].buffer,
+ order);
+ pg_vec[i].buffer = NULL;
+ }
}
kfree(pg_vec);
}
-static inline char *alloc_one_pg_vec_page(unsigned long order)
+static inline char *alloc_one_pg_vec_page(unsigned long order,
+ unsigned char *flags)
{
- gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP | __GFP_ZERO | __GFP_NOWARN;
+ char *buffer = NULL;
+ gfp_t gfp_flags = GFP_KERNEL | __GFP_COMP |
+ __GFP_ZERO | __GFP_NOWARN | __GFP_NORETRY;
+
+ buffer = (char *) __get_free_pages(gfp_flags, order);
- return (char *) __get_free_pages(gfp_flags, order);
+ if (buffer)
+ return buffer;
+
+ /*
+ * __get_free_pages failed, fall back to vmalloc
+ */
+ *flags |= PGV_FROM_VMALLOC;
+ buffer = vmalloc((1 << order) * PAGE_SIZE);
+
+ if (buffer) {
+ memset(buffer, 0, (1 << order) * PAGE_SIZE);
+ return buffer;
+ }
+
+ /*
+ * vmalloc failed, lets dig into swap here
+ */
+ *flags = 0;
+ gfp_flags &= ~__GFP_NORETRY;
+ buffer = (char *)__get_free_pages(gfp_flags, order);
+ if (buffer)
+ return buffer;
+
+ /*
+ * complete and utter failure
+ */
+ return NULL;
}
-static char **alloc_pg_vec(struct tpacket_req *req, int order)
+static struct pgv *alloc_pg_vec(struct tpacket_req *req, int order)
{
unsigned int block_nr = req->tp_block_nr;
- char **pg_vec;
+ struct pgv *pg_vec;
int i;
- pg_vec = kzalloc(block_nr * sizeof(char *), GFP_KERNEL);
+ pg_vec = kcalloc(block_nr, sizeof(struct pgv), GFP_KERNEL);
if (unlikely(!pg_vec))
goto out;
for (i = 0; i < block_nr; i++) {
- pg_vec[i] = alloc_one_pg_vec_page(order);
- if (unlikely(!pg_vec[i]))
+ pg_vec[i].buffer = alloc_one_pg_vec_page(order,
+ &pg_vec[i].flags);
+ if (unlikely(!pg_vec[i].buffer))
goto out_free_pgvec;
}
@@ -2276,7 +2325,7 @@ out_free_pgvec:
static int packet_set_ring(struct sock *sk, struct tpacket_req *req,
int closing, int tx_ring)
{
- char **pg_vec = NULL;
+ struct pgv *pg_vec = NULL;
struct packet_sock *po = pkt_sk(sk);
int was_running, order = 0;
struct packet_ring_buffer *rb;
@@ -2438,15 +2487,22 @@ static int packet_mmap(struct file *file
continue;
for (i = 0; i < rb->pg_vec_len; i++) {
- struct page *page = virt_to_page(rb->pg_vec[i]);
+ struct page *page;
+ void *kaddr = rb->pg_vec[i].buffer;
int pg_num;
for (pg_num = 0; pg_num < rb->pg_vec_pages;
- pg_num++, page++) {
+ pg_num++) {
+ if (rb->pg_vec[i].flags & PGV_FROM_VMALLOC)
+ page = vmalloc_to_page(kaddr);
+ else
+ page = virt_to_page(kaddr);
+
err = vm_insert_page(vma, start, page);
if (unlikely(err))
goto out;
start += PAGE_SIZE;
+ kaddr += PAGE_SIZE;
}
}
}
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