Commit 5a8fb33e authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

skmsg: convert struct sk_msg_sg::copy to a bitmap 



We have plans for increasing MAX_SKB_FRAGS, but sk_msg_sg::copy
is currently an unsigned long, limiting MAX_SKB_FRAGS to 30 on 32bit arches.

Convert it to a bitmap, as Jakub suggested.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d2692eee

include/linux/skmsg.h

+5 −6
Original line number Diff line number Diff line
@@ -29,7 +29,7 @@ struct sk_msg_sg { 
	u32				end;

	u32				size;

	u32				copybreak;

	unsigned long			copy;

	DECLARE_BITMAP(copy, MAX_MSG_FRAGS + 2);

	/* The extra two elements:

	 * 1) used for chaining the front and sections when the list becomes

	 *    partitioned (e.g. end < start). The crypto APIs require the
@@ -38,7 +38,6 @@ struct sk_msg_sg { 
	 */

	struct scatterlist		data[MAX_MSG_FRAGS + 2];

};

static_assert(BITS_PER_LONG >= NR_MSG_FRAG_IDS);



/* UAPI in filter.c depends on struct sk_msg_sg being first element. */

struct sk_msg {
@@ -234,7 +233,7 @@ static inline void sk_msg_compute_data_pointers(struct sk_msg *msg) 
{

	struct scatterlist *sge = sk_msg_elem(msg, msg->sg.start);



	if (test_bit(msg->sg.start, &msg->sg.copy)) {

	if (test_bit(msg->sg.start, msg->sg.copy)) {

		msg->data = NULL;

		msg->data_end = NULL;

	} else {
@@ -253,7 +252,7 @@ static inline void sk_msg_page_add(struct sk_msg *msg, struct page *page, 
	sg_set_page(sge, page, len, offset);

	sg_unmark_end(sge);



	__set_bit(msg->sg.end, &msg->sg.copy);

	__set_bit(msg->sg.end, msg->sg.copy);

	msg->sg.size += len;

	sk_msg_iter_next(msg, end);

}
@@ -262,9 +261,9 @@ static inline void sk_msg_sg_copy(struct sk_msg *msg, u32 i, bool copy_state) 
{

	do {

		if (copy_state)

			__set_bit(i, &msg->sg.copy);

			__set_bit(i, msg->sg.copy);

		else

			__clear_bit(i, &msg->sg.copy);

			__clear_bit(i, msg->sg.copy);

		sk_msg_iter_var_next(i);

		if (i == msg->sg.end)

			break;

net/core/filter.c

+2 −2
Original line number Diff line number Diff line
@@ -2603,7 +2603,7 @@ BPF_CALL_4(bpf_msg_pull_data, struct sk_msg *, msg, u32, start, 
	 * account for the headroom.

	 */

	bytes_sg_total = start - offset + bytes;

	if (!test_bit(i, &msg->sg.copy) && bytes_sg_total <= len)

	if (!test_bit(i, msg->sg.copy) && bytes_sg_total <= len)

		goto out;



	/* At this point we need to linearize multiple scatterlist
@@ -2809,7 +2809,7 @@ BPF_CALL_4(bpf_msg_push_data, struct sk_msg *, msg, u32, start, 
	/* Place newly allocated data buffer */

	sk_mem_charge(msg->sk, len);

	msg->sg.size += len;

	__clear_bit(new, &msg->sg.copy);

	__clear_bit(new, msg->sg.copy);

	sg_set_page(&msg->sg.data[new], page, len + copy, 0);

	if (rsge.length) {

		get_page(sg_page(&rsge));