| From d4b5bd98faec345933d6080989e035a833b1077a Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Wed, 12 Jun 2019 09:52:27 -0700 |
| Subject: [PATCH] net/packet: constify packet_lookup_frame() and |
| __tpacket_has_room() |
| |
| commit d4b5bd98faec345933d6080989e035a833b1077a upstream. |
| |
| Goal is to be able to use __tpacket_has_room() without holding a lock. |
| |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| |
| diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c |
| index 66fcfd5b51f8..273bffd2130d 100644 |
| --- a/net/packet/af_packet.c |
| +++ b/net/packet/af_packet.c |
| @@ -460,10 +460,10 @@ static __u32 __packet_set_timestamp(struct packet_sock *po, void *frame, |
| return ts_status; |
| } |
| |
| -static void *packet_lookup_frame(struct packet_sock *po, |
| - struct packet_ring_buffer *rb, |
| - unsigned int position, |
| - int status) |
| +static void *packet_lookup_frame(const struct packet_sock *po, |
| + const struct packet_ring_buffer *rb, |
| + unsigned int position, |
| + int status) |
| { |
| unsigned int pg_vec_pos, frame_offset; |
| union tpacket_uhdr h; |
| @@ -1198,12 +1198,12 @@ static void packet_free_pending(struct packet_sock *po) |
| #define ROOM_LOW 0x1 |
| #define ROOM_NORMAL 0x2 |
| |
| -static bool __tpacket_has_room(struct packet_sock *po, int pow_off) |
| +static bool __tpacket_has_room(const struct packet_sock *po, int pow_off) |
| { |
| int idx, len; |
| |
| - len = po->rx_ring.frame_max + 1; |
| - idx = po->rx_ring.head; |
| + len = READ_ONCE(po->rx_ring.frame_max) + 1; |
| + idx = READ_ONCE(po->rx_ring.head); |
| if (pow_off) |
| idx += len >> pow_off; |
| if (idx >= len) |
| -- |
| 1.9.1 |
| |
