This is a note to let you know that I've just added the patch titled net/packet: make packet_fanout.arr size configurable up to 64K to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-packet-make-packet_fanout.arr-size-configurable-.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 3f885eb4e7613c9922850a17d0a6a8e5790fff51 Author: Tanner Love <tannerlove@xxxxxxxxxx> Date: Fri Nov 6 13:07:40 2020 -0500 net/packet: make packet_fanout.arr size configurable up to 64K [ Upstream commit 9c661b0b85444e426d3f23250305eeb16f6ffe88 ] One use case of PACKET_FANOUT is lockless reception with one socket per CPU. 256 is a practical limit on increasingly many machines. Increase PACKET_FANOUT_MAX to 64K. Expand setsockopt PACKET_FANOUT to take an extra argument max_num_members. Also explicitly define a fanout_args struct, instead of implicitly casting to an integer. This documents the API and simplifies the control flow. If max_num_members is not specified or is set to 0, then 256 is used, same as before. Signed-off-by: Tanner Love <tannerlove@xxxxxxxxxx> Signed-off-by: Willem de Bruijn <willemb@xxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h index 3d884d68eb30..c07caf7b40db 100644 --- a/include/uapi/linux/if_packet.h +++ b/include/uapi/linux/if_packet.h @@ -2,6 +2,7 @@ #ifndef __LINUX_IF_PACKET_H #define __LINUX_IF_PACKET_H +#include <asm/byteorder.h> #include <linux/types.h> struct sockaddr_pkt { @@ -296,6 +297,17 @@ struct packet_mreq { unsigned char mr_address[8]; }; +struct fanout_args { +#if defined(__LITTLE_ENDIAN_BITFIELD) + __u16 id; + __u16 type_flags; +#else + __u16 type_flags; + __u16 id; +#endif + __u32 max_num_members; +}; + #define PACKET_MR_MULTICAST 0 #define PACKET_MR_PROMISC 1 #define PACKET_MR_ALLMULTI 2 diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index a0121e7c98b1..92501e5f9d49 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -1636,13 +1636,15 @@ static bool fanout_find_new_id(struct sock *sk, u16 *new_id) return false; } -static int fanout_add(struct sock *sk, u16 id, u16 type_flags) +static int fanout_add(struct sock *sk, struct fanout_args *args) { struct packet_rollover *rollover = NULL; struct packet_sock *po = pkt_sk(sk); + u16 type_flags = args->type_flags; struct packet_fanout *f, *match; u8 type = type_flags & 0xff; u8 flags = type_flags >> 8; + u16 id = args->id; int err; switch (type) { @@ -1700,11 +1702,21 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) } } err = -EINVAL; - if (match && match->flags != flags) - goto out; - if (!match) { + if (match) { + if (match->flags != flags) + goto out; + if (args->max_num_members && + args->max_num_members != match->max_num_members) + goto out; + } else { + if (args->max_num_members > PACKET_FANOUT_MAX) + goto out; + if (!args->max_num_members) + /* legacy PACKET_FANOUT_MAX */ + args->max_num_members = 256; err = -ENOMEM; - match = kzalloc(sizeof(*match), GFP_KERNEL); + match = kvzalloc(struct_size(match, arr, args->max_num_members), + GFP_KERNEL); if (!match) goto out; write_pnet(&match->net, sock_net(sk)); @@ -1720,6 +1732,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) match->prot_hook.func = packet_rcv_fanout; match->prot_hook.af_packet_priv = match; match->prot_hook.id_match = match_fanout_group; + match->max_num_members = args->max_num_members; list_add(&match->list, &fanout_list); } err = -EINVAL; @@ -1730,7 +1743,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) match->prot_hook.type == po->prot_hook.type && match->prot_hook.dev == po->prot_hook.dev) { err = -ENOSPC; - if (refcount_read(&match->sk_ref) < PACKET_FANOUT_MAX) { + if (refcount_read(&match->sk_ref) < match->max_num_members) { __dev_remove_pack(&po->prot_hook); po->fanout = match; po->rollover = rollover; @@ -1744,7 +1757,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags) if (err && !refcount_read(&match->sk_ref)) { list_del(&match->list); - kfree(match); + kvfree(match); } out: @@ -3075,7 +3088,7 @@ static int packet_release(struct socket *sock) kfree(po->rollover); if (f) { fanout_release_data(f); - kfree(f); + kvfree(f); } /* * Now the socket is dead. No more input will appear. @@ -3866,14 +3879,14 @@ packet_setsockopt(struct socket *sock, int level, int optname, sockptr_t optval, } case PACKET_FANOUT: { - int val; + struct fanout_args args = { 0 }; - if (optlen != sizeof(val)) + if (optlen != sizeof(int) && optlen != sizeof(args)) return -EINVAL; - if (copy_from_sockptr(&val, optval, sizeof(val))) + if (copy_from_sockptr(&args, optval, optlen)) return -EFAULT; - return fanout_add(sk, val & 0xffff, val >> 16); + return fanout_add(sk, &args); } case PACKET_FANOUT_DATA: { diff --git a/net/packet/internal.h b/net/packet/internal.h index fd41ecb7f605..baafc3f3fa25 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -77,11 +77,12 @@ struct packet_ring_buffer { }; extern struct mutex fanout_mutex; -#define PACKET_FANOUT_MAX 256 +#define PACKET_FANOUT_MAX (1 << 16) struct packet_fanout { possible_net_t net; unsigned int num_members; + u32 max_num_members; u16 id; u8 type; u8 flags; @@ -90,10 +91,10 @@ struct packet_fanout { struct bpf_prog __rcu *bpf_prog; }; struct list_head list; - struct sock *arr[PACKET_FANOUT_MAX]; spinlock_t lock; refcount_t sk_ref; struct packet_type prot_hook ____cacheline_aligned_in_smp; + struct sock *arr[]; }; struct packet_rollover {