Commit 10369080 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: reclaim skb->scm_io_uring bit 



Commit 0091bfc8 ("io_uring/af_unix: defer registered
files gc to io_uring release") added one bit to struct sk_buff.

This structure is critical for networking, and we try very hard
to not add bloat on it, unless absolutely required.

For instance, we can use a specific destructor as a wrapper
around unix_destruct_scm(), to identify skbs that unix_gc()
has to special case.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Pavel Begunkov <asml.silence@gmail.com>
Cc: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: Jens Axboe <axboe@kernel.dk>
Reviewed-by: default avatarJens Axboe <axboe@kernel.dk>
Reviewed-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b3f4cd07

include/linux/skbuff.h

+0 −2
Original line number Diff line number Diff line
@@ -810,7 +810,6 @@ typedef unsigned char *sk_buff_data_t; 
 *	@csum_level: indicates the number of consecutive checksums found in

 *		the packet minus one that have been verified as

 *		CHECKSUM_UNNECESSARY (max 3)

 *	@scm_io_uring: SKB holds io_uring registered files

 *	@dst_pending_confirm: need to confirm neighbour

 *	@decrypted: Decrypted SKB

 *	@slow_gro: state present at GRO time, slower prepare step required
@@ -989,7 +988,6 @@ struct sk_buff { 
#endif

	__u8			slow_gro:1;

	__u8			csum_not_inet:1;

	__u8			scm_io_uring:1;



#ifdef CONFIG_NET_SCHED

	__u16			tc_index;	/* traffic control index */

include/net/af_unix.h

+1 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
void unix_inflight(struct user_struct *user, struct file *fp);

void unix_notinflight(struct user_struct *user, struct file *fp);

void unix_destruct_scm(struct sk_buff *skb);

void io_uring_destruct_scm(struct sk_buff *skb);

void unix_gc(void);

void wait_for_unix_gc(void);

struct sock *unix_get_socket(struct file *filp);

io_uring/rsrc.c

+1 −2
Original line number Diff line number Diff line
@@ -867,8 +867,7 @@ int __io_scm_file_account(struct io_ring_ctx *ctx, struct file *file) 


		UNIXCB(skb).fp = fpl;

		skb->sk = sk;

		skb->scm_io_uring = 1;

		skb->destructor = unix_destruct_scm;

		skb->destructor = io_uring_destruct_scm;

		refcount_add(skb->truesize, &sk->sk_wmem_alloc);

	}

net/unix/garbage.c

+1 −1
Original line number Diff line number Diff line
@@ -305,7 +305,7 @@ void unix_gc(void) 
	 * release.path eventually putting registered files.

	 */

	skb_queue_walk_safe(&hitlist, skb, next_skb) {

		if (skb->scm_io_uring) {

		if (skb->destructor == io_uring_destruct_scm) {

			__skb_unlink(skb, &hitlist);

			skb_queue_tail(&skb->sk->sk_receive_queue, skb);

		}

net/unix/scm.c

+6 −0
Original line number Diff line number Diff line
@@ -152,3 +152,9 @@ void unix_destruct_scm(struct sk_buff *skb) 
	sock_wfree(skb);

}

EXPORT_SYMBOL(unix_destruct_scm);



void io_uring_destruct_scm(struct sk_buff *skb)

{

	unix_destruct_scm(skb);

}

EXPORT_SYMBOL(io_uring_destruct_scm);