// SPDX-License-Identifier: GPL-2.0#include <linux/kernel.h>#include <linux/errno.h>#include <linux/file.h>#include <linux/slab.h>#include <linux/net.h>#include <linux/io_uring.h> #include "io_uring.h"#include "notif.h"#include "rsrc.h" static const struct ubuf_info_ops io_ubuf_ops; static void io_notif_tw_complete(struct io_tw_req tw_req, io_tw_token_t tw){	struct io_kiocb *notif = tw_req.req;	struct io_notif_data *nd = io_notif_to_data(notif);	struct io_ring_ctx *ctx = notif->ctx; 	lockdep_assert_held(&ctx->uring_lock); 	do {		notif = cmd_to_io_kiocb(nd); 		if (WARN_ON_ONCE(ctx != notif->ctx))			return;		lockdep_assert(refcount_read(&nd->uarg.refcnt) == 0); 		if (unlikely(nd->zc_report) && (nd->zc_copied || !nd->zc_used))			notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED; 		if (nd->account_pages && notif->ctx->user) {			__io_unaccount_mem(notif->ctx->user, nd->account_pages);			nd->account_pages = 0;		} 		nd = nd->next;		io_req_task_complete((struct io_tw_req){notif}, tw);	} while (nd);} void io_tx_ubuf_complete(struct sk_buff *skb, struct ubuf_info *uarg,			 bool success){	struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);	struct io_kiocb *notif = cmd_to_io_kiocb(nd);	unsigned tw_flags; 	if (nd->zc_report) {		if (success && !nd->zc_used && skb)			WRITE_ONCE(nd->zc_used, true);		else if (!success && !nd->zc_copied)			WRITE_ONCE(nd->zc_copied, true);	} 	if (!refcount_dec_and_test(&uarg->refcnt))		return; 	if (nd->head != nd) {		io_tx_ubuf_complete(skb, &nd->head->uarg, success);		return;	} 	tw_flags = nd->next ? 0 : IOU_F_TWQ_LAZY_WAKE;	notif->io_task_work.func = io_notif_tw_complete;	__io_req_task_work_add(notif, tw_flags);} static int io_link_skb(struct sk_buff *skb, struct ubuf_info *uarg){	struct io_notif_data *nd, *prev_nd;	struct io_kiocb *prev_notif, *notif;	struct ubuf_info *prev_uarg = skb_zcopy(skb); 	nd = container_of(uarg, struct io_notif_data, uarg);	notif = cmd_to_io_kiocb(nd); 	if (!prev_uarg) {		net_zcopy_get(&nd->uarg);		skb_zcopy_init(skb, &nd->uarg);		return 0;	}	/* handle it separately as we can't link a notif to itself */	if (unlikely(prev_uarg == &nd->uarg))		return 0;	/* we can't join two links together, just request a fresh skb */	if (unlikely(nd->head != nd || nd->next))		return -EEXIST;	/* don't mix zc providers */	if (unlikely(prev_uarg->ops != &io_ubuf_ops))		return -EEXIST; 	prev_nd = container_of(prev_uarg, struct io_notif_data, uarg);	prev_notif = cmd_to_io_kiocb(prev_nd); 	/* make sure all notifications can be finished in the same task_work */	if (unlikely(notif->ctx != prev_notif->ctx ||		     notif->tctx != prev_notif->tctx))		return -EEXIST; 	nd->head = prev_nd->head;	nd->next = prev_nd->next;	prev_nd->next = nd;	net_zcopy_get(&nd->head->uarg);	return 0;} static const struct ubuf_info_ops io_ubuf_ops = {	.complete = io_tx_ubuf_complete,	.link_skb = io_link_skb,}; struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx)	__must_hold(&ctx->uring_lock){	struct io_kiocb *notif;	struct io_notif_data *nd; 	if (unlikely(!io_alloc_req(ctx, &notif)))		return NULL;	notif->ctx = ctx;	notif->opcode = IORING_OP_NOP;	notif->flags = 0;	notif->file = NULL;	notif->tctx = current->io_uring;	io_get_task_refs(1);	notif->file_node = NULL;	notif->buf_node = NULL; 	nd = io_notif_to_data(notif);	nd->zc_report = false;	nd->account_pages = 0;	nd->next = NULL;	nd->head = nd; 	nd->uarg.flags = IO_NOTIF_UBUF_FLAGS;	nd->uarg.ops = &io_ubuf_ops;	refcount_set(&nd->uarg.refcnt, 1);	return notif;}