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Revision 8daaf39f7f6ef53a11817f6a11ec104016c3545f authored by Arseniy Krasnov on 14 March 2023, 11:08:20 UTC, committed by David S. Miller on 16 March 2023, 17:28:23 UTC 
virtio/vsock: don't drop skbuff on copy failure
 
This returns behaviour of SOCK_STREAM read as before skbuff usage. When
copying to user fails current skbuff won't be dropped, but returned to
sockets's queue. Technically instead of 'skb_dequeue()', 'skb_peek()' is
called and when skbuff becomes empty, it is removed from queue by
'__skb_unlink()'.

Fixes: 71dc9ec9ac7d ("virtio/vsock: replace virtio_vsock_pkt with sk_buff")
Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Acked-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent 6825e6b
Raw File
notif.c 
#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 void io_notif_complete_tw_ext(struct io_kiocb *notif, bool *locked)
{
	struct io_notif_data *nd = io_notif_to_data(notif);
	struct io_ring_ctx *ctx = notif->ctx;

	if (nd->zc_report && (nd->zc_copied || !nd->zc_used))
		notif->cqe.res |= IORING_NOTIF_USAGE_ZC_COPIED;

	if (nd->account_pages && ctx->user) {
		__io_unaccount_mem(ctx->user, nd->account_pages);
		nd->account_pages = 0;
	}
	io_req_task_complete(notif, locked);
}

static void io_tx_ubuf_callback(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);

	if (refcount_dec_and_test(&uarg->refcnt))
		io_req_task_work_add(notif);
}

static void io_tx_ubuf_callback_ext(struct sk_buff *skb, struct ubuf_info *uarg,
			     bool success)
{
	struct io_notif_data *nd = container_of(uarg, struct io_notif_data, uarg);

	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);
	}
	io_tx_ubuf_callback(skb, uarg, success);
}

void io_notif_set_extended(struct io_kiocb *notif)
{
	struct io_notif_data *nd = io_notif_to_data(notif);

	if (nd->uarg.callback != io_tx_ubuf_callback_ext) {
		nd->account_pages = 0;
		nd->zc_report = false;
		nd->zc_used = false;
		nd->zc_copied = false;
		nd->uarg.callback = io_tx_ubuf_callback_ext;
		notif->io_task_work.func = io_notif_complete_tw_ext;
	}
}

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->opcode = IORING_OP_NOP;
	notif->flags = 0;
	notif->file = NULL;
	notif->task = current;
	io_get_task_refs(1);
	notif->rsrc_node = NULL;
	notif->io_task_work.func = io_req_task_complete;

	nd = io_notif_to_data(notif);
	nd->uarg.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN;
	nd->uarg.callback = io_tx_ubuf_callback;
	refcount_set(&nd->uarg.refcnt, 1);
	return notif;
}
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