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6fe4220912
The network stack allows only one ubuf_info per skb, and unlike MSG_ZEROCOPY, each io_uring zerocopy send will carry a separate ubuf_info. That means that send requests can't reuse a previosly allocated skb and need to get one more or more of new ones. That's fine for large sends, but otherwise it would spam the stack with lots of skbs carrying just a little data each. To help with that implement linking notification (i.e. an io_uring wrapper around ubuf_info) into a list. Each is refcounted by skbs and the stack as usual. additionally all non head entries keep a reference to the head, which they put down when their refcount hits 0. When the head have no more users, it'll efficiently put all notifications in a batch. As mentioned previously about ->io_link_skb, the callback implementation always allows to bind to an skb without a ubuf_info. Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/bf1e7f9b72f9ecc99999fdc0d2cded5eea87fd0b.1713369317.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/net.h>
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#include <linux/uio.h>
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#include <net/sock.h>
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#include <linux/nospec.h>
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#include "rsrc.h"
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#define IO_NOTIF_UBUF_FLAGS (SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN)
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#define IO_NOTIF_SPLICE_BATCH 32
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struct io_notif_data {
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struct file *file;
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struct ubuf_info uarg;
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struct io_notif_data *next;
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struct io_notif_data *head;
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unsigned account_pages;
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bool zc_report;
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bool zc_used;
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bool zc_copied;
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};
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struct io_kiocb *io_alloc_notif(struct io_ring_ctx *ctx);
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void io_tx_ubuf_complete(struct sk_buff *skb, struct ubuf_info *uarg,
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bool success);
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static inline struct io_notif_data *io_notif_to_data(struct io_kiocb *notif)
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{
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return io_kiocb_to_cmd(notif, struct io_notif_data);
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}
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static inline void io_notif_flush(struct io_kiocb *notif)
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__must_hold(¬if->ctx->uring_lock)
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{
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struct io_notif_data *nd = io_notif_to_data(notif);
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io_tx_ubuf_complete(NULL, &nd->uarg, true);
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}
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static inline int io_notif_account_mem(struct io_kiocb *notif, unsigned len)
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{
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struct io_ring_ctx *ctx = notif->ctx;
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struct io_notif_data *nd = io_notif_to_data(notif);
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unsigned nr_pages = (len >> PAGE_SHIFT) + 2;
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int ret;
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if (ctx->user) {
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ret = __io_account_mem(ctx->user, nr_pages);
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if (ret)
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return ret;
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nd->account_pages += nr_pages;
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}
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return 0;
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}
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