linux/io_uring/notif.c
Jens Axboe 0701db7439 io_uring/rsrc: add an empty io_rsrc_node for sparse buffer entries
Rather than allocate an io_rsrc_node for an empty/sparse buffer entry,
add a const entry that can be used for that. This just needs checking
for writing the tag, and the put check needs to check for that sparse
node rather than NULL for validity.

This avoids allocating rsrc nodes for sparse buffer entries.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2024-11-02 15:44:30 -06:00

134 lines
3.3 KiB
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 const struct ubuf_info_ops io_ubuf_ops;
static void io_notif_tw_complete(struct io_kiocb *notif, struct io_tw_state *ts)
{
struct io_notif_data *nd = io_notif_to_data(notif);
do {
notif = cmd_to_io_kiocb(nd);
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(notif, ts);
} 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(nd);
/* make sure all noifications can be finished in the same task_work */
if (unlikely(notif->ctx != prev_notif->ctx ||
notif->task != prev_notif->task))
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->opcode = IORING_OP_NOP;
notif->flags = 0;
notif->file = NULL;
notif->task = current;
io_get_task_refs(1);
notif->rsrc_nodes[IORING_RSRC_FILE] = rsrc_empty_node;
notif->rsrc_nodes[IORING_RSRC_BUFFER] = rsrc_empty_node;
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;
}