Commit 68ef5578 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: add rsrc referencing for notifiers 



In preparation to zerocopy sends with fixed buffers make notifiers to
reference the rsrc node to protect the used fixed buffers. We can't just
grab it for a send request as notifiers can likely outlive requests that
used it.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/3cd7a01d26837945b6982fa9cf15a63230f2ed4f.1657643355.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent e58d498e

io_uring/notif.c

+5 −0
Original line number Diff line number Diff line
@@ -7,10 +7,12 @@ 


#include "io_uring.h"

#include "notif.h"

#include "rsrc.h"



static void __io_notif_complete_tw(struct callback_head *cb)

{

	struct io_notif *notif = container_of(cb, struct io_notif, task_work);

	struct io_rsrc_node *rsrc_node = notif->rsrc_node;

	struct io_ring_ctx *ctx = notif->ctx;



	if (likely(notif->task)) {
@@ -25,6 +27,7 @@ static void __io_notif_complete_tw(struct callback_head *cb) 
	ctx->notif_locked_nr++;

	io_cq_unlock_post(ctx);



	io_rsrc_put_node(rsrc_node, 1);

	percpu_ref_put(&ctx->refs);

}
@@ -119,6 +122,8 @@ struct io_notif *io_alloc_notif(struct io_ring_ctx *ctx, 
	/* master ref owned by io_notif_slot, will be dropped on flush */

	refcount_set(&notif->uarg.refcnt, 1);

	percpu_ref_get(&ctx->refs);

	notif->rsrc_node = ctx->rsrc_node;

	io_charge_rsrc_node(ctx);

	return notif;

}

io_uring/notif.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
struct io_notif {

	struct ubuf_info	uarg;

	struct io_ring_ctx	*ctx;

	struct io_rsrc_node	*rsrc_node;



	/* complete via tw if ->task is non-NULL, fallback to wq otherwise */

	struct task_struct	*task;

io_uring/rsrc.h

+9 −3
Original line number Diff line number Diff line
@@ -135,6 +135,13 @@ static inline void io_req_put_rsrc_locked(struct io_kiocb *req, 
	}

}



static inline void io_charge_rsrc_node(struct io_ring_ctx *ctx)

{

	ctx->rsrc_cached_refs--;

	if (unlikely(ctx->rsrc_cached_refs < 0))

		io_rsrc_refs_refill(ctx);

}



static inline void io_req_set_rsrc_node(struct io_kiocb *req,

					struct io_ring_ctx *ctx,

					unsigned int issue_flags)
@@ -144,9 +151,8 @@ static inline void io_req_set_rsrc_node(struct io_kiocb *req, 


		if (!(issue_flags & IO_URING_F_UNLOCKED)) {

			lockdep_assert_held(&ctx->uring_lock);

			ctx->rsrc_cached_refs--;

			if (unlikely(ctx->rsrc_cached_refs < 0))

				io_rsrc_refs_refill(ctx);



			io_charge_rsrc_node(ctx);

		} else {

			percpu_ref_get(&req->rsrc_node->refs);

		}