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io_uring/rsrc: kill rsrc_ref_lock

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We use ->rsrc_ref_lock spinlock to protect ->rsrc_ref_list in
io_rsrc_node_ref_zero(). Now we removed pcpu refcounting, which means
io_rsrc_node_ref_zero() is not executed from the irq context as an RCU
callback anymore, and we also put it under ->uring_lock.
io_rsrc_node_switch(), which queues up nodes into the list, is also
protected by ->uring_lock, so we can safely get rid of ->rsrc_ref_lock.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/6b60af883c263551190b526a55ff2c9d5ae07141.1680576071.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2023-04-04 13:39:50 +01:00 committed by Jens Axboe
parent ef8ae64ffa
commit 0a4813b1ab
3 changed files with 1 additions and 7 deletions
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2
include/linux/io_uring_types.h
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@ -333,8 +333,8 @@ struct io_ring_ctx {
struct delayed_work rsrc_put_work;
struct callback_head rsrc_put_tw;
struct llist_head rsrc_put_llist;
/* protected by ->uring_lock */
struct list_head rsrc_ref_list;
spinlock_t rsrc_ref_lock;
struct list_head io_buffers_pages;

1
io_uring/io_uring.c
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@ -325,7 +325,6 @@ static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
INIT_LIST_HEAD(&ctx->ltimeout_list);
spin_lock_init(&ctx->rsrc_ref_lock);
INIT_LIST_HEAD(&ctx->rsrc_ref_list);
INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work);
init_task_work(&ctx->rsrc_put_tw, io_rsrc_put_tw);

5
io_uring/rsrc.c
View File

@ -209,11 +209,9 @@ void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
__must_hold(&node->rsrc_data->ctx->uring_lock)
{
struct io_ring_ctx *ctx = node->rsrc_data->ctx;
unsigned long flags;
bool first_add = false;
unsigned long delay = HZ;
spin_lock_irqsave(&ctx->rsrc_ref_lock, flags);
node->done = true;
/* if we are mid-quiesce then do not delay */
@ -229,7 +227,6 @@ void io_rsrc_node_ref_zero(struct io_rsrc_node *node)
list_del(&node->node);
first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist);
}
spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags);
if (!first_add)
return;
@ -268,9 +265,7 @@ void io_rsrc_node_switch(struct io_ring_ctx *ctx,
struct io_rsrc_node *rsrc_node = ctx->rsrc_node;
rsrc_node->rsrc_data = data_to_kill;
spin_lock_irq(&ctx->rsrc_ref_lock);
list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list);
spin_unlock_irq(&ctx->rsrc_ref_lock);
atomic_inc(&data_to_kill->refs);
/* put master ref */