From b60c8dce33895f79cbb54700fbeffc7db8aee3f7 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Sun, 25 Apr 2021 14:32:18 +0100 Subject: [PATCH] io_uring: preparation for rsrc tagging We need a way to notify userspace when a lazily removed resource actually died out. This will be done by associating a tag, which is u64 exactly like req->user_data, with each rsrc (e.g. buffer of file). A CQE will be posted once a resource is actually put down. Tag 0 is a special value set by default, for whcih it don't generate an CQE, so providing the old behaviour. Don't expose it to the userspace yet, but prepare internally, allocate buffers, add all posting hooks, etc. Signed-off-by: Pavel Begunkov Link: https://lore.kernel.org/r/2e6beec5eabe7216bb61fb93cdf5aaf65812a9b0.1619356238.git.asml.silence@gmail.com Signed-off-by: Jens Axboe --- fs/io_uring.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index cb10d3266d1a..9796998ef100 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -214,6 +214,7 @@ struct io_fixed_file { struct io_rsrc_put { struct list_head list; + u64 tag; union { void *rsrc; struct file *file; @@ -239,6 +240,7 @@ typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); struct io_rsrc_data { struct io_ring_ctx *ctx; + u64 *tags; rsrc_put_fn *do_put; atomic_t refs; struct completion done; @@ -7117,11 +7119,13 @@ static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, struct io_ring_ctx *ct static void io_rsrc_data_free(struct io_rsrc_data *data) { + kvfree(data->tags); kfree(data); } static struct io_rsrc_data *io_rsrc_data_alloc(struct io_ring_ctx *ctx, - rsrc_put_fn *do_put) + rsrc_put_fn *do_put, + unsigned nr) { struct io_rsrc_data *data; @@ -7129,6 +7133,12 @@ static struct io_rsrc_data *io_rsrc_data_alloc(struct io_ring_ctx *ctx, if (!data) return NULL; + data->tags = kvcalloc(nr, sizeof(*data->tags), GFP_KERNEL); + if (!data->tags) { + kfree(data); + return NULL; + } + atomic_set(&data->refs, 1); data->ctx = ctx; data->do_put = do_put; @@ -7493,6 +7503,20 @@ static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) { list_del(&prsrc->list); + + if (prsrc->tag) { + bool lock_ring = ctx->flags & IORING_SETUP_IOPOLL; + unsigned long flags; + + io_ring_submit_lock(ctx, lock_ring); + spin_lock_irqsave(&ctx->completion_lock, flags); + io_cqring_fill_event(ctx, prsrc->tag, 0, 0); + io_commit_cqring(ctx); + spin_unlock_irqrestore(&ctx->completion_lock, flags); + io_cqring_ev_posted(ctx); + io_ring_submit_unlock(ctx, lock_ring); + } + rsrc_data->do_put(ctx, prsrc); kfree(prsrc); } @@ -7582,7 +7606,7 @@ static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, if (ret) return ret; - file_data = io_rsrc_data_alloc(ctx, io_rsrc_file_put); + file_data = io_rsrc_data_alloc(ctx, io_rsrc_file_put, nr_args); if (!file_data) return -ENOMEM; ctx->file_data = file_data; @@ -7683,7 +7707,7 @@ static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, #endif } -static int io_queue_rsrc_removal(struct io_rsrc_data *data, +static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, struct io_rsrc_node *node, void *rsrc) { struct io_rsrc_put *prsrc; @@ -7692,6 +7716,7 @@ static int io_queue_rsrc_removal(struct io_rsrc_data *data, if (!prsrc) return -ENOMEM; + prsrc->tag = data->tags[idx]; prsrc->rsrc = rsrc; list_add(&prsrc->list, &node->rsrc_list); return 0; @@ -7732,7 +7757,8 @@ static int __io_sqe_files_update(struct io_ring_ctx *ctx, if (file_slot->file_ptr) { file = (struct file *)(file_slot->file_ptr & FFS_MASK); - err = io_queue_rsrc_removal(data, ctx->rsrc_node, file); + err = io_queue_rsrc_removal(data, up->offset + done, + ctx->rsrc_node, file); if (err) break; file_slot->file_ptr = 0; -- 2.20.1