From 36f72fe2792c4304f1203a44a6a7178e49b447f7 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 18 Nov 2020 19:57:26 +0000 Subject: io_uring: share fixed_file_refs b/w multiple rsrcs Double fixed files for splice/tee are done in a nasty way, it takes 2 ref_node refs, and during the second time it blindly overrides req->fixed_file_refs hoping that it haven't changed. That works because all that is done under iouring_lock in a single go but is error-prone. Bind everything explicitly to a single ref_node and take only one ref, with current ref_node ordering it's guaranteed to keep all files valid awhile the request is inflight. That's mainly a cleanup + preparation for generic resource handling, but also saves pcpu_ref get/put for splice/tee with 2 fixed files. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe --- fs/io_uring.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) (limited to 'fs/io_uring.c') diff --git a/fs/io_uring.c b/fs/io_uring.c index c42321ecda5d..5818a7b3d29b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1037,6 +1037,16 @@ static inline void io_clean_op(struct io_kiocb *req) __io_clean_op(req); } +static inline void io_set_resource_node(struct io_kiocb *req) +{ + struct io_ring_ctx *ctx = req->ctx; + + if (!req->fixed_file_refs) { + req->fixed_file_refs = &ctx->file_data->node->refs; + percpu_ref_get(req->fixed_file_refs); + } +} + static bool io_match_task(struct io_kiocb *head, struct task_struct *task, struct files_struct *files) @@ -1919,9 +1929,7 @@ fallback: static inline void io_put_file(struct io_kiocb *req, struct file *file, bool fixed) { - if (fixed) - percpu_ref_put(req->fixed_file_refs); - else + if (!fixed) fput(file); } @@ -1933,7 +1941,8 @@ static void io_dismantle_req(struct io_kiocb *req) kfree(req->async_data); if (req->file) io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE)); - + if (req->fixed_file_refs) + percpu_ref_put(req->fixed_file_refs); io_req_clean_work(req); } @@ -6310,10 +6319,7 @@ static struct file *io_file_get(struct io_submit_state *state, return NULL; fd = array_index_nospec(fd, ctx->nr_user_files); file = io_file_from_index(ctx, fd); - if (file) { - req->fixed_file_refs = &ctx->file_data->node->refs; - percpu_ref_get(req->fixed_file_refs); - } + io_set_resource_node(req); } else { trace_io_uring_file_get(ctx, fd); file = __io_file_get(state, fd); @@ -6691,6 +6697,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, req->ctx = ctx; req->flags = 0; req->link = NULL; + req->fixed_file_refs = NULL; /* one is dropped after submission, the other at completion */ refcount_set(&req->refs, 2); req->task = current; -- cgit v1.2.3-59-g8ed1b