From 82733d168cbd3fe9dab603f05894316b99008924 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 10 Apr 2022 19:05:09 -0600 Subject: [PATCH] io_uring: stop using io_wq_work as an fd placeholder There are two reasons why this isn't the best idea: - It's an odd area to grab a bit of storage space, hence it's an odd area to grab storage from. - It puts the 3rd io_kiocb cacheline into the hot path, where normal hot path just needs the first two. Use 'cflags' for joint fd/cflags storage. We only need fd until we successfully issue, and we only need cflags once a request is done and is completed. Fixes: 6bf9c47a3989 ("io_uring: defer file assignment") Signed-off-by: Jens Axboe --- fs/io-wq.h | 1 - fs/io_uring.c | 12 ++++++++---- 2 files changed, 8 insertions(+), 5 deletions(-) diff --git a/fs/io-wq.h b/fs/io-wq.h index 04d374e6..dbecd27 100644 --- a/fs/io-wq.h +++ b/fs/io-wq.h @@ -155,7 +155,6 @@ struct io_wq_work_node *wq_stack_extract(struct io_wq_work_node *stack) struct io_wq_work { struct io_wq_work_node list; unsigned flags; - int fd; }; static inline struct io_wq_work *wq_next_work(struct io_wq_work *work) diff --git a/fs/io_uring.c b/fs/io_uring.c index 3a97535..38e62b1 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -907,7 +907,11 @@ struct io_kiocb { u64 user_data; u32 result; - u32 cflags; + /* fd initially, then cflags for completion */ + union { + u32 cflags; + int fd; + }; struct io_ring_ctx *ctx; struct task_struct *task; @@ -7090,9 +7094,9 @@ static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags) return true; if (req->flags & REQ_F_FIXED_FILE) - req->file = io_file_get_fixed(req, req->work.fd, issue_flags); + req->file = io_file_get_fixed(req, req->fd, issue_flags); else - req->file = io_file_get_normal(req, req->work.fd); + req->file = io_file_get_normal(req, req->fd); if (req->file) return true; @@ -7630,7 +7634,7 @@ static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, if (io_op_defs[opcode].needs_file) { struct io_submit_state *state = &ctx->submit_state; - req->work.fd = READ_ONCE(sqe->fd); + req->fd = READ_ONCE(sqe->fd); /* * Plug now if we have more than 2 IO left after this, and the -- 2.7.4