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[109.152.100.135]) by smtp.gmail.com with ESMTPSA id h17sm30549828wrp.54.2020.11.18.12.00.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Nov 2020 12:00:40 -0800 (PST) From: Pavel Begunkov To: Jens Axboe , io-uring@vger.kernel.org, bijan.mottahedeh@oracle.com Subject: [PATCH 5.11] io_uring: share fixed_file_refs b/w multiple rsrcs Date: Wed, 18 Nov 2020 19:57:26 +0000 Message-Id: X-Mailer: git-send-email 2.24.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org 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 --- fs/io_uring.c | 23 +++++++++++++++-------- 1 file changed, 15 insertions(+), 8 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 6e052011a186..8e769d3f96ca 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -1039,6 +1039,16 @@ 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) @@ -1927,9 +1937,7 @@ static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx, 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); } @@ -1941,7 +1949,8 @@ 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); } @@ -6344,10 +6353,7 @@ 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); @@ -6725,6 +6731,7 @@ 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; -- 2.24.0