From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- io_uring/nop.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 90 insertions(+) create mode 100644 io_uring/nop.c (limited to 'io_uring/nop.c') diff --git a/io_uring/nop.c b/io_uring/nop.c new file mode 100644 index 000000000..60ab19604 --- /dev/null +++ b/io_uring/nop.c @@ -0,0 +1,90 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +#include + +#include "io_uring.h" +#include "rsrc.h" +#include "nop.h" + +struct io_nop { + struct file *file; + int result; + int fd; + unsigned int flags; + __u64 extra1; + __u64 extra2; +}; + +#define NOP_FLAGS (IORING_NOP_INJECT_RESULT | IORING_NOP_FIXED_FILE | \ + IORING_NOP_FIXED_BUFFER | IORING_NOP_FILE | \ + IORING_NOP_TW | IORING_NOP_CQE32) + +int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) +{ + struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop); + + nop->flags = READ_ONCE(sqe->nop_flags); + if (nop->flags & ~NOP_FLAGS) + return -EINVAL; + + if (nop->flags & IORING_NOP_INJECT_RESULT) + nop->result = READ_ONCE(sqe->len); + else + nop->result = 0; + if (nop->flags & IORING_NOP_FILE) + nop->fd = READ_ONCE(sqe->fd); + else + nop->fd = -1; + if (nop->flags & IORING_NOP_FIXED_FILE) + req->flags |= REQ_F_FIXED_FILE; + if (nop->flags & IORING_NOP_FIXED_BUFFER) + req->buf_index = READ_ONCE(sqe->buf_index); + if (nop->flags & IORING_NOP_CQE32) { + struct io_ring_ctx *ctx = req->ctx; + + if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED))) + return -EINVAL; + nop->extra1 = READ_ONCE(sqe->off); + nop->extra2 = READ_ONCE(sqe->addr); + } + return 0; +} + +int io_nop(struct io_kiocb *req, unsigned int issue_flags) +{ + struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop); + int ret = nop->result; + + if (nop->flags & IORING_NOP_FILE) { + if (req->flags & REQ_F_FIXED_FILE) + req->file = io_file_get_fixed(req, nop->fd, issue_flags); + else + req->file = io_file_get_normal(req, nop->fd); + if (!req->file) { + ret = -EBADF; + goto done; + } + } + if (nop->flags & IORING_NOP_FIXED_BUFFER) { + if (!io_find_buf_node(req, issue_flags)) + ret = -EFAULT; + } +done: + if (ret < 0) + req_set_fail(req); + if (nop->flags & IORING_NOP_CQE32) + io_req_set_res32(req, ret, 0, nop->extra1, nop->extra2); + else + io_req_set_res(req, ret, 0); + if (nop->flags & IORING_NOP_TW) { + req->io_task_work.func = io_req_task_complete; + io_req_task_work_add(req); + return IOU_ISSUE_SKIP_COMPLETE; + } + return IOU_COMPLETE; +} -- cgit v1.3.1