From patchwork Thu Nov 28 11:53:22 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Penyaev X-Patchwork-Id: 11265881 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C9C96112B for ; Thu, 28 Nov 2019 11:53:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B2E0821789 for ; Thu, 28 Nov 2019 11:53:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726281AbfK1Lxf (ORCPT ); Thu, 28 Nov 2019 06:53:35 -0500 Received: from mx2.suse.de ([195.135.220.15]:45362 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726191AbfK1Lxe (ORCPT ); Thu, 28 Nov 2019 06:53:34 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 25474AF37; Thu, 28 Nov 2019 11:53:33 +0000 (UTC) From: Roman Penyaev Cc: Jens Axboe , linux-block@vger.kernel.org, Roman Penyaev Subject: [PATCH 1/1] io_uring: add mapping support for NOMMU archs Date: Thu, 28 Nov 2019 12:53:22 +0100 Message-Id: <20191128115322.416956-1-rpenyaev@suse.de> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org That is a bit weird scenario but I find it interesting to run fio loads using LKL linux, where MMU is disabled. Probably other real archs which run uClinux can also benefit from this patch. Signed-off-by: Roman Penyaev --- fs/io_uring.c | 57 +++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 51 insertions(+), 6 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 8a0381f1a43b..ebe9f9e6e81b 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3536,12 +3536,11 @@ static int io_uring_release(struct inode *inode, struct file *file) return 0; } -static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) +static void *io_uring_validate_mmap_request(struct file *file, + loff_t pgoff, size_t sz) { - loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT; - unsigned long sz = vma->vm_end - vma->vm_start; struct io_ring_ctx *ctx = file->private_data; - unsigned long pfn; + loff_t offset = pgoff << PAGE_SHIFT; struct page *page; void *ptr; @@ -3554,17 +3553,59 @@ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) ptr = ctx->sq_sqes; break; default: - return -EINVAL; + return ERR_PTR(-EINVAL); } page = virt_to_head_page(ptr); if (sz > page_size(page)) - return -EINVAL; + return ERR_PTR(-EINVAL); + + return ptr; +} + +#ifdef CONFIG_MMU + +static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) +{ + size_t sz = vma->vm_end - vma->vm_start; + unsigned long pfn; + void *ptr; + + ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); + if (IS_ERR(ptr)) + return PTR_ERR(ptr); pfn = virt_to_phys(ptr) >> PAGE_SHIFT; return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); } +#else /* !CONFIG_MMU */ + +static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) +{ + return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; +} + +static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) +{ + return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; +} + +static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, + unsigned long addr, unsigned long len, + unsigned long pgoff, unsigned long flags) +{ + void *ptr; + + ptr = io_uring_validate_mmap_request(file, pgoff, len); + if (IS_ERR(ptr)) + return PTR_ERR(ptr); + + return (unsigned long) ptr; +} + +#endif /* !CONFIG_MMU */ + SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, u32, min_complete, u32, flags, const sigset_t __user *, sig, size_t, sigsz) @@ -3639,6 +3680,10 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, static const struct file_operations io_uring_fops = { .release = io_uring_release, .mmap = io_uring_mmap, +#ifndef CONFIG_MMU + .get_unmapped_area = io_uring_nommu_get_unmapped_area, + .mmap_capabilities = io_uring_nommu_mmap_capabilities, +#endif .poll = io_uring_poll, .fasync = io_uring_fasync, };