Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41D8BC4332F for ; Mon, 13 Dec 2021 14:39:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239573AbhLMOjh (ORCPT ); Mon, 13 Dec 2021 09:39:37 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230147AbhLMOjh (ORCPT ); Mon, 13 Dec 2021 09:39:37 -0500 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C7410C061574; Mon, 13 Dec 2021 06:39:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Mve6YnzXsqBMMCppqUc6IwojZlJXv+ZjBpIx4fnZ0fc=; b=WcCglPcIoiKUn8rkSdvwSPczyv GMWmzp2AC1UXJVBmBn2hP9feb51Gq9YzKxGZXC88vM+B2ing14V0jRW1QHuyhcUqKpbXbrbgWU8Ly VbqSM6c4+jiP9MgtBn5XQWYlEe+X3tijO7J97zlJAAgef59QeB5ghSlk+D20TQpti5u+4KW+pNnom R5zJ5LshIoM2s1SvMwGaJU11doQsmTkl+6Mcawwt1DNsq2oBWEyJNQpQMcFUW1mnNcPZhC2/13VUv 4eKBbDJCDW/2IIu2qWzbIV8On1POEgTbmoIvnylq5M37y/ZA+o/M71GjytNL5d1x12hvt8MsTZdeM p4wBf+lw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mwmUC-00CsXO-Bt; Mon, 13 Dec 2021 14:39:28 +0000 From: "Matthew Wilcox (Oracle)" To: Baoquan He , Vivek Goyal , Dave Young , kexec@lists.infradead.org Cc: "Matthew Wilcox (Oracle)" , Tiezhu Yang , linux-kernel@vger.kernel.org, Amit Daniel Kachhap , Christoph Hellwig , linux-fsdevel@vger.kernel.org Subject: [PATCH v3 2/3] vmcore: Convert __read_vmcore to use an iov_iter Date: Mon, 13 Dec 2021 14:39:26 +0000 Message-Id: <20211213143927.3069508-3-willy@infradead.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211213143927.3069508-1-willy@infradead.org> References: <20211213143927.3069508-1-willy@infradead.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This gets rid of copy_to() and let us use proc_read_iter() instead of proc_read(). Signed-off-by: Matthew Wilcox (Oracle) --- fs/proc/vmcore.c | 81 +++++++++++++++++------------------------------- 1 file changed, 29 insertions(+), 52 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 958cad6476e6..7b25f568d20d 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -252,22 +252,8 @@ ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter, return copy_oldmem_page(iter, pfn, csize, offset); } -/* - * Copy to either kernel or user space - */ -static int copy_to(void *target, void *src, size_t size, int userbuf) -{ - if (userbuf) { - if (copy_to_user((char __user *) target, src, size)) - return -EFAULT; - } else { - memcpy(target, src, size); - } - return 0; -} - #ifdef CONFIG_PROC_VMCORE_DEVICE_DUMP -static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf) +static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t size) { struct vmcoredd_node *dump; u64 offset = 0; @@ -280,14 +266,13 @@ static int vmcoredd_copy_dumps(void *dst, u64 start, size_t size, int userbuf) if (start < offset + dump->size) { tsz = min(offset + (u64)dump->size - start, (u64)size); buf = dump->buf + start - offset; - if (copy_to(dst, buf, tsz, userbuf)) { + if (copy_to_iter(buf, tsz, iter) < tsz) { ret = -EFAULT; goto out_unlock; } size -= tsz; start += tsz; - dst += tsz; /* Leave now if buffer filled already */ if (!size) @@ -343,33 +328,28 @@ static int vmcoredd_mmap_dumps(struct vm_area_struct *vma, unsigned long dst, /* Read from the ELF header and then the crash dump. On error, negative value is * returned otherwise number of bytes read are returned. */ -static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, - int userbuf) +static ssize_t __read_vmcore(struct iov_iter *iter, loff_t *fpos) { ssize_t acc = 0, tmp; size_t tsz; u64 start; struct vmcore *m = NULL; - if (buflen == 0 || *fpos >= vmcore_size) + if (iter->count == 0 || *fpos >= vmcore_size) return 0; - /* trim buflen to not go beyond EOF */ - if (buflen > vmcore_size - *fpos) - buflen = vmcore_size - *fpos; + iov_iter_truncate(iter, vmcore_size - *fpos); /* Read ELF core header */ if (*fpos < elfcorebuf_sz) { - tsz = min(elfcorebuf_sz - (size_t)*fpos, buflen); - if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf)) + tsz = min(elfcorebuf_sz - (size_t)*fpos, iter->count); + if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz) return -EFAULT; - buflen -= tsz; *fpos += tsz; - buffer += tsz; acc += tsz; /* leave now if filled buffer already */ - if (buflen == 0) + if (iter->count == 0) return acc; } @@ -390,35 +370,31 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, /* Read device dumps */ if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) { tsz = min(elfcorebuf_sz + vmcoredd_orig_sz - - (size_t)*fpos, buflen); + (size_t)*fpos, iter->count); start = *fpos - elfcorebuf_sz; - if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf)) + if (vmcoredd_copy_dumps(iter, start, tsz)) return -EFAULT; - buflen -= tsz; *fpos += tsz; - buffer += tsz; acc += tsz; /* leave now if filled buffer already */ - if (!buflen) + if (!iter->count) return acc; } #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ /* Read remaining elf notes */ - tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen); + tsz = min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, iter->count); kaddr = elfnotes_buf + *fpos - elfcorebuf_sz - vmcoredd_orig_sz; - if (copy_to(buffer, kaddr, tsz, userbuf)) + if (copy_to_iter(kaddr, tsz, iter) < tsz) return -EFAULT; - buflen -= tsz; *fpos += tsz; - buffer += tsz; acc += tsz; /* leave now if filled buffer already */ - if (buflen == 0) + if (iter->count == 0) return acc; } @@ -426,19 +402,17 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, if (*fpos < m->offset + m->size) { tsz = (size_t)min_t(unsigned long long, m->offset + m->size - *fpos, - buflen); + iter->count); start = m->paddr + *fpos - m->offset; - tmp = read_from_oldmem(buffer, tsz, &start, - userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); + tmp = read_from_oldmem_iter(iter, tsz, &start, + cc_platform_has(CC_ATTR_MEM_ENCRYPT)); if (tmp < 0) return tmp; - buflen -= tsz; *fpos += tsz; - buffer += tsz; acc += tsz; /* leave now if filled buffer already */ - if (buflen == 0) + if (iter->count == 0) return acc; } } @@ -446,15 +420,14 @@ static ssize_t __read_vmcore(char *buffer, size_t buflen, loff_t *fpos, return acc; } -static ssize_t read_vmcore(struct file *file, char __user *buffer, - size_t buflen, loff_t *fpos) +static ssize_t read_vmcore(struct kiocb *iocb, struct iov_iter *iter) { - return __read_vmcore((__force char *) buffer, buflen, fpos, 1); + return __read_vmcore(iter, &iocb->ki_pos); } /* * The vmcore fault handler uses the page cache and fills data using the - * standard __vmcore_read() function. + * standard __read_vmcore() function. * * On s390 the fault handler is used for memory regions that can't be mapped * directly with remap_pfn_range(). @@ -464,9 +437,10 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf) #ifdef CONFIG_S390 struct address_space *mapping = vmf->vma->vm_file->f_mapping; pgoff_t index = vmf->pgoff; + struct iov_iter iter; + struct kvec kvec; struct page *page; loff_t offset; - char *buf; int rc; page = find_or_create_page(mapping, index, GFP_KERNEL); @@ -474,8 +448,11 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *vmf) return VM_FAULT_OOM; if (!PageUptodate(page)) { offset = (loff_t) index << PAGE_SHIFT; - buf = __va((page_to_pfn(page) << PAGE_SHIFT)); - rc = __read_vmcore(buf, PAGE_SIZE, &offset, 0); + kvec.iov_base = page_address(page); + kvec.iov_len = PAGE_SIZE; + iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE); + + rc = __read_vmcore(&iter, &offset); if (rc < 0) { unlock_page(page); put_page(page); @@ -725,7 +702,7 @@ static int mmap_vmcore(struct file *file, struct vm_area_struct *vma) static const struct proc_ops vmcore_proc_ops = { .proc_open = open_vmcore, - .proc_read = read_vmcore, + .proc_read_iter = read_vmcore, .proc_lseek = default_llseek, .proc_mmap = mmap_vmcore, }; -- 2.33.0