From nobody Tue Jun 9 20:01:11 2026 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 0E283C433EF for ; Fri, 8 Apr 2022 09:07:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232546AbiDHJJR (ORCPT ); Fri, 8 Apr 2022 05:09:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57640 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232645AbiDHJJA (ORCPT ); Fri, 8 Apr 2022 05:09:00 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 22C7B100764 for ; Fri, 8 Apr 2022 02:06:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1649408816; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rh0Hpvt4uG7v7kaZ8wWJL2/QNlicmVUp2UwxJSuxITw=; b=L6i3l+naNyWh9wgoya4gkzw3U+EjfEcMOiaeHAftFxVs3+5oRpte5L4zsYca9TFD9+DbWK DkShYGeCWv1KXotHC8r1lzNAH12HIiLhR+SH6S0hZK0lAgc+zB6yr+iA9xmsCUYrPdRbvg M9ZeMzDubx5cQUbPA53PU/V5R3S8BDs= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-389-eNliwG11OqawML9My83IVg-1; Fri, 08 Apr 2022 05:06:50 -0400 X-MC-Unique: eNliwG11OqawML9My83IVg-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4BF561C00BA1; Fri, 8 Apr 2022 09:06:50 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-202.pek2.redhat.com [10.72.12.202]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5CF7E40D2962; Fri, 8 Apr 2022 09:06:44 +0000 (UTC) From: Baoquan He To: akpm@linux-foundation.org, willy@infradead.org Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, hch@lst.de, yangtiezhu@loongson.cn, amit.kachhap@arm.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, bhe@redhat.com Subject: [PATCH v5 RESEND 1/3] vmcore: Convert copy_oldmem_page() to take an iov_iter Date: Fri, 8 Apr 2022 17:06:34 +0800 Message-Id: <20220408090636.560886-2-bhe@redhat.com> In-Reply-To: <20220408090636.560886-1-bhe@redhat.com> References: <20220408090636.560886-1-bhe@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Matthew Wilcox (Oracle)" Instead of passing in a 'buf' and 'userbuf' argument, pass in an iov_iter. s390 needs more work to pass the iov_iter down further, or refactor, but I'd be more comfortable if someone who can test on s390 did that work. It's more convenient to convert the whole of read_from_oldmem() to take an iov_iter at the same time, so rename it to read_from_oldmem_iter() and add a temporary read_from_oldmem() wrapper that creates an iov_iter. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reported-by: kernel test robot Reviewed-by: Christoph Hellwig --- arch/arm/kernel/crash_dump.c | 27 +++------------- arch/arm64/kernel/crash_dump.c | 29 +++-------------- arch/ia64/kernel/crash_dump.c | 32 +++---------------- arch/mips/kernel/crash_dump.c | 27 +++------------- arch/powerpc/kernel/crash_dump.c | 35 +++------------------ arch/riscv/kernel/crash_dump.c | 26 +++------------ arch/s390/kernel/crash_dump.c | 13 +++++--- arch/sh/kernel/crash_dump.c | 29 +++-------------- arch/x86/kernel/crash_dump_32.c | 29 +++-------------- arch/x86/kernel/crash_dump_64.c | 41 +++++++----------------- fs/proc/vmcore.c | 54 ++++++++++++++++++++------------ include/linux/crash_dump.h | 9 +++--- 12 files changed, 91 insertions(+), 260 deletions(-) diff --git a/arch/arm/kernel/crash_dump.c b/arch/arm/kernel/crash_dump.c index 53cb92435392..938bd932df9a 100644 --- a/arch/arm/kernel/crash_dump.c +++ b/arch/arm/kernel/crash_dump.c @@ -14,22 +14,10 @@ #include #include #include +#include =20 -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is int he user address space - * - * This function copies one page from old kernel memory into buffer pointe= d by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of by= tes - * copied or negative error in case of failure. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; =20 @@ -40,14 +28,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; =20 - if (userbuf) { - if (copy_to_user(buf, vaddr + offset, csize)) { - iounmap(vaddr); - return -EFAULT; - } - } else { - memcpy(buf, vaddr + offset, csize); - } + csize =3D copy_to_iter(vaddr + offset, csize, iter); =20 iounmap(vaddr); return csize; diff --git a/arch/arm64/kernel/crash_dump.c b/arch/arm64/kernel/crash_dump.c index 58303a9ec32c..670e4ce81822 100644 --- a/arch/arm64/kernel/crash_dump.c +++ b/arch/arm64/kernel/crash_dump.c @@ -9,25 +9,11 @@ #include #include #include -#include -#include +#include #include =20 -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space - * - * This function copies one page from old kernel memory into buffer pointe= d by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of by= tes - * copied or negative error in case of failure. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; =20 @@ -38,14 +24,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; =20 - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { - memunmap(vaddr); - return -EFAULT; - } - } else { - memcpy(buf, vaddr + offset, csize); - } + csize =3D copy_to_iter(vaddr + offset, csize, iter); =20 memunmap(vaddr); =20 diff --git a/arch/ia64/kernel/crash_dump.c b/arch/ia64/kernel/crash_dump.c index 0ed3c3dee4cd..4ef68e2aa757 100644 --- a/arch/ia64/kernel/crash_dump.c +++ b/arch/ia64/kernel/crash_dump.c @@ -10,42 +10,18 @@ #include #include #include - +#include #include -#include =20 -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there is no pte mapped - * in the current kernel. We stitch up a pte, similar to kmap_atomic. - * - * Calling copy_to_user() in atomic context is not desirable. Hence first - * copying the data to a pre-allocated kernel page and then copying to user - * space in non-atomic context. - */ -ssize_t -copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; =20 if (!csize) return 0; vaddr =3D __va(pfn< #include +#include =20 -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there is no pte mapped - * in the current kernel. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; =20 @@ -24,14 +12,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, return 0; =20 vaddr =3D kmap_local_pfn(pfn); - - if (!userbuf) { - memcpy(buf, vaddr + offset, csize); - } else { - if (copy_to_user(buf, vaddr + offset, csize)) - csize =3D -EFAULT; - } - + csize =3D copy_to_iter(vaddr + offset, csize, iter); kunmap_local(vaddr); =20 return csize; diff --git a/arch/powerpc/kernel/crash_dump.c b/arch/powerpc/kernel/crash_d= ump.c index 5693e1c67c2b..32b4a97f1b79 100644 --- a/arch/powerpc/kernel/crash_dump.c +++ b/arch/powerpc/kernel/crash_dump.c @@ -16,7 +16,7 @@ #include #include #include -#include +#include #include #include =20 @@ -68,33 +68,8 @@ void __init setup_kdump_trampoline(void) } #endif /* CONFIG_NONSTATIC_KERNEL */ =20 -static size_t copy_oldmem_vaddr(void *vaddr, char *buf, size_t csize, - unsigned long offset, int userbuf) -{ - if (userbuf) { - if (copy_to_user((char __user *)buf, (vaddr + offset), csize)) - return -EFAULT; - } else - memcpy(buf, (vaddr + offset), csize); - - return csize; -} - -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there is no pte mapped - * in the current kernel. We stitch up a pte, similar to kmap_atomic. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; phys_addr_t paddr; @@ -107,10 +82,10 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, =20 if (memblock_is_region_memory(paddr, csize)) { vaddr =3D __va(paddr); - csize =3D copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize =3D copy_to_iter(vaddr + offset, csize, iter); } else { vaddr =3D ioremap_cache(paddr, PAGE_SIZE); - csize =3D copy_oldmem_vaddr(vaddr, buf, csize, offset, userbuf); + csize =3D copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); } =20 diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c index 86cc0ada5752..ea2158cee97b 100644 --- a/arch/riscv/kernel/crash_dump.c +++ b/arch/riscv/kernel/crash_dump.c @@ -7,22 +7,10 @@ =20 #include #include +#include =20 -/** - * copy_oldmem_page() - copy one page from old kernel memory - * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed - * @csize: number of bytes to copy - * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space - * - * This function copies one page from old kernel memory into buffer pointe= d by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of by= tes - * copied or negative error in case of failure. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void *vaddr; =20 @@ -33,13 +21,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; =20 - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { - memunmap(vaddr); - return -EFAULT; - } - } else - memcpy(buf, vaddr + offset, csize); + csize =3D copy_to_iter(vaddr + offset, csize, iter); =20 memunmap(vaddr); return csize; diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c index 69819b765250..a2c1c55daec0 100644 --- a/arch/s390/kernel/crash_dump.c +++ b/arch/s390/kernel/crash_dump.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -212,8 +213,8 @@ static int copy_oldmem_user(void __user *dst, unsigned = long src, size_t count) /* * Copy one page from "oldmem" */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t = csize, + unsigned long offset) { unsigned long src; int rc; @@ -221,10 +222,12 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf= , size_t csize, if (!csize) return 0; src =3D pfn_to_phys(pfn) + offset; - if (userbuf) - rc =3D copy_oldmem_user((void __force __user *) buf, src, csize); + + /* XXX: pass the iov_iter down to a common function */ + if (iter_is_iovec(iter)) + rc =3D copy_oldmem_user(iter->iov->iov_base, src, csize); else - rc =3D copy_oldmem_kernel((void *) buf, src, csize); + rc =3D copy_oldmem_kernel(iter->kvec->iov_base, src, csize); return rc; } =20 diff --git a/arch/sh/kernel/crash_dump.c b/arch/sh/kernel/crash_dump.c index 5b41b59698c1..19ce6a950aac 100644 --- a/arch/sh/kernel/crash_dump.c +++ b/arch/sh/kernel/crash_dump.c @@ -8,23 +8,11 @@ #include #include #include +#include #include =20 -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there is no pte mapped - * in the current kernel. We stitch up a pte, similar to kmap_atomic. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, int use= rbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset) { void __iomem *vaddr; =20 @@ -32,15 +20,8 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, return 0; =20 vaddr =3D ioremap(pfn << PAGE_SHIFT, PAGE_SIZE); - - if (userbuf) { - if (copy_to_user((void __user *)buf, (vaddr + offset), csize)) { - iounmap(vaddr); - return -EFAULT; - } - } else - memcpy(buf, (vaddr + offset), csize); - + csize =3D copy_to_iter(vaddr + offset, csize, iter); iounmap(vaddr); + return csize; } diff --git a/arch/x86/kernel/crash_dump_32.c b/arch/x86/kernel/crash_dump_3= 2.c index 5fcac46aaf6b..5f4ae5476e19 100644 --- a/arch/x86/kernel/crash_dump_32.c +++ b/arch/x86/kernel/crash_dump_32.c @@ -10,8 +10,7 @@ #include #include #include - -#include +#include =20 static inline bool is_crashed_pfn_valid(unsigned long pfn) { @@ -29,21 +28,8 @@ static inline bool is_crashed_pfn_valid(unsigned long pf= n) #endif } =20 -/** - * copy_oldmem_page - copy one page from "oldmem" - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from "oldmem". For this page, there might be no pte mapped - * in the current kernel. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t = csize, + unsigned long offset) { void *vaddr; =20 @@ -54,14 +40,7 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, s= ize_t csize, return -EFAULT; =20 vaddr =3D kmap_local_pfn(pfn); - - if (!userbuf) { - memcpy(buf, vaddr + offset, csize); - } else { - if (copy_to_user(buf, vaddr + offset, csize)) - csize =3D -EFAULT; - } - + csize =3D copy_to_iter(vaddr + offset, csize, iter); kunmap_local(vaddr); =20 return csize; diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_6= 4.c index a7f617a3981d..f922d51c9d1f 100644 --- a/arch/x86/kernel/crash_dump_64.c +++ b/arch/x86/kernel/crash_dump_64.c @@ -8,12 +8,12 @@ =20 #include #include -#include +#include #include #include =20 -static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csi= ze, - unsigned long offset, int userbuf, +static ssize_t __copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, + size_t csize, unsigned long offset, bool encrypted) { void *vaddr; @@ -29,47 +29,28 @@ static ssize_t __copy_oldmem_page(unsigned long pfn, ch= ar *buf, size_t csize, if (!vaddr) return -ENOMEM; =20 - if (userbuf) { - if (copy_to_user((void __user *)buf, vaddr + offset, csize)) { - iounmap((void __iomem *)vaddr); - return -EFAULT; - } - } else - memcpy(buf, vaddr + offset, csize); + csize =3D copy_to_iter(vaddr + offset, csize, iter); =20 set_iounmap_nonlazy(); iounmap((void __iomem *)vaddr); return csize; } =20 -/** - * copy_oldmem_page - copy one page of memory - * @pfn: page frame number to be copied - * @buf: target memory address for the copy; this can be in kernel address - * space or user address space (see @userbuf) - * @csize: number of bytes to copy - * @offset: offset in bytes into the page (based on pfn) to begin the copy - * @userbuf: if set, @buf is in user address space, use copy_to_user(), - * otherwise @buf is in kernel address space, use memcpy(). - * - * Copy a page from the old kernel's memory. For this page, there is no pte - * mapped in the current kernel. We stitch up a pte, similar to kmap_atomi= c. - */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t = csize, + unsigned long offset) { - return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false); + return __copy_oldmem_page(iter, pfn, csize, offset, false); } =20 -/** +/* * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but iorem= ap the * memory with the encryption mask set to accommodate kdump on SME-enabled * machines. */ -ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t cs= ize, - unsigned long offset, int userbuf) +ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pf= n, + size_t csize, unsigned long offset) { - return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true); + return __copy_oldmem_page(iter, pfn, csize, offset, true); } =20 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 6f1b8ddc6f7a..54dda2e19ed1 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include "internal.h" @@ -128,9 +129,8 @@ static int open_vmcore(struct inode *inode, struct file= *file) } =20 /* Reads a page from the oldmem device from given offset. */ -ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted) +static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count, + u64 *ppos, bool encrypted) { unsigned long pfn, offset; size_t nr_bytes; @@ -152,29 +152,23 @@ ssize_t read_from_oldmem(char *buf, size_t count, =20 /* If pfn is not ram, return zeros for sparse dump files */ if (!pfn_is_ram(pfn)) { - tmp =3D 0; - if (!userbuf) - memset(buf, 0, nr_bytes); - else if (clear_user(buf, nr_bytes)) - tmp =3D -EFAULT; + tmp =3D iov_iter_zero(nr_bytes, iter); } else { if (encrypted) - tmp =3D copy_oldmem_page_encrypted(pfn, buf, + tmp =3D copy_oldmem_page_encrypted(iter, pfn, nr_bytes, - offset, - userbuf); + offset); else - tmp =3D copy_oldmem_page(pfn, buf, nr_bytes, - offset, userbuf); + tmp =3D copy_oldmem_page(iter, pfn, nr_bytes, + offset); } - if (tmp < 0) { + if (tmp < nr_bytes) { srcu_read_unlock(&vmcore_cb_srcu, idx); - return tmp; + return -EFAULT; } =20 *ppos +=3D nr_bytes; count -=3D nr_bytes; - buf +=3D nr_bytes; read +=3D nr_bytes; ++pfn; offset =3D 0; @@ -184,6 +178,27 @@ ssize_t read_from_oldmem(char *buf, size_t count, return read; } =20 +ssize_t read_from_oldmem(char *buf, size_t count, + u64 *ppos, int userbuf, + bool encrypted) +{ + struct iov_iter iter; + struct iovec iov; + struct kvec kvec; + + if (userbuf) { + iov.iov_base =3D (__force void __user *)buf; + iov.iov_len =3D count; + iov_iter_init(&iter, READ, &iov, 1, count); + } else { + kvec.iov_base =3D buf; + kvec.iov_len =3D count; + iov_iter_kvec(&iter, READ, &kvec, 1, count); + } + + return read_from_oldmem_iter(&iter, count, ppos, encrypted); +} + /* * Architectures may override this function to allocate ELF header in 2nd = kernel */ @@ -228,11 +243,10 @@ int __weak remap_oldmem_pfn_range(struct vm_area_stru= ct *vma, /* * Architectures which support memory encryption override this. */ -ssize_t __weak -copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize, - unsigned long offset, int userbuf) +ssize_t __weak copy_oldmem_page_encrypted(struct iov_iter *iter, + unsigned long pfn, size_t csize, unsigned long offset) { - return copy_oldmem_page(pfn, buf, csize, offset, userbuf); + return copy_oldmem_page(iter, pfn, csize, offset); } =20 /* diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h index 620821549b23..a1cf7d5c03c7 100644 --- a/include/linux/crash_dump.h +++ b/include/linux/crash_dump.h @@ -24,11 +24,10 @@ extern int remap_oldmem_pfn_range(struct vm_area_struct= *vma, unsigned long from, unsigned long pfn, unsigned long size, pgprot_t prot); =20 -extern ssize_t copy_oldmem_page(unsigned long, char *, size_t, - unsigned long, int); -extern ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf); +ssize_t copy_oldmem_page(struct iov_iter *i, unsigned long pfn, size_t csi= ze, + unsigned long offset); +ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pf= n, + size_t csize, unsigned long offset); =20 void vmcore_cleanup(void); =20 --=20 2.34.1 From nobody Tue Jun 9 20:01:11 2026 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 1BF7BC433EF for ; Fri, 8 Apr 2022 09:07:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232596AbiDHJJY (ORCPT ); Fri, 8 Apr 2022 05:09:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57764 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232661AbiDHJJD (ORCPT ); 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Fri, 08 Apr 2022 05:06:55 -0400 X-MC-Unique: dB-rUNAUN5eCVWNUQkVEpQ-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3806C299E772; Fri, 8 Apr 2022 09:06:55 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-202.pek2.redhat.com [10.72.12.202]) by smtp.corp.redhat.com (Postfix) with ESMTP id 08DAD40D296B; Fri, 8 Apr 2022 09:06:50 +0000 (UTC) From: Baoquan He To: akpm@linux-foundation.org, willy@infradead.org Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, hch@lst.de, yangtiezhu@loongson.cn, amit.kachhap@arm.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, bhe@redhat.com Subject: [PATCH v5 RESEND 2/3] vmcore: Convert __read_vmcore to use an iov_iter Date: Fri, 8 Apr 2022 17:06:35 +0800 Message-Id: <20220408090636.560886-3-bhe@redhat.com> In-Reply-To: <20220408090636.560886-1-bhe@redhat.com> References: <20220408090636.560886-1-bhe@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Matthew Wilcox (Oracle)" This gets rid of copy_to() and let us use proc_read_iter() instead of proc_read(). Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig --- fs/proc/vmcore.c | 82 ++++++++++++++++++------------------------------ 1 file changed, 30 insertions(+), 52 deletions(-) diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 54dda2e19ed1..4a721865b5cd 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -249,22 +249,8 @@ ssize_t __weak copy_oldmem_page_encrypted(struct iov_i= ter *iter, return copy_oldmem_page(iter, pfn, csize, offset); } =20 -/* - * 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 user= buf) +static int vmcoredd_copy_dumps(struct iov_iter *iter, u64 start, size_t si= ze) { struct vmcoredd_node *dump; u64 offset =3D 0; @@ -277,14 +263,13 @@ static int vmcoredd_copy_dumps(void *dst, u64 start, = size_t size, int userbuf) if (start < offset + dump->size) { tsz =3D min(offset + (u64)dump->size - start, (u64)size); buf =3D dump->buf + start - offset; - if (copy_to(dst, buf, tsz, userbuf)) { + if (copy_to_iter(buf, tsz, iter) < tsz) { ret =3D -EFAULT; goto out_unlock; } =20 size -=3D tsz; start +=3D tsz; - dst +=3D tsz; =20 /* Leave now if buffer filled already */ if (!size) @@ -340,33 +325,28 @@ 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 va= lue 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 =3D 0, tmp; size_t tsz; u64 start; struct vmcore *m =3D NULL; =20 - if (buflen =3D=3D 0 || *fpos >=3D vmcore_size) + if (!iov_iter_count(iter) || *fpos >=3D vmcore_size) return 0; =20 - /* trim buflen to not go beyond EOF */ - if (buflen > vmcore_size - *fpos) - buflen =3D vmcore_size - *fpos; + iov_iter_truncate(iter, vmcore_size - *fpos); =20 /* Read ELF core header */ if (*fpos < elfcorebuf_sz) { - tsz =3D min(elfcorebuf_sz - (size_t)*fpos, buflen); - if (copy_to(buffer, elfcorebuf + *fpos, tsz, userbuf)) + tsz =3D min(elfcorebuf_sz - (size_t)*fpos, iov_iter_count(iter)); + if (copy_to_iter(elfcorebuf + *fpos, tsz, iter) < tsz) return -EFAULT; - buflen -=3D tsz; *fpos +=3D tsz; - buffer +=3D tsz; acc +=3D tsz; =20 /* leave now if filled buffer already */ - if (buflen =3D=3D 0) + if (!iov_iter_count(iter)) return acc; } =20 @@ -387,35 +367,32 @@ static ssize_t __read_vmcore(char *buffer, size_t buf= len, loff_t *fpos, /* Read device dumps */ if (*fpos < elfcorebuf_sz + vmcoredd_orig_sz) { tsz =3D min(elfcorebuf_sz + vmcoredd_orig_sz - - (size_t)*fpos, buflen); + (size_t)*fpos, iov_iter_count(iter)); start =3D *fpos - elfcorebuf_sz; - if (vmcoredd_copy_dumps(buffer, start, tsz, userbuf)) + if (vmcoredd_copy_dumps(iter, start, tsz)) return -EFAULT; =20 - buflen -=3D tsz; *fpos +=3D tsz; - buffer +=3D tsz; acc +=3D tsz; =20 /* leave now if filled buffer already */ - if (!buflen) + if (!iov_iter_count(iter)) return acc; } #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ =20 /* Read remaining elf notes */ - tsz =3D min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, buflen); + tsz =3D min(elfcorebuf_sz + elfnotes_sz - (size_t)*fpos, + iov_iter_count(iter)); kaddr =3D 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; =20 - buflen -=3D tsz; *fpos +=3D tsz; - buffer +=3D tsz; acc +=3D tsz; =20 /* leave now if filled buffer already */ - if (buflen =3D=3D 0) + if (!iov_iter_count(iter)) return acc; } =20 @@ -423,19 +400,17 @@ static ssize_t __read_vmcore(char *buffer, size_t buf= len, loff_t *fpos, if (*fpos < m->offset + m->size) { tsz =3D (size_t)min_t(unsigned long long, m->offset + m->size - *fpos, - buflen); + iov_iter_count(iter)); start =3D m->paddr + *fpos - m->offset; - tmp =3D read_from_oldmem(buffer, tsz, &start, - userbuf, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); + tmp =3D read_from_oldmem_iter(iter, tsz, &start, + cc_platform_has(CC_ATTR_MEM_ENCRYPT)); if (tmp < 0) return tmp; - buflen -=3D tsz; *fpos +=3D tsz; - buffer +=3D tsz; acc +=3D tsz; =20 /* leave now if filled buffer already */ - if (buflen =3D=3D 0) + if (!iov_iter_count(iter)) return acc; } } @@ -443,15 +418,14 @@ static ssize_t __read_vmcore(char *buffer, size_t buf= len, loff_t *fpos, return acc; } =20 -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); } =20 /* * 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 mapp= ed * directly with remap_pfn_range(). @@ -461,9 +435,10 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *v= mf) #ifdef CONFIG_S390 struct address_space *mapping =3D vmf->vma->vm_file->f_mapping; pgoff_t index =3D vmf->pgoff; + struct iov_iter iter; + struct kvec kvec; struct page *page; loff_t offset; - char *buf; int rc; =20 page =3D find_or_create_page(mapping, index, GFP_KERNEL); @@ -471,8 +446,11 @@ static vm_fault_t mmap_vmcore_fault(struct vm_fault *v= mf) return VM_FAULT_OOM; if (!PageUptodate(page)) { offset =3D (loff_t) index << PAGE_SHIFT; - buf =3D __va((page_to_pfn(page) << PAGE_SHIFT)); - rc =3D __read_vmcore(buf, PAGE_SIZE, &offset, 0); + kvec.iov_base =3D page_address(page); + kvec.iov_len =3D PAGE_SIZE; + iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE); + + rc =3D __read_vmcore(&iter, &offset); if (rc < 0) { unlock_page(page); put_page(page); @@ -722,7 +700,7 @@ static int mmap_vmcore(struct file *file, struct vm_are= a_struct *vma) =20 static const struct proc_ops vmcore_proc_ops =3D { .proc_open =3D open_vmcore, - .proc_read =3D read_vmcore, + .proc_read_iter =3D read_vmcore, .proc_lseek =3D default_llseek, .proc_mmap =3D mmap_vmcore, }; --=20 2.34.1 From nobody Tue Jun 9 20:01:11 2026 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 6EE9DC433FE for ; Fri, 8 Apr 2022 09:07:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232667AbiDHJJ2 (ORCPT ); Fri, 8 Apr 2022 05:09:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231255AbiDHJJP (ORCPT ); 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Fri, 08 Apr 2022 05:07:01 -0400 X-MC-Unique: ZUiCTedzO7a7AlXgx5iI0w-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 74A6B28EA702; Fri, 8 Apr 2022 09:07:00 +0000 (UTC) Received: from MiWiFi-R3L-srv.redhat.com (ovpn-12-202.pek2.redhat.com [10.72.12.202]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0734E40D2962; Fri, 8 Apr 2022 09:06:55 +0000 (UTC) From: Baoquan He To: akpm@linux-foundation.org, willy@infradead.org Cc: linux-kernel@vger.kernel.org, kexec@lists.infradead.org, hch@lst.de, yangtiezhu@loongson.cn, amit.kachhap@arm.com, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, bhe@redhat.com Subject: [PATCH v5 RESEND 3/3] vmcore: Convert read_from_oldmem() to take an iov_iter Date: Fri, 8 Apr 2022 17:06:36 +0800 Message-Id: <20220408090636.560886-4-bhe@redhat.com> In-Reply-To: <20220408090636.560886-1-bhe@redhat.com> References: <20220408090636.560886-1-bhe@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: "Matthew Wilcox (Oracle)" Remove the read_from_oldmem() wrapper introduced earlier and convert all the remaining callers to pass an iov_iter. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Baoquan He Reviewed-by: Christoph Hellwig --- arch/x86/kernel/crash_dump_64.c | 7 +++++- fs/proc/vmcore.c | 40 +++++++++++++-------------------- include/linux/crash_dump.h | 10 ++++----- 3 files changed, 25 insertions(+), 32 deletions(-) diff --git a/arch/x86/kernel/crash_dump_64.c b/arch/x86/kernel/crash_dump_6= 4.c index f922d51c9d1f..0fa87648e55c 100644 --- a/arch/x86/kernel/crash_dump_64.c +++ b/arch/x86/kernel/crash_dump_64.c @@ -55,6 +55,11 @@ ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter= , unsigned long pfn, =20 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, + struct kvec kvec =3D { .iov_base =3D buf, .iov_len =3D count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)); } diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c index 4a721865b5cd..4eaeb645e759 100644 --- a/fs/proc/vmcore.c +++ b/fs/proc/vmcore.c @@ -129,7 +129,7 @@ static int open_vmcore(struct inode *inode, struct file= *file) } =20 /* Reads a page from the oldmem device from given offset. */ -static ssize_t read_from_oldmem_iter(struct iov_iter *iter, size_t count, +ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, u64 *ppos, bool encrypted) { unsigned long pfn, offset; @@ -178,27 +178,6 @@ static ssize_t read_from_oldmem_iter(struct iov_iter *= iter, size_t count, return read; } =20 -ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted) -{ - struct iov_iter iter; - struct iovec iov; - struct kvec kvec; - - if (userbuf) { - iov.iov_base =3D (__force void __user *)buf; - iov.iov_len =3D count; - iov_iter_init(&iter, READ, &iov, 1, count); - } else { - kvec.iov_base =3D buf; - kvec.iov_len =3D count; - iov_iter_kvec(&iter, READ, &kvec, 1, count); - } - - return read_from_oldmem_iter(&iter, count, ppos, encrypted); -} - /* * Architectures may override this function to allocate ELF header in 2nd = kernel */ @@ -218,7 +197,12 @@ void __weak elfcorehdr_free(unsigned long long addr) */ ssize_t __weak elfcorehdr_read(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, false); + struct kvec kvec =3D { .iov_base =3D buf, .iov_len =3D count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, false); } =20 /* @@ -226,7 +210,13 @@ ssize_t __weak elfcorehdr_read(char *buf, size_t count= , u64 *ppos) */ ssize_t __weak elfcorehdr_read_notes(char *buf, size_t count, u64 *ppos) { - return read_from_oldmem(buf, count, ppos, 0, cc_platform_has(CC_ATTR_MEM_= ENCRYPT)); + struct kvec kvec =3D { .iov_base =3D buf, .iov_len =3D count }; + struct iov_iter iter; + + iov_iter_kvec(&iter, READ, &kvec, 1, count); + + return read_from_oldmem(&iter, count, ppos, + cc_platform_has(CC_ATTR_MEM_ENCRYPT)); } =20 /* @@ -402,7 +392,7 @@ static ssize_t __read_vmcore(struct iov_iter *iter, lof= f_t *fpos) m->offset + m->size - *fpos, iov_iter_count(iter)); start =3D m->paddr + *fpos - m->offset; - tmp =3D read_from_oldmem_iter(iter, tsz, &start, + tmp =3D read_from_oldmem(iter, tsz, &start, cc_platform_has(CC_ATTR_MEM_ENCRYPT)); if (tmp < 0) return tmp; diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h index a1cf7d5c03c7..0f3a656293b0 100644 --- a/include/linux/crash_dump.h +++ b/include/linux/crash_dump.h @@ -134,13 +134,11 @@ static inline int vmcore_add_device_dump(struct vmcor= edd_data *data) #endif /* CONFIG_PROC_VMCORE_DEVICE_DUMP */ =20 #ifdef CONFIG_PROC_VMCORE -ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted); +ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, + u64 *ppos, bool encrypted); #else -static inline ssize_t read_from_oldmem(char *buf, size_t count, - u64 *ppos, int userbuf, - bool encrypted) +static inline ssize_t read_from_oldmem(struct iov_iter *iter, size_t count, + u64 *ppos, bool encrypted) { return -EOPNOTSUPP; } --=20 2.34.1