From mboxrd@z Thu Jan 1 00:00:00 1970 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 572C8C6FD1D for ; Tue, 21 Mar 2023 21:15:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229676AbjCUVPM (ORCPT ); Tue, 21 Mar 2023 17:15:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229717AbjCUVPJ (ORCPT ); Tue, 21 Mar 2023 17:15:09 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4BC5B3B3E2 for ; Tue, 21 Mar 2023 14:15:07 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 01BE4B8197F for ; Tue, 21 Mar 2023 21:15:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2579C433D2; Tue, 21 Mar 2023 21:15:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1679433304; bh=Fh5Q2OLHCmK8evZYePbYb8uuARyNqbzDznCON1x/n3Y=; h=Date:To:From:Subject:From; b=j8T0hTSFazY/upfi0nsJz6/LuZzLjrjRM/qOqVBpgy89QB5FpsWAPwwjAfBc7ZrGQ Kz529GOy1wiCXov2s5q+/7blt8/RDcl+TVVtFDVOsAfRY3APq0/TGb4EraG2X1oPIk fpsbRW8doigKISDlPxq5e+NcrmjbpJHz0dAPTgDE= Date: Tue, 21 Mar 2023 14:15:04 -0700 To: mm-commits@vger.kernel.org, willy@infradead.org, viro@zeniv.linux.org.uk, urezki@gmail.com, liushixin2@huawei.com, jolsa@kernel.org, david@redhat.com, bhe@redhat.com, axboe@kernel.dk, lstoakes@gmail.com, akpm@linux-foundation.org From: Andrew Morton Subject: + fs-proc-kcore-convert-read_kcore-to-read_kcore_iter.patch added to mm-unstable branch Message-Id: <20230321211504.B2579C433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: fs/proc/kcore: convert read_kcore() to read_kcore_iter() has been added to the -mm mm-unstable branch. Its filename is fs-proc-kcore-convert-read_kcore-to-read_kcore_iter.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/fs-proc-kcore-convert-read_kcore-to-read_kcore_iter.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Lorenzo Stoakes Subject: fs/proc/kcore: convert read_kcore() to read_kcore_iter() Date: Tue, 21 Mar 2023 20:54:31 +0000 Now we have eliminated spinlocks from the vread() case, convert read_kcore() to read_kcore_iter(). For the time being we still use a bounce buffer for vread(), however in the next patch we will convert this to interact directly with the iterator and eliminate the bounce buffer altogether. Link: https://lkml.kernel.org/r/a84da6cc458b44d949058b5f475ed3225008cfd9.1679431886.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Cc: Alexander Viro Cc: Baoquan He Cc: David Hildenbrand Cc: Jens Axboe Cc: Jiri Olsa Cc: Liu Shixin Cc: Matthew Wilcox (Oracle) Cc: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton --- fs/proc/kcore.c | 58 +++++++++++++++++++++++----------------------- 1 file changed, 29 insertions(+), 29 deletions(-) --- a/fs/proc/kcore.c~fs-proc-kcore-convert-read_kcore-to-read_kcore_iter +++ a/fs/proc/kcore.c @@ -24,7 +24,7 @@ #include #include #include -#include +#include #include #include #include @@ -308,9 +308,12 @@ static void append_kcore_note(char *note } static ssize_t -read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) +read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter) { + struct file *file = iocb->ki_filp; char *buf = file->private_data; + loff_t *ppos = &iocb->ki_pos; + size_t phdrs_offset, notes_offset, data_offset; size_t page_offline_frozen = 1; size_t phdrs_len, notes_len; @@ -318,6 +321,7 @@ read_kcore(struct file *file, char __use size_t tsz; int nphdr; unsigned long start; + size_t buflen = iov_iter_count(iter); size_t orig_buflen = buflen; int ret = 0; @@ -333,7 +337,7 @@ read_kcore(struct file *file, char __use notes_offset = phdrs_offset + phdrs_len; /* ELF file header. */ - if (buflen && *fpos < sizeof(struct elfhdr)) { + if (buflen && *ppos < sizeof(struct elfhdr)) { struct elfhdr ehdr = { .e_ident = { [EI_MAG0] = ELFMAG0, @@ -355,19 +359,18 @@ read_kcore(struct file *file, char __use .e_phnum = nphdr, }; - tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos); - if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) { + tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *ppos); + if (copy_to_iter((char *)&ehdr + *ppos, tsz, iter) != tsz) { ret = -EFAULT; goto out; } - buffer += tsz; buflen -= tsz; - *fpos += tsz; + *ppos += tsz; } /* ELF program headers. */ - if (buflen && *fpos < phdrs_offset + phdrs_len) { + if (buflen && *ppos < phdrs_offset + phdrs_len) { struct elf_phdr *phdrs, *phdr; phdrs = kzalloc(phdrs_len, GFP_KERNEL); @@ -397,22 +400,21 @@ read_kcore(struct file *file, char __use phdr++; } - tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos); - if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset, - tsz)) { + tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *ppos); + if (copy_to_iter((char *)phdrs + *ppos - phdrs_offset, tsz, + iter) != tsz) { kfree(phdrs); ret = -EFAULT; goto out; } kfree(phdrs); - buffer += tsz; buflen -= tsz; - *fpos += tsz; + *ppos += tsz; } /* ELF note segment. */ - if (buflen && *fpos < notes_offset + notes_len) { + if (buflen && *ppos < notes_offset + notes_len) { struct elf_prstatus prstatus = {}; struct elf_prpsinfo prpsinfo = { .pr_sname = 'R', @@ -447,24 +449,23 @@ read_kcore(struct file *file, char __use vmcoreinfo_data, min(vmcoreinfo_size, notes_len - i)); - tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos); - if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) { + tsz = min_t(size_t, buflen, notes_offset + notes_len - *ppos); + if (copy_to_iter(notes + *ppos - notes_offset, tsz, iter) != tsz) { kfree(notes); ret = -EFAULT; goto out; } kfree(notes); - buffer += tsz; buflen -= tsz; - *fpos += tsz; + *ppos += tsz; } /* * Check to see if our file offset matches with any of * the addresses in the elf_phdr on our list. */ - start = kc_offset_to_vaddr(*fpos - data_offset); + start = kc_offset_to_vaddr(*ppos - data_offset); if ((tsz = (PAGE_SIZE - (start & ~PAGE_MASK))) > buflen) tsz = buflen; @@ -497,7 +498,7 @@ read_kcore(struct file *file, char __use } if (!m) { - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -508,14 +509,14 @@ read_kcore(struct file *file, char __use case KCORE_VMALLOC: vread(buf, (char *)start, tsz); /* we have to zero-fill user buffer even if no read */ - if (copy_to_user(buffer, buf, tsz)) { + if (copy_to_iter(buf, tsz, iter) != tsz) { ret = -EFAULT; goto out; } break; case KCORE_USER: /* User page is handled prior to normal kernel page: */ - if (copy_to_user(buffer, (char *)start, tsz)) { + if (copy_to_iter((char *)start, tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -531,7 +532,7 @@ read_kcore(struct file *file, char __use */ if (!page || PageOffline(page) || is_page_hwpoison(page) || !pfn_is_ram(pfn)) { - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -541,25 +542,24 @@ read_kcore(struct file *file, char __use case KCORE_VMEMMAP: case KCORE_TEXT: /* - * We use _copy_to_user() to bypass usermode hardening + * We use _copy_to_iter() to bypass usermode hardening * which would otherwise prevent this operation. */ - if (_copy_to_user(buffer, (char *)start, tsz)) { + if (_copy_to_iter((char *)start, tsz, iter) != tsz) { ret = -EFAULT; goto out; } break; default: pr_warn_once("Unhandled KCORE type: %d\n", m->type); - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } } skip: buflen -= tsz; - *fpos += tsz; - buffer += tsz; + *ppos += tsz; start += tsz; tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); } @@ -603,7 +603,7 @@ static int release_kcore(struct inode *i } static const struct proc_ops kcore_proc_ops = { - .proc_read = read_kcore, + .proc_read_iter = read_kcore_iter, .proc_open = open_kcore, .proc_release = release_kcore, .proc_lseek = default_llseek, _ Patches currently in -mm which might be from lstoakes@gmail.com are mm-prefer-xxx_page-alloc-free-functions-for-order-0-pages.patch mm-refactor-do_fault_around.patch mm-pefer-fault_around_pages-to-fault_around_bytes.patch maintainers-add-myself-as-vmalloc-reviewer.patch mm-remove-unused-vmf_insert_mixed_prot.patch mm-remove-vmf_insert_pfn_xxx_prot-for-huge-page-table-entries.patch drm-ttm-remove-comment-referencing-now-removed-vmf_insert_mixed_prot.patch mm-mmap-vma_merge-further-improve-prev-next-vma-naming.patch mm-mmap-vma_merge-set-next-to-null-if-not-applicable.patch mm-mmap-vma_merge-extend-invariants-avoid-invalid-res-vma.patch mm-mmap-vma_merge-init-cleanup-be-explicit-about-the-non-mergeable-case.patch fs-proc-kcore-avoid-bounce-buffer-for-ktext-data.patch fs-proc-kcore-convert-read_kcore-to-read_kcore_iter.patch iov_iter-add-copy_page_to_iter_atomic.patch mm-vmalloc-convert-vread-to-vread_iter.patch