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5d8de293c2
Patch series "Convert vmcore to use an iov_iter", v5. For some reason several people have been sending bad patches to fix compiler warnings in vmcore recently. Here's how it should be done. Compile-tested only on x86. As noted in the first patch, s390 should take this conversion a bit further, but I'm not inclined to do that work myself. This patch (of 3): 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. Link: https://lkml.kernel.org/r/20220408090636.560886-1-bhe@redhat.com Link: https://lkml.kernel.org/r/20220408090636.560886-2-bhe@redhat.com Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
48 lines
1.1 KiB
C
48 lines
1.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Memory preserving reboot related code.
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*
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
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* Copyright (C) IBM Corporation, 2004. All rights reserved
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*/
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/crash_dump.h>
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#include <linux/uio.h>
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static inline bool is_crashed_pfn_valid(unsigned long pfn)
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{
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#ifndef CONFIG_X86_PAE
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/*
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* non-PAE kdump kernel executed from a PAE one will crop high pte
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* bits and poke unwanted space counting again from address 0, we
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* don't want that. pte must fit into unsigned long. In fact the
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* test checks high 12 bits for being zero (pfn will be shifted left
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* by PAGE_SHIFT).
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*/
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return pte_pfn(pfn_pte(pfn, __pgprot(0))) == pfn;
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#else
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return true;
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#endif
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}
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ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize,
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unsigned long offset)
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{
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void *vaddr;
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if (!csize)
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return 0;
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if (!is_crashed_pfn_valid(pfn))
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return -EFAULT;
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vaddr = kmap_local_pfn(pfn);
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csize = copy_to_iter(vaddr + offset, csize, iter);
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kunmap_local(vaddr);
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return csize;
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}
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