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git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
crypto: scatterwalk - Use nth_page instead of doing it by hand
Curiously, the Crypto API scatterwalk incremented pages by hand
rather than using nth_page. Possibly because scatterwalk predates
nth_page (the following commit is from the history tree):
commit 3957f2b34960d85b63e814262a8be7d5ad91444d
Author: James Morris <jmorris@intercode.com.au>
Date: Sun Feb 2 07:35:32 2003 -0800
[CRYPTO]: in/out scatterlist support for ciphers.
Fix this by using nth_page.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
+20
-10
+20
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include/crypto/scatterwalk.h
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-10
include/crypto/scatterwalk.h
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static inline void scatterwalk_map(struct scatter_walk *walk)
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{
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struct page *base_page = sg_page(walk->sg);
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unsigned int offset = walk->offset;
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void *addr;
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if (IS_ENABLED(CONFIG_HIGHMEM)) {
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walk->__addr = kmap_local_page(base_page +
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(walk->offset >> PAGE_SHIFT)) +
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offset_in_page(walk->offset);
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struct page *page;
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page = nth_page(base_page, offset >> PAGE_SHIFT);
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offset = offset_in_page(offset);
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addr = kmap_local_page(page) + offset;
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} else {
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/*
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* When !HIGHMEM we allow the walker to return segments that
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* in the direct map, but this makes it clearer what is really
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* going on.
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*/
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walk->__addr = page_address(base_page) + walk->offset;
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addr = page_address(base_page) + offset;
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}
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walk->__addr = addr;
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}
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/**
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* reliably optimized out or not.
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*/
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if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE) {
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struct page *base_page, *start_page, *end_page, *page;
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struct page *base_page;
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unsigned int offset;
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int start, end, i;
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base_page = sg_page(walk->sg);
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start_page = base_page + (walk->offset >> PAGE_SHIFT);
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end_page = base_page + ((walk->offset + nbytes +
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PAGE_SIZE - 1) >> PAGE_SHIFT);
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for (page = start_page; page < end_page; page++)
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flush_dcache_page(page);
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offset = walk->offset;
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start = offset >> PAGE_SHIFT;
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end = start + (nbytes >> PAGE_SHIFT);
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end += (offset_in_page(offset) + offset_in_page(nbytes) +
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PAGE_SIZE - 1) >> PAGE_SHIFT;
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for (i = start; i < end; i++)
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flush_dcache_page(nth_page(base_page, i));
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}
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scatterwalk_advance(walk, nbytes);
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}