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crypto: skcipher - Use scatterwalk (un)map interface for dst and src buffers 

The skcipher walk API implementation avoids scatterwalk_map() for
mapping the source and destination buffers, and invokes kmap_atomic()
directly if the buffer in question is not in low memory (which can only
happen on 32-bit architectures). This avoids some overhead on 64-bit
architectures, and most notably, permits the skcipher code to run with
preemption enabled.

Now that scatterwalk_map() has been updated to use kmap_local(), none of
this is needed, so we can simply use scatterwalk_map/unmap instead.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Ard Biesheuvel 2023-01-02 11:18:46 +01:00 committed by Herbert Xu
parent 0781bbd7ea
commit d07bd950b9
1 changed files with 4 additions and 18 deletions
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22
crypto/skcipher.c
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@ -42,38 +42,24 @@ struct skcipher_walk_buffer {
static int skcipher_walk_next(struct skcipher_walk *walk);
static inline void skcipher_unmap(struct scatter_walk *walk, void *vaddr)
{
if (PageHighMem(scatterwalk_page(walk)))
kunmap_atomic(vaddr);
}
static inline void *skcipher_map(struct scatter_walk *walk)
{
struct page *page = scatterwalk_page(walk);
return (PageHighMem(page) ? kmap_atomic(page) : page_address(page)) +
offset_in_page(walk->offset);
}
static inline void skcipher_map_src(struct skcipher_walk *walk)
{
walk->src.virt.addr = skcipher_map(&walk->in);
walk->src.virt.addr = scatterwalk_map(&walk->in);
}
static inline void skcipher_map_dst(struct skcipher_walk *walk)
{
walk->dst.virt.addr = skcipher_map(&walk->out);
walk->dst.virt.addr = scatterwalk_map(&walk->out);
}
static inline void skcipher_unmap_src(struct skcipher_walk *walk)
{
skcipher_unmap(&walk->in, walk->src.virt.addr);
scatterwalk_unmap(walk->src.virt.addr);
}
static inline void skcipher_unmap_dst(struct skcipher_walk *walk)
{
skcipher_unmap(&walk->out, walk->dst.virt.addr);
scatterwalk_unmap(walk->dst.virt.addr);
}
static inline gfp_t skcipher_walk_gfp(struct skcipher_walk *walk)