Commit 21b56c84 authored by Al Viro's avatar Al Viro
Browse files

iov_iter: get rid of separate bvec and xarray callbacks 



After the previous commit we have
	* xarray and bvec callbacks idential in all cases
	* both equivalent to kvec callback wrapped into
kmap_local_page()/kunmap_local() pair.

So we can pass only two (iovec and kvec) callbacks to
iterate_and_advance() and let iterate_{bvec,xarray} wrap
it into kmap_local_page()/kunmap_local_page().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 1b4fb5ff

lib/iov_iter.c

+30 −82
Original line number Diff line number Diff line
@@ -42,18 +42,20 @@ 
	while (n) {						\

		unsigned offset = p->bv_offset + skip;		\

		unsigned left;					\

		__v.bv_offset = offset % PAGE_SIZE;		\

		__v.bv_page = p->bv_page + offset / PAGE_SIZE;	\

		__v.bv_len = min(min(n, p->bv_len - skip),	\

		void *kaddr = kmap_local_page(p->bv_page +	\

					offset / PAGE_SIZE);	\

		__v.iov_base = kaddr + offset % PAGE_SIZE;	\

		__v.iov_len = min(min(n, p->bv_len - skip),	\

		     (size_t)(PAGE_SIZE - offset % PAGE_SIZE));	\

		left = (STEP);					\

		__v.bv_len -= left;				\

		skip += __v.bv_len;				\

		kunmap_local(kaddr);				\

		__v.iov_len -= left;				\

		skip += __v.iov_len;				\

		if (skip == p->bv_len) {			\

			skip = 0;				\

			p++;					\

		}						\

		n -= __v.bv_len;				\

		n -= __v.iov_len;				\

		if (left)					\

			break;					\

	}							\
@@ -81,15 +83,16 @@ 
			break;						\

		for (j = (head->index < index) ? index - head->index : 0; \

		     j < thp_nr_pages(head); j++) {			\

			__v.bv_page = head + j;				\

			offset = (i->xarray_start + skip) & ~PAGE_MASK;	\

			void *kaddr = kmap_local_page(head + j);	\

			offset = (i->xarray_start + skip) % PAGE_SIZE;	\

			__v.iov_base = kaddr + offset;			\

			seg = PAGE_SIZE - offset;			\

			__v.bv_offset = offset;				\

			__v.bv_len = min(n, seg);			\

			__v.iov_len = min(n, seg);			\

			left = (STEP);					\

			__v.bv_len -= left;				\

			n -= __v.bv_len;				\

			skip += __v.bv_len;				\

			kunmap_local(kaddr);				\

			__v.iov_len -= left;				\

			n -= __v.iov_len;				\

			skip += __v.iov_len;				\

			if (left || n == 0)				\

				goto __out;				\

		}							\
@@ -99,7 +102,7 @@ __out: \ 
	n = wanted - n;						\

}



#define __iterate_and_advance(i, n, v, I, B, K, X) {		\

#define __iterate_and_advance(i, n, v, I, K) {			\

	if (unlikely(i->count < n))				\

		n = i->count;					\

	if (likely(n)) {					\
@@ -112,8 +115,8 @@ __out: \ 
			i->iov = iov;				\

		} else if (iov_iter_is_bvec(i)) {		\

			const struct bio_vec *bvec = i->bvec;	\

			struct bio_vec v;			\

			iterate_bvec(i, n, v, bvec, skip, (B))	\

			struct kvec v;				\

			iterate_bvec(i, n, v, bvec, skip, (K))	\

			i->nr_segs -= bvec - i->bvec;		\

			i->bvec = bvec;				\

		} else if (iov_iter_is_kvec(i)) {		\
@@ -123,16 +126,15 @@ __out: \ 
			i->nr_segs -= kvec - i->kvec;		\

			i->kvec = kvec;				\

		} else if (iov_iter_is_xarray(i)) {		\

			struct bio_vec v;			\

			iterate_xarray(i, n, v, skip, (X))	\

			struct kvec v;				\

			iterate_xarray(i, n, v, skip, (K))	\

		}						\

		i->count -= n;					\

		i->iov_offset = skip;				\

	}							\

}

#define iterate_and_advance(i, n, v, I, B, K, X) \

	__iterate_and_advance(i, n, v, I, ((void)(B),0),	\

				((void)(K),0), ((void)(X),0))

#define iterate_and_advance(i, n, v, I, K) \

	__iterate_and_advance(i, n, v, I, ((void)(K),0))



static int copyout(void __user *to, const void *from, size_t n)

{
@@ -612,11 +614,7 @@ size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 
		might_fault();

	iterate_and_advance(i, bytes, v,

		copyout(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),

		memcpy_to_page(v.bv_page, v.bv_offset,

			       (from += v.bv_len) - v.bv_len, v.bv_len),

		memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len),

		memcpy_to_page(v.bv_page, v.bv_offset,

			       (from += v.bv_len) - v.bv_len, v.bv_len)

		memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)

	)



	return bytes;
@@ -714,12 +712,8 @@ size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i) 
	__iterate_and_advance(i, bytes, v,

		copyout_mc(v.iov_base, (from += v.iov_len) - v.iov_len,

			   v.iov_len),

		copy_mc_to_page(v.bv_page, v.bv_offset,

				      (from += v.bv_len) - v.bv_len, v.bv_len),

		copy_mc_to_kernel(v.iov_base, (from += v.iov_len)

					- v.iov_len, v.iov_len),

		copy_mc_to_page(v.bv_page, v.bv_offset,

				      (from += v.bv_len) - v.bv_len, v.bv_len)

					- v.iov_len, v.iov_len)

	)



	return bytes;
@@ -738,11 +732,7 @@ size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) 
		might_fault();

	iterate_and_advance(i, bytes, v,

		copyin((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),

		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len),

		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),

		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len)

		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)

	)



	return bytes;
@@ -759,11 +749,7 @@ size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) 
	iterate_and_advance(i, bytes, v,

		__copy_from_user_inatomic_nocache((to += v.iov_len) - v.iov_len,

					 v.iov_base, v.iov_len),

		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len),

		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),

		memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len)

		memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)

	)



	return bytes;
@@ -795,12 +781,8 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i) 
	iterate_and_advance(i, bytes, v,

		__copy_from_user_flushcache((to += v.iov_len) - v.iov_len,

					 v.iov_base, v.iov_len),

		memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len),

		memcpy_flushcache((to += v.iov_len) - v.iov_len, v.iov_base,

			v.iov_len),

		memcpy_page_flushcache((to += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len)

			v.iov_len)

	)



	return bytes;
@@ -931,9 +913,7 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i) 
		return pipe_zero(bytes, i);

	iterate_and_advance(i, bytes, v,

		clear_user(v.iov_base, v.iov_len),

		memzero_page(v.bv_page, v.bv_offset, v.bv_len),

		memset(v.iov_base, 0, v.iov_len),

		memzero_page(v.bv_page, v.bv_offset, v.bv_len)

		memset(v.iov_base, 0, v.iov_len)

	)



	return bytes;
@@ -955,11 +935,7 @@ size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t byt 
	}

	iterate_and_advance(i, bytes, v,

		copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),

		memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len),

		memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len),

		memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,

				 v.bv_offset, v.bv_len)

		memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)

	)

	kunmap_atomic(kaddr);

	return bytes;
@@ -1697,25 +1673,11 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, 
			off += v.iov_len;

		}

		next ? 0 : v.iov_len;

	}), ({

		char *p = kmap_atomic(v.bv_page);

		sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,

				      p + v.bv_offset, v.bv_len,

				      sum, off);

		kunmap_atomic(p);

		off += v.bv_len;

	}), ({

		sum = csum_and_memcpy((to += v.iov_len) - v.iov_len,

				      v.iov_base, v.iov_len,

				      sum, off);

		off += v.iov_len;

	}), ({

		char *p = kmap_atomic(v.bv_page);

		sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,

				      p + v.bv_offset, v.bv_len,

				      sum, off);

		kunmap_atomic(p);

		off += v.bv_len;

	})

	)

	*csum = sum;
@@ -1749,25 +1711,11 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate, 
			off += v.iov_len;

		}

		next ? 0 : v.iov_len;

	}), ({

		char *p = kmap_atomic(v.bv_page);

		sum = csum_and_memcpy(p + v.bv_offset,

				      (from += v.bv_len) - v.bv_len,

				      v.bv_len, sum, off);

		kunmap_atomic(p);

		off += v.bv_len;

	}), ({

		sum = csum_and_memcpy(v.iov_base,

				     (from += v.iov_len) - v.iov_len,

				     v.iov_len, sum, off);

		off += v.iov_len;

	}), ({

		char *p = kmap_atomic(v.bv_page);

		sum = csum_and_memcpy(p + v.bv_offset,

				      (from += v.bv_len) - v.bv_len,

				      v.bv_len, sum, off);

		kunmap_atomic(p);

		off += v.bv_len;

	})

	)

	csstate->csum = csum_shift(sum, csstate->off);