csum_and_copy_..._iter()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 1618e37..1d2cdeb 100644
--- a/mm/iov_iter.c
+++ b/mm/iov_iter.c
@@ -3,6 +3,7 @@
#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
+#include <net/checksum.h>
#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
size_t left; \
@@ -586,6 +587,94 @@
}
EXPORT_SYMBOL(iov_iter_get_pages_alloc);
+size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
+ struct iov_iter *i)
+{
+ char *to = addr;
+ __wsum sum, next;
+ size_t off = 0;
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ sum = *csum;
+ iterate_and_advance(i, bytes, v, ({
+ int err = 0;
+ next = csum_and_copy_from_user(v.iov_base,
+ (to += v.iov_len) - v.iov_len,
+ v.iov_len, 0, &err);
+ if (!err) {
+ sum = csum_block_add(sum, next, off);
+ off += v.iov_len;
+ }
+ err ? v.iov_len : 0;
+ }), ({
+ char *p = kmap_atomic(v.bv_page);
+ next = csum_partial_copy_nocheck(p + v.bv_offset,
+ (to += v.bv_len) - v.bv_len,
+ v.bv_len, 0);
+ kunmap_atomic(p);
+ sum = csum_block_add(sum, next, off);
+ off += v.bv_len;
+ }),({
+ next = csum_partial_copy_nocheck(v.iov_base,
+ (to += v.iov_len) - v.iov_len,
+ v.iov_len, 0);
+ sum = csum_block_add(sum, next, off);
+ off += v.iov_len;
+ })
+ )
+ *csum = sum;
+ return bytes;
+}
+EXPORT_SYMBOL(csum_and_copy_from_iter);
+
+size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum,
+ struct iov_iter *i)
+{
+ char *from = addr;
+ __wsum sum, next;
+ size_t off = 0;
+ if (unlikely(bytes > i->count))
+ bytes = i->count;
+
+ if (unlikely(!bytes))
+ return 0;
+
+ sum = *csum;
+ iterate_and_advance(i, bytes, v, ({
+ int err = 0;
+ next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
+ v.iov_base,
+ v.iov_len, 0, &err);
+ if (!err) {
+ sum = csum_block_add(sum, next, off);
+ off += v.iov_len;
+ }
+ err ? v.iov_len : 0;
+ }), ({
+ char *p = kmap_atomic(v.bv_page);
+ next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
+ p + v.bv_offset,
+ v.bv_len, 0);
+ kunmap_atomic(p);
+ sum = csum_block_add(sum, next, off);
+ off += v.bv_len;
+ }),({
+ next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
+ v.iov_base,
+ v.iov_len, 0);
+ sum = csum_block_add(sum, next, off);
+ off += v.iov_len;
+ })
+ )
+ *csum = sum;
+ return bytes;
+}
+EXPORT_SYMBOL(csum_and_copy_to_iter);
+
int iov_iter_npages(const struct iov_iter *i, int maxpages)
{
size_t size = i->count;
