csum_and_copy_..._iter()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 6e16945..28ed2d9 100644 (file)
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -124,6 +124,8 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
 {
        i->count = count;
 }
+size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
 
 int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len);
 int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len);

diff --git a/mm/iov_iter.c b/mm/iov_iter.c
index 1618e37..1d2cdeb 100644 (file)
--- 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 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
 }
 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;