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authorAl Viro <viro@zeniv.linux.org.uk>2016-11-01 22:09:04 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-12-05 14:33:36 -0500
commitcbbd26b8b1a6af9c02e2b6523e12bd50cc765059 (patch)
tree6d1b258c99e83f320cf3611bdc927121df7e9b03 /lib/iov_iter.c
parente5517c2a5a49ed5e99047008629f1cd60246ea0e (diff)
downloadlinux-cbbd26b8b1a6af9c02e2b6523e12bd50cc765059.tar.bz2
[iov_iter] new primitives - copy_from_iter_full() and friends
copy_from_iter_full(), copy_from_iter_full_nocache() and csum_and_copy_from_iter_full() - counterparts of copy_from_iter() et.al., advancing iterator only in case of successful full copy and returning whether it had been successful or not. Convert some obvious users. *NOTE* - do not blindly assume that something is a good candidate for those unless you are sure that not advancing iov_iter in failure case is the right thing in this case. Anything that does short read/short write kind of stuff (or is in a loop, etc.) is unlikely to be a good one. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'lib/iov_iter.c')
-rw-r--r--lib/iov_iter.c98
1 files changed, 96 insertions, 2 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f2bd21b93dfc..83c00b7f59b5 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -568,6 +568,31 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
}
EXPORT_SYMBOL(copy_from_iter);
+bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
+{
+ char *to = addr;
+ if (unlikely(i->type & ITER_PIPE)) {
+ WARN_ON(1);
+ return false;
+ }
+ if (unlikely(i->count < bytes)) \
+ return false;
+
+ iterate_all_kinds(i, bytes, v, ({
+ if (__copy_from_user((to += v.iov_len) - v.iov_len,
+ v.iov_base, v.iov_len))
+ return false;
+ 0;}),
+ 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)
+ )
+
+ iov_iter_advance(i, bytes);
+ return true;
+}
+EXPORT_SYMBOL(copy_from_iter_full);
+
size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
@@ -587,6 +612,30 @@ size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
}
EXPORT_SYMBOL(copy_from_iter_nocache);
+bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
+{
+ char *to = addr;
+ if (unlikely(i->type & ITER_PIPE)) {
+ WARN_ON(1);
+ return false;
+ }
+ if (unlikely(i->count < bytes)) \
+ return false;
+ iterate_all_kinds(i, bytes, v, ({
+ if (__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
+ v.iov_base, v.iov_len))
+ return false;
+ 0;}),
+ 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)
+ )
+
+ iov_iter_advance(i, bytes);
+ return true;
+}
+EXPORT_SYMBOL(copy_from_iter_full_nocache);
+
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
@@ -1008,7 +1057,7 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
}
iterate_and_advance(i, bytes, v, ({
int err = 0;
- next = csum_and_copy_from_user(v.iov_base,
+ next = csum_and_copy_from_user(v.iov_base,
(to += v.iov_len) - v.iov_len,
v.iov_len, 0, &err);
if (!err) {
@@ -1037,6 +1086,51 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
}
EXPORT_SYMBOL(csum_and_copy_from_iter);
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
+ struct iov_iter *i)
+{
+ char *to = addr;
+ __wsum sum, next;
+ size_t off = 0;
+ sum = *csum;
+ if (unlikely(i->type & ITER_PIPE)) {
+ WARN_ON(1);
+ return false;
+ }
+ if (unlikely(i->count < bytes))
+ return false;
+ iterate_all_kinds(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)
+ return false;
+ sum = csum_block_add(sum, next, off);
+ off += 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;
+ iov_iter_advance(i, bytes);
+ return true;
+}
+EXPORT_SYMBOL(csum_and_copy_from_iter_full);
+
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
struct iov_iter *i)
{
@@ -1051,7 +1145,7 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *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_base,
v.iov_len, 0, &err);
if (!err) {
sum = csum_block_add(sum, next, off);