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Subject[PATCH 02/29] iov_iter: Split copy_page_to_iter()
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Date
Split copy_page_to_iter() by type.

Signed-off-by: David Howells <dhowells@redhat.com>
---

lib/iov_iter.c | 44 +++++++++++++++++++++++++-------------------
1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index e403d524c797..fee8e99fbb9c 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -19,6 +19,8 @@ static const struct iov_iter_ops bvec_iter_ops;
static const struct iov_iter_ops pipe_iter_ops;
static const struct iov_iter_ops discard_iter_ops;

+static inline bool page_copy_sane(struct page *page, size_t offset, size_t n);
+
#define PIPE_PARANOIA /* for now */

#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
@@ -167,7 +169,7 @@ static int copyin(void *to, const void __user *from, size_t n)
return n;
}

-static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes,
+static size_t iovec_copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
size_t skip, copy, left, wanted;
@@ -175,6 +177,8 @@ static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t b
char __user *buf;
void *kaddr, *from;

+ if (unlikely(!page_copy_sane(page, offset, bytes)))
+ return 0;
if (unlikely(bytes > i->count))
bytes = i->count;

@@ -378,7 +382,7 @@ static bool sanity(const struct iov_iter *i)
#define sanity(i) true
#endif

-static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t bytes,
+static size_t pipe_copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
struct pipe_inode_info *pipe = i->pipe;
@@ -388,6 +392,8 @@ static size_t copy_page_to_iter_pipe(struct page *page, size_t offset, size_t by
unsigned int i_head = i->head;
size_t off;

+ if (unlikely(!page_copy_sane(page, offset, bytes)))
+ return 0;
if (unlikely(bytes > i->count))
bytes = i->count;

@@ -910,22 +916,22 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
return false;
}

-static size_t xxx_copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
+static size_t bkvec_copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
- if (unlikely(!page_copy_sane(page, offset, bytes)))
- return 0;
- if (iov_iter_type(i) & (ITER_BVEC|ITER_KVEC)) {
+ size_t wanted = 0;
+ if (likely(page_copy_sane(page, offset, bytes))) {
void *kaddr = kmap_atomic(page);
- size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
+ wanted = copy_to_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
- return wanted;
- } else if (unlikely(iov_iter_is_discard(i)))
- return bytes;
- else if (likely(!iov_iter_is_pipe(i)))
- return copy_page_to_iter_iovec(page, offset, bytes, i);
- else
- return copy_page_to_iter_pipe(page, offset, bytes, i);
+ }
+ return wanted;
+}
+
+static size_t discard_copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ return bytes;
}

static size_t xxx_copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
@@ -1842,7 +1848,7 @@ static const struct iov_iter_ops iovec_iter_ops = {
.revert = xxx_revert,
.fault_in_readable = xxx_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
- .copy_page_to_iter = xxx_copy_page_to_iter,
+ .copy_page_to_iter = iovec_copy_page_to_iter,
.copy_page_from_iter = xxx_copy_page_from_iter,
.copy_to_iter = xxx_copy_to_iter,
.copy_from_iter = xxx_copy_from_iter,
@@ -1876,7 +1882,7 @@ static const struct iov_iter_ops kvec_iter_ops = {
.revert = xxx_revert,
.fault_in_readable = xxx_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
- .copy_page_to_iter = xxx_copy_page_to_iter,
+ .copy_page_to_iter = bkvec_copy_page_to_iter,
.copy_page_from_iter = xxx_copy_page_from_iter,
.copy_to_iter = xxx_copy_to_iter,
.copy_from_iter = xxx_copy_from_iter,
@@ -1910,7 +1916,7 @@ static const struct iov_iter_ops bvec_iter_ops = {
.revert = xxx_revert,
.fault_in_readable = xxx_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
- .copy_page_to_iter = xxx_copy_page_to_iter,
+ .copy_page_to_iter = bkvec_copy_page_to_iter,
.copy_page_from_iter = xxx_copy_page_from_iter,
.copy_to_iter = xxx_copy_to_iter,
.copy_from_iter = xxx_copy_from_iter,
@@ -1944,7 +1950,7 @@ static const struct iov_iter_ops pipe_iter_ops = {
.revert = xxx_revert,
.fault_in_readable = xxx_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
- .copy_page_to_iter = xxx_copy_page_to_iter,
+ .copy_page_to_iter = pipe_copy_page_to_iter,
.copy_page_from_iter = xxx_copy_page_from_iter,
.copy_to_iter = xxx_copy_to_iter,
.copy_from_iter = xxx_copy_from_iter,
@@ -1978,7 +1984,7 @@ static const struct iov_iter_ops discard_iter_ops = {
.revert = xxx_revert,
.fault_in_readable = xxx_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
- .copy_page_to_iter = xxx_copy_page_to_iter,
+ .copy_page_to_iter = discard_copy_page_to_iter,
.copy_page_from_iter = xxx_copy_page_from_iter,
.copy_to_iter = xxx_copy_to_iter,
.copy_from_iter = xxx_copy_from_iter,

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