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Subject[PATCH 13/29] iov_iter: Split copy_page_from_iter()
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Date
Split copy_page_from_iter() by type.

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

lib/iov_iter.c | 39 +++++++++++++++++++++------------------
1 file changed, 21 insertions(+), 18 deletions(-)

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 544e532e3e9f..54029aeab3ec 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -344,7 +344,7 @@ static size_t iovec_copy_page_to_iter(struct page *page, size_t offset, size_t b
return wanted - bytes;
}

-static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t bytes,
+static size_t iovec_copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
size_t skip, copy, left, wanted;
@@ -352,6 +352,8 @@ static size_t copy_page_from_iter_iovec(struct page *page, size_t offset, size_t
char __user *buf;
void *kaddr, *to;

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

@@ -1120,22 +1122,23 @@ static size_t discard_copy_page_to_iter(struct page *page, size_t offset, size_t
return bytes;
}

-static size_t xxx_copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
+static size_t bkvec_copy_page_from_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 (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
- WARN_ON(1);
- 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_from_iter(kaddr + offset, bytes, i);
+ wanted = copy_from_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
- return wanted;
- } else
- return copy_page_from_iter_iovec(page, offset, bytes, i);
+ }
+ return wanted;
+}
+
+static size_t no_copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
+ struct iov_iter *i)
+{
+ WARN_ON(1);
+ return 0;
}

static size_t pipe_zero(size_t bytes, struct iov_iter *i)
@@ -2035,7 +2038,7 @@ static const struct iov_iter_ops iovec_iter_ops = {
.fault_in_readable = iovec_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
.copy_page_to_iter = iovec_copy_page_to_iter,
- .copy_page_from_iter = xxx_copy_page_from_iter,
+ .copy_page_from_iter = iovec_copy_page_from_iter,
.copy_to_iter = iovec_copy_to_iter,
.copy_from_iter = iovec_copy_from_iter,
.copy_from_iter_full = iovec_copy_from_iter_full,
@@ -2069,7 +2072,7 @@ static const struct iov_iter_ops kvec_iter_ops = {
.fault_in_readable = no_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
.copy_page_to_iter = bkvec_copy_page_to_iter,
- .copy_page_from_iter = xxx_copy_page_from_iter,
+ .copy_page_from_iter = bkvec_copy_page_from_iter,
.copy_to_iter = kvec_copy_to_iter,
.copy_from_iter = kvec_copy_from_iter,
.copy_from_iter_full = kvec_copy_from_iter_full,
@@ -2103,7 +2106,7 @@ static const struct iov_iter_ops bvec_iter_ops = {
.fault_in_readable = no_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
.copy_page_to_iter = bkvec_copy_page_to_iter,
- .copy_page_from_iter = xxx_copy_page_from_iter,
+ .copy_page_from_iter = bkvec_copy_page_from_iter,
.copy_to_iter = bvec_copy_to_iter,
.copy_from_iter = bvec_copy_from_iter,
.copy_from_iter_full = bvec_copy_from_iter_full,
@@ -2137,7 +2140,7 @@ static const struct iov_iter_ops pipe_iter_ops = {
.fault_in_readable = no_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
.copy_page_to_iter = pipe_copy_page_to_iter,
- .copy_page_from_iter = xxx_copy_page_from_iter,
+ .copy_page_from_iter = no_copy_page_from_iter,
.copy_to_iter = pipe_copy_to_iter,
.copy_from_iter = no_copy_from_iter,
.copy_from_iter_full = no_copy_from_iter_full,
@@ -2171,7 +2174,7 @@ static const struct iov_iter_ops discard_iter_ops = {
.fault_in_readable = no_fault_in_readable,
.single_seg_count = xxx_single_seg_count,
.copy_page_to_iter = discard_copy_page_to_iter,
- .copy_page_from_iter = xxx_copy_page_from_iter,
+ .copy_page_from_iter = no_copy_page_from_iter,
.copy_to_iter = discard_copy_to_iter,
.copy_from_iter = no_copy_from_iter,
.copy_from_iter_full = no_copy_from_iter_full,

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