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Date: Sun, 6 Jun 2021 19:10:23 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
David Sterba <dsterba@...e.com>,
Miklos Szeredi <miklos@...redi.hu>,
Anton Altaparmakov <anton@...era.com>,
David Howells <dhowells@...hat.com>,
Matthew Wilcox <willy@...radead.org>,
Pavel Begunkov <asml.silence@...il.com>
Subject: [RFC PATCH 09/37] iov_iter: switch ..._full() variants of primitives to use of iov_iter_revert()
Use corresponding plain variants, revert on short copy. That's the way it
should've been done from the very beginning, except that we didn't have
iov_iter_revert() back then...
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
include/linux/uio.h | 32 ++++++++++------
lib/iov_iter.c | 104 ----------------------------------------------------
2 files changed, 21 insertions(+), 115 deletions(-)
diff --git a/include/linux/uio.h b/include/linux/uio.h
index 74a401f04bd3..c697c23138b5 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -132,9 +132,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i);
-bool _copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i);
-bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i);
static __always_inline __must_check
size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
@@ -157,10 +155,11 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
static __always_inline __must_check
bool copy_from_iter_full(void *addr, size_t bytes, struct iov_iter *i)
{
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return false;
- else
- return _copy_from_iter_full(addr, bytes, i);
+ size_t copied = copy_from_iter(addr, bytes, i);
+ if (likely(copied == bytes))
+ return true;
+ iov_iter_revert(i, bytes - copied);
+ return false;
}
static __always_inline __must_check
@@ -175,10 +174,11 @@ size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
static __always_inline __must_check
bool copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
- if (unlikely(!check_copy_size(addr, bytes, false)))
- return false;
- else
- return _copy_from_iter_full_nocache(addr, bytes, i);
+ size_t copied = copy_from_iter_nocache(addr, bytes, i);
+ if (likely(copied == bytes))
+ return true;
+ iov_iter_revert(i, bytes - copied);
+ return false;
}
#ifdef CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
@@ -278,7 +278,17 @@ struct csum_state {
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *csstate, struct iov_iter *i);
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
-bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
+
+static __always_inline __must_check
+bool csum_and_copy_from_iter_full(void *addr, size_t bytes,
+ __wsum *csum, struct iov_iter *i)
+{
+ size_t copied = csum_and_copy_from_iter(addr, bytes, csum, i);
+ if (likely(copied == bytes))
+ return true;
+ iov_iter_revert(i, bytes - copied);
+ return false;
+}
size_t hash_and_copy_to_iter(const void *addr, size_t bytes, void *hashp,
struct iov_iter *i);
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index bdbe6691457d..ce9f8b9168ea 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -819,35 +819,6 @@ 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(iov_iter_is_pipe(i))) {
- WARN_ON(1);
- return false;
- }
- if (unlikely(i->count < bytes))
- return false;
-
- if (iter_is_iovec(i))
- might_fault();
- iterate_all_kinds(i, bytes, v, ({
- if (copyin((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),
- memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
- v.bv_offset, v.bv_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;
@@ -907,32 +878,6 @@ size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
#endif
-bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
-{
- char *to = addr;
- if (unlikely(iov_iter_is_pipe(i))) {
- WARN_ON(1);
- return false;
- }
- if (unlikely(i->count < bytes))
- return false;
- iterate_all_kinds(i, bytes, v, ({
- if (__copy_from_user_inatomic_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),
- memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
- v.bv_offset, v.bv_len)
- )
-
- iov_iter_advance(i, bytes);
- return true;
-}
-EXPORT_SYMBOL(_copy_from_iter_full_nocache);
-
static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
{
struct page *head;
@@ -1740,55 +1685,6 @@ 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(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
- WARN_ON(1);
- return false;
- }
- if (unlikely(i->count < bytes))
- return false;
- iterate_all_kinds(i, bytes, v, ({
- next = csum_and_copy_from_user(v.iov_base,
- (to += v.iov_len) - v.iov_len,
- v.iov_len);
- if (!next)
- return false;
- sum = csum_block_add(sum, next, off);
- off += v.iov_len;
- 0;
- }), ({
- char *p = kmap_atomic(v.bv_page);
- sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,
- p + v.bv_offset, v.bv_len,
- sum, off);
- kunmap_atomic(p);
- off += v.bv_len;
- }),({
- sum = csum_and_memcpy((to += v.iov_len) - v.iov_len,
- v.iov_base, v.iov_len,
- sum, off);
- off += v.iov_len;
- }), ({
- char *p = kmap_atomic(v.bv_page);
- sum = csum_and_memcpy((to += v.bv_len) - v.bv_len,
- p + v.bv_offset, v.bv_len,
- sum, off);
- kunmap_atomic(p);
- off += v.bv_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, void *_csstate,
struct iov_iter *i)
{
--
2.11.0
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