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authorLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 05:29:54 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2022-12-13 05:29:54 +0300
commit75f4d9af8b67d7415afe50afcb4e96fd0bbd3ae2 (patch)
treeccc9f8e2359d27bc38e8b001f6af563bc437981f /lib
parent268369b171ff1be6a68ae8f33d0602c6bea48d2e (diff)
parentde4eda9de2d957ef2d6a8365a01e26a435e958cb (diff)
downloadlinux-75f4d9af8b67d7415afe50afcb4e96fd0bbd3ae2.tar.xz
Merge tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull iov_iter updates from Al Viro: "iov_iter work; most of that is about getting rid of direction misannotations and (hopefully) preventing more of the same for the future" * tag 'pull-iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: use less confusing names for iov_iter direction initializers iov_iter: saner checks for attempt to copy to/from iterator [xen] fix "direction" argument of iov_iter_kvec() [vhost] fix 'direction' argument of iov_iter_{init,bvec}() [target] fix iov_iter_bvec() "direction" argument [s390] memcpy_real(): WRITE is "data source", not destination... [s390] zcore: WRITE is "data source", not destination... [infiniband] READ is "data destination", not source... [fsi] WRITE is "data source", not destination... [s390] copy_oldmem_kernel() - WRITE is "data source", not destination csum_and_copy_to_iter(): handle ITER_DISCARD get rid of unlikely() on page_copy_sane() calls
Diffstat (limited to 'lib')
-rw-r--r--lib/iov_iter.c50
1 files changed, 28 insertions, 22 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index c3ca28ca68a6..98e8425b060d 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -520,6 +520,8 @@ static size_t csum_and_copy_to_pipe_iter(const void *addr, size_t bytes,
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
+ if (WARN_ON_ONCE(i->data_source))
+ return 0;
if (unlikely(iov_iter_is_pipe(i)))
return copy_pipe_to_iter(addr, bytes, i);
if (user_backed_iter(i))
@@ -606,6 +608,8 @@ static size_t copy_mc_pipe_to_iter(const void *addr, size_t bytes,
*/
size_t _copy_mc_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
+ if (WARN_ON_ONCE(i->data_source))
+ return 0;
if (unlikely(iov_iter_is_pipe(i)))
return copy_mc_pipe_to_iter(addr, bytes, i);
if (user_backed_iter(i))
@@ -622,10 +626,9 @@ EXPORT_SYMBOL_GPL(_copy_mc_to_iter);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
- if (unlikely(iov_iter_is_pipe(i))) {
- WARN_ON(1);
+ if (WARN_ON_ONCE(!i->data_source))
return 0;
- }
+
if (user_backed_iter(i))
might_fault();
iterate_and_advance(i, bytes, base, len, off,
@@ -639,10 +642,9 @@ EXPORT_SYMBOL(_copy_from_iter);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
- if (unlikely(iov_iter_is_pipe(i))) {
- WARN_ON(1);
+ if (WARN_ON_ONCE(!i->data_source))
return 0;
- }
+
iterate_and_advance(i, bytes, base, len, off,
__copy_from_user_inatomic_nocache(addr + off, base, len),
memcpy(addr + off, base, len)
@@ -671,10 +673,9 @@ EXPORT_SYMBOL(_copy_from_iter_nocache);
*/
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
{
- if (unlikely(iov_iter_is_pipe(i))) {
- WARN_ON(1);
+ if (WARN_ON_ONCE(!i->data_source))
return 0;
- }
+
iterate_and_advance(i, bytes, base, len, off,
__copy_from_user_flushcache(addr + off, base, len),
memcpy_flushcache(addr + off, base, len)
@@ -703,17 +704,18 @@ static inline bool page_copy_sane(struct page *page, size_t offset, size_t n)
head = compound_head(page);
v += (page - head) << PAGE_SHIFT;
- if (likely(n <= v && v <= (page_size(head))))
- return true;
- WARN_ON(1);
- return false;
+ if (WARN_ON(n > v || v > page_size(head)))
+ return false;
+ return true;
}
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i)
{
size_t res = 0;
- if (unlikely(!page_copy_sane(page, offset, bytes)))
+ if (!page_copy_sane(page, offset, bytes))
+ return 0;
+ if (WARN_ON_ONCE(i->data_source))
return 0;
if (unlikely(iov_iter_is_pipe(i)))
return copy_page_to_iter_pipe(page, offset, bytes, i);
@@ -808,13 +810,12 @@ size_t copy_page_from_iter_atomic(struct page *page, unsigned offset, size_t byt
struct iov_iter *i)
{
char *kaddr = kmap_atomic(page), *p = kaddr + offset;
- if (unlikely(!page_copy_sane(page, offset, bytes))) {
+ if (!page_copy_sane(page, offset, bytes)) {
kunmap_atomic(kaddr);
return 0;
}
- if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
+ if (WARN_ON_ONCE(!i->data_source)) {
kunmap_atomic(kaddr);
- WARN_ON(1);
return 0;
}
iterate_and_advance(i, bytes, base, len, off,
@@ -1526,10 +1527,9 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
{
__wsum sum, next;
sum = *csum;
- if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
- WARN_ON(1);
+ if (WARN_ON_ONCE(!i->data_source))
return 0;
- }
+
iterate_and_advance(i, bytes, base, len, off, ({
next = csum_and_copy_from_user(base, addr + off, len);
sum = csum_block_add(sum, next, off);
@@ -1549,9 +1549,15 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, void *_csstate,
struct csum_state *csstate = _csstate;
__wsum sum, next;
- if (unlikely(iov_iter_is_discard(i))) {
- WARN_ON(1); /* for now */
+ if (WARN_ON_ONCE(i->data_source))
return 0;
+ if (unlikely(iov_iter_is_discard(i))) {
+ // can't use csum_memcpy() for that one - data is not copied
+ csstate->csum = csum_block_add(csstate->csum,
+ csum_partial(addr, bytes, 0),
+ csstate->off);
+ csstate->off += bytes;
+ return bytes;
}
sum = csum_shift(csstate->csum, csstate->off);