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-rw-r--r--lib/iov_iter.c125
1 files changed, 84 insertions, 41 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 8be175df3075..7ebccb5c1637 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -83,6 +83,7 @@
const struct kvec *kvec; \
struct kvec v; \
iterate_kvec(i, n, v, kvec, skip, (K)) \
+ } else if (unlikely(i->type & ITER_DISCARD)) { \
} else { \
const struct iovec *iov; \
struct iovec v; \
@@ -114,6 +115,8 @@
} \
i->nr_segs -= kvec - i->kvec; \
i->kvec = kvec; \
+ } else if (unlikely(i->type & ITER_DISCARD)) { \
+ skip += n; \
} else { \
const struct iovec *iov; \
struct iovec v; \
@@ -428,17 +431,19 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
}
EXPORT_SYMBOL(iov_iter_fault_in_readable);
-void iov_iter_init(struct iov_iter *i, int direction,
+void iov_iter_init(struct iov_iter *i, unsigned int direction,
const struct iovec *iov, unsigned long nr_segs,
size_t count)
{
+ WARN_ON(direction & ~(READ | WRITE));
+ direction &= READ | WRITE;
+
/* It will get better. Eventually... */
if (uaccess_kernel()) {
- direction |= ITER_KVEC;
- i->type = direction;
+ i->type = ITER_KVEC | direction;
i->kvec = (struct kvec *)iov;
} else {
- i->type = direction;
+ i->type = ITER_IOVEC | direction;
i->iov = iov;
}
i->nr_segs = nr_segs;
@@ -558,7 +563,7 @@ static size_t copy_pipe_to_iter(const void *addr, size_t bytes,
size_t _copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
{
const char *from = addr;
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return copy_pipe_to_iter(addr, bytes, i);
if (iter_is_iovec(i))
might_fault();
@@ -658,7 +663,7 @@ size_t _copy_to_iter_mcsafe(const void *addr, size_t bytes, struct iov_iter *i)
const char *from = addr;
unsigned long rem, curr_addr, s_addr = (unsigned long) addr;
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return copy_pipe_to_iter_mcsafe(addr, bytes, i);
if (iter_is_iovec(i))
might_fault();
@@ -692,7 +697,7 @@ EXPORT_SYMBOL_GPL(_copy_to_iter_mcsafe);
size_t _copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -712,7 +717,7 @@ 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)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return false;
}
@@ -739,7 +744,7 @@ EXPORT_SYMBOL(_copy_from_iter_full);
size_t _copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -773,7 +778,7 @@ EXPORT_SYMBOL(_copy_from_iter_nocache);
size_t _copy_from_iter_flushcache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return 0;
}
@@ -794,7 +799,7 @@ EXPORT_SYMBOL_GPL(_copy_from_iter_flushcache);
bool _copy_from_iter_full_nocache(void *addr, size_t bytes, struct iov_iter *i)
{
char *to = addr;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
WARN_ON(1);
return false;
}
@@ -836,7 +841,9 @@ size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
kunmap_atomic(kaddr);
return wanted;
- } else if (likely(!(i->type & ITER_PIPE)))
+ } 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);
@@ -848,7 +855,7 @@ size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
{
if (unlikely(!page_copy_sane(page, offset, bytes)))
return 0;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
WARN_ON(1);
return 0;
}
@@ -888,7 +895,7 @@ static size_t pipe_zero(size_t bytes, struct iov_iter *i)
size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
{
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_zero(bytes, i);
iterate_and_advance(i, bytes, v,
clear_user(v.iov_base, v.iov_len),
@@ -908,7 +915,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
kunmap_atomic(kaddr);
return 0;
}
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
kunmap_atomic(kaddr);
WARN_ON(1);
return 0;
@@ -972,10 +979,14 @@ static void pipe_advance(struct iov_iter *i, size_t size)
void iov_iter_advance(struct iov_iter *i, size_t size)
{
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
pipe_advance(i, size);
return;
}
+ if (unlikely(iov_iter_is_discard(i))) {
+ i->count -= size;
+ return;
+ }
iterate_and_advance(i, size, v, 0, 0, 0)
}
EXPORT_SYMBOL(iov_iter_advance);
@@ -987,7 +998,7 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
if (WARN_ON(unroll > MAX_RW_COUNT))
return;
i->count += unroll;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
struct pipe_inode_info *pipe = i->pipe;
int idx = i->idx;
size_t off = i->iov_offset;
@@ -1011,12 +1022,14 @@ void iov_iter_revert(struct iov_iter *i, size_t unroll)
pipe_truncate(i);
return;
}
+ if (unlikely(iov_iter_is_discard(i)))
+ return;
if (unroll <= i->iov_offset) {
i->iov_offset -= unroll;
return;
}
unroll -= i->iov_offset;
- if (i->type & ITER_BVEC) {
+ if (iov_iter_is_bvec(i)) {
const struct bio_vec *bvec = i->bvec;
while (1) {
size_t n = (--bvec)->bv_len;
@@ -1049,23 +1062,25 @@ EXPORT_SYMBOL(iov_iter_revert);
*/
size_t iov_iter_single_seg_count(const struct iov_iter *i)
{
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return i->count; // it is a silly place, anyway
if (i->nr_segs == 1)
return i->count;
- else if (i->type & ITER_BVEC)
+ if (unlikely(iov_iter_is_discard(i)))
+ return i->count;
+ else if (iov_iter_is_bvec(i))
return min(i->count, i->bvec->bv_len - i->iov_offset);
else
return min(i->count, i->iov->iov_len - i->iov_offset);
}
EXPORT_SYMBOL(iov_iter_single_seg_count);
-void iov_iter_kvec(struct iov_iter *i, int direction,
+void iov_iter_kvec(struct iov_iter *i, unsigned int direction,
const struct kvec *kvec, unsigned long nr_segs,
size_t count)
{
- BUG_ON(!(direction & ITER_KVEC));
- i->type = direction;
+ WARN_ON(direction & ~(READ | WRITE));
+ i->type = ITER_KVEC | (direction & (READ | WRITE));
i->kvec = kvec;
i->nr_segs = nr_segs;
i->iov_offset = 0;
@@ -1073,12 +1088,12 @@ void iov_iter_kvec(struct iov_iter *i, int direction,
}
EXPORT_SYMBOL(iov_iter_kvec);
-void iov_iter_bvec(struct iov_iter *i, int direction,
+void iov_iter_bvec(struct iov_iter *i, unsigned int direction,
const struct bio_vec *bvec, unsigned long nr_segs,
size_t count)
{
- BUG_ON(!(direction & ITER_BVEC));
- i->type = direction;
+ WARN_ON(direction & ~(READ | WRITE));
+ i->type = ITER_BVEC | (direction & (READ | WRITE));
i->bvec = bvec;
i->nr_segs = nr_segs;
i->iov_offset = 0;
@@ -1086,13 +1101,13 @@ void iov_iter_bvec(struct iov_iter *i, int direction,
}
EXPORT_SYMBOL(iov_iter_bvec);
-void iov_iter_pipe(struct iov_iter *i, int direction,
+void iov_iter_pipe(struct iov_iter *i, unsigned int direction,
struct pipe_inode_info *pipe,
size_t count)
{
- BUG_ON(direction != ITER_PIPE);
+ BUG_ON(direction != READ);
WARN_ON(pipe->nrbufs == pipe->buffers);
- i->type = direction;
+ i->type = ITER_PIPE | READ;
i->pipe = pipe;
i->idx = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
i->iov_offset = 0;
@@ -1101,12 +1116,30 @@ void iov_iter_pipe(struct iov_iter *i, int direction,
}
EXPORT_SYMBOL(iov_iter_pipe);
+/**
+ * iov_iter_discard - Initialise an I/O iterator that discards data
+ * @i: The iterator to initialise.
+ * @direction: The direction of the transfer.
+ * @count: The size of the I/O buffer in bytes.
+ *
+ * Set up an I/O iterator that just discards everything that's written to it.
+ * It's only available as a READ iterator.
+ */
+void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count)
+{
+ BUG_ON(direction != READ);
+ i->type = ITER_DISCARD | READ;
+ i->count = count;
+ i->iov_offset = 0;
+}
+EXPORT_SYMBOL(iov_iter_discard);
+
unsigned long iov_iter_alignment(const struct iov_iter *i)
{
unsigned long res = 0;
size_t size = i->count;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
if (size && i->iov_offset && allocated(&i->pipe->bufs[i->idx]))
return size | i->iov_offset;
return size;
@@ -1125,7 +1158,7 @@ unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
unsigned long res = 0;
size_t size = i->count;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
WARN_ON(1);
return ~0U;
}
@@ -1193,8 +1226,11 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
if (maxsize > i->count)
maxsize = i->count;
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_get_pages(i, pages, maxsize, maxpages, start);
+ if (unlikely(iov_iter_is_discard(i)))
+ return -EFAULT;
+
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -1205,7 +1241,7 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
len = maxpages * PAGE_SIZE;
addr &= ~(PAGE_SIZE - 1);
n = DIV_ROUND_UP(len, PAGE_SIZE);
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, pages);
+ res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, pages);
if (unlikely(res < 0))
return res;
return (res == n ? len : res * PAGE_SIZE) - *start;
@@ -1270,8 +1306,11 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
if (maxsize > i->count)
maxsize = i->count;
- if (unlikely(i->type & ITER_PIPE))
+ if (unlikely(iov_iter_is_pipe(i)))
return pipe_get_pages_alloc(i, pages, maxsize, start);
+ if (unlikely(iov_iter_is_discard(i)))
+ return -EFAULT;
+
iterate_all_kinds(i, maxsize, v, ({
unsigned long addr = (unsigned long)v.iov_base;
size_t len = v.iov_len + (*start = addr & (PAGE_SIZE - 1));
@@ -1283,7 +1322,7 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
p = get_pages_array(n);
if (!p)
return -ENOMEM;
- res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
+ res = get_user_pages_fast(addr, n, iov_iter_rw(i) != WRITE, p);
if (unlikely(res < 0)) {
kvfree(p);
return res;
@@ -1313,7 +1352,7 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
WARN_ON(1);
return 0;
}
@@ -1355,7 +1394,7 @@ bool csum_and_copy_from_iter_full(void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
WARN_ON(1);
return false;
}
@@ -1400,7 +1439,7 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
__wsum sum, next;
size_t off = 0;
sum = *csum;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i) || iov_iter_is_discard(i))) {
WARN_ON(1); /* for now */
return 0;
}
@@ -1442,8 +1481,10 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
if (!size)
return 0;
+ if (unlikely(iov_iter_is_discard(i)))
+ return 0;
- if (unlikely(i->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(i))) {
struct pipe_inode_info *pipe = i->pipe;
size_t off;
int idx;
@@ -1481,11 +1522,13 @@ EXPORT_SYMBOL(iov_iter_npages);
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
{
*new = *old;
- if (unlikely(new->type & ITER_PIPE)) {
+ if (unlikely(iov_iter_is_pipe(new))) {
WARN_ON(1);
return NULL;
}
- if (new->type & ITER_BVEC)
+ if (unlikely(iov_iter_is_discard(new)))
+ return NULL;
+ if (iov_iter_is_bvec(new))
return new->bvec = kmemdup(new->bvec,
new->nr_segs * sizeof(struct bio_vec),
flags);
generated by cgit v1.2.3-70-g09d2 (git 2.47.1) at 2024-12-28 07:56:15 +0000