iov_iter.c: handle ITER_KVEC directly
... without bothering with copy_..._user() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
Родитель
3d4d3e4826
Коммит
a280455fa8
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@ -31,6 +31,7 @@ struct iov_iter {
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size_t count;
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union {
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const struct iovec *iov;
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const struct kvec *kvec;
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const struct bio_vec *bvec;
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};
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unsigned long nr_segs;
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@ -32,6 +32,29 @@
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n = wanted - n; \
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}
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#define iterate_kvec(i, n, __v, __p, skip, STEP) { \
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size_t wanted = n; \
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__p = i->kvec; \
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__v.iov_len = min(n, __p->iov_len - skip); \
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if (likely(__v.iov_len)) { \
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__v.iov_base = __p->iov_base + skip; \
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(void)(STEP); \
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skip += __v.iov_len; \
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n -= __v.iov_len; \
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} \
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while (unlikely(n)) { \
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__p++; \
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__v.iov_len = min(n, __p->iov_len); \
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if (unlikely(!__v.iov_len)) \
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continue; \
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__v.iov_base = __p->iov_base; \
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(void)(STEP); \
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skip = __v.iov_len; \
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n -= __v.iov_len; \
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} \
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n = wanted; \
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}
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#define iterate_bvec(i, n, __v, __p, skip, STEP) { \
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size_t wanted = n; \
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__p = i->bvec; \
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@ -57,12 +80,16 @@
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n = wanted; \
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}
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#define iterate_all_kinds(i, n, v, I, B) { \
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#define iterate_all_kinds(i, n, v, I, B, K) { \
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size_t skip = i->iov_offset; \
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if (unlikely(i->type & ITER_BVEC)) { \
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const struct bio_vec *bvec; \
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struct bio_vec v; \
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iterate_bvec(i, n, v, bvec, skip, (B)) \
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} else if (unlikely(i->type & ITER_KVEC)) { \
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const struct kvec *kvec; \
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struct kvec v; \
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iterate_kvec(i, n, v, kvec, skip, (K)) \
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} else { \
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const struct iovec *iov; \
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struct iovec v; \
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@ -70,7 +97,7 @@
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} \
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}
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#define iterate_and_advance(i, n, v, I, B) { \
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#define iterate_and_advance(i, n, v, I, B, K) { \
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size_t skip = i->iov_offset; \
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if (unlikely(i->type & ITER_BVEC)) { \
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const struct bio_vec *bvec; \
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@ -82,6 +109,16 @@
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} \
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i->nr_segs -= bvec - i->bvec; \
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i->bvec = bvec; \
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} else if (unlikely(i->type & ITER_KVEC)) { \
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const struct kvec *kvec; \
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struct kvec v; \
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iterate_kvec(i, n, v, kvec, skip, (K)) \
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if (skip == kvec->iov_len) { \
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kvec++; \
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skip = 0; \
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} \
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i->nr_segs -= kvec - i->kvec; \
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i->kvec = kvec; \
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} else { \
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const struct iovec *iov; \
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struct iovec v; \
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@ -270,7 +307,7 @@ done:
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*/
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int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
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{
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if (!(i->type & ITER_BVEC)) {
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if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
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char __user *buf = i->iov->iov_base + i->iov_offset;
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bytes = min(bytes, i->iov->iov_len - i->iov_offset);
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return fault_in_pages_readable(buf, bytes);
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@ -284,10 +321,14 @@ void iov_iter_init(struct iov_iter *i, int direction,
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size_t count)
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{
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/* It will get better. Eventually... */
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if (segment_eq(get_fs(), KERNEL_DS))
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if (segment_eq(get_fs(), KERNEL_DS)) {
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direction |= ITER_KVEC;
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i->type = direction;
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i->iov = iov;
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i->type = direction;
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i->kvec = (struct kvec *)iov;
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} else {
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i->type = direction;
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i->iov = iov;
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}
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i->nr_segs = nr_segs;
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i->iov_offset = 0;
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i->count = count;
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@ -328,7 +369,8 @@ size_t copy_to_iter(void *addr, size_t bytes, struct iov_iter *i)
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__copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len,
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v.iov_len),
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memcpy_to_page(v.bv_page, v.bv_offset,
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(from += v.bv_len) - v.bv_len, v.bv_len)
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(from += v.bv_len) - v.bv_len, v.bv_len),
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memcpy(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len)
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)
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return bytes;
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@ -348,7 +390,8 @@ size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
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__copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base,
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v.iov_len),
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memcpy_from_page((to += v.bv_len) - v.bv_len, v.bv_page,
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v.bv_offset, v.bv_len)
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v.bv_offset, v.bv_len),
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memcpy((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
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)
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return bytes;
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@ -371,7 +414,7 @@ EXPORT_SYMBOL(copy_page_to_iter);
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size_t copy_page_from_iter(struct page *page, size_t offset, size_t bytes,
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struct iov_iter *i)
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{
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if (i->type & ITER_BVEC) {
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if (i->type & (ITER_BVEC|ITER_KVEC)) {
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void *kaddr = kmap_atomic(page);
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size_t wanted = copy_from_iter(kaddr + offset, bytes, i);
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kunmap_atomic(kaddr);
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@ -391,7 +434,8 @@ size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
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iterate_and_advance(i, bytes, v,
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__clear_user(v.iov_base, v.iov_len),
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memzero_page(v.bv_page, v.bv_offset, v.bv_len)
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memzero_page(v.bv_page, v.bv_offset, v.bv_len),
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memset(v.iov_base, 0, v.iov_len)
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)
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return bytes;
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@ -406,7 +450,8 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
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__copy_from_user_inatomic((p += v.iov_len) - v.iov_len,
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v.iov_base, v.iov_len),
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memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page,
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v.bv_offset, v.bv_len)
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v.bv_offset, v.bv_len),
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memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
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)
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kunmap_atomic(kaddr);
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return bytes;
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@ -415,7 +460,7 @@ EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
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void iov_iter_advance(struct iov_iter *i, size_t size)
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{
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iterate_and_advance(i, size, v, 0, 0)
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iterate_and_advance(i, size, v, 0, 0, 0)
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}
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EXPORT_SYMBOL(iov_iter_advance);
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@ -443,7 +488,8 @@ unsigned long iov_iter_alignment(const struct iov_iter *i)
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iterate_all_kinds(i, size, v,
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(res |= (unsigned long)v.iov_base | v.iov_len, 0),
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res |= v.bv_offset | v.bv_len
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res |= v.bv_offset | v.bv_len,
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res |= (unsigned long)v.iov_base | v.iov_len
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)
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return res;
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}
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@ -478,6 +524,8 @@ ssize_t iov_iter_get_pages(struct iov_iter *i,
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*start = v.bv_offset;
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get_page(*pages = v.bv_page);
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return v.bv_len;
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}),({
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return -EFAULT;
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})
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)
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return 0;
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@ -530,6 +578,8 @@ ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
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return -ENOMEM;
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get_page(*p = v.bv_page);
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return v.bv_len;
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}),({
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return -EFAULT;
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})
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)
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return 0;
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@ -554,6 +604,12 @@ int iov_iter_npages(const struct iov_iter *i, int maxpages)
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npages++;
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if (npages >= maxpages)
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return maxpages;
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}),({
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unsigned long p = (unsigned long)v.iov_base;
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npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
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- p / PAGE_SIZE;
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if (npages >= maxpages)
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return maxpages;
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})
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)
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return npages;
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