840 lines
20 KiB
C
840 lines
20 KiB
C
#include <linux/export.h>
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#include <linux/uio.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <net/checksum.h>
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#define iterate_iovec(i, n, __v, __p, skip, STEP) { \
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size_t left; \
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size_t wanted = n; \
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__p = i->iov; \
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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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left = (STEP); \
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__v.iov_len -= left; \
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skip += __v.iov_len; \
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n -= __v.iov_len; \
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} else { \
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left = 0; \
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} \
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while (unlikely(!left && 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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left = (STEP); \
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__v.iov_len -= left; \
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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 - 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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__v.bv_len = min_t(size_t, n, __p->bv_len - skip); \
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if (likely(__v.bv_len)) { \
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__v.bv_page = __p->bv_page; \
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__v.bv_offset = __p->bv_offset + skip; \
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(void)(STEP); \
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skip += __v.bv_len; \
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n -= __v.bv_len; \
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} \
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while (unlikely(n)) { \
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__p++; \
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__v.bv_len = min_t(size_t, n, __p->bv_len); \
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if (unlikely(!__v.bv_len)) \
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continue; \
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__v.bv_page = __p->bv_page; \
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__v.bv_offset = __p->bv_offset; \
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(void)(STEP); \
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skip = __v.bv_len; \
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n -= __v.bv_len; \
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} \
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n = wanted; \
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}
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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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iterate_iovec(i, n, v, iov, skip, (I)) \
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} \
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}
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#define iterate_and_advance(i, n, v, I, B, K) { \
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if (unlikely(i->count < n)) \
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n = i->count; \
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if (i->count) { \
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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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if (skip == bvec->bv_len) { \
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bvec++; \
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skip = 0; \
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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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iterate_iovec(i, n, v, iov, skip, (I)) \
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if (skip == iov->iov_len) { \
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iov++; \
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skip = 0; \
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} \
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i->nr_segs -= iov - i->iov; \
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i->iov = iov; \
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} \
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i->count -= n; \
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i->iov_offset = skip; \
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} \
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}
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static size_t copy_page_to_iter_iovec(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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size_t skip, copy, left, wanted;
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const struct iovec *iov;
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char __user *buf;
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void *kaddr, *from;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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wanted = bytes;
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iov = i->iov;
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skip = i->iov_offset;
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buf = iov->iov_base + skip;
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copy = min(bytes, iov->iov_len - skip);
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if (!fault_in_pages_writeable(buf, copy)) {
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kaddr = kmap_atomic(page);
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from = kaddr + offset;
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/* first chunk, usually the only one */
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left = __copy_to_user_inatomic(buf, from, copy);
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copy -= left;
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skip += copy;
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from += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_to_user_inatomic(buf, from, copy);
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copy -= left;
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skip = copy;
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from += copy;
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bytes -= copy;
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}
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if (likely(!bytes)) {
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kunmap_atomic(kaddr);
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goto done;
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}
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offset = from - kaddr;
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buf += copy;
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kunmap_atomic(kaddr);
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copy = min(bytes, iov->iov_len - skip);
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}
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/* Too bad - revert to non-atomic kmap */
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kaddr = kmap(page);
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from = kaddr + offset;
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left = __copy_to_user(buf, from, copy);
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copy -= left;
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skip += copy;
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from += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_to_user(buf, from, copy);
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copy -= left;
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skip = copy;
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from += copy;
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bytes -= copy;
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}
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kunmap(page);
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done:
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if (skip == iov->iov_len) {
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iov++;
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skip = 0;
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}
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i->count -= wanted - bytes;
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i->nr_segs -= iov - i->iov;
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i->iov = iov;
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i->iov_offset = skip;
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return wanted - bytes;
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}
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static size_t copy_page_from_iter_iovec(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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size_t skip, copy, left, wanted;
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const struct iovec *iov;
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char __user *buf;
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void *kaddr, *to;
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if (unlikely(bytes > i->count))
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bytes = i->count;
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if (unlikely(!bytes))
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return 0;
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wanted = bytes;
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iov = i->iov;
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skip = i->iov_offset;
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buf = iov->iov_base + skip;
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copy = min(bytes, iov->iov_len - skip);
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if (!fault_in_pages_readable(buf, copy)) {
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kaddr = kmap_atomic(page);
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to = kaddr + offset;
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/* first chunk, usually the only one */
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left = __copy_from_user_inatomic(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_from_user_inatomic(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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if (likely(!bytes)) {
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kunmap_atomic(kaddr);
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goto done;
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}
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offset = to - kaddr;
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buf += copy;
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kunmap_atomic(kaddr);
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copy = min(bytes, iov->iov_len - skip);
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}
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/* Too bad - revert to non-atomic kmap */
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kaddr = kmap(page);
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to = kaddr + offset;
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left = __copy_from_user(to, buf, copy);
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copy -= left;
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skip += copy;
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to += copy;
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bytes -= copy;
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while (unlikely(!left && bytes)) {
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iov++;
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buf = iov->iov_base;
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copy = min(bytes, iov->iov_len);
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left = __copy_from_user(to, buf, copy);
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copy -= left;
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skip = copy;
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to += copy;
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bytes -= copy;
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}
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kunmap(page);
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done:
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if (skip == iov->iov_len) {
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iov++;
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skip = 0;
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}
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i->count -= wanted - bytes;
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i->nr_segs -= iov - i->iov;
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i->iov = iov;
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i->iov_offset = skip;
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return wanted - bytes;
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}
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/*
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* Fault in the first iovec of the given iov_iter, to a maximum length
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* of bytes. Returns 0 on success, or non-zero if the memory could not be
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* accessed (ie. because it is an invalid address).
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*
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* writev-intensive code may want this to prefault several iovecs -- that
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* would be possible (callers must not rely on the fact that _only_ the
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* first iovec will be faulted with the current implementation).
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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|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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}
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return 0;
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}
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EXPORT_SYMBOL(iov_iter_fault_in_readable);
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/*
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* Fault in one or more iovecs of the given iov_iter, to a maximum length of
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* bytes. For each iovec, fault in each page that constitutes the iovec.
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*
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* Return 0 on success, or non-zero if the memory could not be accessed (i.e.
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* because it is an invalid address).
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*/
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int iov_iter_fault_in_multipages_readable(struct iov_iter *i, size_t bytes)
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{
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size_t skip = i->iov_offset;
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const struct iovec *iov;
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int err;
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struct iovec v;
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if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
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iterate_iovec(i, bytes, v, iov, skip, ({
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err = fault_in_multipages_readable(v.iov_base,
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v.iov_len);
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if (unlikely(err))
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return err;
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0;}))
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}
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return 0;
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}
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EXPORT_SYMBOL(iov_iter_fault_in_multipages_readable);
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void iov_iter_init(struct iov_iter *i, int direction,
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const struct iovec *iov, unsigned long nr_segs,
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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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direction |= ITER_KVEC;
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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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}
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EXPORT_SYMBOL(iov_iter_init);
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static void memcpy_from_page(char *to, struct page *page, size_t offset, size_t len)
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{
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char *from = kmap_atomic(page);
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memcpy(to, from + offset, len);
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kunmap_atomic(from);
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}
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static void memcpy_to_page(struct page *page, size_t offset, const char *from, size_t len)
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{
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char *to = kmap_atomic(page);
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memcpy(to + offset, from, len);
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kunmap_atomic(to);
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}
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static void memzero_page(struct page *page, size_t offset, size_t len)
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{
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char *addr = kmap_atomic(page);
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memset(addr + offset, 0, len);
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kunmap_atomic(addr);
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}
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size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i)
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{
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const char *from = addr;
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iterate_and_advance(i, bytes, v,
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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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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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}
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EXPORT_SYMBOL(copy_to_iter);
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size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i)
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{
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char *to = addr;
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iterate_and_advance(i, bytes, v,
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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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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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}
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EXPORT_SYMBOL(copy_from_iter);
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size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i)
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{
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char *to = addr;
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iterate_and_advance(i, bytes, v,
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__copy_from_user_nocache((to += v.iov_len) - v.iov_len,
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v.iov_base, 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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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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}
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EXPORT_SYMBOL(copy_from_iter_nocache);
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size_t copy_page_to_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|ITER_KVEC)) {
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void *kaddr = kmap_atomic(page);
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size_t wanted = copy_to_iter(kaddr + offset, bytes, i);
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kunmap_atomic(kaddr);
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return wanted;
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} else
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return copy_page_to_iter_iovec(page, offset, bytes, i);
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}
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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|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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return wanted;
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} else
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return copy_page_from_iter_iovec(page, offset, bytes, i);
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}
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EXPORT_SYMBOL(copy_page_from_iter);
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size_t iov_iter_zero(size_t bytes, struct iov_iter *i)
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{
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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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memset(v.iov_base, 0, v.iov_len)
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)
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return bytes;
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}
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EXPORT_SYMBOL(iov_iter_zero);
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size_t iov_iter_copy_from_user_atomic(struct page *page,
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struct iov_iter *i, unsigned long offset, size_t bytes)
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{
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char *kaddr = kmap_atomic(page), *p = kaddr + offset;
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iterate_all_kinds(i, bytes, v,
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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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memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len)
|
|
)
|
|
kunmap_atomic(kaddr);
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_copy_from_user_atomic);
|
|
|
|
void iov_iter_advance(struct iov_iter *i, size_t size)
|
|
{
|
|
iterate_and_advance(i, size, v, 0, 0, 0)
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_advance);
|
|
|
|
/*
|
|
* Return the count of just the current iov_iter segment.
|
|
*/
|
|
size_t iov_iter_single_seg_count(const struct iov_iter *i)
|
|
{
|
|
if (i->nr_segs == 1)
|
|
return i->count;
|
|
else if (i->type & ITER_BVEC)
|
|
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,
|
|
const struct kvec *kvec, unsigned long nr_segs,
|
|
size_t count)
|
|
{
|
|
BUG_ON(!(direction & ITER_KVEC));
|
|
i->type = direction;
|
|
i->kvec = kvec;
|
|
i->nr_segs = nr_segs;
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_kvec);
|
|
|
|
void iov_iter_bvec(struct iov_iter *i, int direction,
|
|
const struct bio_vec *bvec, unsigned long nr_segs,
|
|
size_t count)
|
|
{
|
|
BUG_ON(!(direction & ITER_BVEC));
|
|
i->type = direction;
|
|
i->bvec = bvec;
|
|
i->nr_segs = nr_segs;
|
|
i->iov_offset = 0;
|
|
i->count = count;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_bvec);
|
|
|
|
unsigned long iov_iter_alignment(const struct iov_iter *i)
|
|
{
|
|
unsigned long res = 0;
|
|
size_t size = i->count;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
iterate_all_kinds(i, size, v,
|
|
(res |= (unsigned long)v.iov_base | v.iov_len, 0),
|
|
res |= v.bv_offset | v.bv_len,
|
|
res |= (unsigned long)v.iov_base | v.iov_len
|
|
)
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_alignment);
|
|
|
|
unsigned long iov_iter_gap_alignment(const struct iov_iter *i)
|
|
{
|
|
unsigned long res = 0;
|
|
size_t size = i->count;
|
|
if (!size)
|
|
return 0;
|
|
|
|
iterate_all_kinds(i, size, v,
|
|
(res |= (!res ? 0 : (unsigned long)v.iov_base) |
|
|
(size != v.iov_len ? size : 0), 0),
|
|
(res |= (!res ? 0 : (unsigned long)v.bv_offset) |
|
|
(size != v.bv_len ? size : 0)),
|
|
(res |= (!res ? 0 : (unsigned long)v.iov_base) |
|
|
(size != v.iov_len ? size : 0))
|
|
);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_gap_alignment);
|
|
|
|
ssize_t iov_iter_get_pages(struct iov_iter *i,
|
|
struct page **pages, size_t maxsize, unsigned maxpages,
|
|
size_t *start)
|
|
{
|
|
if (maxsize > i->count)
|
|
maxsize = i->count;
|
|
|
|
if (!maxsize)
|
|
return 0;
|
|
|
|
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));
|
|
int n;
|
|
int res;
|
|
|
|
if (len > maxpages * PAGE_SIZE)
|
|
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);
|
|
if (unlikely(res < 0))
|
|
return res;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
0;}),({
|
|
/* can't be more than PAGE_SIZE */
|
|
*start = v.bv_offset;
|
|
get_page(*pages = v.bv_page);
|
|
return v.bv_len;
|
|
}),({
|
|
return -EFAULT;
|
|
})
|
|
)
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages);
|
|
|
|
static struct page **get_pages_array(size_t n)
|
|
{
|
|
struct page **p = kmalloc(n * sizeof(struct page *), GFP_KERNEL);
|
|
if (!p)
|
|
p = vmalloc(n * sizeof(struct page *));
|
|
return p;
|
|
}
|
|
|
|
ssize_t iov_iter_get_pages_alloc(struct iov_iter *i,
|
|
struct page ***pages, size_t maxsize,
|
|
size_t *start)
|
|
{
|
|
struct page **p;
|
|
|
|
if (maxsize > i->count)
|
|
maxsize = i->count;
|
|
|
|
if (!maxsize)
|
|
return 0;
|
|
|
|
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));
|
|
int n;
|
|
int res;
|
|
|
|
addr &= ~(PAGE_SIZE - 1);
|
|
n = DIV_ROUND_UP(len, PAGE_SIZE);
|
|
p = get_pages_array(n);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p);
|
|
if (unlikely(res < 0)) {
|
|
kvfree(p);
|
|
return res;
|
|
}
|
|
*pages = p;
|
|
return (res == n ? len : res * PAGE_SIZE) - *start;
|
|
0;}),({
|
|
/* can't be more than PAGE_SIZE */
|
|
*start = v.bv_offset;
|
|
*pages = p = get_pages_array(1);
|
|
if (!p)
|
|
return -ENOMEM;
|
|
get_page(*p = v.bv_page);
|
|
return v.bv_len;
|
|
}),({
|
|
return -EFAULT;
|
|
})
|
|
)
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_get_pages_alloc);
|
|
|
|
size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum,
|
|
struct iov_iter *i)
|
|
{
|
|
char *to = addr;
|
|
__wsum sum, next;
|
|
size_t off = 0;
|
|
sum = *csum;
|
|
iterate_and_advance(i, bytes, v, ({
|
|
int err = 0;
|
|
next = csum_and_copy_from_user(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0, &err);
|
|
if (!err) {
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
}
|
|
err ? v.iov_len : 0;
|
|
}), ({
|
|
char *p = kmap_atomic(v.bv_page);
|
|
next = csum_partial_copy_nocheck(p + v.bv_offset,
|
|
(to += v.bv_len) - v.bv_len,
|
|
v.bv_len, 0);
|
|
kunmap_atomic(p);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.bv_len;
|
|
}),({
|
|
next = csum_partial_copy_nocheck(v.iov_base,
|
|
(to += v.iov_len) - v.iov_len,
|
|
v.iov_len, 0);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
})
|
|
)
|
|
*csum = sum;
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(csum_and_copy_from_iter);
|
|
|
|
size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum,
|
|
struct iov_iter *i)
|
|
{
|
|
const char *from = addr;
|
|
__wsum sum, next;
|
|
size_t off = 0;
|
|
sum = *csum;
|
|
iterate_and_advance(i, bytes, v, ({
|
|
int err = 0;
|
|
next = csum_and_copy_to_user((from += v.iov_len) - v.iov_len,
|
|
v.iov_base,
|
|
v.iov_len, 0, &err);
|
|
if (!err) {
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
}
|
|
err ? v.iov_len : 0;
|
|
}), ({
|
|
char *p = kmap_atomic(v.bv_page);
|
|
next = csum_partial_copy_nocheck((from += v.bv_len) - v.bv_len,
|
|
p + v.bv_offset,
|
|
v.bv_len, 0);
|
|
kunmap_atomic(p);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.bv_len;
|
|
}),({
|
|
next = csum_partial_copy_nocheck((from += v.iov_len) - v.iov_len,
|
|
v.iov_base,
|
|
v.iov_len, 0);
|
|
sum = csum_block_add(sum, next, off);
|
|
off += v.iov_len;
|
|
})
|
|
)
|
|
*csum = sum;
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL(csum_and_copy_to_iter);
|
|
|
|
int iov_iter_npages(const struct iov_iter *i, int maxpages)
|
|
{
|
|
size_t size = i->count;
|
|
int npages = 0;
|
|
|
|
if (!size)
|
|
return 0;
|
|
|
|
iterate_all_kinds(i, size, v, ({
|
|
unsigned long p = (unsigned long)v.iov_base;
|
|
npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
|
|
- p / PAGE_SIZE;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
0;}),({
|
|
npages++;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
}),({
|
|
unsigned long p = (unsigned long)v.iov_base;
|
|
npages += DIV_ROUND_UP(p + v.iov_len, PAGE_SIZE)
|
|
- p / PAGE_SIZE;
|
|
if (npages >= maxpages)
|
|
return maxpages;
|
|
})
|
|
)
|
|
return npages;
|
|
}
|
|
EXPORT_SYMBOL(iov_iter_npages);
|
|
|
|
const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
|
|
{
|
|
*new = *old;
|
|
if (new->type & ITER_BVEC)
|
|
return new->bvec = kmemdup(new->bvec,
|
|
new->nr_segs * sizeof(struct bio_vec),
|
|
flags);
|
|
else
|
|
/* iovec and kvec have identical layout */
|
|
return new->iov = kmemdup(new->iov,
|
|
new->nr_segs * sizeof(struct iovec),
|
|
flags);
|
|
}
|
|
EXPORT_SYMBOL(dup_iter);
|
|
|
|
int import_iovec(int type, const struct iovec __user * uvector,
|
|
unsigned nr_segs, unsigned fast_segs,
|
|
struct iovec **iov, struct iov_iter *i)
|
|
{
|
|
ssize_t n;
|
|
struct iovec *p;
|
|
n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
|
|
*iov, &p);
|
|
if (n < 0) {
|
|
if (p != *iov)
|
|
kfree(p);
|
|
*iov = NULL;
|
|
return n;
|
|
}
|
|
iov_iter_init(i, type, p, nr_segs, n);
|
|
*iov = p == *iov ? NULL : p;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(import_iovec);
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
#include <linux/compat.h>
|
|
|
|
int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
|
|
unsigned nr_segs, unsigned fast_segs,
|
|
struct iovec **iov, struct iov_iter *i)
|
|
{
|
|
ssize_t n;
|
|
struct iovec *p;
|
|
n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
|
|
*iov, &p);
|
|
if (n < 0) {
|
|
if (p != *iov)
|
|
kfree(p);
|
|
*iov = NULL;
|
|
return n;
|
|
}
|
|
iov_iter_init(i, type, p, nr_segs, n);
|
|
*iov = p == *iov ? NULL : p;
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
int import_single_range(int rw, void __user *buf, size_t len,
|
|
struct iovec *iov, struct iov_iter *i)
|
|
{
|
|
if (len > MAX_RW_COUNT)
|
|
len = MAX_RW_COUNT;
|
|
if (unlikely(!access_ok(!rw, buf, len)))
|
|
return -EFAULT;
|
|
|
|
iov->iov_base = buf;
|
|
iov->iov_len = len;
|
|
iov_iter_init(i, rw, iov, 1, len);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(import_single_range);
|