diff options
Diffstat (limited to 'lib/iov_iter.c')
| -rw-r--r-- | lib/iov_iter.c | 123 |
1 files changed, 55 insertions, 68 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 5fecddc32b1b..0cd522753ff5 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -99,40 +99,44 @@ } #define iterate_and_advance(i, n, v, I, B, K) { \ - size_t skip = i->iov_offset; \ - if (unlikely(i->type & ITER_BVEC)) { \ - const struct bio_vec *bvec; \ - struct bio_vec v; \ - iterate_bvec(i, n, v, bvec, skip, (B)) \ - if (skip == bvec->bv_len) { \ - bvec++; \ - skip = 0; \ - } \ - i->nr_segs -= bvec - i->bvec; \ - i->bvec = bvec; \ - } else if (unlikely(i->type & ITER_KVEC)) { \ - const struct kvec *kvec; \ - struct kvec v; \ - iterate_kvec(i, n, v, kvec, skip, (K)) \ - if (skip == kvec->iov_len) { \ - kvec++; \ - skip = 0; \ - } \ - i->nr_segs -= kvec - i->kvec; \ - i->kvec = kvec; \ - } else { \ - const struct iovec *iov; \ - struct iovec v; \ - iterate_iovec(i, n, v, iov, skip, (I)) \ - if (skip == iov->iov_len) { \ - iov++; \ - skip = 0; \ + if (unlikely(i->count < n)) \ + n = i->count; \ + if (i->count) { \ + size_t skip = i->iov_offset; \ + if (unlikely(i->type & ITER_BVEC)) { \ + const struct bio_vec *bvec; \ + struct bio_vec v; \ + iterate_bvec(i, n, v, bvec, skip, (B)) \ + if (skip == bvec->bv_len) { \ + bvec++; \ + skip = 0; \ + } \ + i->nr_segs -= bvec - i->bvec; \ + i->bvec = bvec; \ + } else if (unlikely(i->type & ITER_KVEC)) { \ + const struct kvec *kvec; \ + struct kvec v; \ + iterate_kvec(i, n, v, kvec, skip, (K)) \ + if (skip == kvec->iov_len) { \ + kvec++; \ + skip = 0; \ + } \ + i->nr_segs -= kvec - i->kvec; \ + i->kvec = kvec; \ + } else { \ + const struct iovec *iov; \ + struct iovec v; \ + iterate_iovec(i, n, v, iov, skip, (I)) \ + if (skip == iov->iov_len) { \ + iov++; \ + skip = 0; \ + } \ + i->nr_segs -= iov - i->iov; \ + i->iov = iov; \ } \ - i->nr_segs -= iov - i->iov; \ - i->iov = iov; \ + i->count -= n; \ + i->iov_offset = skip; \ } \ - i->count -= n; \ - i->iov_offset = skip; \ } static size_t copy_page_to_iter_iovec(struct page *page, size_t offset, size_t bytes, @@ -386,12 +390,6 @@ static void memzero_page(struct page *page, size_t offset, size_t len) size_t copy_to_iter(const void *addr, size_t bytes, struct iov_iter *i) { const char *from = addr; - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - iterate_and_advance(i, bytes, v, __copy_to_user(v.iov_base, (from += v.iov_len) - v.iov_len, v.iov_len), @@ -407,12 +405,6 @@ EXPORT_SYMBOL(copy_to_iter); size_t copy_from_iter(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - iterate_and_advance(i, bytes, v, __copy_from_user((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), @@ -428,12 +420,6 @@ EXPORT_SYMBOL(copy_from_iter); size_t copy_from_iter_nocache(void *addr, size_t bytes, struct iov_iter *i) { char *to = addr; - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - iterate_and_advance(i, bytes, v, __copy_from_user_nocache((to += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), @@ -474,12 +460,6 @@ EXPORT_SYMBOL(copy_page_from_iter); size_t iov_iter_zero(size_t bytes, struct iov_iter *i) { - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - iterate_and_advance(i, bytes, v, __clear_user(v.iov_base, v.iov_len), memzero_page(v.bv_page, v.bv_offset, v.bv_len), @@ -569,6 +549,25 @@ unsigned long iov_iter_alignment(const struct iov_iter *i) } 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) @@ -666,12 +665,6 @@ size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, char *to = addr; __wsum sum, next; size_t off = 0; - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - sum = *csum; iterate_and_advance(i, bytes, v, ({ int err = 0; @@ -710,12 +703,6 @@ size_t csum_and_copy_to_iter(const void *addr, size_t bytes, __wsum *csum, const char *from = addr; __wsum sum, next; size_t off = 0; - if (unlikely(bytes > i->count)) - bytes = i->count; - - if (unlikely(!bytes)) - return 0; - sum = *csum; iterate_and_advance(i, bytes, v, ({ int err = 0; |