diff options
| -rw-r--r-- | lib/iov_iter.c | 63 |
1 files changed, 53 insertions, 10 deletions
diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 2b543bea1e0d..ed9318358b68 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -1328,27 +1328,70 @@ void iov_iter_discard(struct iov_iter *i, unsigned int direction, size_t count) } EXPORT_SYMBOL(iov_iter_discard); -unsigned long iov_iter_alignment(const struct iov_iter *i) +static unsigned long iov_iter_alignment_iovec(const struct iov_iter *i) { unsigned long res = 0; size_t size = i->count; + size_t skip = i->iov_offset; + unsigned k; + + for (k = 0; k < i->nr_segs; k++, skip = 0) { + size_t len = i->iov[k].iov_len - skip; + if (len) { + res |= (unsigned long)i->iov[k].iov_base + skip; + if (len > size) + len = size; + res |= len; + size -= len; + if (!size) + break; + } + } + return res; +} - if (unlikely(iov_iter_is_pipe(i))) { +static unsigned long iov_iter_alignment_bvec(const struct iov_iter *i) +{ + unsigned res = 0; + size_t size = i->count; + unsigned skip = i->iov_offset; + unsigned k; + + for (k = 0; k < i->nr_segs; k++, skip = 0) { + size_t len = i->bvec[k].bv_len - skip; + res |= (unsigned long)i->bvec[k].bv_offset + skip; + if (len > size) + len = size; + res |= len; + size -= len; + if (!size) + break; + } + return res; +} + +unsigned long iov_iter_alignment(const struct iov_iter *i) +{ + /* iovec and kvec have identical layouts */ + if (likely(iter_is_iovec(i) || iov_iter_is_kvec(i))) + return iov_iter_alignment_iovec(i); + + if (iov_iter_is_bvec(i)) + return iov_iter_alignment_bvec(i); + + if (iov_iter_is_pipe(i)) { unsigned int p_mask = i->pipe->ring_size - 1; + size_t size = i->count; if (size && i->iov_offset && allocated(&i->pipe->bufs[i->head & p_mask])) return size | i->iov_offset; return size; } - if (unlikely(iov_iter_is_xarray(i))) + + if (iov_iter_is_xarray(i)) return (i->xarray_start + i->iov_offset) | i->count; - 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, - res |= v.bv_offset | v.bv_len - ) - return res; + + return 0; } EXPORT_SYMBOL(iov_iter_alignment); |