diff options
Diffstat (limited to 'net/ceph/messenger.c')
| -rw-r--r-- | net/ceph/messenger.c | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 5eb4898cccd4..10a41cd9c523 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -969,6 +969,62 @@ static bool ceph_msg_data_pagelist_advance(struct ceph_msg_data_cursor *cursor, return true; } +static void ceph_msg_data_iter_cursor_init(struct ceph_msg_data_cursor *cursor, + size_t length) +{ + struct ceph_msg_data *data = cursor->data; + + cursor->iov_iter = data->iter; + cursor->lastlen = 0; + iov_iter_truncate(&cursor->iov_iter, length); + cursor->resid = iov_iter_count(&cursor->iov_iter); +} + +static struct page *ceph_msg_data_iter_next(struct ceph_msg_data_cursor *cursor, + size_t *page_offset, size_t *length) +{ + struct page *page; + ssize_t len; + + if (cursor->lastlen) + iov_iter_revert(&cursor->iov_iter, cursor->lastlen); + + len = iov_iter_get_pages2(&cursor->iov_iter, &page, PAGE_SIZE, + 1, page_offset); + BUG_ON(len < 0); + + cursor->lastlen = len; + + /* + * FIXME: The assumption is that the pages represented by the iov_iter + * are pinned, with the references held by the upper-level + * callers, or by virtue of being under writeback. Eventually, + * we'll get an iov_iter_get_pages2 variant that doesn't take + * page refs. Until then, just put the page ref. + */ + VM_BUG_ON_PAGE(!PageWriteback(page) && page_count(page) < 2, page); + put_page(page); + + *length = min_t(size_t, len, cursor->resid); + return page; +} + +static bool ceph_msg_data_iter_advance(struct ceph_msg_data_cursor *cursor, + size_t bytes) +{ + BUG_ON(bytes > cursor->resid); + cursor->resid -= bytes; + + if (bytes < cursor->lastlen) { + cursor->lastlen -= bytes; + } else { + iov_iter_advance(&cursor->iov_iter, bytes - cursor->lastlen); + cursor->lastlen = 0; + } + + return cursor->resid; +} + /* * Message data is handled (sent or received) in pieces, where each * piece resides on a single page. The network layer might not @@ -996,6 +1052,9 @@ static void __ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor) case CEPH_MSG_DATA_BVECS: ceph_msg_data_bvecs_cursor_init(cursor, length); break; + case CEPH_MSG_DATA_ITER: + ceph_msg_data_iter_cursor_init(cursor, length); + break; case CEPH_MSG_DATA_NONE: default: /* BUG(); */ @@ -1013,6 +1072,7 @@ void ceph_msg_data_cursor_init(struct ceph_msg_data_cursor *cursor, cursor->total_resid = length; cursor->data = msg->data; + cursor->sr_resid = 0; __ceph_msg_data_cursor_init(cursor); } @@ -1042,6 +1102,9 @@ struct page *ceph_msg_data_next(struct ceph_msg_data_cursor *cursor, case CEPH_MSG_DATA_BVECS: page = ceph_msg_data_bvecs_next(cursor, page_offset, length); break; + case CEPH_MSG_DATA_ITER: + page = ceph_msg_data_iter_next(cursor, page_offset, length); + break; case CEPH_MSG_DATA_NONE: default: page = NULL; @@ -1080,6 +1143,9 @@ void ceph_msg_data_advance(struct ceph_msg_data_cursor *cursor, size_t bytes) case CEPH_MSG_DATA_BVECS: new_piece = ceph_msg_data_bvecs_advance(cursor, bytes); break; + case CEPH_MSG_DATA_ITER: + new_piece = ceph_msg_data_iter_advance(cursor, bytes); + break; case CEPH_MSG_DATA_NONE: default: BUG(); @@ -1879,6 +1945,18 @@ void ceph_msg_data_add_bvecs(struct ceph_msg *msg, } EXPORT_SYMBOL(ceph_msg_data_add_bvecs); +void ceph_msg_data_add_iter(struct ceph_msg *msg, + struct iov_iter *iter) +{ + struct ceph_msg_data *data; + + data = ceph_msg_data_add(msg); + data->type = CEPH_MSG_DATA_ITER; + data->iter = *iter; + + msg->data_length += iov_iter_count(&data->iter); +} + /* * construct a new message with given type, size * the new msg has a ref count of 1. |