If the read is an async operation, send a 9p request and return EIOCBQUEUED. Do not wait for completion.
Complete the read operation from a callback instead. Signed-off-by: Stefano Stabellini <[email protected]> --- Changes in v2: - use work_struct to schedule callback - a few variable renames - improve the completion function so that it can be called multiple times on the same request --- net/9p/client.c | 97 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 95 insertions(+), 2 deletions(-) diff --git a/net/9p/client.c b/net/9p/client.c index 0ff1216..c17596f 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -28,6 +28,7 @@ #include <linux/module.h> #include <linux/errno.h> #include <linux/fs.h> +#include <linux/pagemap.h> #include <linux/poll.h> #include <linux/idr.h> #include <linux/mutex.h> @@ -1558,13 +1559,74 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags) } EXPORT_SYMBOL(p9_client_unlinkat); +static void +p9_client_read_complete(struct work_struct *work) +{ + struct p9_req_t *req = container_of(work, struct p9_req_t, work); + struct p9_client *clnt = req->fid->clnt; + uint32_t count = 0, n = 0, total = 0; + u64 offset; + int err, i; + char *dataptr, *to; + + if (req->status == REQ_STATUS_ERROR) { + p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err); + err = req->t_err; + goto out; + } + err = p9_check_errors(clnt, req); + if (err) + goto out; + + err = p9pdu_readf(req->rc, clnt->proto_version, + "D", &count, &dataptr); + if (err) { + trace_9p_protocol_dump(clnt, req->rc); + goto out; + } + if (!count) { + p9_debug(P9_DEBUG_ERROR, "count=%d\n", count); + err = 0; + goto out; + } + + p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count); + if (count > req->rsize) + count = req->rsize; + + offset = req->page_offset; + total = count; + for (i = offset / PAGE_SIZE; i < ((total + PAGE_SIZE - 1) / PAGE_SIZE); i++) { + to = kmap(req->pagevec[i]); + to += offset; + n = PAGE_SIZE - offset; + if (n > count) + n = count; + else + offset = 0; + memcpy(to, dataptr, n); + kunmap(req->pagevec[i]); + count -= n; + } + + err = total; + req->kiocb->ki_pos += total; + +out: + req->kiocb->ki_complete(req->kiocb, err, 0); + + release_pages(req->pagevec, (req->tot_size + PAGE_SIZE - 1) / PAGE_SIZE, false); + kvfree(req->pagevec); + p9_free_req(clnt, req); +} + int p9_client_read(struct p9_fid *fid, struct kiocb *iocb, u64 offset, struct iov_iter *to, int *err) { struct p9_client *clnt = fid->clnt; struct p9_req_t *req; - int total = 0; + int total = 0, i; *err = 0; p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", @@ -1591,10 +1653,41 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags) req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize, 0, 11, "dqd", fid->fid, offset, rsize); - } else { + /* sync request */ + } else if(iocb == NULL || is_sync_kiocb(iocb)) { non_zc = 1; req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize); + /* async request */ + } else { + req = p9_client_get_req(clnt, P9_TREAD, "dqd", fid->fid, offset, rsize); + if (IS_ERR(req)) { + *err = PTR_ERR(req); + break; + } + req->fid = fid; + req->file_offset = offset; + req->rsize = rsize; + req->tot_size = iov_iter_get_pages_alloc(to, &req->pagevec, + (size_t)rsize, &req->page_offset); + req->kiocb = iocb; + for (i = 0; i < req->tot_size; i += PAGE_SIZE) + page_cache_get_speculative(req->pagevec[i/PAGE_SIZE]); + INIT_WORK(&req->work, p9_client_read_complete); + + *err = clnt->trans_mod->request(clnt, req); + if (*err < 0) { + clnt->status = Disconnected; + release_pages(req->pagevec, + (req->tot_size + PAGE_SIZE - 1) / PAGE_SIZE, + true); + kvfree(req->pagevec); + p9_free_req(clnt, req); + break; + } + + *err = -EIOCBQUEUED; + break; } if (IS_ERR(req)) { *err = PTR_ERR(req); -- 1.9.1
