From 1bab88b2310998de18b32529a27ea835d164254a Mon Sep 17 00:00:00 2001 From: Latchesar Ionkov Date: Sun, 5 Apr 2009 16:28:59 -0500 Subject: [PATCH] net/9p: handle correctly interrupted 9P requests Currently the 9p code crashes when a operation is interrupted, i.e. for example when the user presses ^C while reading from a file. This patch fixes the code that is responsible for interruption and flushing of 9P operations. Signed-off-by: Latchesar Ionkov --- include/net/9p/client.h | 1 - net/9p/client.c | 74 +++++++++++------------------------------ net/9p/trans_fd.c | 14 +++++--- net/9p/trans_rdma.c | 1 + net/9p/trans_virtio.c | 1 + 5 files changed, 30 insertions(+), 61 deletions(-) diff --git a/include/net/9p/client.h b/include/net/9p/client.h index 4012e07162e5..e26812274b75 100644 --- a/include/net/9p/client.h +++ b/include/net/9p/client.h @@ -98,7 +98,6 @@ enum p9_req_status_t { struct p9_req_t { int status; int t_err; - u16 flush_tag; wait_queue_head_t *wq; struct p9_fcall *tc; struct p9_fcall *rc; diff --git a/net/9p/client.c b/net/9p/client.c index 781d89a952e4..dd43a8289b0d 100644 --- a/net/9p/client.c +++ b/net/9p/client.c @@ -203,7 +203,6 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag) p9pdu_reset(req->tc); p9pdu_reset(req->rc); - req->flush_tag = 0; req->tc->tag = tag-1; req->status = REQ_STATUS_ALLOC; @@ -324,35 +323,9 @@ static void p9_free_req(struct p9_client *c, struct p9_req_t *r) */ void p9_client_cb(struct p9_client *c, struct p9_req_t *req) { - struct p9_req_t *other_req; - unsigned long flags; - P9_DPRINTK(P9_DEBUG_MUX, " tag %d\n", req->tc->tag); - - if (req->status == REQ_STATUS_ERROR) - wake_up(req->wq); - - if (req->flush_tag) { /* flush receive path */ - P9_DPRINTK(P9_DEBUG_9P, "<<< RFLUSH %d\n", req->tc->tag); - spin_lock_irqsave(&c->lock, flags); - other_req = p9_tag_lookup(c, req->flush_tag); - if (other_req->status != REQ_STATUS_FLSH) /* stale flush */ - spin_unlock_irqrestore(&c->lock, flags); - else { - other_req->status = REQ_STATUS_FLSHD; - spin_unlock_irqrestore(&c->lock, flags); - wake_up(other_req->wq); - } - p9_free_req(c, req); - } else { /* normal receive path */ - P9_DPRINTK(P9_DEBUG_MUX, "normal: tag %d\n", req->tc->tag); - spin_lock_irqsave(&c->lock, flags); - if (req->status != REQ_STATUS_FLSHD) - req->status = REQ_STATUS_RCVD; - spin_unlock_irqrestore(&c->lock, flags); - wake_up(req->wq); - P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag); - } + wake_up(req->wq); + P9_DPRINTK(P9_DEBUG_MUX, "wakeup: %d\n", req->tc->tag); } EXPORT_SYMBOL(p9_client_cb); @@ -486,9 +459,15 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq) if (IS_ERR(req)) return PTR_ERR(req); - req->flush_tag = oldtag; - /* we don't free anything here because RPC isn't complete */ + /* if we haven't received a response for oldreq, + remove it from the list. */ + spin_lock(&c->lock); + if (oldreq->status == REQ_STATUS_FLSH) + list_del(&oldreq->req_list); + spin_unlock(&c->lock); + + p9_free_req(c, req); return 0; } @@ -509,7 +488,6 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) struct p9_req_t *req; unsigned long flags; int sigpending; - int flushed = 0; P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type); @@ -546,42 +524,28 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...) goto reterr; } - /* if it was a flush we just transmitted, return our tag */ - if (type == P9_TFLUSH) - return req; -again: P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag); err = wait_event_interruptible(*req->wq, req->status >= REQ_STATUS_RCVD); - P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d (flushed=%d)\n", - req->wq, tag, err, flushed); + P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n", + req->wq, tag, err); if (req->status == REQ_STATUS_ERROR) { P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err); err = req->t_err; - } else if (err == -ERESTARTSYS && flushed) { - P9_DPRINTK(P9_DEBUG_MUX, "flushed - going again\n"); - goto again; - } else if (req->status == REQ_STATUS_FLSHD) { - P9_DPRINTK(P9_DEBUG_MUX, "flushed - erestartsys\n"); - err = -ERESTARTSYS; } - if ((err == -ERESTARTSYS) && (c->status == Connected) && (!flushed)) { + if ((err == -ERESTARTSYS) && (c->status == Connected)) { P9_DPRINTK(P9_DEBUG_MUX, "flushing\n"); - spin_lock_irqsave(&c->lock, flags); - if (req->status == REQ_STATUS_SENT) - req->status = REQ_STATUS_FLSH; - spin_unlock_irqrestore(&c->lock, flags); sigpending = 1; - flushed = 1; clear_thread_flag(TIF_SIGPENDING); - if (c->trans_mod->cancel(c, req)) { - err = p9_client_flush(c, req); - if (err == 0) - goto again; - } + if (c->trans_mod->cancel(c, req)) + p9_client_flush(c, req); + + /* if we received the response anyway, don't signal error */ + if (req->status == REQ_STATUS_RCVD) + err = 0; } if (sigpending) { diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c index c613ed08a5ee..a2a1814c7a8d 100644 --- a/net/9p/trans_fd.c +++ b/net/9p/trans_fd.c @@ -213,8 +213,8 @@ static void p9_conn_cancel(struct p9_conn *m, int err) spin_unlock_irqrestore(&m->client->lock, flags); list_for_each_entry_safe(req, rtmp, &cancel_list, req_list) { - list_del(&req->req_list); P9_DPRINTK(P9_DEBUG_ERROR, "call back req %p\n", req); + list_del(&req->req_list); p9_client_cb(m->client, req); } } @@ -336,7 +336,8 @@ static void p9_read_work(struct work_struct *work) "mux %p pkt: size: %d bytes tag: %d\n", m, n, tag); m->req = p9_tag_lookup(m->client, tag); - if (!m->req) { + if (!m->req || (m->req->status != REQ_STATUS_SENT && + m->req->status != REQ_STATUS_FLSH)) { P9_DPRINTK(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", tag); err = -EIO; @@ -361,10 +362,11 @@ static void p9_read_work(struct work_struct *work) if ((m->req) && (m->rpos == m->rsize)) { /* packet is read in */ P9_DPRINTK(P9_DEBUG_TRANS, "got new packet\n"); spin_lock(&m->client->lock); + if (m->req->status != REQ_STATUS_ERROR) + m->req->status = REQ_STATUS_RCVD; list_del(&m->req->req_list); spin_unlock(&m->client->lock); p9_client_cb(m->client, m->req); - m->rbuf = NULL; m->rpos = 0; m->rsize = 0; @@ -454,6 +456,7 @@ static void p9_write_work(struct work_struct *work) req = list_entry(m->unsent_req_list.next, struct p9_req_t, req_list); req->status = REQ_STATUS_SENT; + P9_DPRINTK(P9_DEBUG_TRANS, "move req %p\n", req); list_move_tail(&req->req_list, &m->req_list); m->wbuf = req->tc->sdata; @@ -683,12 +686,13 @@ static int p9_fd_cancel(struct p9_client *client, struct p9_req_t *req) P9_DPRINTK(P9_DEBUG_TRANS, "client %p req %p\n", client, req); spin_lock(&client->lock); - list_del(&req->req_list); if (req->status == REQ_STATUS_UNSENT) { + list_del(&req->req_list); req->status = REQ_STATUS_FLSHD; ret = 0; - } + } else if (req->status == REQ_STATUS_SENT) + req->status = REQ_STATUS_FLSH; spin_unlock(&client->lock); diff --git a/net/9p/trans_rdma.c b/net/9p/trans_rdma.c index 7fa0eb20b2f6..ac4990041ebb 100644 --- a/net/9p/trans_rdma.c +++ b/net/9p/trans_rdma.c @@ -295,6 +295,7 @@ handle_recv(struct p9_client *client, struct p9_trans_rdma *rdma, goto err_out; req->rc = c->rc; + req->status = REQ_STATUS_RCVD; p9_client_cb(client, req); return; diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c index 2d7781ec663b..bb8579a141a8 100644 --- a/net/9p/trans_virtio.c +++ b/net/9p/trans_virtio.c @@ -134,6 +134,7 @@ static void req_done(struct virtqueue *vq) P9_DPRINTK(P9_DEBUG_TRANS, ": rc %p\n", rc); P9_DPRINTK(P9_DEBUG_TRANS, ": lookup tag %d\n", rc->tag); req = p9_tag_lookup(chan->client, rc->tag); + req->status = REQ_STATUS_RCVD; p9_client_cb(chan->client, req); } } -- 2.34.1