Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751794AbdIOXAw (ORCPT ); Fri, 15 Sep 2017 19:00:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:37042 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751672AbdIOXAr (ORCPT ); Fri, 15 Sep 2017 19:00:47 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 80C8D22A78 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=sstabellini@kernel.org From: Stefano Stabellini To: xen-devel@lists.xen.org Cc: linux-kernel@vger.kernel.org, sstabellini@kernel.org, jgross@suse.com, boris.ostrovsky@oracle.com, Stefano Stabellini Subject: [PATCH v4 12/13] xen/pvcalls: implement release command Date: Fri, 15 Sep 2017 16:00:39 -0700 Message-Id: <1505516440-11111-12-git-send-email-sstabellini@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1505516440-11111-1-git-send-email-sstabellini@kernel.org> References: <1505516440-11111-1-git-send-email-sstabellini@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4206 Lines: 151 Send PVCALLS_RELEASE to the backend and wait for a reply. Take both in_mutex and out_mutex to avoid concurrent accesses. Then, free the socket. For passive sockets, check whether we have already pre-allocated an active socket for the purpose of being accepted. If so, free that as well. Signed-off-by: Stefano Stabellini CC: boris.ostrovsky@oracle.com CC: jgross@suse.com --- drivers/xen/pvcalls-front.c | 104 ++++++++++++++++++++++++++++++++++++++++++++ drivers/xen/pvcalls-front.h | 1 + 2 files changed, 105 insertions(+) diff --git a/drivers/xen/pvcalls-front.c b/drivers/xen/pvcalls-front.c index 8a90213..5f8e94a 100644 --- a/drivers/xen/pvcalls-front.c +++ b/drivers/xen/pvcalls-front.c @@ -209,6 +209,24 @@ static irqreturn_t pvcalls_front_conn_handler(int irq, void *sock_map) return IRQ_HANDLED; } +static void pvcalls_front_free_map(struct pvcalls_bedata *bedata, + struct sock_mapping *map) +{ + int i; + + unbind_from_irqhandler(map->active.irq, map); + + spin_lock(&bedata->socket_lock); + if (!list_empty(&map->list)) + list_del_init(&map->list); + spin_unlock(&bedata->socket_lock); + + for (i = 0; i < (1 << PVCALLS_RING_ORDER); i++) + gnttab_end_foreign_access(map->active.ring->ref[i], 0, 0); + gnttab_end_foreign_access(map->active.ref, 0, 0); + free_page((unsigned long)map->active.ring); +} + int pvcalls_front_socket(struct socket *sock) { struct pvcalls_bedata *bedata; @@ -960,6 +978,92 @@ unsigned int pvcalls_front_poll(struct file *file, struct socket *sock, return ret; } +int pvcalls_front_release(struct socket *sock) +{ + struct pvcalls_bedata *bedata; + struct sock_mapping *map; + int req_id, notify, ret; + struct xen_pvcalls_request *req; + + pvcalls_enter; + if (!pvcalls_front_dev) { + pvcalls_exit; + return -EIO; + } + if (sock->sk == NULL) { + pvcalls_exit; + return 0; + } + + bedata = dev_get_drvdata(&pvcalls_front_dev->dev); + + map = (struct sock_mapping *) sock->sk->sk_send_head; + if (map == NULL) { + pvcalls_exit; + return 0; + } + + spin_lock(&bedata->socket_lock); + ret = get_request(bedata, &req_id); + if (ret < 0) { + spin_unlock(&bedata->socket_lock); + pvcalls_exit; + return ret; + } + sock->sk->sk_send_head = NULL; + + req = RING_GET_REQUEST(&bedata->ring, req_id); + req->req_id = req_id; + req->cmd = PVCALLS_RELEASE; + req->u.release.id = (uint64_t)map; + + bedata->ring.req_prod_pvt++; + RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&bedata->ring, notify); + spin_unlock(&bedata->socket_lock); + if (notify) + notify_remote_via_irq(bedata->irq); + + wait_event(bedata->inflight_req, + READ_ONCE(bedata->rsp[req_id].req_id) == req_id); + + if (map->active_socket) { + /* + * Set in_error and wake up inflight_conn_req to force + * recvmsg waiters to exit. + */ + map->active.ring->in_error = -EBADF; + wake_up_interruptible(&map->active.inflight_conn_req); + + /* + * Wait until there are no more waiters on the mutexes. + * We know that no new waiters can be added because sk_send_head + * is set to NULL -- we only need to wait for the existing + * waiters to return. + */ + while (!mutex_trylock(&map->active.in_mutex) || + !mutex_trylock(&map->active.out_mutex)) + cpu_relax(); + + pvcalls_front_free_map(bedata, map); + kfree(map); + } else { + spin_lock(&bedata->socket_lock); + if (READ_ONCE(map->passive.inflight_req_id) != + PVCALLS_INVALID_ID) { + pvcalls_front_free_map(bedata, + map->passive.accept_map); + kfree(map->passive.accept_map); + } + list_del_init(&map->list); + kfree(map); + spin_unlock(&bedata->socket_lock); + } + WRITE_ONCE(bedata->rsp[req_id].req_id, PVCALLS_INVALID_ID); + + pvcalls_exit; + return 0; +} + static const struct xenbus_device_id pvcalls_front_ids[] = { { "pvcalls" }, { "" } diff --git a/drivers/xen/pvcalls-front.h b/drivers/xen/pvcalls-front.h index 25e05b8..3332978 100644 --- a/drivers/xen/pvcalls-front.h +++ b/drivers/xen/pvcalls-front.h @@ -23,5 +23,6 @@ int pvcalls_front_recvmsg(struct socket *sock, unsigned int pvcalls_front_poll(struct file *file, struct socket *sock, poll_table *wait); +int pvcalls_front_release(struct socket *sock); #endif -- 1.9.1