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Re: [Qemu-devel] [RFC PATCH v4 14/15] slirp: handle race condition
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [RFC PATCH v4 14/15] slirp: handle race condition |
Date: |
Thu, 18 Apr 2013 09:13:42 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2013-04-17 10:39, Liu Ping Fan wrote:
> From: Liu Ping Fan <address@hidden>
>
> Slirp and its peer can run on different context at the same time.
> Using lock to protect
What are the usage rules for this lock, what precisely is it protecting?
Is it ensured that we do not take the BQL while holding this one?
Jan
>
> Signed-off-by: Liu Ping Fan <address@hidden>
> ---
> slirp/slirp.c | 16 ++++++++++++++--
> slirp/slirp.h | 3 +++
> 2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/slirp/slirp.c b/slirp/slirp.c
> index 883b7bd..6bfcc67 100644
> --- a/slirp/slirp.c
> +++ b/slirp/slirp.c
> @@ -206,6 +206,7 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
>
> slirp_init_once();
>
> + qemu_mutex_init(&slirp->lock);
> slirp->restricted = restricted;
>
> if_init(slirp);
> @@ -248,6 +249,7 @@ void slirp_cleanup(Slirp *slirp)
>
> ip_cleanup(slirp);
> m_cleanup(slirp);
> + qemu_mutex_destroy(&slirp->lock);
>
> g_free(slirp->vdnssearch);
> g_free(slirp->tftp_prefix);
> @@ -411,6 +413,7 @@ gboolean slirp_handler(gpointer data)
> struct socket *so, *so_next;
> int ret;
>
> + qemu_mutex_lock(&slirp->lock);
> /*
> * See if anything has timed out
> */
> @@ -594,6 +597,7 @@ gboolean slirp_handler(gpointer data)
> }
>
> if_start(slirp);
> + qemu_mutex_unlock(&slirp->lock);
> return true;
> }
>
> @@ -665,6 +669,7 @@ void slirp_input(Slirp *slirp, const uint8_t *pkt, int
> pkt_len)
> return;
>
> proto = ntohs(*(uint16_t *)(pkt + 12));
> + qemu_mutex_lock(&slirp->lock);
> switch(proto) {
> case ETH_P_ARP:
> arp_input(slirp, pkt, pkt_len);
> @@ -688,6 +693,7 @@ void slirp_input(Slirp *slirp, const uint8_t *pkt, int
> pkt_len)
> default:
> break;
> }
> + qemu_mutex_unlock(&slirp->lock);
> }
>
> /* Output the IP packet to the ethernet device. Returns 0 if the packet must
> be
> @@ -860,15 +866,21 @@ void slirp_socket_recv(Slirp *slirp, struct in_addr
> guest_addr, int guest_port,
> const uint8_t *buf, int size)
> {
> int ret;
> - struct socket *so = slirp_find_ctl_socket(slirp, guest_addr, guest_port);
> + struct socket *so;
> +
> + qemu_mutex_lock(&slirp->lock);
> + so = slirp_find_ctl_socket(slirp, guest_addr, guest_port);
>
> - if (!so)
> + if (!so) {
> + qemu_mutex_unlock(&slirp->lock);
> return;
> + }
>
> ret = soreadbuf(so, (const char *)buf, size);
>
> if (ret > 0)
> tcp_output(sototcpcb(so));
> + qemu_mutex_unlock(&slirp->lock);
> }
>
> static void slirp_tcp_save(QEMUFile *f, struct tcpcb *tp)
> diff --git a/slirp/slirp.h b/slirp/slirp.h
> index 008360e..7ab0c70 100644
> --- a/slirp/slirp.h
> +++ b/slirp/slirp.h
> @@ -135,6 +135,7 @@ void free(void *ptr);
>
> #include "qemu/queue.h"
> #include "qemu/sockets.h"
> +#include "qemu/thread.h"
>
> #include "libslirp.h"
> #include "ip.h"
> @@ -207,6 +208,8 @@ struct Slirp {
> u_int last_slowtimo;
> int do_slowtimo;
>
> + /* lock to protect slirp running both on frontend or SlirpState context
> */
> + QemuMutex lock;
> /* virtual network configuration */
> struct in_addr vnetwork_addr;
> struct in_addr vnetwork_mask;
>
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] [RFC PATCH v4 06/15] net: port socket to GSource, (continued)
- [Qemu-devel] [RFC PATCH v4 07/15] net: port tap-win32 onto GSource, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 08/15] net: hub use lock to protect ports list, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 09/15] net: introduce lock to protect NetQueue, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 10/15] net: introduce lock to protect NetClientState's peer's access, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 11/15] net: make netclient re-entrant with refcnt, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 12/15] slirp: make timeout local, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 13/15] slirp: make slirp event dispatch based on slirp instance, not global, Liu Ping Fan, 2013/04/17
- [Qemu-devel] [RFC PATCH v4 14/15] slirp: handle race condition, Liu Ping Fan, 2013/04/17
- Re: [Qemu-devel] [RFC PATCH v4 14/15] slirp: handle race condition,
Jan Kiszka <=
[Qemu-devel] [RFC PATCH v4 15/15] slirp: use lock to protect the slirp_instances, Liu Ping Fan, 2013/04/17