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dm: enhence the mevent API

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There is one race issue between mevent callback (which is called
in mevent_dispatch thread) and mevent_delete (which could be called
in dev thread). And the callback is called after mevent_delete.

libevent have the exactly same issue. The issue is decripted here:
https://github.com/libevent/libevent/blob/master/whatsnew-2.1.txt

The fixing is:
We introduce a teardown callback to mevent and make sure there is
no race issue between callback and teardown call.

This patch updates the mevent API and the caller as well.

Tracked-On: #1877
Signed-off-by: Yin Fengwei <fengwei.yin@intel.com>
Acked-by: Yu Wang <yu1.wang@intel.com>
This commit is contained in:
Yin Fengwei 2018-11-22 14:42:01 +08:00 committed by wenlingz
parent eec3a342c4
commit 64d9c59aa1
10 changed files with 52 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
devicemodel/arch/x86/pm.c
View File

@ -296,7 +296,7 @@ smi_cmd_handler(struct vmctx *ctx, int vcpu, int in, int port, int bytes,
pm1_control |= PM1_SCI_EN;
if (power_button == NULL) {
power_button = mevent_add(SIGTERM, EVF_SIGNAL,
power_button_handler, ctx);
power_button_handler, ctx, NULL, NULL);
old_power_handler = signal(SIGTERM, SIG_IGN);
}
break;

62
devicemodel/core/mevent.c
View File

@ -56,10 +56,13 @@ static int mevent_pipefd[2];
static pthread_mutex_t mevent_lmutex = PTHREAD_MUTEX_INITIALIZER;
struct mevent {
void (*me_func)(int, enum ev_type, void *);
void (*run)(int, enum ev_type, void *);
void *run_param;
void (*teardown)(void *);
void *teardown_param;
int me_fd;
enum ev_type me_type;
void *me_param;
int me_cq;
int me_state;
@ -114,7 +117,7 @@ mevent_notify(void)
* If calling from outside the i/o thread, write a byte on the
* pipe to force the i/o thread to exit the blocking epoll call.
*/
if (mevent_pipefd[1] != 0 && pthread_self() != mevent_tid)
if (mevent_pipefd[1] != 0 && !is_dispatch_thread())
if (write(mevent_pipefd[1], &c, 1) <= 0)
return -1;
return 0;
@ -152,12 +155,15 @@ mevent_destroy(void)
LIST_REMOVE(mevp, me_list);
epoll_ctl(epoll_fd, EPOLL_CTL_DEL, mevp->me_fd, NULL);
if ((mevp->me_type == EVF_READ ||
mevp->me_type == EVF_READ_ET ||
mevp->me_type == EVF_WRITE ||
mevp->me_type == EVF_WRITE_ET) &&
mevp->me_fd != STDIN_FILENO)
close(mevp->me_fd);
if ((mevp->me_type == EVF_READ ||
mevp->me_type == EVF_READ_ET ||
mevp->me_type == EVF_WRITE ||
mevp->me_type == EVF_WRITE_ET) &&
mevp->me_fd != STDIN_FILENO)
close(mevp->me_fd);
if (mevp->teardown)
mevp->teardown(mevp->teardown_param);
free(mevp);
}
@ -168,12 +174,15 @@ mevent_destroy(void)
list_foreach_safe(mevp, &del_head, me_list, tmpp) {
LIST_REMOVE(mevp, me_list);
if ((mevp->me_type == EVF_READ ||
mevp->me_type == EVF_READ_ET ||
mevp->me_type == EVF_WRITE ||
mevp->me_type == EVF_WRITE_ET) &&
mevp->me_fd != STDIN_FILENO)
close(mevp->me_fd);
if ((mevp->me_type == EVF_READ ||
mevp->me_type == EVF_READ_ET ||
mevp->me_type == EVF_WRITE ||
mevp->me_type == EVF_WRITE_ET) &&
mevp->me_fd != STDIN_FILENO)
close(mevp->me_fd);
if (mevp->teardown)
mevp->teardown(mevp->teardown_param);
free(mevp);
}
@ -190,19 +199,20 @@ mevent_handle(struct epoll_event *kev, int numev)
mevp = kev[i].data.ptr;
if (mevp->me_state)
(*mevp->me_func)(mevp->me_fd, mevp->me_type, mevp->me_param);
(*mevp->run)(mevp->me_fd, mevp->me_type, mevp->run_param);
}
}
struct mevent *
mevent_add(int tfd, enum ev_type type,
void (*func)(int, enum ev_type, void *), void *param)
void (*run)(int, enum ev_type, void *), void *run_param,
void (*teardown)(void *), void *teardown_param)
{
int ret;
struct epoll_event ee;
struct mevent *lp, *mevp;
if (tfd < 0 || func == NULL)
if (tfd < 0 || run == NULL)
return NULL;
if (type == EVF_TIMER)
@ -227,10 +237,13 @@ mevent_add(int tfd, enum ev_type type,
mevp->me_fd = tfd;
mevp->me_type = type;
mevp->me_func = func;
mevp->me_param = param;
mevp->me_state = 1;
mevp->run = run;
mevp->run_param = run_param;
mevp->teardown = teardown;
mevp->teardown_param = teardown_param;
ee.events = mevent_kq_filter(mevp);
ee.data.ptr = mevp;
ret = epoll_ctl(epoll_fd, EPOLL_CTL_ADD, mevp->me_fd, &ee);
@ -241,6 +254,8 @@ mevent_add(int tfd, enum ev_type type,
return mevp;
} else {
if (mevp->teardown)
mevp->teardown(mevp->teardown_param);
free(mevp);
return NULL;
}
@ -308,6 +323,9 @@ mevent_drain_del_list(void)
if (evp->closefd) {
close(evp->me_fd);
}
if (evp->teardown)
evp->teardown(evp->teardown_param);
free(evp);
}
mevent_qunlock();
@ -323,7 +341,7 @@ mevent_delete_event(struct mevent *evp, int closefd)
evp->closefd = closefd;
epoll_ctl(epoll_fd, EPOLL_CTL_DEL, evp->me_fd, NULL);
if (!is_dispatch_thread()) {
if (!is_dispatch_thread() && evp->teardown != NULL) {
mevent_add_to_del_list(evp, closefd);
} else {
if (evp->closefd) {
@ -398,7 +416,7 @@ mevent_dispatch(void)
/*
* Add internal event handler for the pipe write fd
*/
pipev = mevent_add(mevent_pipefd[0], EVF_READ, mevent_pipe_read, NULL);
pipev = mevent_add(mevent_pipefd[0], EVF_READ, mevent_pipe_read, NULL, NULL, NULL);
assert(pipev != NULL);
for (;;) {

2
devicemodel/core/timer.c
View File

@ -71,7 +71,7 @@ acrn_timer_init(struct acrn_timer *timer, void (*cb)(void *), void *param)
return -1;
}
timer->mevp = mevent_add(timer->fd, EVF_READ, timer_handler, timer);
timer->mevp = mevent_add(timer->fd, EVF_READ, timer_handler, timer, NULL, NULL);
if (timer->mevp == NULL) {
close(timer->fd);
perror("acrn_timer mevent add failed.\n");

2
devicemodel/hw/pci/virtio/vhost.c
View File

@ -283,7 +283,7 @@ vhost_vq_register_eventfd(struct vhost_dev *vdev,
*/
if (is_register) {
vq->mevp = mevent_add(vq->call_fd, EVF_READ,
vhost_vq_notify, vq);
vhost_vq_notify, vq, NULL, NULL);
if (!vq->mevp) {
WPRINTF("mevent_add failed\n");
rc = -1;

2
devicemodel/hw/pci/virtio/virtio_console.c
View File

@ -679,7 +679,7 @@ virtio_console_add_backend(struct virtio_console *console,
if (virtio_console_backend_can_read(be_type)) {
if (isatty(fd)) {
be->evp = mevent_add(fd, EVF_READ,
virtio_console_backend_read, be);
virtio_console_backend_read, be, NULL, NULL);
if (be->evp == NULL) {
WPRINTF(("vtcon: mevent_add failed\n"));
error = -1;

2
devicemodel/hw/pci/virtio/virtio_input.c
View File

@ -634,7 +634,7 @@ virtio_input_init(struct vmctx *ctx, struct pci_vdev *dev, char *opts)
goto fail;
}
vi->mevp = mevent_add(vi->fd, EVF_READ, virtio_input_read_event, vi);
vi->mevp = mevent_add(vi->fd, EVF_READ, virtio_input_read_event, vi, NULL, NULL);
if (vi->mevp == NULL) {
WPRINTF(("vtinput: could not register event\n"));
goto fail;

6
devicemodel/hw/pci/virtio/virtio_mei.c
View File

@ -1017,7 +1017,7 @@ vmei_host_client_native_connect(struct vmei_host_client *hclient)
/* add READ event into mevent */
hclient->rx_mevp = mevent_add(hclient->client_fd, EVF_READ,
vmei_rx_callback, hclient);
vmei_rx_callback, hclient, NULL, NULL);
if (!hclient->rx_mevp)
return MEI_HBM_REJECTED;
@ -1951,7 +1951,7 @@ vmei_start(struct virtio_mei *vmei, bool do_rescan)
hclient->client_fd = pipefd[0];
hclient->rx_mevp = mevent_add(hclient->client_fd, EVF_READ,
vmei_rx_callback, hclient);
vmei_rx_callback, hclient, NULL, NULL);
vmei->hbm_fd = pipefd[1];
if (do_rescan) {
@ -2051,7 +2051,7 @@ static int vmei_add_reset_event(struct virtio_mei *vmei)
vmei->dev_state_first = true;
vmei->reset_mevp = mevent_add(dev_state_fd, EVF_READ_ET,
vmei_reset_callback, vmei);
vmei_reset_callback, vmei, NULL, NULL);
if (!vmei->reset_mevp) {
close(dev_state_fd);
return -ENOMEM;

2
devicemodel/hw/pci/virtio/virtio_net.c
View File

@ -707,7 +707,7 @@ virtio_net_tap_setup(struct virtio_net *net, char *devname)
if (vhost_fd < 0) {
net->mevp = mevent_add(net->tapfd, EVF_READ,
virtio_net_rx_callback, net);
virtio_net_rx_callback, net, NULL, NULL);
if (net->mevp == NULL) {
WPRINTF(("Could not register event\n"));
close(net->tapfd);

3
devicemodel/hw/uart_core.c
View File

@ -270,8 +270,7 @@ uart_opentty(struct uart_vdev *uart)
{
ttyopen(&uart->tty);
if (isatty(uart->tty.fd_in)) {
uart->mev = mevent_add(uart->tty.fd_in, EVF_READ,
uart_drain, uart);
uart->mev = mevent_add(uart->tty.fd_in, EVF_READ, uart_drain, uart, NULL, NULL);
assert(uart->mev != NULL);
}
}

4
devicemodel/include/mevent.h
View File

@ -41,8 +41,8 @@ enum ev_type {
struct mevent;
struct mevent *mevent_add(int fd, enum ev_type type,
void (*func)(int, enum ev_type, void *),
void *param);
void (*run)(int, enum ev_type, void *), void *param,
void (*teardown)(void *), void *teardown_param);
int mevent_enable(struct mevent *evp);
int mevent_disable(struct mevent *evp);
int mevent_delete(struct mevent *evp);