[dpdk-dev,RFC,v2,07/12] lib/librte_vhost: async event and callback

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
---
 lib/librte_vhost/vhost_user/fd_man.c | 205 +++++++++++++++++++++++++++++++++++
 lib/librte_vhost/vhost_user/fd_man.h |  64 +++++++++++
 2 files changed, 269 insertions(+)
 create mode 100644 lib/librte_vhost/vhost_user/fd_man.c
 create mode 100644 lib/librte_vhost/vhost_user/fd_man.h
  

(2014/12/11 6:37), Huawei Xie wrote:
> Signed-off-by: Huawei Xie <huawei.xie@intel.com>
> ---
>  lib/librte_vhost/vhost_user/fd_man.c | 205 +++++++++++++++++++++++++++++++++++
>  lib/librte_vhost/vhost_user/fd_man.h |  64 +++++++++++
>  2 files changed, 269 insertions(+)
>  create mode 100644 lib/librte_vhost/vhost_user/fd_man.c
>  create mode 100644 lib/librte_vhost/vhost_user/fd_man.h
>
> diff --git a/lib/librte_vhost/vhost_user/fd_man.c b/lib/librte_vhost/vhost_user/fd_man.c
> new file mode 100644
> index 0000000..f4db68b
> --- /dev/null
> +++ b/lib/librte_vhost/vhost_user/fd_man.c
> @@ -0,0 +1,205 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
> + *   All rights reserved.
> + *
> + *   Redistribution and use in source and binary forms, with or without
> + *   modification, are permitted provided that the following conditions
> + *   are met:
> + *
> + *     * Redistributions of source code must retain the above copyright
> + *       notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *       notice, this list of conditions and the following disclaimer in
> + *       the documentation and/or other materials provided with the
> + *       distribution.
> + *     * Neither the name of Intel Corporation nor the names of its
> + *       contributors may be used to endorse or promote products derived
> + *       from this software without specific prior written permission.
> + *
> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#include <stdint.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +#include <sys/socket.h>
> +#include <sys/select.h>
> +#include <sys/time.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include <rte_log.h>
> +
> +#include "fd_man.h"
> +
> +/**
> + * Returns the index in the fdset for a given fd.
> + * If fd is -1, it means to search for a free entry.
> + * @return
> + *   index for the fd, or -1 if fd isn't in the fdset.
> + */
> +static int
> +fdset_find_fd(struct fdset *pfdset, int fd)
> +{
> +	int i;
> +
> +	if (pfdset == NULL)
> +		return -1;
> +
> +	for (i = 0; i < pfdset->num && pfdset->fd[i].fd != fd; i++);

I got error from checkpatch.pl like followings.

ERROR: trailing statements should be on next line
#74: FILE: lib/librte_vhost/vhost_user/fd_man.c:61:
+ for (i = 0; i < pfdset->num && pfdset->fd[i].fd != fd; i++);


> +
> +	return i ==  pfdset->num ? -1 : i;
> +}
> +
> +static int
> +fdset_find_free_slot(struct fdset *pfdset)
> +{
> +	return fdset_find_fd(pfdset, -1);
> +}
> +
> +static void
> +fdset_add_fd(struct fdset  *pfdset, int idx, int fd,
> +	fd_cb rcb, fd_cb wcb, uint64_t dat)
> +{
> +	struct fdentry *pfdentry;
> +
> +	if (pfdset == NULL || idx >= pfdset->num)
> +		return;
> +
> +	pfdentry = &pfdset->fd[idx];
> +	pfdentry->fd = fd;
> +	pfdentry->rcb = rcb;
> +	pfdentry->wcb = wcb;
> +	pfdentry->dat = dat;
> +}
> +
> +/**
> + * Fill the read/write fdset with the fds in the fdset.
> + * @return
> + *  the maximum fds filled in the read/write fd_set.
> + */
> +static int
> +fdset_fill(fd_set *rfset, fd_set *wfset, struct fdset *pfdset)
> +{
> +	struct fdentry *pfdentry;
> +	int i, maxfds = -1;
> +	int num = MAX_FDS;

Is it possible to use pfdset->num?

> +
> +	if (pfdset == NULL)
> +		return -1;
> +
> +	for (i = 0; i < num ; i++) {
> +		pfdentry = &pfdset->fd[i];
> +		if (pfdentry->fd != -1) {
> +			int added = 0;

Need a line?

> +			if (pfdentry->rcb && rfset) {
> +				FD_SET(pfdentry->fd, rfset);
> +				added = 1;
> +			}
> +			if (pfdentry->wcb && wfset) {
> +				FD_SET(pfdentry->fd, wfset);
> +				added = 1;
> +			}
> +			if (added)
> +				maxfds = pfdentry->fd < maxfds ?
> +					maxfds : pfdentry->fd;
> +		}
> +	}
> +	return maxfds;
> +}
> +
> +void
> +fdset_init(struct fdset *pfdset)
> +{
> +	int i;
> +
> +	if (pfdset == NULL)
> +		return;
> +
> +	for (i = 0; i < MAX_FDS; i++)
> +		pfdset->fd[i].fd = -1;
> +	pfdset->num = MAX_FDS;
> +}
> +
> +/**
> + * Register the fd in the fdset with read/write handler and context.
> + */
> +int
> +fdset_add(struct fdset *pfdset, int fd, fd_cb rcb, fd_cb wcb, uint64_t dat)
> +{
> +	int i;
> +
> +	if (pfdset == NULL || fd == -1)
> +		return -1;
> +
> +	/* Find a free slot in the list. */
> +	i = fdset_find_free_slot(pfdset);
> +	if (i == -1)
> +		return -2;
> +
> +	fdset_add_fd(pfdset, i, fd, rcb, wcb, dat);
> +
> +	return 0;
> +}
> +
> +/**
> + *  Unregister the fd from the fdset.
> + */
> +void
> +fdset_del(struct fdset *pfdset, int fd)
> +{
> +	int i;
> +
> +	i = fdset_find_fd(pfdset, fd);
> +	if (i != -1) {
> +		pfdset->fd[i].fd = -1;
> +		pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL;
> +	}
> +}
> +
> +/**
> + * This functions runs in infinite blocking loop until there is no fd in
> + * pfdset. It calls corresponding r/w handler if there is event on the fd.
> + */
> +void
> +fdset_event_dispatch(struct fdset *pfdset)
> +{
> +	fd_set rfds,wfds;

Need a space between rfds and wfds.

> +	int i, maxfds;
> +	struct fdentry *pfdentry;
> +	int num = MAX_FDS;

Is it possible to use pfdset->num?

> +
> +	if (pfdset == NULL)
> +		return;
> +
> +	while (1) {
> +		FD_ZERO(&rfds);
> +		FD_ZERO(&wfds);
> +		maxfds = fdset_fill(&rfds, &wfds, pfdset);
> +		if (maxfds == -1) {
> +			return;
> +		}
> +
> +		select(maxfds + 1, &rfds, &wfds, NULL, NULL);
> +
> +		for (i = 0; i < num; i++) {
> +			pfdentry = &pfdset->fd[i];
> +			if (FD_ISSET(pfdentry->fd, &rfds) && pfdentry->rcb)
> +				pfdentry->rcb(pfdentry->fd, pfdentry->dat);
> +			if (FD_ISSET(pfdentry->fd, &wfds) && pfdentry->wcb)
> +				pfdentry->wcb(pfdentry->fd, pfdentry->dat);
> +		}
> +	}
> +}
> diff --git a/lib/librte_vhost/vhost_user/fd_man.h b/lib/librte_vhost/vhost_user/fd_man.h
> new file mode 100644
> index 0000000..1722954
> --- /dev/null
> +++ b/lib/librte_vhost/vhost_user/fd_man.h
> @@ -0,0 +1,64 @@
> +/*-
> + *   BSD LICENSE
> + *
> + *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
> + *   All rights reserved.
> + *
> + *   Redistribution and use in source and binary forms, with or without
> + *   modification, are permitted provided that the following conditions
> + *   are met:
> + *
> + *     * Redistributions of source code must retain the above copyright
> + *       notice, this list of conditions and the following disclaimer.
> + *     * Redistributions in binary form must reproduce the above copyright
> + *       notice, this list of conditions and the following disclaimer in
> + *       the documentation and/or other materials provided with the
> + *       distribution.
> + *     * Neither the name of Intel Corporation nor the names of its
> + *       contributors may be used to endorse or promote products derived
> + *       from this software without specific prior written permission.
> + *
> + *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
> + *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
> + *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
> + *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
> + *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
> + *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
> + *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
> + *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
> + *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
> + *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
> + *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
> + */
> +
> +#ifndef _FD_MAN_H_
> +#define _FD_MAN_H_
> +#include <stdint.h>
> +
> +#define MAX_FDS 1024
> +
> +typedef void (*fd_cb)(int fd, uint64_t dat);
> +
> +struct fdentry {
> +	int fd;		/* -1 indicates this entry is empty */
> +	fd_cb rcb;	/* callback when this fd is readable. */
> +	fd_cb wcb;	/* callback when this fd is writeable.*/
> +	uint64_t dat;	/* fd context */
> +};
> +
> +struct fdset {
> +	struct fdentry fd[MAX_FDS];
> +	int num;	/* capacity of this fdset */
> +};
> +
> +
> +void fdset_init(struct fdset *pfdset);
> +
> +int fdset_add(struct fdset *pfdset, int fd,
> +	fd_cb rcb, fd_cb wcb, uint64_t ctx);
> +
> +void fdset_del(struct fdset *pfdset, int fd);
> +
> +void fdset_event_dispatch(struct fdset *pfdset);
> +
> +#endif
  

> 
> I got error from checkpatch.pl like followings.
> 
> ERROR: trailing statements should be on next line
> #74: FILE: lib/librte_vhost/vhost_user/fd_man.c:61:
> + for (i = 0; i < pfdset->num && pfdset->fd[i].fd != fd; i++);
Thanks.
This is RFC, so maybe it is far from perfection, :).

> > +	int num = MAX_FDS;
> 
> Is it possible to use pfdset->num?
> 

Had considered this.
It is not performance critical code, and it is easier to use MAX_FDS.
We could improve this after we have processed all the critical things.

> > +
> > +			int added = 0;
> 
> Need a line?

Thanks!
> 
> > +			if (pfdentry->rcb && rfset) {
> > +				FD_SET(pfdentry->fd, rfset);
> > +				added = 1;
> > +			


> > +	fd_set rfds,wfds;
> 
> Need a space between rfds and wfds.

Agree.
> 
> > +	int i, maxfds;
> > +	struct fdentry *pfdentry;
> > +	int num = MAX_FDS;
> 
> Is it possible to use pfdset->num?
>

> > +
> > +	if (pfdset == NULL)
> > +		return;
> > +
> > +	while (1) {
> > +		FD_ZERO(&rfds);
> > +		FD_ZERO(&wfds);
> > +		maxfds = fdset_fill(&rfds, &wfds, pfdset);
> > +		if (maxfds == -1) {
> > +			return;
> > +		}
> > +
> > +		select(maxfds + 1, &rfds, &wfds, NULL, NULL);
> > +
> > +		for (i = 0; i < num; i++) {
> > +			pfdentry = &pfdset->fd[i];
> > +			if (FD_ISSET(pfdentry->fd, &rfds) && pfdentry->rcb)
> > +				pfdentry->rcb(pfdentry->fd, pfdentry->dat);
> > +			if (FD_ISSET(pfdentry->fd, &wfds) && pfdentry->wcb)
> > +				pfdentry->wcb(pfdentry->fd, pfdentry->dat);
> > +		}
> > +	}
> > +}