> -----Original Message-----
> From: jblu...@gmail.com [mailto:jblu...@gmail.com] On Behalf Of Jan Blunck
> Sent: Tuesday, December 20, 2016 6:47 PM
> To: Shreyansh Jain <shreyansh.j...@nxp.com>
> Cc: dev@dpdk.org; David Marchand <david.march...@6wind.com>; Thomas Monjalon
> <thomas.monja...@6wind.com>; Ferruh Yigit <ferruh.yi...@intel.com>;
> jianbo....@linaro.org
> Subject: Re: [dpdk-dev] [PATCH v3 02/12] eal/bus: introduce bus abstraction
>
> On Fri, Dec 16, 2016 at 2:10 PM, Shreyansh Jain <shreyansh.j...@nxp.com>
> wrote:
> > This patch introduces the rte_bus abstraction for devices and drivers in
> > EAL framework. The model is:
> > - One or more buses are connected to a CPU (or core)
> > - One or more devices are conneted to a Bus
> > - Drivers are running instances which manage one or more devices
> > - Bus is responsible for identifying devices (and interrupt propogation)
> > - Driver is responsible for initializing the device
> >
> > This patch adds a 'rte_bus' class which rte_driver and rte_device refer.
> > This way, each device (rte_xxx_device) would have reference to the bus
> > it is based on. As well as, each driver (rte_xxx_driver) would have link
> > to the bus and devices on it for servicing.
> >
> > __ rte_bus_list
> > /
> > +----------'---+
> > |rte_bus |
> > | driver_list------> List of rte_bus specific
> > | device_list---- devices
> > | | `-> List of rte_bus associated
> > | | drivers
> > +--|------|----+
> > _________/ \_________
> > +--------/----+ +-\---------------+
> > |rte_device | |rte_driver |
> > | rte_bus | | rte_bus |
> > | rte_driver | | ... |
> > | ... | +---------...-----+
> > | | |||
> > +---||--------+ |||
> > || |||
> > | \ \\\
> > | \_____________ \\\
> > | \ |||
> > +------|---------+ +----|----------+ |||
> > |rte_pci_device | |rte_xxx_device | |||
> > | .... | | .... | |||
> > +----------------+ +---------------+ / | \
> > / | \
> > _____________________/ / \
> > / ___/ \
> > +-------------'--+ +------------'---+ +--'------------+
> > |rte_pci_driver | |rte_vdev_driver | |rte_xxx_driver |
> > | .... | | .... | | .... |
> > +----------------+ +----------------+ +---------------+
> >
> > This patch only enables the bus references on rte_driver and rte_driver.
> > EAL wide global device and driver list continue to exist until an instance
> > of bus is added in subsequent patches.
> >
> > This patch also introduces RTE_REGISTER_BUS macro on the lines of
> > RTE_PMD_REGISTER_XXX. Key difference is that the constructor priority has
> > been explicitly set to 101 so as to execute bus registration before PMD.
> >
> > Signed-off-by: Shreyansh Jain <shreyansh.j...@nxp.com>
> >
> > --
> > v2:
> > - fix bsdapp compilation issue because of missing export symbols in map
> > file
> > ---
> > lib/librte_eal/bsdapp/eal/Makefile | 1 +
> > lib/librte_eal/bsdapp/eal/rte_eal_version.map | 15 ++
> > lib/librte_eal/common/Makefile | 2 +-
> > lib/librte_eal/common/eal_common_bus.c | 192
> ++++++++++++++++++++++++
> > lib/librte_eal/common/include/rte_bus.h | 174
> +++++++++++++++++++++
> > lib/librte_eal/common/include/rte_dev.h | 2 +
> > lib/librte_eal/linuxapp/eal/Makefile | 1 +
> > lib/librte_eal/linuxapp/eal/rte_eal_version.map | 15 ++
> > 8 files changed, 401 insertions(+), 1 deletion(-)
> > create mode 100644 lib/librte_eal/common/eal_common_bus.c
> > create mode 100644 lib/librte_eal/common/include/rte_bus.h
> >
> > diff --git a/lib/librte_eal/bsdapp/eal/Makefile
> b/lib/librte_eal/bsdapp/eal/Makefile
> > index a15b762..cce99f7 100644
> > --- a/lib/librte_eal/bsdapp/eal/Makefile
> > +++ b/lib/librte_eal/bsdapp/eal/Makefile
> > @@ -78,6 +78,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) +=
> eal_common_cpuflags.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_string_fns.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_hexdump.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_devargs.c
> > +SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_bus.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_dev.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_options.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_BSDAPP) += eal_common_thread.c
> > diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > index 2f81f7c..23fc1c1 100644
> > --- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > +++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > @@ -174,3 +174,18 @@ DPDK_16.11 {
> > rte_eal_vdrv_unregister;
> >
> > } DPDK_16.07;
> > +
> > +DPDK_17.02 {
> > + global:
> > +
> > + rte_bus_list;
> > + rte_eal_bus_add_device;
> > + rte_eal_bus_add_driver;
> > + rte_eal_get_bus;
> > + rte_eal_bus_dump;
> > + rte_eal_bus_register;
> > + rte_eal_bus_remove_device;
> > + rte_eal_bus_remove_driver;
> > + rte_eal_bus_unregister;
> > +
> > +} DPDK_16.11;
> > diff --git a/lib/librte_eal/common/Makefile
> b/lib/librte_eal/common/Makefile
> > index a92c984..0c39414 100644
> > --- a/lib/librte_eal/common/Makefile
> > +++ b/lib/librte_eal/common/Makefile
> > @@ -38,7 +38,7 @@ INC += rte_per_lcore.h rte_random.h
> > INC += rte_tailq.h rte_interrupts.h rte_alarm.h
> > INC += rte_string_fns.h rte_version.h
> > INC += rte_eal_memconfig.h rte_malloc_heap.h
> > -INC += rte_hexdump.h rte_devargs.h rte_dev.h rte_vdev.h
> > +INC += rte_hexdump.h rte_devargs.h rte_bus.h rte_dev.h rte_vdev.h
> > INC += rte_pci_dev_feature_defs.h rte_pci_dev_features.h
> > INC += rte_malloc.h rte_keepalive.h rte_time.h
> >
> > diff --git a/lib/librte_eal/common/eal_common_bus.c
> b/lib/librte_eal/common/eal_common_bus.c
> > new file mode 100644
> > index 0000000..612f64e
> > --- /dev/null
> > +++ b/lib/librte_eal/common/eal_common_bus.c
> > @@ -0,0 +1,192 @@
> > +/*-
> > + * BSD LICENSE
> > + *
> > + * Copyright(c) 2016 NXP
> > + * 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 NXP 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 <stdio.h>
> > +#include <string.h>
> > +#include <inttypes.h>
> > +#include <sys/queue.h>
> > +
> > +#include <rte_bus.h>
> > +#include <rte_devargs.h>
> > +#include <rte_debug.h>
> > +
> > +#include "eal_private.h"
> > +
> > +struct rte_bus_list rte_bus_list =
> > + TAILQ_HEAD_INITIALIZER(rte_bus_list);
> > +
> > +/** @internal
> > + * Add a device to a bus.
> > + */
> > +void
> > +rte_eal_bus_add_device(struct rte_bus *bus, struct rte_device *dev)
> > +{
> > + RTE_VERIFY(bus);
> > + RTE_VERIFY(dev);
> > +
> > + TAILQ_INSERT_TAIL(&bus->device_list, dev, next);
> > + dev->bus = bus;
> > +}
> > +
> > +/** @internal
> > + * Remove a device from its bus.
> > + */
> > +void
> > +rte_eal_bus_remove_device(struct rte_device *dev)
> > +{
> > + struct rte_bus *bus;
> > +
> > + RTE_VERIFY(dev);
> > + RTE_VERIFY(dev->bus);
> > +
> > + bus = dev->bus;
> > + TAILQ_REMOVE(&bus->device_list, dev, next);
> > + dev->bus = NULL;
> > +}
> > +
> > +/** @internal
> > + * Associate a driver with a bus.
> > + */
> > +void
> > +rte_eal_bus_add_driver(struct rte_bus *bus, struct rte_driver *drv)
> > +{
> > + RTE_VERIFY(bus);
> > + RTE_VERIFY(drv);
> > +
> > + TAILQ_INSERT_TAIL(&bus->driver_list, drv, next);
> > + drv->bus = bus;
> > +}
> > +
> > +/** @internal
> > + * Disassociate a driver from bus.
> > + */
> > +void
> > +rte_eal_bus_remove_driver(struct rte_driver *drv)
> > +{
> > + struct rte_bus *bus;
> > +
> > + RTE_VERIFY(drv);
> > + RTE_VERIFY(drv->bus);
> > +
> > + bus = drv->bus;
> > + TAILQ_REMOVE(&bus->driver_list, drv, next);
> > + drv->bus = NULL;
> > +}
> > +
> > +/**
> > + * Get the bus handle using its name
> > + */
> > +struct rte_bus *
> > +rte_eal_get_bus(const char *bus_name)
> > +{
> > + struct rte_bus *bus;
> > +
> > + RTE_VERIFY(bus_name);
> > +
> > + TAILQ_FOREACH(bus, &rte_bus_list, next) {
> > + RTE_VERIFY(bus->name);
> > +
> > + if (!strcmp(bus_name, bus->name)) {
> > + RTE_LOG(DEBUG, EAL, "Returning Bus object %p\n",
> bus);
> > + return bus;
> > + }
> > + }
> > +
> > + /* Unable to find bus requested */
> > + return NULL;
> > +}
> > +
> > +/* register a bus */
> > +void
> > +rte_eal_bus_register(struct rte_bus *bus)
> > +{
> > + RTE_VERIFY(bus);
> > + RTE_VERIFY(bus->name && strlen(bus->name));
> > +
> > + /* Initialize the driver and device list associated with the bus */
> > + TAILQ_INIT(&(bus->driver_list));
> > + TAILQ_INIT(&(bus->device_list));
> > +
> > + TAILQ_INSERT_TAIL(&rte_bus_list, bus, next);
> > + RTE_LOG(INFO, EAL, "Registered [%s] bus.\n", bus->name);
> > +}
> > +
> > +/* unregister a bus */
> > +void
> > +rte_eal_bus_unregister(struct rte_bus *bus)
> > +{
> > + /* All devices and drivers associated with the bus should have been
> > + * 'device->uninit' and 'driver->remove()' already.
> > + */
> > + RTE_VERIFY(TAILQ_EMPTY(&(bus->driver_list)));
> > + RTE_VERIFY(TAILQ_EMPTY(&(bus->device_list)));
> > +
> > + /* TODO: For each device, call its rte_device->driver->remove()
> > + * and rte_eal_bus_remove_driver()
> > + */
> > +
> > + TAILQ_REMOVE(&rte_bus_list, bus, next);
> > + RTE_LOG(INFO, EAL, "Unregistered [%s] bus.\n", bus->name);
> > +}
> > +
> > +/* dump one bus info */
> > +static int
> > +bus_dump_one(FILE *f, struct rte_bus *bus)
> > +{
> > + int ret;
> > +
> > + /* For now, dump only the bus name */
> > + ret = fprintf(f, " %s\n", bus->name);
> > +
> > + /* Error in case of inability in writing to stream */
> > + if (ret < 0)
> > + return ret;
> > +
> > + return 0;
> > +}
> > +
> > +void
> > +rte_eal_bus_dump(FILE *f)
> > +{
> > + int ret;
> > + struct rte_bus *bus;
> > +
> > + TAILQ_FOREACH(bus, &rte_bus_list, next) {
> > + ret = bus_dump_one(f, bus);
> > + if (ret) {
> > + RTE_LOG(ERR, EAL, "Unable to write to stream
> (%d)\n",
> > + ret);
> > + break;
> > + }
> > + }
> > +}
> > diff --git a/lib/librte_eal/common/include/rte_bus.h
> b/lib/librte_eal/common/include/rte_bus.h
> > new file mode 100644
> > index 0000000..f0297a9
> > --- /dev/null
> > +++ b/lib/librte_eal/common/include/rte_bus.h
> > @@ -0,0 +1,174 @@
> > +/*-
> > + * BSD LICENSE
> > + *
> > + * Copyright(c) 2016 NXP
> > + * 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 NXP 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 _RTE_BUS_H_
> > +#define _RTE_BUS_H_
> > +
> > +/**
> > + * @file
> > + *
> > + * RTE PMD Bus Abstraction interfaces
> > + *
> > + * This file exposes APIs and Interfaces for Bus Abstraction over the
> devices
> > + * drivers in EAL.
> > + */
> > +
> > +#ifdef __cplusplus
> > +extern "C" {
> > +#endif
> > +
> > +#include <stdio.h>
> > +#include <sys/queue.h>
> > +
> > +#include <rte_log.h>
> > +#include <rte_dev.h>
> > +
> > +/** Double linked list of buses */
> > +TAILQ_HEAD(rte_bus_list, rte_bus);
> > +
> > +/* Global Bus list */
> > +extern struct rte_bus_list rte_bus_list;
> > +
> > +struct rte_bus {
> > + TAILQ_ENTRY(rte_bus) next; /**< Next bus object in linked list */
> > + struct rte_driver_list driver_list;
> > + /**< List of all drivers on bus */
> > + struct rte_device_list device_list;
> > + /**< List of all devices on bus */
> > + const char *name; /**< Name of the bus */
> > +};
> > +
> > +/** @internal
> > + * Add a device to a bus.
> > + *
> > + * @param bus
> > + * Bus on which device is to be added
> > + * @param dev
> > + * Device handle
> > + * @return
> > + * None
> > + */
> > +void
> > +rte_eal_bus_add_device(struct rte_bus *bus, struct rte_device *dev);
> > +
> > +/** @internal
> > + * Remove a device from its bus.
> > + *
> > + * @param dev
> > + * Device handle to remove
> > + * @return
> > + * None
> > + */
> > +void
> > +rte_eal_bus_remove_device(struct rte_device *dev);
> > +
> > +/** @internal
> > + * Associate a driver with a bus.
> > + *
> > + * @param bus
> > + * Bus on which driver is to be added
> > + * @param dev
> > + * Driver handle
> > + * @return
> > + * None
> > + */
> > +void
> > +rte_eal_bus_add_driver(struct rte_bus *bus, struct rte_driver *drv);
> > +
> > +/** @internal
> > + * Disassociate a driver from its bus.
> > + *
> > + * @param dev
> > + * Driver handle to remove
> > + * @return
> > + * None
> > + */
> > +void
> > +rte_eal_bus_remove_driver(struct rte_driver *drv);
> > +
> > +/**
> > + * Register a Bus handler.
> > + *
> > + * @param driver
> > + * A pointer to a rte_bus structure describing the bus
> > + * to be registered.
> > + */
> > +void rte_eal_bus_register(struct rte_bus *bus);
> > +
> > +/**
> > + * Unregister a Bus handler.
> > + *
> > + * @param driver
> > + * A pointer to a rte_bus structure describing the bus
> > + * to be unregistered.
> > + */
> > +void rte_eal_bus_unregister(struct rte_bus *bus);
> > +
> > +/**
> > + * Obtain handle for bus given its name.
> > + *
> > + * @param bus_name
> > + * Name of the bus handle to search
> > + * @return
> > + * Pointer to Bus object if name matches any registered bus object
> > + * NULL, if no matching bus found
> > + */
> > +struct rte_bus *rte_eal_get_bus(const char *bus_name);
> > +
> > +/**
> > + * Dump information of all the buses registered with EAL.
> > + *
> > + * @param f
> > + * A valid and open output stream handle
> > + *
> > + * @return
> > + * 0 in case of success
> > + * !0 in case there is error in opening the output stream
> > + */
> > +void rte_eal_bus_dump(FILE *f);
> > +
> > +/** Helper for Bus registration. The constructor has higher priority than
> > + * PMD constructors
> > + */
> > +#define RTE_REGISTER_BUS(nm, bus) \
> > +static void __attribute__((constructor(101), used)) businitfn_ ##nm(void)
> \
> > +{\
> > + (bus).name = RTE_STR(nm);\
> > + rte_eal_bus_register(&bus); \
> > +}
> > +
> > +#ifdef __cplusplus
> > +}
> > +#endif
> > +
> > +#endif /* _RTE_BUS_H */
> > diff --git a/lib/librte_eal/common/include/rte_dev.h
> b/lib/librte_eal/common/include/rte_dev.h
> > index 8840380..4004f9a 100644
> > --- a/lib/librte_eal/common/include/rte_dev.h
> > +++ b/lib/librte_eal/common/include/rte_dev.h
> > @@ -122,6 +122,7 @@ struct rte_driver;
> > */
> > struct rte_device {
> > TAILQ_ENTRY(rte_device) next; /**< Next device */
> > + struct rte_bus *bus; /**< Device connected to this bus */
>
> Is there a reason why this isn't const?
No reason. Miss from my end. I will fix this.
(I also took hint from Stephen's recent patches)
>
>
> > struct rte_driver *driver; /**< Associated driver */
> > int numa_node; /**< NUMA node connection */
> > struct rte_devargs *devargs; /**< Device user arguments */
> > @@ -148,6 +149,7 @@ void rte_eal_device_remove(struct rte_device *dev);
> > */
> > struct rte_driver {
> > TAILQ_ENTRY(rte_driver) next; /**< Next in list. */
> > + struct rte_bus *bus; /**< Bus serviced by this driver */
>
> Same thing here.
I will send out v4 with this. Thanks for comments.
>
> > const char *name; /**< Driver name. */
> > const char *alias; /**< Driver alias. */
> > };
> > diff --git a/lib/librte_eal/linuxapp/eal/Makefile
> b/lib/librte_eal/linuxapp/eal/Makefile
> > index 4e206f0..aa874a5 100644
> > --- a/lib/librte_eal/linuxapp/eal/Makefile
> > +++ b/lib/librte_eal/linuxapp/eal/Makefile
> > @@ -87,6 +87,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) +=
> eal_common_cpuflags.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_string_fns.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_hexdump.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_devargs.c
> > +SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_bus.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_dev.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_options.c
> > SRCS-$(CONFIG_RTE_EXEC_ENV_LINUXAPP) += eal_common_thread.c
> > diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > index 83721ba..c873a7f 100644
> > --- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > +++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
> > @@ -178,3 +178,18 @@ DPDK_16.11 {
> > rte_eal_vdrv_unregister;
> >
> > } DPDK_16.07;
> > +
> > +DPDK_17.02 {
> > + global:
> > +
> > + rte_bus_list;
> > + rte_eal_bus_add_device;
> > + rte_eal_bus_add_driver;
> > + rte_eal_get_bus;
> > + rte_eal_bus_dump;
> > + rte_eal_bus_register;
> > + rte_eal_bus_remove_device;
> > + rte_eal_bus_remove_driver;
> > + rte_eal_bus_unregister;
> > +
> > +} DPDK_16.11;
> > --
> > 2.7.4
> >
