[dpdk-dev] [PATCH v3 10/20] eal/dev: implement device iteration initialization

Gaëtan Rivet gaetan.rivet at 6wind.com
Tue Mar 27 22:23:21 CEST 2018


On Tue, Mar 27, 2018 at 03:04:13PM +0200, Gaëtan Rivet wrote:
> On Tue, Mar 27, 2018 at 02:40:00PM +0200, Gaëtan Rivet wrote:
> > On Tue, Mar 27, 2018 at 07:47:50AM -0400, Neil Horman wrote:
> > > On Tue, Mar 27, 2018 at 01:18:34AM +0200, Gaetan Rivet wrote:
> > > > Parse a device description.
> > > > Split this description in their relevant part for each layers.
> > > > No dynamic allocation is performed.
> > > > 
> > > > Cc: Neil Horman <nhorman at tuxdriver.com>
> > > > Cc: "Wiles, Keith" <keith.wiles at intel.com>
> > > > Signed-off-by: Gaetan Rivet <gaetan.rivet at 6wind.com>
> > > > ---
> > > > 
> > > > This version uses librte_kvargs.
> > > > 
> > > >  lib/Makefile                            |   1 +
> > > >  lib/librte_eal/bsdapp/eal/Makefile      |   1 +
> > > >  lib/librte_eal/common/eal_common_dev.c  | 147 ++++++++++++++++++++++++++++++++
> > > >  lib/librte_eal/common/include/rte_dev.h |  23 +++++
> > > >  lib/librte_eal/linuxapp/eal/Makefile    |   1 +
> > > >  lib/librte_eal/rte_eal_version.map      |   1 +
> > > >  6 files changed, 174 insertions(+)
> > > > 
> > > > diff --git a/lib/Makefile b/lib/Makefile
> > > > index fc7a55a37..1b17526f7 100644
> > > > --- a/lib/Makefile
> > > > +++ b/lib/Makefile
> > > > @@ -6,6 +6,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
> > > >  DIRS-y += librte_compat
> > > >  DIRS-$(CONFIG_RTE_LIBRTE_KVARGS) += librte_kvargs
> > > >  DIRS-$(CONFIG_RTE_LIBRTE_EAL) += librte_eal
> > > > +DEPDIRS-librte_eal := librte_kvargs
> > > >  DIRS-$(CONFIG_RTE_LIBRTE_PCI) += librte_pci
> > > >  DEPDIRS-librte_pci := librte_eal
> > > >  DIRS-$(CONFIG_RTE_LIBRTE_RING) += librte_ring
> > > > diff --git a/lib/librte_eal/bsdapp/eal/Makefile b/lib/librte_eal/bsdapp/eal/Makefile
> > > > index 17ff1ac45..f6cea7fc2 100644
> > > > --- a/lib/librte_eal/bsdapp/eal/Makefile
> > > > +++ b/lib/librte_eal/bsdapp/eal/Makefile
> > > > @@ -18,6 +18,7 @@ CFLAGS += $(WERROR_FLAGS) -O3
> > > >  LDLIBS += -lexecinfo
> > > >  LDLIBS += -lpthread
> > > >  LDLIBS += -lgcc_s
> > > > +LDLIBS += -lrte_kvargs
> > > >  
> > > >  EXPORT_MAP := ../../rte_eal_version.map
> > > >  
> > > > diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
> > > > index cd071442f..1f6df2351 100644
> > > > --- a/lib/librte_eal/common/eal_common_dev.c
> > > > +++ b/lib/librte_eal/common/eal_common_dev.c
> > > > @@ -10,9 +10,12 @@
> > > >  
> > > >  #include <rte_compat.h>
> > > >  #include <rte_bus.h>
> > > > +#include <rte_class.h>
> > > >  #include <rte_dev.h>
> > > >  #include <rte_devargs.h>
> > > >  #include <rte_debug.h>
> > > > +#include <rte_errno.h>
> > > > +#include <rte_kvargs.h>
> > > >  #include <rte_log.h>
> > > >  
> > > >  #include "eal_private.h"
> > > > @@ -207,3 +210,147 @@ rte_eal_hotplug_remove(const char *busname, const char *devname)
> > > >  	rte_eal_devargs_remove(busname, devname);
> > > >  	return ret;
> > > >  }
> > > > +
> > > > +static size_t
> > > > +dev_layer_count(const char *s)
> > > > +{
> > > > +	size_t i = s ? 1 : 0;
> > > > +
> > > > +	while (s != NULL && s[0] != '\0') {
> > > > +		i += s[0] == '/';
> > > > +		s++;
> > > > +	}
> > > > +	return i;
> > > > +}
> > > > +
> > > So the above code really just counts the number characters in the string,
> > > omitting the delimiter character '/', right?  If thats all you want to do, you can just
> > > use strtok and strnlen for that, cant you?
> > 
> > Will do.
> > 
> 
> Answered too quickly.
> No, this function only counts the number of occurences of '/' in the
> text.
> 
> strtok could be used however in the main function.
> Will see for a simpler implementation using it.
> 

After a few tries, I see no benefit in using strtok.
The original const text must still be tokenized, strtok would modify it.

Duplicating would force finding the references in the original text,
which would make the code as complex as it is now.

> > > 
> > > Otherwise, this looks pretty good to me
> > 
> > Please look into the librte_kvargs compatibility patch as well (quite
> > short). I'm very unhappy about the logging hack.
> > There is always the solution of setting a function pointer on rte_log
> > with the proper loglevels and so on.
> > Ideally rte_log could be made independent (starting skimming EAL from
> > all the fat), but this is much less trivial.
> > 
> > This implementation relies on librte_kvargs being available. If this is
> > not the case, there isn't much point to it.
> > 
> > -- 
> > Gaëtan Rivet
> > 6WIND
> 
> -- 
> Gaëtan Rivet
> 6WIND

-- 
Gaëtan Rivet
6WIND


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