[dpdk-dev,v5,01/12] bus: add bus iterator to find a bus

Message ID ad9258bced8eba6443e0eeb08bde921d3d29cafe.1498436062.git.gaetan.rivet@6wind.com (mailing list archive)
State Superseded, archived
Headers

Checks

Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Gaëtan Rivet June 26, 2017, 12:21 a.m. UTC
  From: Jan Blunck <jblunck@infradead.org>

This helper allows to iterate over all registered buses and find one
matching data used as parameter.

Signed-off-by: Jan Blunck <jblunck@infradead.org>
Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
---
 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
 lib/librte_eal/common/eal_common_bus.c          | 20 ++++++++++++
 lib/librte_eal/common/include/rte_bus.h         | 43 +++++++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 4 files changed, 65 insertions(+)
  

Comments

Bruce Richardson June 26, 2017, 3:30 p.m. UTC | #1
On Mon, Jun 26, 2017 at 02:21:59AM +0200, Gaetan Rivet wrote:
> From: Jan Blunck <jblunck@infradead.org>
> 
> This helper allows to iterate over all registered buses and find one
> matching data used as parameter.
> 
> Signed-off-by: Jan Blunck <jblunck@infradead.org>
> Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> ---
>  lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
>  lib/librte_eal/common/eal_common_bus.c          | 20 ++++++++++++
>  lib/librte_eal/common/include/rte_bus.h         | 43 +++++++++++++++++++++++++
>  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
>  4 files changed, 65 insertions(+)
> 

Two minor suggestions below. Otherwise:

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

> diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> index 2e48a73..ed09ab2 100644
> --- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> +++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> @@ -162,6 +162,7 @@ DPDK_17.02 {
>  DPDK_17.05 {
>  	global:
>  
> +	rte_bus_find;
>  	rte_cpu_is_supported;
>  	rte_log_dump;
>  	rte_log_register;
> diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
> index 8f9baf8..4619eb2 100644
> --- a/lib/librte_eal/common/eal_common_bus.c
> +++ b/lib/librte_eal/common/eal_common_bus.c
> @@ -145,3 +145,23 @@ rte_bus_dump(FILE *f)
>  		}
>  	}
>  }
> +
> +struct rte_bus *
> +rte_bus_find(rte_bus_cmp_t cmp,
> +	     const void *data,
> +	     const struct rte_bus *start)
> +{
> +	struct rte_bus *bus = NULL;
> +	int started = start == NULL;

Please put brackets around the "start == NULL" to improve readability.
My first reading of this I assumed it was doing multiple assignment of
both start and started to NULL. To make it extra clear, prefix the
comparison with "!!".

> +
> +	TAILQ_FOREACH(bus, &rte_bus_list, next) {
> +		if (!started) {
> +			if (bus == start)
> +				started = 1;
> +			continue;
> +		}
> +		if (cmp(bus, data) == 0)
> +			break;
> +	}
> +	return bus;
> +}

I also think the name "started" is confusing, and might be better as the
slighly longer "start_found".
  
Gaëtan Rivet June 26, 2017, 8:53 p.m. UTC | #2
Hi Bruce,

Thanks for reading.

On Mon, Jun 26, 2017 at 04:30:55PM +0100, Bruce Richardson wrote:
> On Mon, Jun 26, 2017 at 02:21:59AM +0200, Gaetan Rivet wrote:
> > From: Jan Blunck <jblunck@infradead.org>
> > 
> > This helper allows to iterate over all registered buses and find one
> > matching data used as parameter.
> > 
> > Signed-off-by: Jan Blunck <jblunck@infradead.org>
> > Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>
> > ---
> >  lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
> >  lib/librte_eal/common/eal_common_bus.c          | 20 ++++++++++++
> >  lib/librte_eal/common/include/rte_bus.h         | 43 +++++++++++++++++++++++++
> >  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
> >  4 files changed, 65 insertions(+)
> > 
> 
> Two minor suggestions below. Otherwise:
> 
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> 
> > diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > index 2e48a73..ed09ab2 100644
> > --- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > +++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
> > @@ -162,6 +162,7 @@ DPDK_17.02 {
> >  DPDK_17.05 {
> >  	global:
> >  
> > +	rte_bus_find;
> >  	rte_cpu_is_supported;
> >  	rte_log_dump;
> >  	rte_log_register;
> > diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
> > index 8f9baf8..4619eb2 100644
> > --- a/lib/librte_eal/common/eal_common_bus.c
> > +++ b/lib/librte_eal/common/eal_common_bus.c
> > @@ -145,3 +145,23 @@ rte_bus_dump(FILE *f)
> >  		}
> >  	}
> >  }
> > +
> > +struct rte_bus *
> > +rte_bus_find(rte_bus_cmp_t cmp,
> > +	     const void *data,
> > +	     const struct rte_bus *start)
> > +{
> > +	struct rte_bus *bus = NULL;
> > +	int started = start == NULL;
> 
> Please put brackets around the "start == NULL" to improve readability.
> My first reading of this I assumed it was doing multiple assignment of
> both start and started to NULL. To make it extra clear, prefix the
> comparison with "!!".
> 
> > +
> > +	TAILQ_FOREACH(bus, &rte_bus_list, next) {
> > +		if (!started) {
> > +			if (bus == start)
> > +				started = 1;
> > +			continue;
> > +		}
> > +		if (cmp(bus, data) == 0)
> > +			break;
> > +	}
> > +	return bus;
> > +}
> 
> I also think the name "started" is confusing, and might be better as the
> slighly longer "start_found".
> 

Agreed on both account, it will be fixed in the next version.
  

Patch

diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 2e48a73..ed09ab2 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -162,6 +162,7 @@  DPDK_17.02 {
 DPDK_17.05 {
 	global:
 
+	rte_bus_find;
 	rte_cpu_is_supported;
 	rte_log_dump;
 	rte_log_register;
diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
index 8f9baf8..4619eb2 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -145,3 +145,23 @@  rte_bus_dump(FILE *f)
 		}
 	}
 }
+
+struct rte_bus *
+rte_bus_find(rte_bus_cmp_t cmp,
+	     const void *data,
+	     const struct rte_bus *start)
+{
+	struct rte_bus *bus = NULL;
+	int started = start == NULL;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+		if (!started) {
+			if (bus == start)
+				started = 1;
+			continue;
+		}
+		if (cmp(bus, data) == 0)
+			break;
+	}
+	return bus;
+}
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 5f47b82..ecf839b 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -141,6 +141,49 @@  int rte_bus_probe(void);
 void rte_bus_dump(FILE *f);
 
 /**
+ * Bus comparison function.
+ *
+ * @param bus
+ *	Bus under test.
+ *
+ * @param data
+ *	Data to compare against.
+ *
+ * @return
+ *	0 if the bus matches the data.
+ *	!0 if the bus does not match.
+ *	<0 if ordering is possible and the bus is lower than the data.
+ *	>0 if ordering is possible and the bus is greater than the data.
+ */
+typedef int (*rte_bus_cmp_t)(const struct rte_bus *bus, const void *data);
+
+/**
+ * Bus iterator to find a particular bus.
+ *
+ * This function compares each registered bus to find one that matches
+ * the data passed as parameter.
+ *
+ * If the comparison function returns zero this function will stop iterating
+ * over any more buses. To continue a search the bus of a previous search can
+ * be passed via the start parameter.
+ *
+ * @param cmp
+ *	Comparison function.
+ *
+ * @param data
+ *	 Data to pass to comparison function.
+ *
+ * @param start
+ *	Starting point for the iteration.
+ *
+ * @return
+ *	 A pointer to a rte_bus structure or NULL in case no bus matches
+ */
+struct rte_bus *rte_bus_find(rte_bus_cmp_t cmp,
+			     const void *data,
+			     const struct rte_bus *start);
+
+/**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
  */
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index 670bab3..6efa517 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -166,6 +166,7 @@  DPDK_17.02 {
 DPDK_17.05 {
 	global:
 
+	rte_bus_find;
 	rte_cpu_is_supported;
 	rte_intr_free_epoll_fd;
 	rte_log_dump;