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greybus: use ida for cport id allocation

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The ida mechanism for allocating ids may be overkill but it works.

Don't preallocate the id 0 for control.  That should be done
when initializing connections based on the manifest anyway.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Alex Elder 2014-10-03 14:14:24 -05:00 committed by Greg Kroah-Hartman
parent 063e6ec221
commit 177404bd20
3 changed files with 40 additions and 77 deletions
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40
drivers/staging/greybus/connection.c
View File

@ -13,6 +13,39 @@
static DEFINE_SPINLOCK(gb_connections_lock);
/*
* Allocate an available CPort Id for use for the host side of the
* given connection. The lowest-available id is returned, so the
* first call is guaranteed to allocate CPort Id 0.
*
* Assigns the connection's hd_cport_id and returns true if successful.
* Returns false otherwise.
*/
static bool hd_connection_hd_cport_id_alloc(struct gb_connection *connection)
{
struct ida *ida = &connection->hd->cport_id_map;
int id;
id = ida_simple_get(ida, 0, HOST_DEV_CPORT_ID_MAX, GFP_KERNEL);
if (id < 0)
return false;
connection->hd_cport_id = (u16)id;
return true;
}
/*
* Free a previously-allocated CPort Id on the given host device.
*/
static void hd_connection_hd_cport_id_free(struct gb_connection *connection)
{
struct ida *ida = &connection->hd->cport_id_map;
ida_simple_remove(ida, connection->hd_cport_id);
connection->hd_cport_id = CPORT_ID_BAD;
}
/*
* Set up a Greybus connection, representing the bidirectional link
* between a CPort on a (local) Greybus host device and a CPort on
@ -35,8 +68,9 @@ struct gb_connection *gb_connection_create(struct gb_interface *interface,
return NULL;
hd = interface->gmod->hd;
connection->hd_cport_id = greybus_hd_cport_id_alloc(hd);
if (connection->hd_cport_id == CPORT_ID_BAD) {
connection->hd = hd; /* XXX refcount? */
if (!hd_connection_hd_cport_id_alloc(connection)) {
/* kref_put(connection->hd); */
kfree(connection);
return NULL;
}
@ -72,7 +106,7 @@ void gb_connection_destroy(struct gb_connection *connection)
list_del(&connection->interface_links);
spin_unlock_irq(&gb_connections_lock);
greybus_hd_cport_id_free(connection->hd, connection->hd_cport_id);
hd_connection_hd_cport_id_free(connection);
/* kref_put(connection->interface); */
/* kref_put(connection->hd); */
kfree(connection);

71
drivers/staging/greybus/core.c
View File

@ -282,69 +282,6 @@ void greybus_remove_device(struct gb_module *gmod)
static DEFINE_MUTEX(hd_mutex);
/*
* Allocate an available CPort Id for use on the given host device.
* Returns the CPort Id, or CPORT_ID_BAD of none remain.
*
* The lowest-available id is returned, so the first call is
* guaranteed to allocate CPort Id 0.
*/
u16 greybus_hd_cport_id_alloc(struct greybus_host_device *hd)
{
unsigned long cport_id;
/* If none left, return BAD */
if (hd->cport_id_count == HOST_DEV_CPORT_ID_MAX)
return CPORT_ID_BAD;
spin_lock_irq(&cport_id_map_lock);
cport_id = find_next_zero_bit(hd->cport_id_map, HOST_DEV_CPORT_ID_MAX,
hd->cport_id_next_free);
if (cport_id < HOST_DEV_CPORT_ID_MAX) {
hd->cport_id_next_free = cport_id + 1; /* Success */
hd->cport_id_count++;
} else {
/* Lost a race for the last one */
if (hd->cport_id_count != HOST_DEV_CPORT_ID_MAX) {
pr_err("bad cport_id_count in alloc");
hd->cport_id_count = HOST_DEV_CPORT_ID_MAX;
}
cport_id = CPORT_ID_BAD;
}
spin_unlock_irq(&cport_id_map_lock);
return cport_id;
}
/*
* Free a previously-allocated CPort Id on the given host device.
*/
void greybus_hd_cport_id_free(struct greybus_host_device *hd, u16 cport_id)
{
if (cport_id >= HOST_DEV_CPORT_ID_MAX) {
pr_err("bad cport_id %hu\n", cport_id);
return;
}
if (!hd->cport_id_count) {
pr_err("too many cport_id frees\n");
return;
}
spin_lock_irq(&cport_id_map_lock);
if (test_and_clear_bit(cport_id, hd->cport_id_map)) {
if (hd->cport_id_count) {
hd->cport_id_count--;
if (cport_id < hd->cport_id_next_free)
hd->cport_id_next_free = cport_id;
} else {
pr_err("bad cport_id_count in free");
}
} else {
pr_err("duplicate cport_id %hu free\n", cport_id);
}
spin_unlock_irq(&cport_id_map_lock);
}
static void free_hd(struct kref *kref)
{
struct greybus_host_device *hd;
@ -368,13 +305,7 @@ struct greybus_host_device *greybus_create_hd(struct greybus_host_driver *driver
hd->driver = driver;
INIT_LIST_HEAD(&hd->modules);
INIT_LIST_HEAD(&hd->connections);
/* Pre-allocate CPort 0 for control stuff. XXX */
if (greybus_hd_cport_id_alloc(hd) != 0) {
pr_err("couldn't allocate cport 0\n");
kfree(hd);
return NULL;
}
ida_init(&hd->cport_id_map);
return hd;
}

6
drivers/staging/greybus/greybus.h
View File

@ -17,6 +17,7 @@
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/idr.h>
#include "kernel_ver.h"
#include "greybus_id.h"
@ -194,7 +195,7 @@ struct greybus_host_device {
struct list_head modules;
struct list_head connections;
DECLARE_BITMAP(cport_id_map, HOST_DEV_CPORT_ID_MAX);
struct ida cport_id_map;
u16 cport_id_count; /* How many have been allocated */
u16 cport_id_next_free; /* Where to start checking anyway */
@ -202,9 +203,6 @@ struct greybus_host_device {
unsigned long hd_priv[0] __attribute__ ((aligned(sizeof(s64))));
};
u16 greybus_hd_cport_id_alloc(struct greybus_host_device *hd);
void greybus_hd_cport_id_free(struct greybus_host_device *hd, u16 cport_id);
struct greybus_host_device *greybus_create_hd(struct greybus_host_driver *host_driver,
struct device *parent);
void greybus_remove_hd(struct greybus_host_device *hd);