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Message-Id: <1407156896-3246-8-git-send-email-email@christophjaeger.info>
Date: Mon, 4 Aug 2014 14:54:53 +0200
From: Christoph Jaeger <email@...istophjaeger.info>
To: shigekatsu.tateno@...el.com, gregkh@...uxfoundation.org
Cc: devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
Christoph Jaeger <email@...istophjaeger.info>
Subject: [PATCH 07/10] staging: ozwpan: Use slab cache for oz_urb_link allocation
Use a slab cache rather than rolling our own free list.
Signed-off-by: Christoph Jaeger <email@...istophjaeger.info>
---
drivers/staging/ozwpan/ozhcd.c | 70 ++++++++----------------------------------
1 file changed, 12 insertions(+), 58 deletions(-)
diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
index 30bd928..3b603c5 100644
--- a/drivers/staging/ozwpan/ozhcd.c
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -45,10 +45,6 @@
*/
#define OZ_PLAT_DEV_NAME "ozwpan"
-/* Maximum number of free urb links that can be kept in the pool.
- */
-#define OZ_MAX_LINK_POOL_SIZE 16
-
/* Get endpoint object from the containing link.
*/
#define ep_from_link(__e) container_of((__e), struct oz_endpoint, link)
@@ -75,6 +71,8 @@ struct oz_urb_link {
unsigned submit_counter;
};
+static struct kmem_cache *oz_urb_link_cache;
+
/* Holds state information about a USB endpoint.
*/
#define OZ_EP_BUFFER_SIZE_ISOC (1024 * 24)
@@ -198,9 +196,6 @@ static struct platform_device *g_plat_dev;
static struct oz_hcd *g_ozhcd;
static DEFINE_SPINLOCK(g_hcdlock); /* Guards g_ozhcd. */
static const char g_hcd_name[] = "Ozmo WPAN";
-static struct list_head *g_link_pool;
-static int g_link_pool_size;
-static DEFINE_SPINLOCK(g_link_lock);
static DEFINE_SPINLOCK(g_tasklet_lock);
static struct tasklet_struct g_urb_process_tasklet;
static struct tasklet_struct g_urb_cancel_tasklet;
@@ -265,68 +260,22 @@ static int oz_get_port_from_addr(struct oz_hcd *ozhcd, u8 bus_addr)
}
/*
- * Allocates an urb link, first trying the pool but going to heap if empty.
* Context: any
*/
static struct oz_urb_link *oz_alloc_urb_link(void)
{
- struct oz_urb_link *urbl = NULL;
- unsigned long irq_state;
-
- spin_lock_irqsave(&g_link_lock, irq_state);
- if (g_link_pool) {
- urbl = container_of(g_link_pool, struct oz_urb_link, link);
- g_link_pool = urbl->link.next;
- --g_link_pool_size;
- }
- spin_unlock_irqrestore(&g_link_lock, irq_state);
- if (urbl == NULL)
- urbl = kmalloc(sizeof(struct oz_urb_link), GFP_ATOMIC);
- return urbl;
+ return kmem_cache_alloc(oz_urb_link_cache, GFP_ATOMIC);
}
/*
- * Frees an urb link by putting it in the pool if there is enough space or
- * deallocating it to heap otherwise.
* Context: any
*/
static void oz_free_urb_link(struct oz_urb_link *urbl)
{
- if (urbl) {
- unsigned long irq_state;
-
- spin_lock_irqsave(&g_link_lock, irq_state);
- if (g_link_pool_size < OZ_MAX_LINK_POOL_SIZE) {
- urbl->link.next = g_link_pool;
- g_link_pool = &urbl->link;
- urbl = NULL;
- g_link_pool_size++;
- }
- spin_unlock_irqrestore(&g_link_lock, irq_state);
- kfree(urbl);
- }
-}
-
-/*
- * Deallocates all the urb links in the pool.
- * Context: unknown
- */
-static void oz_empty_link_pool(void)
-{
- struct list_head *e;
- unsigned long irq_state;
+ if (unlikely(!urbl))
+ return;
- spin_lock_irqsave(&g_link_lock, irq_state);
- e = g_link_pool;
- g_link_pool = NULL;
- g_link_pool_size = 0;
- spin_unlock_irqrestore(&g_link_lock, irq_state);
- while (e) {
- struct oz_urb_link *urbl =
- container_of(e, struct oz_urb_link, link);
- e = e->next;
- kfree(urbl);
- }
+ kmem_cache_free(oz_urb_link_cache, urbl);
}
/*
@@ -2311,7 +2260,6 @@ static int oz_plat_remove(struct platform_device *dev)
oz_dbg(ON, "Removing hcd\n");
usb_remove_hcd(hcd);
usb_put_hcd(hcd);
- oz_empty_link_pool();
return 0;
}
@@ -2341,6 +2289,11 @@ int oz_hcd_init(void)
if (usb_disabled())
return -ENODEV;
+
+ oz_urb_link_cache = KMEM_CACHE(oz_urb_link, 0);
+ if (unlikely(!oz_urb_link_cache))
+ return -ENOMEM;
+
tasklet_init(&g_urb_process_tasklet, oz_urb_process_tasklet, 0);
tasklet_init(&g_urb_cancel_tasklet, oz_urb_cancel_tasklet, 0);
err = platform_driver_register(&g_oz_plat_drv);
@@ -2380,4 +2333,5 @@ void oz_hcd_term(void)
platform_device_unregister(g_plat_dev);
platform_driver_unregister(&g_oz_plat_drv);
oz_dbg(ON, "Pending urbs:%d\n", atomic_read(&g_pending_urbs));
+ kmem_cache_destroy(oz_urb_link_cache);
}
--
1.9.1
--
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