DMAENGINE: ste_dma40: use kmem cache

Use kmem cache instead of own cache, reducing code duplication
and bug sources.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 18 insertions, 34 deletions

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index d72eff6cfaef..b60a6dbf1e09 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -34,10 +34,6 @@
 #define D40_ALLOC_PHY           (1 << 30)
 #define D40_ALLOC_LOG_FREE      0
 
-/* The number of free d40_desc to keep in memory before starting
- * to kfree() them */
-#define D40_DESC_CACHE_SIZE 50
-
 /* Hardware designer of the block */
 #define D40_PERIPHID2_DESIGNER 0x8
 
@@ -172,8 +168,6 @@ struct d40_base;
  * @client: Cliented owned descriptor list.
  * @active: Active descriptor.
  * @queue: Queued jobs.
- * @free: List of free descripts, ready to be reused.
- * @free_len: Number of descriptors in the free list.
  * @dma_cfg: The client configuration of this dma channel.
  * @base: Pointer to the device instance struct.
  * @src_def_cfg: Default cfg register setting for src.
@@ -197,8 +191,6 @@ struct d40_chan {
         struct list_head                 client;
         struct list_head                 active;
         struct list_head                 queue;
-        struct list_head                 free;
-        int                              free_len;
         struct stedma40_chan_cfg         dma_cfg;
         struct d40_base                 *base;
         /* Default register configurations */
@@ -242,6 +234,7 @@ struct d40_chan {
  * @lcpa_base: The virtual mapped address of LCPA.
  * @phy_lcpa: The physical address of the LCPA.
  * @lcpa_size: The size of the LCPA area.
+ * @desc_slab: cache for descriptors.
  */
 struct d40_base {
         spinlock_t                       interrupt_lock;
@@ -268,6 +261,7 @@ struct d40_base {
         void                             *lcpa_base;
         dma_addr_t                        phy_lcpa;
         resource_size_t                   lcpa_size;
+        struct kmem_cache                *desc_slab;
 };
 
 /**
@@ -382,36 +376,21 @@ static struct d40_desc *d40_desc_get(struct d40_chan *d40c)
                         if (async_tx_test_ack(&d->txd)) {
                                 d40_pool_lli_free(d);
                                 d40_desc_remove(d);
-                                desc = d;
-                                goto out;
+                                break;
                         }
-        }
-
-        if (list_empty(&d40c->free)) {
-                /* Alloc new desc because we're out of used ones */
-                desc = kzalloc(sizeof(struct d40_desc), GFP_NOWAIT);
-                if (desc == NULL)
-                        goto out;
-                INIT_LIST_HEAD(&desc->node);
         } else {
-                /* Reuse an old desc. */
-                desc = list_first_entry(&d40c->free,
-                                        struct d40_desc,
-                                        node);
-                list_del(&desc->node);
-                d40c->free_len--;
+                d = kmem_cache_alloc(d40c->base->desc_slab, GFP_NOWAIT);
+                if (d != NULL) {
+                        memset(d, 0, sizeof(struct d40_desc));
+                        INIT_LIST_HEAD(&d->node);
+                }
         }
-out:
-        return desc;
+        return d;
 }
 
 static void d40_desc_free(struct d40_chan *d40c, struct d40_desc *d40d)
 {
-        if (d40c->free_len < D40_DESC_CACHE_SIZE) {
-                list_add_tail(&d40d->node, &d40c->free);
-                d40c->free_len++;
-        } else
-                kfree(d40d);
+        kmem_cache_free(d40c->base->desc_slab, d40d);
 }
 
 static void d40_desc_submit(struct d40_chan *d40c, struct d40_desc *desc)
@@ -2107,13 +2086,10 @@ static void __init d40_chan_init(struct d40_base *base, struct dma_device *dma,
 
                 d40c->log_num = D40_PHY_CHAN;
 
-                INIT_LIST_HEAD(&d40c->free);
                 INIT_LIST_HEAD(&d40c->active);
                 INIT_LIST_HEAD(&d40c->queue);
                 INIT_LIST_HEAD(&d40c->client);
 
-                d40c->free_len = 0;
-
                 tasklet_init(&d40c->tasklet, dma_tasklet,
                              (unsigned long) d40c);
 
@@ -2398,6 +2374,12 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
         if (!base->lcla_pool.alloc_map)
                 goto failure;
 
+        base->desc_slab = kmem_cache_create(D40_NAME, sizeof(struct d40_desc),
+                                            0, SLAB_HWCACHE_ALIGN,
+                                            NULL);
+        if (base->desc_slab == NULL)
+                goto failure;
+
         return base;
 
 failure:
@@ -2612,6 +2594,8 @@ static int __init d40_probe(struct platform_device *pdev)
 
 failure:
         if (base) {
+                if (base->desc_slab)
+                        kmem_cache_destroy(base->desc_slab);
                 if (base->virtbase)
                         iounmap(base->virtbase);
                 if (base->lcla_pool.phy)