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Date: Thu, 06 Dec 2012 01:25:26 -0800
From: Dan Williams <djbw@...com>
To: linux-kernel@...r.kernel.org
Cc: linux@....linux.org.uk,
Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
Vinod Koul <vinod.koul@...el.com>,
Tomasz Figa <t.figa@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>, dave.jiang@...el.com
Subject: [PATCH 03/12] dmaengine: reference counted unmap data
hang a common 'unmap' object off of dma descriptors for the purpose of
providing a unified unmapping interface. The lifetime of a mapping may
span multiple descriptors, so these unmap objects are reference counted
by related descriptor.
Cc: Vinod Koul <vinod.koul@...el.com>
Cc: Tomasz Figa <t.figa@...sung.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Cc: Kyungmin Park <kyungmin.park@...sung.com>
Signed-off-by: Dan Williams <djbw@...com>
---
drivers/dma/dmaengine.c | 157 ++++++++++++++++++++++++++++++++++++++++++---
include/linux/dmaengine.h | 3 +
2 files changed, 151 insertions(+), 9 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index f3cadc6..00f0baf 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -62,6 +62,7 @@
#include <linux/rculist.h>
#include <linux/idr.h>
#include <linux/slab.h>
+#include <linux/mempool.h>
static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDR(dma_idr);
@@ -856,6 +857,131 @@ void dma_async_device_unregister(struct dma_device *device)
}
EXPORT_SYMBOL(dma_async_device_unregister);
+struct dmaengine_unmap_pool {
+ struct kmem_cache *cache;
+ const char *name;
+ mempool_t *pool;
+ size_t size;
+};
+
+#define __UNMAP_POOL(x) { .size = x, .name = "dmaengine-unmap-" __stringify(x) }
+static struct dmaengine_unmap_pool unmap_pool[] = {
+ __UNMAP_POOL(2),
+ #if IS_ENABLED(ASYNC_TX_DMA)
+ __UNMAP_POOL(16),
+ __UNMAP_POOL(128),
+ __UNMAP_POOL(256),
+ #endif
+};
+
+static struct dmaengine_unmap_pool *__get_unmap_pool(int nr)
+{
+ int order = get_count_order(nr);
+
+ switch (order) {
+ case 0 ... 1:
+ return &unmap_pool[0];
+ case 2 ... 4:
+ return &unmap_pool[1];
+ case 5 ... 7:
+ return &unmap_pool[2];
+ case 8:
+ return &unmap_pool[3];
+ default:
+ BUG();
+ return NULL;
+ }
+
+}
+
+static void dmaengine_unmap(struct kref *kref)
+{
+ struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap), kref);
+ struct device *dev = unmap->dev;
+ int cnt, i;
+
+ cnt = unmap->to_cnt;
+ for (i = 0; i < cnt; i++)
+ dma_unmap_page(dev, unmap->addr[i], unmap->len,
+ DMA_TO_DEVICE);
+ cnt += unmap->from_cnt;
+ for (; i < cnt; i++)
+ dma_unmap_page(dev, unmap->addr[i], unmap->len,
+ DMA_FROM_DEVICE);
+ cnt += unmap->bidi_cnt;
+ for (; i < cnt; i++)
+ dma_unmap_page(dev, unmap->addr[i], unmap->len,
+ DMA_BIDIRECTIONAL);
+ kmem_cache_free(__get_unmap_pool(cnt)->cache, unmap);
+}
+
+void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap)
+{
+ if (unmap)
+ kref_put(&unmap->kref, dmaengine_unmap);
+}
+EXPORT_SYMBOL_GPL(dmaengine_unmap_put);
+
+static void dmaengine_destroy_unmap_pool(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
+ struct dmaengine_unmap_pool *p = &unmap_pool[i];
+
+ if (p->cache)
+ kmem_cache_destroy(p->cache);
+ p->cache = NULL;
+ if (p->pool)
+ mempool_destroy(p->pool);
+ p->pool = NULL;
+ }
+}
+
+static int dmaengine_init_unmap_pool(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(unmap_pool); i++) {
+ struct dmaengine_unmap_pool *p = &unmap_pool[i];
+ size_t size;
+
+ size = sizeof(struct dmaengine_unmap_data) +
+ sizeof(dma_addr_t) * p->size;
+
+ p->cache = kmem_cache_create(p->name, size, 0,
+ SLAB_HWCACHE_ALIGN, NULL);
+ if (!p->cache)
+ break;
+ p->pool = mempool_create_slab_pool(1, p->cache);
+ if (!p->pool)
+ break;
+ }
+
+ if (i > ARRAY_SIZE(unmap_pool))
+ return 0;
+
+ dmaengine_destroy_unmap_pool();
+ return -ENOMEM;
+}
+
+static struct dmaengine_unmap_data *
+dmaengine_get_unmap_data(struct device *dev, int nr, gfp_t flags)
+{
+ struct dmaengine_unmap_data *unmap;
+
+ unmap = mempool_alloc(__get_unmap_pool(nr)->pool, flags);
+ if (!unmap)
+ return NULL;
+ unmap->to_cnt = 0;
+ unmap->from_cnt = 0;
+ unmap->bidi_cnt = 0;
+ kref_init(&unmap->kref);
+ unmap->dev = dev;
+
+ return unmap;
+}
+
/**
* dma_async_memcpy_pg_to_pg - offloaded copy from page to page
* @chan: DMA channel to offload copy to
@@ -877,24 +1003,33 @@ dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
{
struct dma_device *dev = chan->device;
struct dma_async_tx_descriptor *tx;
- dma_addr_t dma_dest, dma_src;
+ struct dmaengine_unmap_data *unmap;
dma_cookie_t cookie;
unsigned long flags;
- dma_src = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
- dma_dest = dma_map_page(dev->dev, dest_pg, dest_off, len,
- DMA_FROM_DEVICE);
- flags = DMA_CTRL_ACK;
- tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
+ unmap = dmaengine_get_unmap_data(dev->dev, 2, GFP_NOIO);
+ if (!unmap)
+ return -ENOMEM;
+
+ unmap->to_cnt = 1;
+ unmap->from_cnt = 1;
+ unmap->addr[0] = dma_map_page(dev->dev, src_pg, src_off, len,
+ DMA_TO_DEVICE);
+ unmap->addr[1] = dma_map_page(dev->dev, dest_pg, dest_off, len,
+ DMA_FROM_DEVICE);
+ flags = DMA_CTRL_ACK | DMA_COMPL_SKIP_SRC_UNMAP |
+ DMA_COMPL_SKIP_DEST_UNMAP;
+ tx = dev->device_prep_dma_memcpy(chan, unmap->addr[1], unmap->addr[0],
+ len, flags);
if (!tx) {
- dma_unmap_page(dev->dev, dma_src, len, DMA_TO_DEVICE);
- dma_unmap_page(dev->dev, dma_dest, len, DMA_FROM_DEVICE);
+ dmaengine_unmap_put(unmap);
return -ENOMEM;
}
- tx->callback = NULL;
+ dma_set_unmap(tx, unmap);
cookie = tx->tx_submit(tx);
+ dmaengine_unmap_put(unmap);
preempt_disable();
__this_cpu_add(chan->local->bytes_transferred, len);
@@ -1024,6 +1159,10 @@ EXPORT_SYMBOL_GPL(dma_run_dependencies);
static int __init dma_bus_init(void)
{
+ int err = dmaengine_init_unmap_pool();
+
+ if (err)
+ return err;
return class_register(&dma_devclass);
}
arch_initcall(dma_bus_init);
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index da58d79..c90d6b6 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -443,9 +443,12 @@ static inline void dma_set_unmap(struct dma_async_tx_descriptor *tx,
tx->unmap = unmap;
}
+void dmaengine_unmap_put(struct dmaengine_unmap_data *unmap);
+
static inline void dma_descriptor_unmap(struct dma_async_tx_descriptor *tx)
{
if (tx->unmap) {
+ dmaengine_unmap_put(tx->unmap);
tx->unmap = NULL;
}
}
--
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