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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@intel.com>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: Dave Jiang <dave.jiang@intel.com>
[bzolnier: fix IS_ENABLED() check]
[bzolnier: fix release ordering in dmaengine_destroy_unmap_pool()]
[bzolnier: fix check for success in dmaengine_init_unmap_pool()]
[bzolnier: use mempool_free() instead of kmem_cache_free()]
[bzolnier: add missing unmap->len initializations]
[bzolnier: add __init tag to dmaengine_init_unmap_pool()]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
[djbw: move DMAENGINE=n support to this patch for async_tx]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2013-10-18 19:35:24 +02:00
parent d38a8c622a
commit 45c463ae92
2 changed files with 150 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

154
drivers/dma/dmaengine.c
View File

@ -65,6 +65,7 @@
#include <linux/acpi.h>
#include <linux/acpi_dma.h>
#include <linux/of_dma.h>
#include <linux/mempool.h>
static DEFINE_MUTEX(dma_list_mutex);
static DEFINE_IDR(dma_idr);
@ -901,6 +902,129 @@ 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(CONFIG_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);
mempool_free(unmap, __get_unmap_pool(cnt)->pool);
}
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->pool)
mempool_destroy(p->pool);
p->pool = NULL;
if (p->cache)
kmem_cache_destroy(p->cache);
p->cache = NULL;
}
}
static int __init 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;
memset(unmap, 0, sizeof(*unmap));
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
@ -922,24 +1046,34 @@ 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,
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;
tx = dev->device_prep_dma_memcpy(chan, dma_dest, dma_src, len, flags);
unmap->len = len;
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);
@ -1069,6 +1203,10 @@ 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);

3
include/linux/dmaengine.h
View File

@ -464,9 +464,12 @@ 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;
}
}