[PATCH 1/2] dma-coherent: Add one parameter to save available coherent memory

From: Baolin Wang
Date: Thu May 31 2018 - 01:56:47 EST


It is incorrect to use mem->size to valid if there are enough coherent
memory to allocate in __dma_alloc_from_coherent(), since some devices
may mark some occupied coherent memory by dma_mark_declared_memory_occupied().

So we can introduce one 'avail' parameter to save the available device
coherent memory, to valid if we have enough coherent memory for the device
to allocate.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
---
drivers/base/dma-coherent.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/base/dma-coherent.c b/drivers/base/dma-coherent.c
index 597d408..ce19832 100644
--- a/drivers/base/dma-coherent.c
+++ b/drivers/base/dma-coherent.c
@@ -18,6 +18,7 @@ struct dma_coherent_mem {
unsigned long *bitmap;
spinlock_t spinlock;
bool use_dev_dma_pfn_offset;
+ int avail;
};

static struct dma_coherent_mem *dma_coherent_default_memory __ro_after_init;
@@ -73,6 +74,7 @@ static int dma_init_coherent_memory(
dma_mem->device_base = device_addr;
dma_mem->pfn_base = PFN_DOWN(phys_addr);
dma_mem->size = pages;
+ dma_mem->avail = pages;
dma_mem->flags = flags;
spin_lock_init(&dma_mem->spinlock);

@@ -141,6 +143,7 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
dma_addr_t device_addr, size_t size)
{
struct dma_coherent_mem *mem = dev->dma_mem;
+ int order = get_order(size);
unsigned long flags;
int pos, err;

@@ -151,7 +154,9 @@ void *dma_mark_declared_memory_occupied(struct device *dev,

spin_lock_irqsave(&mem->spinlock, flags);
pos = PFN_DOWN(device_addr - dma_get_device_base(dev, mem));
- err = bitmap_allocate_region(mem->bitmap, pos, get_order(size));
+ err = bitmap_allocate_region(mem->bitmap, pos, order);
+ if (!err)
+ mem->avail -= 1 << order;
spin_unlock_irqrestore(&mem->spinlock, flags);

if (err != 0)
@@ -170,7 +175,7 @@ static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,

spin_lock_irqsave(&mem->spinlock, flags);

- if (unlikely(size > (mem->size << PAGE_SHIFT)))
+ if (unlikely(size > (mem->avail << PAGE_SHIFT)))
goto err;

pageno = bitmap_find_free_region(mem->bitmap, mem->size, order);
@@ -182,6 +187,7 @@ static void *__dma_alloc_from_coherent(struct dma_coherent_mem *mem,
*/
*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
ret = mem->virt_base + (pageno << PAGE_SHIFT);
+ mem->avail -= 1 << order;
spin_unlock_irqrestore(&mem->spinlock, flags);
memset(ret, 0, size);
return ret;
@@ -244,6 +250,7 @@ static int __dma_release_from_coherent(struct dma_coherent_mem *mem,

spin_lock_irqsave(&mem->spinlock, flags);
bitmap_release_region(mem->bitmap, page, order);
+ mem->avail += 1 << order;
spin_unlock_irqrestore(&mem->spinlock, flags);
return 1;
}
--
1.7.9.5