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drivers: dma-coherent: Move spinlock in dma_alloc_from_coherent() 

We don't need to hold the spinlock while zeroing the allocated memory.
In case we handle big buffers this is a severe issue as other CPUs might
be spinning half a second or longer.

Signed-off-by: Bastian Hecht <bhecht@de.adit-jv.com>
Signed-off-by: George G. Davis <george_davis@mentor.com>
Signed-off-by: Mark Craske <Mark_Craske@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Bastian Hecht 2016-09-28 08:51:57 +01:00 committed by Greg Kroah-Hartman
parent 9ca5d4fd08
commit dd01c75f1d
1 changed files with 4 additions and 2 deletions
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6
drivers/base/dma-coherent.c
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@ -165,6 +165,7 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
int order = get_order(size);
unsigned long flags;
int pageno;
int dma_memory_map;
if (!dev)
return 0;
@ -187,11 +188,12 @@ int dma_alloc_from_coherent(struct device *dev, ssize_t size,
*/
*dma_handle = mem->device_base + (pageno << PAGE_SHIFT);
*ret = mem->virt_base + (pageno << PAGE_SHIFT);
if (mem->flags & DMA_MEMORY_MAP)
dma_memory_map = (mem->flags & DMA_MEMORY_MAP);
spin_unlock_irqrestore(&mem->spinlock, flags);
if (dma_memory_map)
memset(*ret, 0, size);
else
memset_io(*ret, 0, size);
spin_unlock_irqrestore(&mem->spinlock, flags);
return 1;