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Commit dd01c75f authored by Bastian Hecht's avatar Bastian Hecht Committed by Greg Kroah-Hartman
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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: default avatarBastian Hecht <bhecht@de.adit-jv.com>
Signed-off-by: default avatarGeorge G. Davis <george_davis@mentor.com>
Signed-off-by: default avatarMark Craske <Mark_Craske@mentor.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9ca5d4fd

drivers/base/dma-coherent.c

+4 −2
Original line number Diff line number Diff line
@@ -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;