From 0036731c88fdb5bf4f04a796a30b5e445fc57f54 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Sat, 2 Feb 2008 19:49:57 -0700 Subject: async_tx: kill tx_set_src and tx_set_dest methods The tx_set_src and tx_set_dest methods were originally implemented to allow an array of addresses to be passed down from async_xor to the dmaengine driver while minimizing stack overhead. Removing these methods allows drivers to have all transaction parameters available at 'prep' time, saves two function pointers in struct dma_async_tx_descriptor, and reduces the number of indirect branches.. A consequence of moving this data to the 'prep' routine is that multi-source routines like async_xor need temporary storage to convert an array of linear addresses into an array of dma addresses. In order to keep the same stack footprint of the previous implementation the input array is reused as storage for the dma addresses. This requires that sizeof(dma_addr_t) be less than or equal to sizeof(void *). As a consequence CONFIG_DMADEVICES now depends on !CONFIG_HIGHMEM64G. It also requires that drivers be able to make descriptor resources available when the 'prep' routine is polled. Signed-off-by: Dan Williams Acked-by: Shannon Nelson --- drivers/dma/Kconfig | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/dma/Kconfig') diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index c46b7c219ee9..a703deffb795 100644 --- a/drivers/dma/Kconfig +++ b/drivers/dma/Kconfig @@ -5,6 +5,7 @@ menuconfig DMADEVICES bool "DMA Engine support" depends on (PCI && X86) || ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX + depends on !HIGHMEM64G help DMA engines can do asynchronous data transfers without involving the host CPU. Currently, this framework can be -- cgit v1.2.3