在对内核4.4->5.10版本DMA的移植时,发现DMA驱动里有一个DMA_SG的枚举被删去.
这对于移植来说带来了很大的麻烦.最坏的情况是,这个枚举消失了,但是合并到其他枚举的功能实现里去了.
然后我就去查找在哪一个版本有对这个枚举有改动.最终在这个版本里发现该枚举被移除了
dmaengine: remove DMA_SG as it is dead code in kernel
There are no in kernel consumers for DMA_SG op. Removing operation,
dead code, and test code in dmatest.
Signed-off-by: Dave Jiang
Reviewed-by: Linus Walleij
Cc: Gary Hook
Cc: Ludovic Desroches
Cc: Kedareswara rao Appana
Cc: Li Yang
Cc: Michal Simek
Signed-off-by: Vinod Koul
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 533680860865a..64fbd380c4309 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -68,7 +68,6 @@ enum dma_transaction_type {
DMA_MEMSET,
DMA_MEMSET_SG,
DMA_INTERRUPT,
- DMA_SG,
DMA_PRIVATE,
DMA_ASYNC_TX,
DMA_SLAVE,
@@ -771,11 +770,6 @@ struct dma_device {
unsigned int nents, int value, unsigned long flags);
struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)(
struct dma_chan *chan, unsigned long flags);
- struct dma_async_tx_descriptor *(*device_prep_dma_sg)(
- struct dma_chan *chan,
- struct scatterlist *dst_sg, unsigned int dst_nents,
- struct scatterlist *src_sg, unsigned int src_nents,
- unsigned long flags);
struct dma_async_tx_descriptor *(*device_prep_slave_sg)(
struct dma_chan *chan, struct scatterlist *sgl,
@@ -905,19 +899,6 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_memcpy(
len, flags);
}
-static inline struct dma_async_tx_descriptor *dmaengine_prep_dma_sg(
- struct dma_chan *chan,
- struct scatterlist *dst_sg, unsigned int dst_nents,
- struct scatterlist *src_sg, unsigned int src_nents,
- unsigned long flags)
-{
- if (!chan || !chan->device || !chan->device->device_prep_dma_sg)
- return NULL;
-
- return chan->device->device_prep_dma_sg(chan, dst_sg, dst_nents,
- src_sg, src_nents, flags);
-}
-
/**
* dmaengine_terminate_all() - Terminate all active DMA transfers
* @chan: The channel for which to terminate the transfers
dmaengine: remove DMA_SG as it is dead code in kernel
There are no in kernel consumers for DMA_SG op. Removing operation,
dead code, and test code in dmatest.
翻译成中文
dmaengine:删除DMA_SG，因为它是内核中的死代码
DMA_SG操作的内核内没有使用者。删除操作，死代码和dmatest中的测试代码。
通过此只知道被删去了,不知道其他属于DMA_SG的部分去了哪里.
所以想问一下DMA_SG这个宏为什么可以直接删除