> From: Cornelia Huck [mailto:cornelia.huck@xxxxxxxxxx] > On Wed, 23 May 2007 10:05:39 +0200, > Martin Schwidefsky <schwidefsky@xxxxxxxxxx> wrote: > > > We are trying to get rid of dma-mapping.h, see the last change to the > > file with commit 411f0f3edc141a582190d3605cadd1d993abb6df. I don't think > > we should reintroduce dma related definition but split the async_tx in a > > way that allows to compile it on an architecture with CONFIG_NO_DMA=y > > (yes I know that is harder that to just add the dma stubs). Not harder, it just a question of which is "uglier", but given the direction taken with CONFIG_HAS_DMA it now appears more appropriate to change async_tx. > > You've said that there is a software implementation if there is no dma > > engine present. This software implementation should be independent of > > dma-mapping.h. Without having looked at the code, isn't it possible to > > isolate that software implementation into its own C file? That would be > > the only one that gets compiled for s390. > > Taking a quick look at the async_*.c stuff, the functions in question > basically seem to be of the form > > check_if_we_can_do_it_async(); > if (async_ok) { > /* do async stuff */ > /* that's where the dma mapping creeps in */ > } else { > /* do it sync */ > /* seems fine for us */ > } > > So you should be able to factor out (say) async_memset_{sync,async}() > and put it into async_memset_{sync,async}.c. async_memset() would then > be > > async_memset() > { > #if CONFIG_HAS_DMA > if (check_if_we_can_do_at_async()) > async_memset_async(); > #endif > return async_memset_sync(); > } > > Kconfig could then do > > config ASYNC_MEMSET > default m > tristate "async_memset support" > select ASYNC_MEMSET_ASYNC if HAS_DMA > > config ASYNC_MEMSET_ASYNC > depends on HAS_DMA > tristate "async_memset async via dma support" > > Thoughts? I took your approach of encasing the HAS_DMA dependent portion of the code in #ifdef CONFIG_HAS_DMA, and I dropped the dma-mapping-stub patch. I let the compiler do the factoring out for me by making async_tx_find_channel become the following when CONFIG_DMA_ENGINE=n: static inline struct dma_chan * async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx, enum dma_transaction_type tx_type) { return NULL; } --- diff --git a/async_tx/async_memcpy.c b/async_tx/async_memcpy.c index 7896ba8..547976e 100644 --- a/async_tx/async_memcpy.c +++ b/async_tx/async_memcpy.c @@ -56,6 +56,7 @@ async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset, int_en) : NULL; if (tx) { /* run the memcpy asynchronously */ + #ifdef CONFIG_HAS_DMA dma_addr_t dma_addr; enum dma_data_direction dir; @@ -75,6 +76,9 @@ async_memcpy(struct page *dest, struct page *src, unsigned int dest_offset, async_tx_submit(chan, tx, flags, depend_tx, callback, callback_param); + #else + BUG(); + #endif /* CONFIG_HAS_DMA */ } else { /* run the memcpy synchronously */ void *dest_buf, *src_buf; pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len); diff --git a/async_tx/async_memset.c b/async_tx/async_memset.c index 736c7c2..9166a27 100644 --- a/async_tx/async_memset.c +++ b/async_tx/async_memset.c @@ -55,6 +55,7 @@ async_memset(struct page *dest, int val, unsigned int offset, int_en) : NULL; if (tx) { /* run the memset asynchronously */ + #ifdef CONFIG_HAS_DMA dma_addr_t dma_addr; enum dma_data_direction dir; @@ -67,6 +68,9 @@ async_memset(struct page *dest, int val, unsigned int offset, async_tx_submit(chan, tx, flags, depend_tx, callback, callback_param); + #else + BUG(); + #endif /* CONFIG_HAS_DMA */ } else { /* run the memset synchronously */ void *dest_buf; pr_debug("%s: (sync) len: %zu\n", __FUNCTION__, len); diff --git a/async_tx/async_xor.c b/async_tx/async_xor.c index 37ae5fc..5e4bc29 100644 --- a/async_tx/async_xor.c +++ b/async_tx/async_xor.c @@ -31,6 +31,7 @@ #include <linux/raid/xor.h> #include <linux/async_tx.h> +#ifdef CONFIG_HAS_DMA static void do_async_xor(struct dma_async_tx_descriptor *tx, struct dma_device *device, struct dma_chan *chan, struct page *dest, struct page **src_list, @@ -62,6 +63,17 @@ do_async_xor(struct dma_async_tx_descriptor *tx, struct dma_device *device, async_tx_submit(chan, tx, flags, depend_tx, callback, callback_param); } +#else +static void +do_async_xor(struct dma_async_tx_descriptor *tx, struct dma_device *device, + struct dma_chan *chan, struct page *dest, struct page **src_list, + unsigned int offset, unsigned int src_cnt, size_t len, + enum async_tx_flags flags, struct dma_async_tx_descriptor *depend_tx, + dma_async_tx_callback callback, void *callback_param) +{ + BUG(); +} +#endif /* CONFIG_HAS_DMA */ static void do_sync_xor(struct page *dest, struct page **src_list, unsigned int offset, @@ -265,6 +277,7 @@ async_xor_zero_sum(struct page *dest, struct page **src_list, BUG_ON(src_cnt <= 1); if (tx) { + #ifdef CONFIG_HAS_DMA dma_addr_t dma_addr; enum dma_data_direction dir; @@ -281,6 +294,9 @@ async_xor_zero_sum(struct page *dest, struct page **src_list, async_tx_submit(chan, tx, flags, depend_tx, callback, callback_param); + #else + BUG(); + #endif /* CONFIG_HAS_DMA */ } else { unsigned long xor_flags = flags; - To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
