From 07f2211e4fbce6990722d78c4f04225da9c0e9cf Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 5 Jan 2009 17:14:31 -0700 Subject: [PATCH] dmaengine: remove dependency on async_tx async_tx.ko is a consumer of dma channels. A circular dependency arises if modules in drivers/dma rely on common code in async_tx.ko. It prevents either module from being unloaded. Move dma_wait_for_async_tx and async_tx_run_dependencies to dmaeninge.o where they should have been from the beginning. Reviewed-by: Andrew Morton Signed-off-by: Dan Williams --- crypto/async_tx/async_tx.c | 75 ----------------------------------------- drivers/dma/Kconfig | 2 -- drivers/dma/dmaengine.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++ drivers/dma/iop-adma.c | 3 +- drivers/dma/mv_xor.c | 3 +- include/linux/async_tx.h | 15 --------- include/linux/dmaengine.h | 9 +++++ 7 files changed, 95 insertions(+), 96 deletions(-) diff --git a/crypto/async_tx/async_tx.c b/crypto/async_tx/async_tx.c index dcbf1be..8cfac18 100644 --- a/crypto/async_tx/async_tx.c +++ b/crypto/async_tx/async_tx.c @@ -72,81 +72,6 @@ void async_tx_issue_pending_all(void) } EXPORT_SYMBOL_GPL(async_tx_issue_pending_all); -/* dma_wait_for_async_tx - spin wait for a transcation to complete - * @tx: transaction to wait on - */ -enum dma_status -dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) -{ - enum dma_status status; - struct dma_async_tx_descriptor *iter; - struct dma_async_tx_descriptor *parent; - - if (!tx) - return DMA_SUCCESS; - - /* poll through the dependency chain, return when tx is complete */ - do { - iter = tx; - - /* find the root of the unsubmitted dependency chain */ - do { - parent = iter->parent; - if (!parent) - break; - else - iter = parent; - } while (parent); - - /* there is a small window for ->parent == NULL and - * ->cookie == -EBUSY - */ - while (iter->cookie == -EBUSY) - cpu_relax(); - - status = dma_sync_wait(iter->chan, iter->cookie); - } while (status == DMA_IN_PROGRESS || (iter != tx)); - - return status; -} -EXPORT_SYMBOL_GPL(dma_wait_for_async_tx); - -/* async_tx_run_dependencies - helper routine for dma drivers to process - * (start) dependent operations on their target channel - * @tx: transaction with dependencies - */ -void async_tx_run_dependencies(struct dma_async_tx_descriptor *tx) -{ - struct dma_async_tx_descriptor *dep = tx->next; - struct dma_async_tx_descriptor *dep_next; - struct dma_chan *chan; - - if (!dep) - return; - - chan = dep->chan; - - /* keep submitting up until a channel switch is detected - * in that case we will be called again as a result of - * processing the interrupt from async_tx_channel_switch - */ - for (; dep; dep = dep_next) { - spin_lock_bh(&dep->lock); - dep->parent = NULL; - dep_next = dep->next; - if (dep_next && dep_next->chan == chan) - dep->next = NULL; /* ->next will be submitted */ - else - dep_next = NULL; /* submit current dep and terminate */ - spin_unlock_bh(&dep->lock); - - dep->tx_submit(dep); - } - - chan->device->device_issue_pending(chan); -} -EXPORT_SYMBOL_GPL(async_tx_run_dependencies); - static void free_dma_chan_ref(struct rcu_head *rcu) { diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig index 904e575..e34b064 100644 --- a/drivers/dma/Kconfig +++ b/drivers/dma/Kconfig @@ -33,7 +33,6 @@ config INTEL_IOATDMA config INTEL_IOP_ADMA tristate "Intel IOP ADMA support" depends on ARCH_IOP32X || ARCH_IOP33X || ARCH_IOP13XX - select ASYNC_CORE select DMA_ENGINE help Enable support for the Intel(R) IOP Series RAID engines. @@ -59,7 +58,6 @@ config FSL_DMA config MV_XOR bool "Marvell XOR engine support" depends on PLAT_ORION - select ASYNC_CORE select DMA_ENGINE ---help--- Enable support for the Marvell XOR engine. diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 6579965..b900893 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -626,6 +626,90 @@ void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx, } EXPORT_SYMBOL(dma_async_tx_descriptor_init); +/* dma_wait_for_async_tx - spin wait for a transaction to complete + * @tx: in-flight transaction to wait on + * + * This routine assumes that tx was obtained from a call to async_memcpy, + * async_xor, async_memset, etc which ensures that tx is "in-flight" (prepped + * and submitted). Walking the parent chain is only meant to cover for DMA + * drivers that do not implement the DMA_INTERRUPT capability and may race with + * the driver's descriptor cleanup routine. + */ +enum dma_status +dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) +{ + enum dma_status status; + struct dma_async_tx_descriptor *iter; + struct dma_async_tx_descriptor *parent; + + if (!tx) + return DMA_SUCCESS; + + WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for" + " %s\n", __func__, dev_name(&tx->chan->dev)); + + /* poll through the dependency chain, return when tx is complete */ + do { + iter = tx; + + /* find the root of the unsubmitted dependency chain */ + do { + parent = iter->parent; + if (!parent) + break; + else + iter = parent; + } while (parent); + + /* there is a small window for ->parent == NULL and + * ->cookie == -EBUSY + */ + while (iter->cookie == -EBUSY) + cpu_relax(); + + status = dma_sync_wait(iter->chan, iter->cookie); + } while (status == DMA_IN_PROGRESS || (iter != tx)); + + return status; +} +EXPORT_SYMBOL_GPL(dma_wait_for_async_tx); + +/* dma_run_dependencies - helper routine for dma drivers to process + * (start) dependent operations on their target channel + * @tx: transaction with dependencies + */ +void dma_run_dependencies(struct dma_async_tx_descriptor *tx) +{ + struct dma_async_tx_descriptor *dep = tx->next; + struct dma_async_tx_descriptor *dep_next; + struct dma_chan *chan; + + if (!dep) + return; + + chan = dep->chan; + + /* keep submitting up until a channel switch is detected + * in that case we will be called again as a result of + * processing the interrupt from async_tx_channel_switch + */ + for (; dep; dep = dep_next) { + spin_lock_bh(&dep->lock); + dep->parent = NULL; + dep_next = dep->next; + if (dep_next && dep_next->chan == chan) + dep->next = NULL; /* ->next will be submitted */ + else + dep_next = NULL; /* submit current dep and terminate */ + spin_unlock_bh(&dep->lock); + + dep->tx_submit(dep); + } + + chan->device->device_issue_pending(chan); +} +EXPORT_SYMBOL_GPL(dma_run_dependencies); + static int __init dma_bus_init(void) { mutex_init(&dma_list_mutex); diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c index 6be3172..be9ea9f 100644 --- a/drivers/dma/iop-adma.c +++ b/drivers/dma/iop-adma.c @@ -24,7 +24,6 @@ #include #include -#include #include #include #include @@ -116,7 +115,7 @@ iop_adma_run_tx_complete_actions(struct iop_adma_desc_slot *desc, } /* run dependent operations */ - async_tx_run_dependencies(&desc->async_tx); + dma_run_dependencies(&desc->async_tx); return cookie; } diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index bcda174..3f46df3 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -18,7 +18,6 @@ #include #include -#include #include #include #include @@ -340,7 +339,7 @@ mv_xor_run_tx_complete_actions(struct mv_xor_desc_slot *desc, } /* run dependent operations */ - async_tx_run_dependencies(&desc->async_tx); + dma_run_dependencies(&desc->async_tx); return cookie; } diff --git a/include/linux/async_tx.h b/include/linux/async_tx.h index 0f50d4c..1c81677 100644 --- a/include/linux/async_tx.h +++ b/include/linux/async_tx.h @@ -60,8 +60,6 @@ enum async_tx_flags { #ifdef CONFIG_DMA_ENGINE void async_tx_issue_pending_all(void); -enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx); -void async_tx_run_dependencies(struct dma_async_tx_descriptor *tx); #ifdef CONFIG_ARCH_HAS_ASYNC_TX_FIND_CHANNEL #include #else @@ -77,19 +75,6 @@ static inline void async_tx_issue_pending_all(void) do { } while (0); } -static inline enum dma_status -dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) -{ - return DMA_SUCCESS; -} - -static inline void -async_tx_run_dependencies(struct dma_async_tx_descriptor *tx, - struct dma_chan *host_chan) -{ - do { } while (0); -} - static inline struct dma_chan * async_tx_find_channel(struct dma_async_tx_descriptor *depend_tx, enum dma_transaction_type tx_type, struct page **dst, int dst_count, diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index adb0b08..e4ec7e7 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -475,11 +475,20 @@ static inline enum dma_status dma_async_is_complete(dma_cookie_t cookie, } enum dma_status dma_sync_wait(struct dma_chan *chan, dma_cookie_t cookie); +#ifdef CONFIG_DMA_ENGINE +enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx); +#else +static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx) +{ + return DMA_SUCCESS; +} +#endif /* --- DMA device --- */ int dma_async_device_register(struct dma_device *device); void dma_async_device_unregister(struct dma_device *device); +void dma_run_dependencies(struct dma_async_tx_descriptor *tx); /* --- Helper iov-locking functions --- */ -- 1.8.2.3