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2009-03-25dmaengine: allow dma support for async_tx to be toggledDan Williams
Provide a config option for blocking the allocation of dma channels to the async_tx api. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25async_tx: provide __async_inline for HAS_DMA=n archsDan Williams
To allow an async_tx routine to be compiled away on HAS_DMA=n arch it needs to be declared __always_inline otherwise the compiler may emit code and cause a link error. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: replace dma_async_client_register with dmaengine_getDan Williams
Now that clients no longer need to be notified of channel arrival dma_async_client_register can simply increment the dmaengine_ref_count. Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: provide a common 'issue_pending_all' implementationDan Williams
async_tx and net_dma each have open-coded versions of issue_pending_all, so provide a common routine in dmaengine. The implementation needs to walk the global device list, so implement rcu to allow dma_issue_pending_all to run lockless. Clients protect themselves from channel removal events by holding a dmaengine reference. Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: centralize channel allocation, introduce dma_find_channelDan Williams
Allowing multiple clients to each define their own channel allocation scheme quickly leads to a pathological situation. For memory-to-memory offload all clients can share a central allocator. This simply moves the existing async_tx allocator to dmaengine with minimal fixups: * async_tx.c:get_chan_ref_by_cap --> dmaengine.c:nth_chan * async_tx.c:async_tx_rebalance --> dmaengine.c:dma_channel_rebalance * split out common code from async_tx.c:__async_tx_find_channel --> dma_find_channel Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: up-level reference counting to the module levelDan Williams
Simply, if a client wants any dmaengine channel then prevent all dmaengine modules from being removed. Once the clients are done re-enable module removal. Why?, beyond reducing complication: 1/ Tracking reference counts per-transaction in an efficient manner, as is currently done, requires a complicated scheme to avoid cache-line bouncing effects. 2/ Per-transaction ref-counting gives the false impression that a dma-driver can be gracefully removed ahead of its user (net, md, or dma-slave) 3/ None of the in-tree dma-drivers talk to hot pluggable hardware, but if such an engine were built one day we still would not need to notify clients of remove events. The driver can simply return NULL to a ->prep() request, something that is much easier for a client to handle. Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: remove dependency on async_txDan Williams
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 <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-12-08async_xor: dma_map destination DMA_BIDIRECTIONALDan Williams
Mapping the destination multiple times is a misuse of the dma-api. Since the destination may be reused as a source, ensure that it is only mapped once and that it is mapped bidirectionally. This appears to add ugliness on the unmap side in that it always reads back the destination address from the descriptor, but gcc can determine that dma_unmap is a nop and not emit the code that calculates its arguments. Cc: <stable@kernel.org> Cc: Saeed Bishara <saeed@marvell.com> Acked-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-09-14async_tx: make async_tx_run_dependencies() easier to readDan Williams
* Rename 'next' to 'dep' * Move the channel switch check inside the loop to simplify termination Acked-by: Ilya Yanok <yanok@emcraft.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-09-05async_tx: fix the bug in async_tx_run_dependenciesYuri Tikhonov
Should clear the next pointer of the TX if we are sure that the next TX (say NXT) will be submitted to the channel too. Overwise, we break the chain of descriptors, because we lose the information about the next descriptor to run. So next time, when invoke async_tx_run_dependencies() with TX, it's TX->next will be NULL, and NXT will be never submitted. Cc: <stable@kernel.org> [2.6.26] Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-08-05async_tx: fix missing braces in async_xor_zero_sumDan Williams
Found-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-23Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (24 commits) I/OAT: I/OAT version 3.0 support I/OAT: tcp_dma_copybreak default value dependent on I/OAT version I/OAT: Add watchdog/reset functionality to ioatdma iop_adma: cleanup iop_chan_xor_slot_count iop_adma: document how to calculate the minimum descriptor pool size iop_adma: directly reclaim descriptors on allocation failure async_tx: make async_tx_test_ack a boolean routine async_tx: remove depend_tx from async_tx_sync_epilog async_tx: export async_tx_quiesce async_tx: fix handling of the "out of descriptor" condition in async_xor async_tx: ensure the xor destination buffer remains dma-mapped async_tx: list_for_each_entry_rcu() cleanup dmaengine: Driver for the Synopsys DesignWare DMA controller dmaengine: Add slave DMA interface dmaengine: add DMA_COMPL_SKIP_{SRC,DEST}_UNMAP flags to control dma unmap dmaengine: Add dma_client parameter to device_alloc_chan_resources dmatest: Simple DMA memcpy test client dmaengine: DMA engine driver for Marvell XOR engine iop-adma: fix platform driver hotplug/coldplug dmaengine: track the number of clients using a channel ... Fixed up conflict in drivers/dca/dca-sysfs.c manually
2008-07-18async_tx: remove depend_tx from async_tx_sync_epilogDan Williams
All callers of async_tx_sync_epilog have called async_tx_quiesce on the depend_tx, so async_tx_sync_epilog need only call the callback to complete the operation. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-18async_tx: export async_tx_quiesceDan Williams
Replace open coded "wait and acknowledge" instances with async_tx_quiesce. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-18async_tx: fix handling of the "out of descriptor" condition in async_xorDan Williams
Ensure forward progress is made when a dmaengine driver is unable to allocate an xor descriptor by breaking the dependency chain with async_tx_quisce() and issue any pending descriptors. Tested with iop-adma by setting device->max_xor = 2 to force multiple calls to device_prep_dma_xor for each call to async_xor and limiting the descriptor slot pool to 5. Discovered that the minimum descriptor pool size for iop-adma is 2 * iop_chan_xor_slot_cnt(device->max_xor) + 1. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-18async_tx: ensure the xor destination buffer remains dma-mappedDan Williams
When the number of source buffers for an xor operation exceeds the hardware channel maximum async_xor creates a chain of dependent operations. The result of one operation is reused as an input to the next to continue the xor calculation. The destination buffer should remain mapped for the duration of the entire chain. To provide this guarantee the code must no longer be allowed to fallback to the synchronous path as this will preclude the buffer from being unmapped, i.e. the dma-driver will potentially miss the descriptor with !DMA_COMPL_SKIP_DEST_UNMAP. Cc: Neil Brown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-18async_tx: list_for_each_entry_rcu() cleanupLi Zefan
In the rcu update side, don't use list_for_each_entry_rcu(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-08async_tx: fix async_memset compile errorDan Williams
commit 636bdeaa 'dmaengine: ack to flags: make use of the unused bits in the 'ack' field' missed an ->ack conversion in crypto/async_tx/async_memset.c Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-05-19rcu: split list.h and move rcu-protected lists into rculist.hFranck Bui-Huu
Move rcu-protected lists from list.h into a new header file rculist.h. This is done because list are a very used primitive structure all over the kernel and it's currently impossible to include other header files in this list.h without creating some circular dependencies. For example, list.h implements rcu-protected list and uses rcu_dereference() without including rcupdate.h. It actually compiles because users of rcu_dereference() are macros. Others RCU functions could be used too but aren't probably because of this. Therefore this patch creates rculist.h which includes rcupdates without to many changes/troubles. Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Josh Triplett <josh@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17dmaengine: ack to flags: make use of the unused bits in the 'ack' fieldDan Williams
'ack' is currently a simple integer that flags whether or not a client is done touching fields in the given descriptor. It is effectively just a single bit of information. Converting this to a flags parameter allows the other bits to be put to use to control completion actions, like dma-unmap, and capture results, like xor-zero-sum == 0. Changes are one of: 1/ convert all open-coded ->ack manipulations to use async_tx_ack and async_tx_test_ack. 2/ set the ack bit at prep time where possible 3/ make drivers store the flags at prep time 4/ add flags to the device_prep_dma_interrupt prototype Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-04-17async_tx: fix multiple dependency submissionDan Williams
Shrink struct dma_async_tx_descriptor and introduce async_tx_channel_switch to properly inject a channel switch interrupt in the descriptor stream. This simplifies the locking model as drivers no longer need to handle dma_async_tx_descriptor.lock. Acked-by: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-03-19async_tx: avoid the async xor_zero_sum path when src_cnt > device->max_xorDan Williams
If the channel cannot perform the operation in one call to ->device_prep_dma_zero_sum, then fallback to the xor+page_is_zero path. This only affects users with arrays larger than 16 devices on iop13xx or 32 devices on iop3xx. Cc: <stable@kernel.org> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-03-13async_tx: checkpatch says s/__FUNCTION__/__func__/gDan Williams
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-02-06async_tx: allow architecture specific async_tx_find_channel implementationsDan Williams
The source and destination addresses are included to allow channel selection based on address alignment. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2008-02-06async_tx: replace 'int_en' with operation preparation flagsDan Williams
Pass a full set of flags to drivers' per-operation 'prep' routines. Currently the only flag passed is DMA_PREP_INTERRUPT. The expectation is that arch-specific async_tx_find_channel() implementations can exploit this capability to find the best channel for an operation. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Shannon Nelson <shannon.nelson@intel.com> Reviewed-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2008-02-06async_tx: kill tx_set_src and tx_set_dest methodsDan Williams
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 <dan.j.williams@intel.com> Acked-by: Shannon Nelson <shannon.nelson@intel.com>
2008-02-06async_tx: kill ASYNC_TX_ASSUME_COHERENTDan Williams
Remove the unused ASYNC_TX_ASSUME_COHERENT flag. Async_tx is meant to hide the difference between asynchronous hardware and synchronous software operations, this flag requires clients to understand cache coherency consequences of the async path. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
2008-02-06async_tx: use LIST_HEAD instead of LIST_HEAD_INITDenis Cheng
single list_head variable initialized with LIST_HEAD_INIT could almost always can be replaced with LIST_HEAD declaration, this shrinks the code and looks better. Signed-off-by: Denis Cheng <crquan@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-02-06async_tx: fix compile breakage, mark do_async_xor __always_inlineDan Williams
do_async_xor must be compiled away on !HAS_DMA archs. Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2007-09-24async_tx: fix dma_wait_for_async_txDan Williams
Fix dma_wait_for_async_tx to not loop forever in the case where a dependency chain is longer than two entries. This condition will not happen with current in-kernel drivers, but fix it for future drivers. Found-by: Saeed Bishara <saeed.bishara@gmail.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2007-07-20async_tx: fix kmap_atomic usage in async_memcpyDan Williams
Andrew Morton: [async_memcpy] is very wrong if both ASYNC_TX_KMAP_DST and ASYNC_TX_KMAP_SRC can ever be set. We'll end up using the same kmap slot for both src add dest and we get either corrupted data or a BUG. Evgeniy Polyakov: Btw, shouldn't it always be kmap_atomic() even if flag is not set. That pages are usual one returned by alloc_page(). So fix the usage of kmap_atomic and kill the ASYNC_TX_KMAP_DST and ASYNC_TX_KMAP_SRC flags. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-13async_tx: add the async_tx apiDan Williams
The async_tx api provides methods for describing a chain of asynchronous bulk memory transfers/transforms with support for inter-transactional dependencies. It is implemented as a dmaengine client that smooths over the details of different hardware offload engine implementations. Code that is written to the api can optimize for asynchronous operation and the api will fit the chain of operations to the available offload resources. I imagine that any piece of ADMA hardware would register with the 'async_*' subsystem, and a call to async_X would be routed as appropriate, or be run in-line. - Neil Brown async_tx exploits the capabilities of struct dma_async_tx_descriptor to provide an api of the following general format: struct dma_async_tx_descriptor * async_<operation>(..., struct dma_async_tx_descriptor *depend_tx, dma_async_tx_callback cb_fn, void *cb_param) { struct dma_chan *chan = async_tx_find_channel(depend_tx, <operation>); struct dma_device *device = chan ? chan->device : NULL; int int_en = cb_fn ? 1 : 0; struct dma_async_tx_descriptor *tx = device ? device->device_prep_dma_<operation>(chan, len, int_en) : NULL; if (tx) { /* run <operation> asynchronously */ ... tx->tx_set_dest(addr, tx, index); ... tx->tx_set_src(addr, tx, index); ... async_tx_submit(chan, tx, flags, depend_tx, cb_fn, cb_param); } else { /* run <operation> synchronously */ ... <operation> ... async_tx_sync_epilog(flags, depend_tx, cb_fn, cb_param); } return tx; } async_tx_find_channel() returns a capable channel from its pool. The channel pool is organized as a per-cpu array of channel pointers. The async_tx_rebalance() routine is tasked with managing these arrays. In the uniprocessor case async_tx_rebalance() tries to spread responsibility evenly over channels of similar capabilities. For example if there are two copy+xor channels, one will handle copy operations and the other will handle xor. In the SMP case async_tx_rebalance() attempts to spread the operations evenly over the cpus, e.g. cpu0 gets copy channel0 and xor channel0 while cpu1 gets copy channel 1 and xor channel 1. When a dependency is specified async_tx_find_channel defaults to keeping the operation on the same channel. A xor->copy->xor chain will stay on one channel if it supports both operation types, otherwise the transaction will transition between a copy and a xor resource. Currently the raid5 implementation in the MD raid456 driver has been converted to the async_tx api. A driver for the offload engines on the Intel Xscale series of I/O processors, iop-adma, is provided in a later commit. With the iop-adma driver and async_tx, raid456 is able to offload copy, xor, and xor-zero-sum operations to hardware engines. On iop342 tiobench showed higher throughput for sequential writes (20 - 30% improvement) and sequential reads to a degraded array (40 - 55% improvement). For the other cases performance was roughly equal, +/- a few percentage points. On a x86-smp platform the performance of the async_tx implementation (in synchronous mode) was also +/- a few percentage points of the original implementation. According to 'top' on iop342 CPU utilization drops from ~50% to ~15% during a 'resync' while the speed according to /proc/mdstat doubles from ~25 MB/s to ~50 MB/s. The tiobench command line used for testing was: tiobench --size 2048 --block 4096 --block 131072 --dir /mnt/raid --numruns 5 * iop342 had 1GB of memory available Details: * if CONFIG_DMA_ENGINE=n the asynchronous path is compiled away by making async_tx_find_channel a static inline routine that always returns NULL * when a callback is specified for a given transaction an interrupt will fire at operation completion time and the callback will occur in a tasklet. if the the channel does not support interrupts then a live polling wait will be performed * the api is written as a dmaengine client that requests all available channels * In support of dependencies the api implicitly schedules channel-switch interrupts. The interrupt triggers the cleanup tasklet which causes pending operations to be scheduled on the next channel * Xor engines treat an xor destination address differently than a software xor routine. To the software routine the destination address is an implied source, whereas engines treat it as a write-only destination. This patch modifies the xor_blocks routine to take a an explicit destination address to mirror the hardware. Changelog: * fixed a leftover debug print * don't allow callbacks in async_interrupt_cond * fixed xor_block changes * fixed usage of ASYNC_TX_XOR_DROP_DEST * drop dma mapping methods, suggested by Chris Leech * printk warning fixups from Andrew Morton * don't use inline in C files, Adrian Bunk * select the API when MD is enabled * BUG_ON xor source counts <= 1 * implicitly handle hardware concerns like channel switching and interrupts, Neil Brown * remove the per operation type list, and distribute operation capabilities evenly amongst the available channels * simplify async_tx_find_channel to optimize the fast path * introduce the channel_table_initialized flag to prevent early calls to the api * reorganize the code to mimic crypto * include mm.h as not all archs include it in dma-mapping.h * make the Kconfig options non-user visible, Adrian Bunk * move async_tx under crypto since it is meant as 'core' functionality, and the two may share algorithms in the future * move large inline functions into c files * checkpatch.pl fixes * gpl v2 only correction Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-By: NeilBrown <neilb@suse.de>