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2021-06-11async_xor: check src_offs is not NULL before updating itXiao Ni1-1/+2
When PAGE_SIZE is greater than 4kB, multiple stripes may share the same page. Thus, src_offs is added to async_xor_offs() with array of offsets. However, async_xor() passes NULL src_offs to async_xor_offs(). In such case, src_offs should not be updated. Add a check before the update. Fixes: ceaf2966ab08(async_xor: increase src_offs when dropping destination page) Cc: stable@vger.kernel.org # v5.10+ Reported-by: Oleksandr Shchirskyi <oleksandr.shchirskyi@linux.intel.com> Tested-by: Oleksandr Shchirskyi <oleksandr.shchirskyi@intel.com> Signed-off-by: Xiao Ni <xni@redhat.com> Signed-off-by: Song Liu <song@kernel.org>
2021-04-26async_xor: increase src_offs when dropping destination pageXiao Ni1-0/+1
Now we support sharing one page if PAGE_SIZE is not equal stripe size. To support this, it needs to support calculating xor value with different offsets for each r5dev. One offset array is used to record those offsets. In RMW mode, parity page is used as a source page. It sets ASYNC_TX_XOR_DROP_DST before calculating xor value in ops_run_prexor5. So it needs to add src_list and src_offs at the same time. Now it only needs src_list. So the xor value which is calculated is wrong. It can cause data corruption problem. I can reproduce this problem 100% on a POWER8 machine. The steps are: mdadm -CR /dev/md0 -l5 -n3 /dev/sdb1 /dev/sdc1 /dev/sdd1 --size=3G mkfs.xfs /dev/md0 mount /dev/md0 /mnt/test mount: /mnt/test: mount(2) system call failed: Structure needs cleaning. Fixes: 29bcff787a25 ("md/raid5: add new xor function to support different page offset") Cc: stable@vger.kernel.org # v5.10+ Signed-off-by: Xiao Ni <xni@redhat.com> Signed-off-by: Song Liu <song@kernel.org>
2020-09-25md/raid5: add new xor function to support different page offsetYufen Yu1-17/+103
raid5 will call async_xor() and async_xor_val() to compute xor. For now, both of them require the common src/dst page offset. But, we want them to support different src/dst page offset for following shared page. Here, adding two new function async_xor_offs() and async_xor_val_offs() respectively for async_xor() and async_xor_val(). Signed-off-by: Yufen Yu <yuyufen@huawei.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2019-06-05treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335Thomas Gleixner1-14/+1
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms and conditions of the gnu general public license version 2 as published by the free software foundation this program is distributed in the hope it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 51 franklin st fifth floor boston ma 02110 1301 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 111 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexios Zavras <alexios.zavras@intel.com> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190530000436.567572064@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-07async_tx: use GFP_NOWAIT rather than GFP_IONeilBrown1-2/+2
These async_XX functions are called from md/raid5 in an atomic section, between get_cpu() and put_cpu(), so they must not sleep. So use GFP_NOWAIT rather than GFP_IO. Dan Williams writes: Longer term async_tx needs to be merged into md directly as we can allocate this unmap data statically per-stripe rather than per request. Fixed: 7476bd79fc01 ("async_pq: convert to dmaengine_unmap_data") Cc: stable@vger.kernel.org (v3.13+) Reported-and-tested-by: Stanislav Samsonov <slava@annapurnalabs.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-08-21dmaengine: fix xor sources continuationXuelin Shi1-2/+1
the partial xor result must be kept until the next tx is generated. Cc: <stable@vger.kernel.org> Signed-off-by: Xuelin Shi <xuelin.shi@freescale.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2013-11-14dmaengine: remove DMA unmap flagsBartlomiej Zolnierkiewicz1-4/+2
Remove no longer needed DMA unmap flags: - DMA_COMPL_SKIP_SRC_UNMAP - DMA_COMPL_SKIP_DEST_UNMAP - DMA_COMPL_SRC_UNMAP_SINGLE - DMA_COMPL_DEST_UNMAP_SINGLE Cc: Vinod Koul <vinod.koul@intel.com> Cc: Tomasz Figa <t.figa@samsung.com> Cc: Dave Jiang <dave.jiang@intel.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Acked-by: Jon Mason <jon.mason@intel.com> Acked-by: Mark Brown <broonie@linaro.org> [djbw: clean up straggling skip unmap flags in ntb] Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2013-11-14async_xor_val: convert to dmaengine_unmap_dataDan Williams1-13/+17
Use the generic unmap object to unmap dma buffers. Cc: Vinod Koul <vinod.koul@intel.com> Cc: Tomasz Figa <t.figa@samsung.com> Cc: Dave Jiang <dave.jiang@intel.com> Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> [bzolnier: minor cleanups] Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2013-11-14async_xor: convert to dmaengine_unmap_dataDan Williams1-44/+51
Use the generic unmap object to unmap dma buffers. Later we can push this unmap object up to the raid layer and get rid of the 'scribble' parameter. Cc: Vinod Koul <vinod.koul@intel.com> Cc: Tomasz Figa <t.figa@samsung.com> Cc: Dave Jiang <dave.jiang@intel.com> Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> [bzolnier: minor cleanups] Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2013-01-08async_tx: use memchr_invAkinobu Mita1-3/+1
Use memchr_inv() to check the specified page is filled with zero. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Vinod Koul <vinod.koul@intel.com> Cc: Dan Williams <djbw@fb.com> Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
2011-11-01crypto: add module.h to those files that are explicitly using itPaul Gortmaker1-0/+1
Part of the include cleanups means that the implicit inclusion of module.h via device.h is going away. So fix things up in advance. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
2011-03-31Fix common misspellingsLucas De Marchi1-1/+1
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2009-11-20async_tx: build-time toggling of async_{syndrome,xor}_val dma supportDan Williams1-3/+12
ioat3.2 does not support asynchronous error notifications which makes the driver experience latencies when non-zero pq validate results are expected. Provide a mechanism for turning off async_xor_val and async_syndrome_val via Kconfig. This approach is generally useful for any driver that specifies ASYNC_TX_DISABLE_CHANNEL_SWITCH and would like to force the async_tx api to fall back to the synchronous path for certain operations. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-10-16raid6/async_tx: handle holes in block list in async_syndrome_valNeilBrown1-7/+11
async_syndrome_val check the P and Q blocks used for RAID6 calculations. With DDF raid6, some of the data blocks might be NULL, so this needs to be handled in the same way that async_gen_syndrome handles it. As async_syndrome_val calls async_xor, also enhance async_xor to detect and skip NULL blocks in the list. Signed-off-by: NeilBrown <neilb@suse.de>
2009-09-09dmaengine, async_tx: support alignment checksDan Williams1-2/+3
Some engines have transfer size and address alignment restrictions. Add a per-operation alignment property to struct dma_device that the async routines and dmatest can use to check alignment capabilities. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-09-09dmaengine: add fence supportDan Williams1-3/+8
Some engines optimize operation by reading ahead in the descriptor chain such that descriptor2 may start execution before descriptor1 completes. If descriptor2 depends on the result from descriptor1 then a fence is required (on descriptor2) to disable this optimization. The async_tx api could implicitly identify dependencies via the 'depend_tx' parameter, but that would constrain cases where the dependency chain only specifies a completion order rather than a data dependency. So, provide an ASYNC_TX_FENCE to explicitly identify data dependencies. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-30async_tx: add support for asynchronous GF multiplicationDan Williams1-1/+1
[ Based on an original patch by Yuri Tikhonov ] This adds support for doing asynchronous GF multiplication by adding two additional functions to the async_tx API: async_gen_syndrome() does simultaneous XOR and Galois field multiplication of sources. async_syndrome_val() validates the given source buffers against known P and Q values. When a request is made to run async_pq against more than the hardware maximum number of supported sources we need to reuse the previous generated P and Q values as sources into the next operation. Care must be taken to remove Q from P' and P from Q'. For example to perform a 5 source pq op with hardware that only supports 4 sources at a time the following approach is taken: p, q = PQ(src0, src1, src2, src3, COEF({01}, {02}, {04}, {08})) p', q' = PQ(p, q, q, src4, COEF({00}, {01}, {00}, {10})) p' = p + q + q + src4 = p + src4 q' = {00}*p + {01}*q + {00}*q + {10}*src4 = q + {10}*src4 Note: 4 is the minimum acceptable maxpq otherwise we punt to synchronous-software path. The DMA_PREP_CONTINUE flag indicates to the driver to reuse p and q as sources (in the above manner) and fill the remaining slots up to maxpq with the new sources/coefficients. Note1: Some devices have native support for P+Q continuation and can skip this extra work. Devices with this capability can advertise it with dma_set_maxpq. It is up to each driver how to handle the DMA_PREP_CONTINUE flag. Note2: The api supports disabling the generation of P when generating Q, this is ignored by the synchronous path but is implemented by some dma devices to save unnecessary writes. In this case the continuation algorithm is simplified to only reuse Q as a source. Cc: H. Peter Anvin <hpa@zytor.com> Cc: David Woodhouse <David.Woodhouse@intel.com> Signed-off-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Ilya Yanok <yanok@emcraft.com> Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-08-30async_tx: add sum check flagsDan Williams1-2/+2
Replace the flat zero_sum_result with a collection of flags to contain the P (xor) zero-sum result, and the soon to be utilized Q (raid6 reed solomon syndrome) zero-sum result. Use the SUM_CHECK_ namespace instead of DMA_ since these flags will be used on non-dma-zero-sum enabled platforms. Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-06-04async_xor: permit callers to pass in a 'dma/page scribble' regionDan Williams1-31/+29
async_xor() needs space to perform dma and page address conversions. In most cases the code can simply reuse the struct page * array because the size of the native pointer matches the size of a dma/page address. In order to support archs where sizeof(dma_addr_t) is larger than sizeof(struct page *), or to preserve the input parameters, we utilize a memory region passed in by the caller. Since the code is now prepared to handle the case where it cannot perform address conversions on the stack, we no longer need the !HIGHMEM64G dependency in drivers/dma/Kconfig. [ Impact: don't clobber input buffers for address conversions ] Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-06-04async_tx: structify submission arguments, add scribbleDan Williams1-63/+60
Prepare the api for the arrival of a new parameter, 'scribble'. This will allow callers to identify scratchpad memory for dma address or page address conversions. As this adds yet another parameter, take this opportunity to convert the common submission parameters (flags, dependency, callback, and callback argument) into an object that is passed by reference. Also, take this opportunity to fix up the kerneldoc and add notes about the relevant ASYNC_TX_* flags for each routine. [ Impact: moves api pass-by-value parameters to a pass-by-reference struct ] Signed-off-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-06-04async_tx: kill ASYNC_TX_DEP_ACK flagDan Williams1-4/+2
In support of inter-channel chaining async_tx utilizes an ack flag to gate whether a dependent operation can be chained to another. While the flag is not set the chain can be considered open for appending. Setting the ack flag closes the chain and flags the descriptor for garbage collection. The ASYNC_TX_DEP_ACK flag essentially means "close the chain after adding this dependency". Since each operation can only have one child the api now implicitly sets the ack flag at dependency submission time. This removes an unnecessary management burden from clients of the api. [ Impact: clean up and enforce one dependency per operation ] Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-04-09async_tx: rename zero_sum to valDan Williams1-8/+8
'zero_sum' does not properly describe the operation of generating parity and checking that it validates against an existing buffer. Change the name of the operation to 'val' (for 'validate'). This is in anticipation of the p+q case where it is a requirement to identify the target parity buffers separately from the source buffers, because the target parity buffers will not have corresponding pq coefficients. Reviewed-by: Andre Noll <maan@systemlinux.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25async_tx: provide __async_inline for HAS_DMA=n archsDan Williams1-5/+2
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>
2008-12-08async_xor: dma_map destination DMA_BIDIRECTIONALDan Williams1-2/+9
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>
2008-08-05async_tx: fix missing braces in async_xor_zero_sumDan Williams1-1/+2
Found-by: Yuri Tikhonov <yur@emcraft.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-18async_tx: remove depend_tx from async_tx_sync_epilogDan Williams1-4/+3
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 Williams1-35/+2
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 Williams1-6/+26
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 Williams1-131/+113
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>
2008-04-18dmaengine: ack to flags: make use of the unused bits in the 'ack' fieldDan Williams1-1/+1
'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>
2008-03-19async_tx: avoid the async xor_zero_sum path when src_cnt > device->max_xorDan Williams1-1/+1
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 Williams1-6/+6
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-02-06async_tx: allow architecture specific async_tx_find_channel implementationsDan Williams1-2/+6
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 Williams1-4/+6
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 Williams1-34/+60
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 Williams1-16/+6
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: fix compile breakage, mark do_async_xor __always_inlineDan Williams1-1/+5
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>
2007-07-13async_tx: add the async_tx apiDan Williams1-0/+327
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>