1. 16 Oct, 2007 1 commit
  2. 10 Oct, 2007 22 commits
  3. 24 Sep, 2007 1 commit
  4. 10 Sep, 2007 1 commit
  5. 09 Sep, 2007 1 commit
    • Herbert Xu's avatar
      [CRYPTO] blkcipher: Fix handling of kmalloc page straddling · e4630f9f
      Herbert Xu authored
      The function blkcipher_get_spot tries to return a buffer of
      the specified length that does not straddle a page.  It has
      an off-by-one bug so it may advance a page unnecessarily.
      
      What's worse, one of its callers doesn't provide a buffer
      that's sufficiently long for this operation.
      
      This patch fixes both problems.  Thanks to Bob Gilligan for
      diagnosing this problem and providing a fix.
      Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
      e4630f9f
  6. 06 Aug, 2007 1 commit
  7. 20 Jul, 2007 1 commit
  8. 16 Jul, 2007 1 commit
  9. 13 Jul, 2007 2 commits
    • Dan Williams's avatar
      async_tx: add the async_tx api · 9bc89cd8
      Dan Williams authored
      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: default avatarDan Williams <dan.j.williams@intel.com>
      Acked-By: default avatarNeilBrown <neilb@suse.de>
      9bc89cd8
    • Dan Williams's avatar
      xor: make 'xor_blocks' a library routine for use with async_tx · 685784aa
      Dan Williams authored
      The async_tx api tries to use a dma engine for an operation, but will fall
      back to an optimized software routine otherwise.  Xor support is
      implemented using the raid5 xor routines.  For organizational purposes this
      routine is moved to a common area.
      
      The following fixes are also made:
      * rename xor_block => xor_blocks, suggested by Adrian Bunk
      * ensure that xor.o initializes before md.o in the built-in case
      * checkpatch.pl fixes
      * mark calibrate_xor_blocks __init, Adrian Bunk
      
      Cc: Adrian Bunk <bunk@stusta.de>
      Cc: NeilBrown <neilb@suse.de>
      Cc: Herbert Xu <herbert@gondor.apana.org.au>
      Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
      685784aa
  10. 11 Jul, 2007 4 commits
  11. 31 May, 2007 1 commit
  12. 18 May, 2007 2 commits
  13. 08 May, 2007 2 commits