On Mon, Jan 12, 2009 at 5:43 PM, Yuri Tikhonov <yur@xxxxxxxxxxx> wrote:
> This adds support for doing asynchronous GF multiplication by adding
> four additional functions to async_tx API:
>
> async_pq() does simultaneous XOR of sources and XOR of sources
> GF-multiplied by given coefficients.
>
> async_pq_zero_sum() checks if results of calculations match given
> ones.
>
> async_gen_syndrome() does sumultaneous XOR and R/S syndrome of sources.
>
> async_syndrome_zerosum() checks if results of XOR/syndrome calculation
> matches given ones.
>
> Latter two functions just use async_pq() with the approprite coefficients
> in asynchronous case but have significant optimizations if synchronous
> case.
>
> To support this API dmaengine driver should set DMA_PQ and
> DMA_PQ_ZERO_SUM capabilities and provide device_prep_dma_pq and
> device_prep_dma_pqzero_sum methods in dma_device structure.
>
> Signed-off-by: Yuri Tikhonov <yur@xxxxxxxxxxx>
> Signed-off-by: Ilya Yanok <yanok@xxxxxxxxxxx>
> ---
> crypto/async_tx/Kconfig | 4 +
> crypto/async_tx/Makefile | 1 +
> crypto/async_tx/async_pq.c | 615 +++++++++++++++++++++++++++++++++++++++++++
> crypto/async_tx/async_xor.c | 2 +-
> include/linux/async_tx.h | 46 +++-
> include/linux/dmaengine.h | 30 ++-
> 6 files changed, 693 insertions(+), 5 deletions(-)
> create mode 100644 crypto/async_tx/async_pq.c
>
> diff --git a/crypto/async_tx/Kconfig b/crypto/async_tx/Kconfig
> index d8fb391..cb6d731 100644
> --- a/crypto/async_tx/Kconfig
> +++ b/crypto/async_tx/Kconfig
> @@ -14,3 +14,7 @@ config ASYNC_MEMSET
> tristate
> select ASYNC_CORE
>
> +config ASYNC_PQ
> + tristate
> + select ASYNC_CORE
> +
> diff --git a/crypto/async_tx/Makefile b/crypto/async_tx/Makefile
> index 27baa7d..1b99265 100644
> --- a/crypto/async_tx/Makefile
> +++ b/crypto/async_tx/Makefile
> @@ -2,3 +2,4 @@ obj-$(CONFIG_ASYNC_CORE) += async_tx.o
> obj-$(CONFIG_ASYNC_MEMCPY) += async_memcpy.o
> obj-$(CONFIG_ASYNC_MEMSET) += async_memset.o
> obj-$(CONFIG_ASYNC_XOR) += async_xor.o
> +obj-$(CONFIG_ASYNC_PQ) += async_pq.o
> diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c
> new file mode 100644
> index 0000000..5871651
> --- /dev/null
> +++ b/crypto/async_tx/async_pq.c
> @@ -0,0 +1,615 @@
> +/*
> + * Copyright(c) 2007 Yuri Tikhonov <yur@xxxxxxxxxxx>
> + *
> + * Developed for DENX Software Engineering GmbH
> + *
> + * Asynchronous GF-XOR calculations ASYNC_TX API.
> + *
> + * based on async_xor.c code written by:
> + * Dan Williams <dan.j.williams@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the Free
> + * Software Foundation; either version 2 of the License, or (at your option)
> + * any later version.
> + *
> + * This program is distributed in the hope that 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., 59
> + * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
> + *
> + * The full GNU General Public License is included in this distribution in the
> + * file called COPYING.
> + */
> +#include <linux/kernel.h>
> +#include <linux/interrupt.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/raid/xor.h>
> +#include <linux/async_tx.h>
> +
> +#include "../drivers/md/raid6.h"
> +
> +/**
> + * The following static variables are used in cases of synchronous
> + * zero sum to save the values to check. Two pages used for zero sum and
> + * the third one is for dumb P destination when calling gen_syndrome()
> + */
> +static spinlock_t spare_lock;
> +static struct page *spare_pages[3];
> +
> +/**
> + * do_async_pq - asynchronously calculate P and/or Q
> + */
> +static struct dma_async_tx_descriptor *
> +do_async_pq(struct dma_chan *chan, struct page **blocks, unsigned char *scfs,
> + unsigned int offset, int src_cnt, size_t len, enum async_tx_flags flags,
> + struct dma_async_tx_descriptor *depend_tx,
> + dma_async_tx_callback cb_fn, void *cb_param)
> +{
> + struct dma_device *dma = chan->device;
> + dma_addr_t dma_dest[2], dma_src[src_cnt];
> + struct dma_async_tx_descriptor *tx = NULL;
> + dma_async_tx_callback _cb_fn;
> + void *_cb_param;
> + unsigned char *scf = NULL;
> + int i, src_off = 0;
> + unsigned short pq_src_cnt;
> + enum async_tx_flags async_flags;
> + enum dma_ctrl_flags dma_flags = 0;
> +
> + /* If we won't handle src_cnt in one shot, then the following
> + * flag(s) will be set only on the first pass of prep_dma
> + */
> + if (flags & ASYNC_TX_PQ_ZERO_P)
> + dma_flags |= DMA_PREP_ZERO_P;
> + if (flags & ASYNC_TX_PQ_ZERO_Q)
> + dma_flags |= DMA_PREP_ZERO_Q;
> +
> + /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */
> + if (blocks[src_cnt]) {
> + dma_dest[0] = dma_map_page(dma->dev, blocks[src_cnt],
> + offset, len, DMA_BIDIRECTIONAL);
> + dma_flags |= DMA_PREP_HAVE_P;
> + }
> + if (blocks[src_cnt+1]) {
> + dma_dest[1] = dma_map_page(dma->dev, blocks[src_cnt+1],
> + offset, len, DMA_BIDIRECTIONAL);
> + dma_flags |= DMA_PREP_HAVE_Q;
> + }
> +
> + for (i = 0; i < src_cnt; i++)
> + dma_src[i] = dma_map_page(dma->dev, blocks[i],
> + offset, len, DMA_TO_DEVICE);
> +
> + while (src_cnt) {
> + async_flags = flags;
> + pq_src_cnt = min(src_cnt, (int)dma->max_pq);
> + /* if we are submitting additional pqs, leave the chain open,
> + * clear the callback parameters, and leave the destination
> + * buffers mapped
> + */
> + if (src_cnt > pq_src_cnt) {
> + async_flags &= ~ASYNC_TX_ACK;
> + dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP;
> + _cb_fn = NULL;
> + _cb_param = NULL;
> + } else {
> + _cb_fn = cb_fn;
> + _cb_param = cb_param;
> + }
> + if (_cb_fn)
> + dma_flags |= DMA_PREP_INTERRUPT;
> + if (scfs)
> + scf = &scfs[src_off];
> +
> + /* Since we have clobbered the src_list we are committed
> + * to doing this asynchronously. Drivers force forward
> + * progress in case they can not provide a descriptor
> + */
> + tx = dma->device_prep_dma_pq(chan, dma_dest,
> + &dma_src[src_off], pq_src_cnt,
> + scf, len, dma_flags);
> + if (unlikely(!tx))
> + async_tx_quiesce(&depend_tx);
> +
> + /* spin wait for the preceeding transactions to complete */
> + while (unlikely(!tx)) {
> + dma_async_issue_pending(chan);
> + tx = dma->device_prep_dma_pq(chan, dma_dest,
> + &dma_src[src_off], pq_src_cnt,
> + scf, len, dma_flags);
> + }
> +
> + async_tx_submit(chan, tx, async_flags, depend_tx,
> + _cb_fn, _cb_param);
> +
> + depend_tx = tx;
> + flags |= ASYNC_TX_DEP_ACK;
> +
> + if (src_cnt > pq_src_cnt) {
> + /* drop completed sources */
> + src_cnt -= pq_src_cnt;
> + src_off += pq_src_cnt;
> +
> + /* use the intermediate result as a source; we
> + * clear DMA_PREP_ZERO, so prep_dma_pq will
> + * include destination(s) into calculations. Thus
> + * keep DMA_PREP_HAVE_x in dma_flags only
> + */
> + dma_flags &= (DMA_PREP_HAVE_P | DMA_PREP_HAVE_Q);
I don't think this will work as we will be mixing Q into the new P and
P into the new Q. In order to support (src_cnt > device->max_pq) we
need to explicitly tell the driver that the operation is being
continued (DMA_PREP_CONTINUE) and to apply different coeffeicients to
P and Q to cancel the effect of including them as sources. Here is an
example of supporting a 5 source pq operation where max_pq == 4 (the
minimum).
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 = P
q' = {00}*p + {01}*q + {00}*q + {10}*src4 = q + {10)*src4 = Q
...at no point do we need to zero P or Q. Yes, this requires a lot of
extra work for incremental sources, but at this point I do not see a
cleaner alternatve for engines like iop13xx.
> + } else
> + break;
> + }
> +
> + return tx;
> +}
> +
> +/**
> + * do_sync_pq - synchronously calculate P and Q
> + */
> +static void
> +do_sync_pq(struct page **blocks, unsigned char *scfs, unsigned int offset,
> + int src_cnt, size_t len, enum async_tx_flags flags,
> + struct dma_async_tx_descriptor *depend_tx,
> + dma_async_tx_callback cb_fn, void *cb_param)
> +{
> + int i, pos;
> + uint8_t *p = NULL, *q = NULL, *src;
> +
> + /* set destination addresses */
> + if (blocks[src_cnt])
> + p = (uint8_t *)(page_address(blocks[src_cnt]) + offset);
> + if (blocks[src_cnt+1])
> + q = (uint8_t *)(page_address(blocks[src_cnt+1]) + offset);
> +
> + if (flags & ASYNC_TX_PQ_ZERO_P) {
> + BUG_ON(!p);
> + memset(p, 0, len);
> + }
> +
> + if (flags & ASYNC_TX_PQ_ZERO_Q) {
> + BUG_ON(!q);
> + memset(q, 0, len);
> + }
> +
> + for (i = 0; i < src_cnt; i++) {
> + src = (uint8_t *)(page_address(blocks[i]) + offset);
> + for (pos = 0; pos < len; pos++) {
> + if (p)
> + p[pos] ^= src[pos];
> + if (q)
> + q[pos] ^= raid6_gfmul[scfs[i]][src[pos]];
> + }
> + }
> + async_tx_sync_epilog(cb_fn, cb_param);
> +}
sync_pq like sync_gensyndrome should not care about the current
contents of p and q, just regenerate from the current sources. This
kills another site where ASYNC_TX_PQ_ZERO_{P,Q} is used.
> +
> +/**
> + * async_pq - attempt to do XOR and Galois calculations in parallel using
> + * a dma engine.
> + * @blocks: source block array from 0 to (src_cnt-1) with the p destination
> + * at blocks[src_cnt] and q at blocks[src_cnt + 1]. Only one of two
> + * destinations may be present (another then has to be set to NULL).
> + * By default, the result of calculations is XOR-ed with the initial
> + * content of the destinationa buffers. Use ASYNC_TX_PQ_ZERO_x flags
> + * to avoid this.
> + * NOTE: client code must assume the contents of this array are destroyed
> + * @scfs: array of source coefficients used in GF-multiplication
> + * @offset: offset in pages to start transaction
> + * @src_cnt: number of source pages
> + * @len: length in bytes
> + * @flags: ASYNC_TX_PQ_ZERO_P, ASYNC_TX_PQ_ZERO_Q, ASYNC_TX_ASSUME_COHERENT,
> + * ASYNC_TX_ACK, ASYNC_TX_DEP_ACK, ASYNC_TX_ASYNC_ONLY
> + * @depend_tx: depends on the result of this transaction.
> + * @cb_fn: function to call when the operation completes
> + * @cb_param: parameter to pass to the callback routine
> + */
> +struct dma_async_tx_descriptor *
> +async_pq(struct page **blocks, unsigned char *scfs, unsigned int offset,
> + int src_cnt, size_t len, enum async_tx_flags flags,
> + 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, DMA_PQ,
> + &blocks[src_cnt], 2,
> + blocks, src_cnt, len);
> + struct dma_device *device = chan ? chan->device : NULL;
> + struct dma_async_tx_descriptor *tx = NULL;
> +
> + if (!device && (flags & ASYNC_TX_ASYNC_ONLY))
> + return NULL;
> +
> + if (device) {
> + /* run pq asynchronously */
> + tx = do_async_pq(chan, blocks, scfs, offset, src_cnt,
> + len, flags, depend_tx, cb_fn,cb_param);
> + } else {
> + /* run pq synchronously */
> + if (!blocks[src_cnt+1]) {
> + struct page *pdst = blocks[src_cnt];
> + int i;
> +
> + /* Calculate P-parity only.
> + * As opposite to async_xor(), async_pq() assumes
> + * that destinations are included into calculations,
> + * so we should re-arrange the xor src list to
> + * achieve the similar behavior.
> + */
> + if (!(flags & ASYNC_TX_PQ_ZERO_P)) {
> + /* If async_pq() user doesn't set ZERO flag,
> + * it's assumed that destination has some
> + * reasonable data to include in calculations.
> + * The destination must be at position 0, so
> + * shift the sources and put pdst at the
> + * beginning of the list.
> + */
> + for (i = src_cnt - 1; i >= 0; i--)
> + blocks[i+1] = blocks[i];
> + blocks[0] = pdst;
> + src_cnt++;
> + flags |= ASYNC_TX_XOR_DROP_DST;
> + } else {
> + /* If async_pq() user want to clear P, then
> + * this will be done automatically in async
> + * case, and with the help of ZERO_DST in
> + * the sync one.
> + */
> + flags &= ~ASYNC_TX_PQ_ZERO_P;
> + flags |= ASYNC_TX_XOR_ZERO_DST;
> + }
> +
> + return async_xor(pdst, blocks, offset,
> + src_cnt, len, flags, depend_tx,
> + cb_fn, cb_param);
If we assume that async_pq always regenerates parity and never reuses
the old value then we can get gid of the !(flags & ASYNC_TX_PQ_ZERO_P)
path. In the case where code does need to reuse the old P,
async_r6recov.c, it should call async_xor directly since that routine
provides this semantic.
> + }
> +
> + /* wait for any prerequisite operations */
> + async_tx_quiesce(&depend_tx);
> +
> + do_sync_pq(blocks, scfs, offset, src_cnt, len, flags,
> + depend_tx, cb_fn, cb_param);
> + }
> +
> + return tx;
> +}
> +EXPORT_SYMBOL_GPL(async_pq);
> +
> +/**
> + * do_sync_gen_syndrome - synchronously calculate P (xor) and Q (Reed-Solomon
> + * code)
> + */
> +static void
> +do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int src_cnt,
> + size_t len, enum async_tx_flags flags,
> + struct dma_async_tx_descriptor *depend_tx,
> + dma_async_tx_callback cb_fn, void *cb_param)
> +{
> + int i;
> + void *tsrc[src_cnt+2];
> +
> + for (i = 0; i < src_cnt + 2; i++)
> + tsrc[i] = page_address(blocks[i]) + offset;
> +
> + raid6_call.gen_syndrome(i, len, tsrc);
> +
> + async_tx_sync_epilog(cb_fn, cb_param);
> +}
> +
[..]
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 64dea2a..4a72082 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -55,7 +55,7 @@ enum dma_status {
> enum dma_transaction_type {
> DMA_MEMCPY,
> DMA_XOR,
> - DMA_PQ_XOR,
> + DMA_PQ,
> DMA_DUAL_XOR,
> DMA_PQ_UPDATE,
> DMA_ZERO_SUM,
> @@ -81,14 +81,28 @@ enum dma_transaction_type {
> * dependency chains
> * @DMA_COMPL_SKIP_SRC_UNMAP - set to disable dma-unmapping the source buffer(s)
> * @DMA_COMPL_SKIP_DEST_UNMAP - set to disable dma-unmapping the destination(s)
> + * @DMA_PREP_HAVE_P - set if the destination list includes the correct
> + * address of P (P-parity should be handled)
> + * @DMA_PREP_HAVE_Q - set if the destination list includes the correct
> + * address of Q (Q-parity should be handled)
> + * @DMA_PREP_ZERO_P - set if P has to be zeroed before proceeding
> + * @DMA_PREP_ZERO_Q - set if Q has to be zeroed before proceeding
> */
> enum dma_ctrl_flags {
> DMA_PREP_INTERRUPT = (1 << 0),
> DMA_CTRL_ACK = (1 << 1),
> DMA_COMPL_SKIP_SRC_UNMAP = (1 << 2),
> DMA_COMPL_SKIP_DEST_UNMAP = (1 << 3),
> +
> + DMA_PREP_HAVE_P = (1 << 4),
> + DMA_PREP_HAVE_Q = (1 << 5),
> + DMA_PREP_ZERO_P = (1 << 6),
> + DMA_PREP_ZERO_Q = (1 << 7),
> };
>
> +#define DMA_PCHECK_FAILED (1 << 0)
> +#define DMA_QCHECK_FAILED (1 << 1)
Perhaps turn these into an enum such that we can pass around a enum
pq_check_flags pointer rather than a non-descript u32 *.
> +
> /**
> * dma_cap_mask_t - capabilities bitmap modeled after cpumask_t.
> * See linux/cpumask.h
> @@ -211,6 +225,7 @@ struct dma_async_tx_descriptor {
> * @global_node: list_head for global dma_device_list
> * @cap_mask: one or more dma_capability flags
> * @max_xor: maximum number of xor sources, 0 if no capability
> + * @max_pq: maximum number of PQ sources, 0 if no capability
> * @refcount: reference count
> * @done: IO completion struct
> * @dev_id: unique device ID
> @@ -220,7 +235,9 @@ struct dma_async_tx_descriptor {
> * @device_free_chan_resources: release DMA channel's resources
> * @device_prep_dma_memcpy: prepares a memcpy operation
> * @device_prep_dma_xor: prepares a xor operation
> + * @device_prep_dma_pq: prepares a pq operation
> * @device_prep_dma_zero_sum: prepares a zero_sum operation
> + * @device_prep_dma_pqzero_sum: prepares a pqzero_sum operation
> * @device_prep_dma_memset: prepares a memset operation
> * @device_prep_dma_interrupt: prepares an end of chain interrupt operation
> * @device_prep_slave_sg: prepares a slave dma operation
> @@ -233,7 +250,8 @@ struct dma_device {
> struct list_head channels;
> struct list_head global_node;
> dma_cap_mask_t cap_mask;
> - int max_xor;
> + unsigned short max_xor;
> + unsigned short max_pq;
>
> int dev_id;
> struct device *dev;
> @@ -247,9 +265,17 @@ struct dma_device {
> struct dma_async_tx_descriptor *(*device_prep_dma_xor)(
> struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
> unsigned int src_cnt, size_t len, unsigned long flags);
> + struct dma_async_tx_descriptor *(*device_prep_dma_pq)(
> + struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
> + unsigned int src_cnt, unsigned char *scf,
> + size_t len, unsigned long flags);
> struct dma_async_tx_descriptor *(*device_prep_dma_zero_sum)(
> struct dma_chan *chan, dma_addr_t *src, unsigned int src_cnt,
> size_t len, u32 *result, unsigned long flags);
> + struct dma_async_tx_descriptor *(*device_prep_dma_pqzero_sum)(
> + struct dma_chan *chan, dma_addr_t *src, unsigned int src_cnt,
> + unsigned char *scf, size_t len, u32 *pqres,
> + unsigned long flags);
> struct dma_async_tx_descriptor *(*device_prep_dma_memset)(
> struct dma_chan *chan, dma_addr_t dest, int value, size_t len,
> unsigned long flags);
> --
> 1.6.0.6
>
Regards,
Dan
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