diff options
Diffstat (limited to 'crypto/async_tx/async_pq.c')
| -rw-r--r-- | crypto/async_tx/async_pq.c | 388 |
1 files changed, 388 insertions, 0 deletions
diff --git a/crypto/async_tx/async_pq.c b/crypto/async_tx/async_pq.c new file mode 100644 index 00000000000..108b21efb49 --- /dev/null +++ b/crypto/async_tx/async_pq.c @@ -0,0 +1,388 @@ +/* + * Copyright(c) 2007 Yuri Tikhonov <yur@emcraft.com> + * Copyright(c) 2009 Intel Corporation + * + * 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/pq.h> +#include <linux/async_tx.h> + +/** + * scribble - space to hold throwaway P buffer for synchronous gen_syndrome + */ +static struct page *scribble; + +static bool is_raid6_zero_block(struct page *p) +{ + return p == (void *) raid6_empty_zero_page; +} + +/* the struct page *blocks[] parameter passed to async_gen_syndrome() + * and async_syndrome_val() contains the 'P' destination address at + * blocks[disks-2] and the 'Q' destination address at blocks[disks-1] + * + * note: these are macros as they are used as lvalues + */ +#define P(b, d) (b[d-2]) +#define Q(b, d) (b[d-1]) + +/** + * do_async_gen_syndrome - asynchronously calculate P and/or Q + */ +static __async_inline struct dma_async_tx_descriptor * +do_async_gen_syndrome(struct dma_chan *chan, struct page **blocks, + const unsigned char *scfs, unsigned int offset, int disks, + size_t len, dma_addr_t *dma_src, + struct async_submit_ctl *submit) +{ + struct dma_async_tx_descriptor *tx = NULL; + struct dma_device *dma = chan->device; + enum dma_ctrl_flags dma_flags = 0; + enum async_tx_flags flags_orig = submit->flags; + dma_async_tx_callback cb_fn_orig = submit->cb_fn; + dma_async_tx_callback cb_param_orig = submit->cb_param; + int src_cnt = disks - 2; + unsigned char coefs[src_cnt]; + unsigned short pq_src_cnt; + dma_addr_t dma_dest[2]; + int src_off = 0; + int idx; + int i; + + /* DMAs use destinations as sources, so use BIDIRECTIONAL mapping */ + if (P(blocks, disks)) + dma_dest[0] = dma_map_page(dma->dev, P(blocks, disks), offset, + len, DMA_BIDIRECTIONAL); + else + dma_flags |= DMA_PREP_PQ_DISABLE_P; + if (Q(blocks, disks)) + dma_dest[1] = dma_map_page(dma->dev, Q(blocks, disks), offset, + len, DMA_BIDIRECTIONAL); + else + dma_flags |= DMA_PREP_PQ_DISABLE_Q; + + /* convert source addresses being careful to collapse 'empty' + * sources and update the coefficients accordingly + */ + for (i = 0, idx = 0; i < src_cnt; i++) { + if (is_raid6_zero_block(blocks[i])) + continue; + dma_src[idx] = dma_map_page(dma->dev, blocks[i], offset, len, + DMA_TO_DEVICE); + coefs[idx] = scfs[i]; + idx++; + } + src_cnt = idx; + + while (src_cnt > 0) { + submit->flags = flags_orig; + pq_src_cnt = min(src_cnt, dma_maxpq(dma, dma_flags)); + /* 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) { + submit->flags &= ~ASYNC_TX_ACK; + dma_flags |= DMA_COMPL_SKIP_DEST_UNMAP; + submit->cb_fn = NULL; + submit->cb_param = NULL; + } else { + dma_flags &= ~DMA_COMPL_SKIP_DEST_UNMAP; + submit->cb_fn = cb_fn_orig; + submit->cb_param = cb_param_orig; + if (cb_fn_orig) + dma_flags |= DMA_PREP_INTERRUPT; + } + + /* 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 + */ + for (;;) { + tx = dma->device_prep_dma_pq(chan, dma_dest, + &dma_src[src_off], + pq_src_cnt, + &coefs[src_off], len, + dma_flags); + if (likely(tx)) + break; + async_tx_quiesce(&submit->depend_tx); + dma_async_issue_pending(chan); + } + + async_tx_submit(chan, tx, submit); + submit->depend_tx = tx; + + /* drop completed sources */ + src_cnt -= pq_src_cnt; + src_off += pq_src_cnt; + + dma_flags |= DMA_PREP_CONTINUE; + } + + return tx; +} + +/** + * do_sync_gen_syndrome - synchronously calculate a raid6 syndrome + */ +static void +do_sync_gen_syndrome(struct page **blocks, unsigned int offset, int disks, + size_t len, struct async_submit_ctl *submit) +{ + void **srcs; + int i; + + if (submit->scribble) + srcs = submit->scribble; + else + srcs = (void **) blocks; + + for (i = 0; i < disks; i++) { + if (is_raid6_zero_block(blocks[i])) { + BUG_ON(i > disks - 3); /* P or Q can't be zero */ + srcs[i] = blocks[i]; + } else + srcs[i] = page_address(blocks[i]) + offset; + } + raid6_call.gen_syndrome(disks, len, srcs); + async_tx_sync_epilog(submit); +} + +/** + * async_gen_syndrome - asynchronously calculate a raid6 syndrome + * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 + * @offset: common offset into each block (src and dest) to start transaction + * @disks: number of blocks (including missing P or Q, see below) + * @len: length of operation in bytes + * @submit: submission/completion modifiers + * + * General note: This routine assumes a field of GF(2^8) with a + * primitive polynomial of 0x11d and a generator of {02}. + * + * 'disks' note: callers can optionally omit either P or Q (but not + * both) from the calculation by setting blocks[disks-2] or + * blocks[disks-1] to NULL. When P or Q is omitted 'len' must be <= + * PAGE_SIZE as a temporary buffer of this size is used in the + * synchronous path. 'disks' always accounts for both destination + * buffers. + * + * 'blocks' note: if submit->scribble is NULL then the contents of + * 'blocks' may be overridden + */ +struct dma_async_tx_descriptor * +async_gen_syndrome(struct page **blocks, unsigned int offset, int disks, + size_t len, struct async_submit_ctl *submit) +{ + int src_cnt = disks - 2; + struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ, + &P(blocks, disks), 2, + blocks, src_cnt, len); + struct dma_device *device = chan ? chan->device : NULL; + dma_addr_t *dma_src = NULL; + + BUG_ON(disks > 255 || !(P(blocks, disks) || Q(blocks, disks))); + + if (submit->scribble) + dma_src = submit->scribble; + else if (sizeof(dma_addr_t) <= sizeof(struct page *)) + dma_src = (dma_addr_t *) blocks; + + if (dma_src && device && + (src_cnt <= dma_maxpq(device, 0) || + dma_maxpq(device, DMA_PREP_CONTINUE) > 0)) { + /* run the p+q asynchronously */ + pr_debug("%s: (async) disks: %d len: %zu\n", + __func__, disks, len); + return do_async_gen_syndrome(chan, blocks, raid6_gfexp, offset, + disks, len, dma_src, submit); + } + + /* run the pq synchronously */ + pr_debug("%s: (sync) disks: %d len: %zu\n", __func__, disks, len); + + /* wait for any prerequisite operations */ + async_tx_quiesce(&submit->depend_tx); + + if (!P(blocks, disks)) { + P(blocks, disks) = scribble; + BUG_ON(len + offset > PAGE_SIZE); + } + if (!Q(blocks, disks)) { + Q(blocks, disks) = scribble; + BUG_ON(len + offset > PAGE_SIZE); + } + do_sync_gen_syndrome(blocks, offset, disks, len, submit); + + return NULL; +} +EXPORT_SYMBOL_GPL(async_gen_syndrome); + +/** + * async_syndrome_val - asynchronously validate a raid6 syndrome + * @blocks: source blocks from idx 0..disks-3, P @ disks-2 and Q @ disks-1 + * @offset: common offset into each block (src and dest) to start transaction + * @disks: number of blocks (including missing P or Q, see below) + * @len: length of operation in bytes + * @pqres: on val failure SUM_CHECK_P_RESULT and/or SUM_CHECK_Q_RESULT are set + * @spare: temporary result buffer for the synchronous case + * @submit: submission / completion modifiers + * + * The same notes from async_gen_syndrome apply to the 'blocks', + * and 'disks' parameters of this routine. The synchronous path + * requires a temporary result buffer and submit->scribble to be + * specified. + */ +struct dma_async_tx_descriptor * +async_syndrome_val(struct page **blocks, unsigned int offset, int disks, + size_t len, enum sum_check_flags *pqres, struct page *spare, + struct async_submit_ctl *submit) +{ + struct dma_chan *chan = async_tx_find_channel(submit, DMA_PQ_VAL, + NULL, 0, blocks, disks, + len); + struct dma_device *device = chan ? chan->device : NULL; + struct dma_async_tx_descriptor *tx; + enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; + dma_addr_t *dma_src = NULL; + + BUG_ON(disks < 4); + + if (submit->scribble) + dma_src = submit->scribble; + else if (sizeof(dma_addr_t) <= sizeof(struct page *)) + dma_src = (dma_addr_t *) blocks; + + if (dma_src && device && disks <= dma_maxpq(device, 0)) { + struct device *dev = device->dev; + dma_addr_t *pq = &dma_src[disks-2]; + int i; + + pr_debug("%s: (async) disks: %d len: %zu\n", + __func__, disks, len); + if (!P(blocks, disks)) + dma_flags |= DMA_PREP_PQ_DISABLE_P; + if (!Q(blocks, disks)) + dma_flags |= DMA_PREP_PQ_DISABLE_Q; + for (i = 0; i < disks; i++) + if (likely(blocks[i])) { + BUG_ON(is_raid6_zero_block(blocks[i])); + dma_src[i] = dma_map_page(dev, blocks[i], + offset, len, + DMA_TO_DEVICE); + } + + for (;;) { + tx = device->device_prep_dma_pq_val(chan, pq, dma_src, + disks - 2, + raid6_gfexp, + len, pqres, + dma_flags); + if (likely(tx)) + break; + async_tx_quiesce(&submit->depend_tx); + dma_async_issue_pending(chan); + } + async_tx_submit(chan, tx, submit); + + return tx; + } else { + struct page *p_src = P(blocks, disks); + struct page *q_src = Q(blocks, disks); + enum async_tx_flags flags_orig = submit->flags; + dma_async_tx_callback cb_fn_orig = submit->cb_fn; + void *scribble = submit->scribble; + void *cb_param_orig = submit->cb_param; + void *p, *q, *s; + + pr_debug("%s: (sync) disks: %d len: %zu\n", + __func__, disks, len); + + /* caller must provide a temporary result buffer and + * allow the input parameters to be preserved + */ + BUG_ON(!spare || !scribble); + + /* wait for any prerequisite operations */ + async_tx_quiesce(&submit->depend_tx); + + /* recompute p and/or q into the temporary buffer and then + * check to see the result matches the current value + */ + tx = NULL; + *pqres = 0; + if (p_src) { + init_async_submit(submit, ASYNC_TX_XOR_ZERO_DST, NULL, + NULL, NULL, scribble); + tx = async_xor(spare, blocks, offset, disks-2, len, submit); + async_tx_quiesce(&tx); + p = page_address(p_src) + offset; + s = page_address(spare) + offset; + *pqres |= !!memcmp(p, s, len) << SUM_CHECK_P; + } + + if (q_src) { + P(blocks, disks) = NULL; + Q(blocks, disks) = spare; + init_async_submit(submit, 0, NULL, NULL, NULL, scribble); + tx = async_gen_syndrome(blocks, offset, disks, len, submit); + async_tx_quiesce(&tx); + q = page_address(q_src) + offset; + s = page_address(spare) + offset; + *pqres |= !!memcmp(q, s, len) << SUM_CHECK_Q; + } + + /* restore P, Q and submit */ + P(blocks, disks) = p_src; + Q(blocks, disks) = q_src; + + submit->cb_fn = cb_fn_orig; + submit->cb_param = cb_param_orig; + submit->flags = flags_orig; + async_tx_sync_epilog(submit); + + return NULL; + } +} +EXPORT_SYMBOL_GPL(async_syndrome_val); + +static int __init async_pq_init(void) +{ + scribble = alloc_page(GFP_KERNEL); + + if (scribble) + return 0; + + pr_err("%s: failed to allocate required spare page\n", __func__); + + return -ENOMEM; +} + +static void __exit async_pq_exit(void) +{ + put_page(scribble); +} + +module_init(async_pq_init); +module_exit(async_pq_exit); + +MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); +MODULE_LICENSE("GPL"); |