/* * 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/module.h> #include <linux/dma-mapping.h> #include <linux/raid/pq.h> #include <linux/async_tx.h> #include <linux/gfp.h> /** * pq_scribble_page - space to hold throwaway P or Q buffer for * synchronous gen_syndrome */ static struct page *pq_scribble_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 (blocks[i] == NULL) 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; submit->flags |= ASYNC_TX_FENCE; 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; } if (submit->flags & ASYNC_TX_FENCE) dma_flags |= DMA_PREP_FENCE; /* 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 (blocks[i] == NULL) { BUG_ON(i > disks - 3); /* P or Q can't be zero */ srcs[i] = (void*)raid6_empty_zero_page; } 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. If any source buffers (blocks[i] where i < disks - 2) are * set to NULL those buffers will be replaced with the raid6_zero_page * in the synchronous path and omitted in the hardware-asynchronous * path. * * 'blocks' note: if submit->scribble is NULL then the contents of * 'blocks' may be overwritten to perform address conversions * (dma_map_page() or page_address()). */ 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) && is_dma_pq_aligned(device, offset, 0, len)) { /* 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) = pq_scribble_page; BUG_ON(len + offset > PAGE_SIZE); } if (!Q(blocks, disks)) { Q(blocks, disks) = pq_scribble_page; BUG_ON(len + offset > PAGE_SIZE); } do_sync_gen_syndrome(blocks, offset, disks, len, submit); return NULL; } EXPORT_SYMBOL_GPL(async_gen_syndrome); static inline struct dma_chan * pq_val_chan(struct async_submit_ctl *submit, struct page **blocks, int disks, size_t len) { #ifdef CONFIG_ASYNC_TX_DISABLE_PQ_VAL_DMA return NULL; #endif return async_tx_find_channel(submit, DMA_PQ_VAL, NULL, 0, blocks, disks, len); } /** * 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 = pq_val_chan(submit, blocks, disks, len); struct dma_device *device = chan ? chan->device : NULL; struct dma_async_tx_descriptor *tx; unsigned char coefs[disks-2]; enum dma_ctrl_flags dma_flags = submit->cb_fn ? DMA_PREP_INTERRUPT : 0; dma_addr_t *dma_src = NULL; int src_cnt = 0; 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) && is_dma_pq_aligned(device, offset, 0, len)) { 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; else pq[0] = dma_map_page(dev, P(blocks, disks), offset, len, DMA_TO_DEVICE); if (!Q(blocks, disks)) dma_flags |= DMA_PREP_PQ_DISABLE_Q; else pq[1] = dma_map_page(dev, Q(blocks, disks), offset, len, DMA_TO_DEVICE); if (submit->flags & ASYNC_TX_FENCE) dma_flags |= DMA_PREP_FENCE; for (i = 0; i < disks-2; i++) if (likely(blocks[i])) { dma_src[src_cnt] = dma_map_page(dev, blocks[i], offset, len, DMA_TO_DEVICE); coefs[src_cnt] = raid6_gfexp[i]; src_cnt++; } for (;;) { tx = device->device_prep_dma_pq_val(chan, pq, dma_src, src_cnt, coefs, 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) { pq_scribble_page = alloc_page(GFP_KERNEL); if (pq_scribble_page) return 0; pr_err("%s: failed to allocate required spare page\n", __func__); return -ENOMEM; } static void __exit async_pq_exit(void) { put_page(pq_scribble_page); } module_init(async_pq_init); module_exit(async_pq_exit); MODULE_DESCRIPTION("asynchronous raid6 syndrome generation/validation"); MODULE_LICENSE("GPL");