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420 lines
12 KiB
420 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* xor offload engine api |
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* |
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* Copyright © 2006, Intel Corporation. |
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* |
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* Dan Williams <[email protected]> |
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* |
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* with architecture considerations by: |
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* Neil Brown <[email protected]> |
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* Jeff Garzik <[email protected]> |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/interrupt.h> |
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#include <linux/module.h> |
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#include <linux/mm.h> |
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#include <linux/dma-mapping.h> |
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#include <linux/raid/xor.h> |
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#include <linux/async_tx.h> |
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/* do_async_xor - dma map the pages and perform the xor with an engine */ |
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static __async_inline struct dma_async_tx_descriptor * |
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do_async_xor(struct dma_chan *chan, struct dmaengine_unmap_data *unmap, |
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struct async_submit_ctl *submit) |
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{ |
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struct dma_device *dma = chan->device; |
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struct dma_async_tx_descriptor *tx = NULL; |
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dma_async_tx_callback cb_fn_orig = submit->cb_fn; |
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void *cb_param_orig = submit->cb_param; |
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enum async_tx_flags flags_orig = submit->flags; |
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enum dma_ctrl_flags dma_flags = 0; |
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int src_cnt = unmap->to_cnt; |
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int xor_src_cnt; |
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dma_addr_t dma_dest = unmap->addr[unmap->to_cnt]; |
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dma_addr_t *src_list = unmap->addr; |
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while (src_cnt) { |
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dma_addr_t tmp; |
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submit->flags = flags_orig; |
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xor_src_cnt = min(src_cnt, (int)dma->max_xor); |
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/* if we are submitting additional xors, leave the chain open |
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* and clear the callback parameters |
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*/ |
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if (src_cnt > xor_src_cnt) { |
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submit->flags &= ~ASYNC_TX_ACK; |
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submit->flags |= ASYNC_TX_FENCE; |
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submit->cb_fn = NULL; |
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submit->cb_param = NULL; |
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} else { |
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submit->cb_fn = cb_fn_orig; |
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submit->cb_param = cb_param_orig; |
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} |
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if (submit->cb_fn) |
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dma_flags |= DMA_PREP_INTERRUPT; |
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if (submit->flags & ASYNC_TX_FENCE) |
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dma_flags |= DMA_PREP_FENCE; |
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/* Drivers force forward progress in case they can not provide a |
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* descriptor |
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*/ |
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tmp = src_list[0]; |
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if (src_list > unmap->addr) |
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src_list[0] = dma_dest; |
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tx = dma->device_prep_dma_xor(chan, dma_dest, src_list, |
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xor_src_cnt, unmap->len, |
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dma_flags); |
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if (unlikely(!tx)) |
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async_tx_quiesce(&submit->depend_tx); |
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/* spin wait for the preceding transactions to complete */ |
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while (unlikely(!tx)) { |
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dma_async_issue_pending(chan); |
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tx = dma->device_prep_dma_xor(chan, dma_dest, |
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src_list, |
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xor_src_cnt, unmap->len, |
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dma_flags); |
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} |
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src_list[0] = tmp; |
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dma_set_unmap(tx, unmap); |
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async_tx_submit(chan, tx, submit); |
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submit->depend_tx = tx; |
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if (src_cnt > xor_src_cnt) { |
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/* drop completed sources */ |
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src_cnt -= xor_src_cnt; |
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/* use the intermediate result a source */ |
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src_cnt++; |
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src_list += xor_src_cnt - 1; |
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} else |
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break; |
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} |
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return tx; |
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} |
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static void |
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do_sync_xor_offs(struct page *dest, unsigned int offset, |
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struct page **src_list, unsigned int *src_offs, |
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int src_cnt, size_t len, struct async_submit_ctl *submit) |
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{ |
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int i; |
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int xor_src_cnt = 0; |
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int src_off = 0; |
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void *dest_buf; |
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void **srcs; |
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if (submit->scribble) |
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srcs = submit->scribble; |
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else |
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srcs = (void **) src_list; |
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/* convert to buffer pointers */ |
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for (i = 0; i < src_cnt; i++) |
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if (src_list[i]) |
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srcs[xor_src_cnt++] = page_address(src_list[i]) + |
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(src_offs ? src_offs[i] : offset); |
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src_cnt = xor_src_cnt; |
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/* set destination address */ |
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dest_buf = page_address(dest) + offset; |
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if (submit->flags & ASYNC_TX_XOR_ZERO_DST) |
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memset(dest_buf, 0, len); |
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while (src_cnt > 0) { |
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/* process up to 'MAX_XOR_BLOCKS' sources */ |
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xor_src_cnt = min(src_cnt, MAX_XOR_BLOCKS); |
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xor_blocks(xor_src_cnt, len, dest_buf, &srcs[src_off]); |
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/* drop completed sources */ |
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src_cnt -= xor_src_cnt; |
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src_off += xor_src_cnt; |
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} |
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async_tx_sync_epilog(submit); |
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} |
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static inline bool |
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dma_xor_aligned_offsets(struct dma_device *device, unsigned int offset, |
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unsigned int *src_offs, int src_cnt, int len) |
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{ |
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int i; |
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if (!is_dma_xor_aligned(device, offset, 0, len)) |
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return false; |
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if (!src_offs) |
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return true; |
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for (i = 0; i < src_cnt; i++) { |
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if (!is_dma_xor_aligned(device, src_offs[i], 0, len)) |
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return false; |
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} |
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return true; |
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} |
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/** |
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* async_xor_offs - attempt to xor a set of blocks with a dma engine. |
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* @dest: destination page |
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* @offset: dst offset to start transaction |
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* @src_list: array of source pages |
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* @src_offs: array of source pages offset, NULL means common src/dst offset |
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* @src_cnt: number of source pages |
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* @len: length in bytes |
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* @submit: submission / completion modifiers |
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* |
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* honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST |
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* |
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* xor_blocks always uses the dest as a source so the |
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* ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in |
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* the calculation. The assumption with dma eninges is that they only |
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* use the destination buffer as a source when it is explicity specified |
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* in the source list. |
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* |
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* src_list note: if the dest is also a source it must be at index zero. |
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* The contents of this array will be overwritten if a scribble region |
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* is not specified. |
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*/ |
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struct dma_async_tx_descriptor * |
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async_xor_offs(struct page *dest, unsigned int offset, |
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struct page **src_list, unsigned int *src_offs, |
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int src_cnt, size_t len, struct async_submit_ctl *submit) |
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{ |
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struct dma_chan *chan = async_tx_find_channel(submit, DMA_XOR, |
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&dest, 1, src_list, |
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src_cnt, len); |
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struct dma_device *device = chan ? chan->device : NULL; |
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struct dmaengine_unmap_data *unmap = NULL; |
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BUG_ON(src_cnt <= 1); |
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if (device) |
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unmap = dmaengine_get_unmap_data(device->dev, src_cnt+1, GFP_NOWAIT); |
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if (unmap && dma_xor_aligned_offsets(device, offset, |
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src_offs, src_cnt, len)) { |
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struct dma_async_tx_descriptor *tx; |
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int i, j; |
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/* run the xor asynchronously */ |
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pr_debug("%s (async): len: %zu\n", __func__, len); |
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unmap->len = len; |
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for (i = 0, j = 0; i < src_cnt; i++) { |
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if (!src_list[i]) |
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continue; |
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unmap->to_cnt++; |
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unmap->addr[j++] = dma_map_page(device->dev, src_list[i], |
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src_offs ? src_offs[i] : offset, |
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len, DMA_TO_DEVICE); |
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} |
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/* map it bidirectional as it may be re-used as a source */ |
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unmap->addr[j] = dma_map_page(device->dev, dest, offset, len, |
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DMA_BIDIRECTIONAL); |
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unmap->bidi_cnt = 1; |
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tx = do_async_xor(chan, unmap, submit); |
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dmaengine_unmap_put(unmap); |
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return tx; |
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} else { |
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dmaengine_unmap_put(unmap); |
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/* run the xor synchronously */ |
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pr_debug("%s (sync): len: %zu\n", __func__, len); |
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WARN_ONCE(chan, "%s: no space for dma address conversion\n", |
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__func__); |
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/* in the sync case the dest is an implied source |
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* (assumes the dest is the first source) |
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*/ |
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if (submit->flags & ASYNC_TX_XOR_DROP_DST) { |
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src_cnt--; |
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src_list++; |
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if (src_offs) |
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src_offs++; |
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} |
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/* wait for any prerequisite operations */ |
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async_tx_quiesce(&submit->depend_tx); |
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do_sync_xor_offs(dest, offset, src_list, src_offs, |
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src_cnt, len, submit); |
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return NULL; |
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} |
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} |
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EXPORT_SYMBOL_GPL(async_xor_offs); |
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/** |
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* async_xor - attempt to xor a set of blocks with a dma engine. |
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* @dest: destination page |
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* @src_list: array of source pages |
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* @offset: common src/dst offset to start transaction |
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* @src_cnt: number of source pages |
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* @len: length in bytes |
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* @submit: submission / completion modifiers |
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* |
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* honored flags: ASYNC_TX_ACK, ASYNC_TX_XOR_ZERO_DST, ASYNC_TX_XOR_DROP_DST |
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* |
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* xor_blocks always uses the dest as a source so the |
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* ASYNC_TX_XOR_ZERO_DST flag must be set to not include dest data in |
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* the calculation. The assumption with dma eninges is that they only |
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* use the destination buffer as a source when it is explicity specified |
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* in the source list. |
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* |
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* src_list note: if the dest is also a source it must be at index zero. |
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* The contents of this array will be overwritten if a scribble region |
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* is not specified. |
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*/ |
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struct dma_async_tx_descriptor * |
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async_xor(struct page *dest, struct page **src_list, unsigned int offset, |
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int src_cnt, size_t len, struct async_submit_ctl *submit) |
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{ |
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return async_xor_offs(dest, offset, src_list, NULL, |
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src_cnt, len, submit); |
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} |
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EXPORT_SYMBOL_GPL(async_xor); |
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static int page_is_zero(struct page *p, unsigned int offset, size_t len) |
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{ |
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return !memchr_inv(page_address(p) + offset, 0, len); |
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} |
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static inline struct dma_chan * |
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xor_val_chan(struct async_submit_ctl *submit, struct page *dest, |
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struct page **src_list, int src_cnt, size_t len) |
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{ |
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#ifdef CONFIG_ASYNC_TX_DISABLE_XOR_VAL_DMA |
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return NULL; |
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#endif |
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return async_tx_find_channel(submit, DMA_XOR_VAL, &dest, 1, src_list, |
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src_cnt, len); |
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} |
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/** |
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* async_xor_val_offs - attempt a xor parity check with a dma engine. |
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* @dest: destination page used if the xor is performed synchronously |
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* @offset: des offset in pages to start transaction |
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* @src_list: array of source pages |
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* @src_offs: array of source pages offset, NULL means common src/det offset |
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* @src_cnt: number of source pages |
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* @len: length in bytes |
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* @result: 0 if sum == 0 else non-zero |
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* @submit: submission / completion modifiers |
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* |
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* honored flags: ASYNC_TX_ACK |
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* |
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* src_list note: if the dest is also a source it must be at index zero. |
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* The contents of this array will be overwritten if a scribble region |
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* is not specified. |
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*/ |
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struct dma_async_tx_descriptor * |
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async_xor_val_offs(struct page *dest, unsigned int offset, |
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struct page **src_list, unsigned int *src_offs, |
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int src_cnt, size_t len, enum sum_check_flags *result, |
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struct async_submit_ctl *submit) |
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{ |
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struct dma_chan *chan = xor_val_chan(submit, dest, src_list, src_cnt, len); |
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struct dma_device *device = chan ? chan->device : NULL; |
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struct dma_async_tx_descriptor *tx = NULL; |
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struct dmaengine_unmap_data *unmap = NULL; |
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BUG_ON(src_cnt <= 1); |
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if (device) |
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unmap = dmaengine_get_unmap_data(device->dev, src_cnt, GFP_NOWAIT); |
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if (unmap && src_cnt <= device->max_xor && |
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dma_xor_aligned_offsets(device, offset, src_offs, src_cnt, len)) { |
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unsigned long dma_prep_flags = 0; |
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int i; |
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pr_debug("%s: (async) len: %zu\n", __func__, len); |
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if (submit->cb_fn) |
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dma_prep_flags |= DMA_PREP_INTERRUPT; |
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if (submit->flags & ASYNC_TX_FENCE) |
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dma_prep_flags |= DMA_PREP_FENCE; |
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for (i = 0; i < src_cnt; i++) { |
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unmap->addr[i] = dma_map_page(device->dev, src_list[i], |
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src_offs ? src_offs[i] : offset, |
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len, DMA_TO_DEVICE); |
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unmap->to_cnt++; |
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} |
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unmap->len = len; |
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tx = device->device_prep_dma_xor_val(chan, unmap->addr, src_cnt, |
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len, result, |
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dma_prep_flags); |
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if (unlikely(!tx)) { |
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async_tx_quiesce(&submit->depend_tx); |
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while (!tx) { |
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dma_async_issue_pending(chan); |
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tx = device->device_prep_dma_xor_val(chan, |
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unmap->addr, src_cnt, len, result, |
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dma_prep_flags); |
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} |
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} |
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dma_set_unmap(tx, unmap); |
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async_tx_submit(chan, tx, submit); |
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} else { |
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enum async_tx_flags flags_orig = submit->flags; |
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pr_debug("%s: (sync) len: %zu\n", __func__, len); |
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WARN_ONCE(device && src_cnt <= device->max_xor, |
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"%s: no space for dma address conversion\n", |
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__func__); |
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submit->flags |= ASYNC_TX_XOR_DROP_DST; |
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submit->flags &= ~ASYNC_TX_ACK; |
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tx = async_xor_offs(dest, offset, src_list, src_offs, |
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src_cnt, len, submit); |
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async_tx_quiesce(&tx); |
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*result = !page_is_zero(dest, offset, len) << SUM_CHECK_P; |
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async_tx_sync_epilog(submit); |
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submit->flags = flags_orig; |
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} |
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dmaengine_unmap_put(unmap); |
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return tx; |
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} |
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EXPORT_SYMBOL_GPL(async_xor_val_offs); |
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/** |
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* async_xor_val - attempt a xor parity check with a dma engine. |
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* @dest: destination page used if the xor is performed synchronously |
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* @src_list: array of source pages |
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* @offset: offset in pages to start transaction |
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* @src_cnt: number of source pages |
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* @len: length in bytes |
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* @result: 0 if sum == 0 else non-zero |
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* @submit: submission / completion modifiers |
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* |
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* honored flags: ASYNC_TX_ACK |
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* |
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* src_list note: if the dest is also a source it must be at index zero. |
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* The contents of this array will be overwritten if a scribble region |
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* is not specified. |
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*/ |
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struct dma_async_tx_descriptor * |
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async_xor_val(struct page *dest, struct page **src_list, unsigned int offset, |
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int src_cnt, size_t len, enum sum_check_flags *result, |
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struct async_submit_ctl *submit) |
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{ |
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return async_xor_val_offs(dest, offset, src_list, NULL, src_cnt, |
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len, result, submit); |
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} |
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EXPORT_SYMBOL_GPL(async_xor_val); |
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MODULE_AUTHOR("Intel Corporation"); |
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MODULE_DESCRIPTION("asynchronous xor/xor-zero-sum api"); |
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MODULE_LICENSE("GPL");
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