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 000000000000..108b21efb499
--- /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");