[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/drivers/md/dm-verity-fec.c b/src/kernel/linux/v4.14/drivers/md/dm-verity-fec.c
new file mode 100644
index 0000000..052419a
--- /dev/null
+++ b/src/kernel/linux/v4.14/drivers/md/dm-verity-fec.c
@@ -0,0 +1,860 @@
+/*
+ * Copyright (C) 2015 Google, Inc.
+ *
+ * Author: Sami Tolvanen <samitolvanen@google.com>
+ *
+ * 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.
+ */
+
+#include "dm-verity-fec.h"
+#include <linux/math64.h>
+#include <linux/sysfs.h>
+
+#define DM_MSG_PREFIX "verity-fec"
+
+/*
+ * If error correction has been configured, returns true.
+ */
+bool verity_fec_is_enabled(struct dm_verity *v)
+{
+ return v->fec && v->fec->dev;
+}
+
+/*
+ * Return a pointer to dm_verity_fec_io after dm_verity_io and its variable
+ * length fields.
+ */
+static inline struct dm_verity_fec_io *fec_io(struct dm_verity_io *io)
+{
+ return (struct dm_verity_fec_io *) verity_io_digest_end(io->v, io);
+}
+
+/*
+ * Return an interleaved offset for a byte in RS block.
+ */
+static inline u64 fec_interleave(struct dm_verity *v, u64 offset)
+{
+ u32 mod;
+
+ mod = do_div(offset, v->fec->rsn);
+ return offset + mod * (v->fec->rounds << v->data_dev_block_bits);
+}
+
+/*
+ * Decode an RS block using Reed-Solomon.
+ */
+static int fec_decode_rs8(struct dm_verity *v, struct dm_verity_fec_io *fio,
+ u8 *data, u8 *fec, int neras)
+{
+ int i;
+ uint16_t par[DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN];
+
+ for (i = 0; i < v->fec->roots; i++)
+ par[i] = fec[i];
+
+ return decode_rs8(fio->rs, data, par, v->fec->rsn, NULL, neras,
+ fio->erasures, 0, NULL);
+}
+
+/*
+ * Read error-correcting codes for the requested RS block. Returns a pointer
+ * to the data block. Caller is responsible for releasing buf.
+ */
+static u8 *fec_read_parity(struct dm_verity *v, u64 rsb, int index,
+ unsigned *offset, struct dm_buffer **buf)
+{
+ u64 position, block;
+ u8 *res;
+
+ position = (index + rsb) * v->fec->roots;
+ block = position >> v->data_dev_block_bits;
+ *offset = (unsigned)(position - (block << v->data_dev_block_bits));
+
+ res = dm_bufio_read(v->fec->bufio, v->fec->start + block, buf);
+ if (unlikely(IS_ERR(res))) {
+ DMERR("%s: FEC %llu: parity read failed (block %llu): %ld",
+ v->data_dev->name, (unsigned long long)rsb,
+ (unsigned long long)(v->fec->start + block),
+ PTR_ERR(res));
+ *buf = NULL;
+ }
+
+ return res;
+}
+
+/* Loop over each preallocated buffer slot. */
+#define fec_for_each_prealloc_buffer(__i) \
+ for (__i = 0; __i < DM_VERITY_FEC_BUF_PREALLOC; __i++)
+
+/* Loop over each extra buffer slot. */
+#define fec_for_each_extra_buffer(io, __i) \
+ for (__i = DM_VERITY_FEC_BUF_PREALLOC; __i < DM_VERITY_FEC_BUF_MAX; __i++)
+
+/* Loop over each allocated buffer. */
+#define fec_for_each_buffer(io, __i) \
+ for (__i = 0; __i < (io)->nbufs; __i++)
+
+/* Loop over each RS block in each allocated buffer. */
+#define fec_for_each_buffer_rs_block(io, __i, __j) \
+ fec_for_each_buffer(io, __i) \
+ for (__j = 0; __j < 1 << DM_VERITY_FEC_BUF_RS_BITS; __j++)
+
+/*
+ * Return a pointer to the current RS block when called inside
+ * fec_for_each_buffer_rs_block.
+ */
+static inline u8 *fec_buffer_rs_block(struct dm_verity *v,
+ struct dm_verity_fec_io *fio,
+ unsigned i, unsigned j)
+{
+ return &fio->bufs[i][j * v->fec->rsn];
+}
+
+/*
+ * Return an index to the current RS block when called inside
+ * fec_for_each_buffer_rs_block.
+ */
+static inline unsigned fec_buffer_rs_index(unsigned i, unsigned j)
+{
+ return (i << DM_VERITY_FEC_BUF_RS_BITS) + j;
+}
+
+/*
+ * Decode all RS blocks from buffers and copy corrected bytes into fio->output
+ * starting from block_offset.
+ */
+static int fec_decode_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio,
+ u64 rsb, int byte_index, unsigned block_offset,
+ int neras)
+{
+ int r, corrected = 0, res;
+ struct dm_buffer *buf;
+ unsigned n, i, offset;
+ u8 *par, *block;
+
+ par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
+ if (IS_ERR(par))
+ return PTR_ERR(par);
+
+ /*
+ * Decode the RS blocks we have in bufs. Each RS block results in
+ * one corrected target byte and consumes fec->roots parity bytes.
+ */
+ fec_for_each_buffer_rs_block(fio, n, i) {
+ block = fec_buffer_rs_block(v, fio, n, i);
+ res = fec_decode_rs8(v, fio, block, &par[offset], neras);
+ if (res < 0) {
+ r = res;
+ goto error;
+ }
+
+ corrected += res;
+ fio->output[block_offset] = block[byte_index];
+
+ block_offset++;
+ if (block_offset >= 1 << v->data_dev_block_bits)
+ goto done;
+
+ /* read the next block when we run out of parity bytes */
+ offset += v->fec->roots;
+ if (offset >= 1 << v->data_dev_block_bits) {
+ dm_bufio_release(buf);
+
+ par = fec_read_parity(v, rsb, block_offset, &offset, &buf);
+ if (unlikely(IS_ERR(par)))
+ return PTR_ERR(par);
+ }
+ }
+done:
+ r = corrected;
+error:
+ dm_bufio_release(buf);
+
+ if (r < 0 && neras)
+ DMERR_LIMIT("%s: FEC %llu: failed to correct: %d",
+ v->data_dev->name, (unsigned long long)rsb, r);
+ else if (r > 0) {
+ DMWARN_LIMIT("%s: FEC %llu: corrected %d errors",
+ v->data_dev->name, (unsigned long long)rsb, r);
+ atomic_add_unless(&v->fec->corrected, 1, INT_MAX);
+ }
+
+ return r;
+}
+
+/*
+ * Locate data block erasures using verity hashes.
+ */
+static int fec_is_erasure(struct dm_verity *v, struct dm_verity_io *io,
+ u8 *want_digest, u8 *data)
+{
+ if (unlikely(verity_hash(v, verity_io_hash_req(v, io),
+ data, 1 << v->data_dev_block_bits,
+ verity_io_real_digest(v, io))))
+ return 0;
+
+ return memcmp(verity_io_real_digest(v, io), want_digest,
+ v->digest_size) != 0;
+}
+
+/*
+ * Read data blocks that are part of the RS block and deinterleave as much as
+ * fits into buffers. Check for erasure locations if @neras is non-NULL.
+ */
+static int fec_read_bufs(struct dm_verity *v, struct dm_verity_io *io,
+ u64 rsb, u64 target, unsigned block_offset,
+ int *neras)
+{
+ bool is_zero;
+ int i, j, target_index = -1;
+ struct dm_buffer *buf;
+ struct dm_bufio_client *bufio;
+ struct dm_verity_fec_io *fio = fec_io(io);
+ u64 block, ileaved;
+ u8 *bbuf, *rs_block;
+ u8 want_digest[v->digest_size];
+ unsigned n, k;
+
+ if (neras)
+ *neras = 0;
+
+ /*
+ * read each of the rsn data blocks that are part of the RS block, and
+ * interleave contents to available bufs
+ */
+ for (i = 0; i < v->fec->rsn; i++) {
+ ileaved = fec_interleave(v, rsb * v->fec->rsn + i);
+
+ /*
+ * target is the data block we want to correct, target_index is
+ * the index of this block within the rsn RS blocks
+ */
+ if (ileaved == target)
+ target_index = i;
+
+ block = ileaved >> v->data_dev_block_bits;
+ bufio = v->fec->data_bufio;
+
+ if (block >= v->data_blocks) {
+ block -= v->data_blocks;
+
+ /*
+ * blocks outside the area were assumed to contain
+ * zeros when encoding data was generated
+ */
+ if (unlikely(block >= v->fec->hash_blocks))
+ continue;
+
+ block += v->hash_start;
+ bufio = v->bufio;
+ }
+
+ bbuf = dm_bufio_read(bufio, block, &buf);
+ if (unlikely(IS_ERR(bbuf))) {
+ DMWARN_LIMIT("%s: FEC %llu: read failed (%llu): %ld",
+ v->data_dev->name,
+ (unsigned long long)rsb,
+ (unsigned long long)block, PTR_ERR(bbuf));
+
+ /* assume the block is corrupted */
+ if (neras && *neras <= v->fec->roots)
+ fio->erasures[(*neras)++] = i;
+
+ continue;
+ }
+
+ /* locate erasures if the block is on the data device */
+ if (bufio == v->fec->data_bufio &&
+ verity_hash_for_block(v, io, block, want_digest,
+ &is_zero) == 0) {
+ /* skip known zero blocks entirely */
+ if (is_zero)
+ goto done;
+
+ /*
+ * skip if we have already found the theoretical
+ * maximum number (i.e. fec->roots) of erasures
+ */
+ if (neras && *neras <= v->fec->roots &&
+ fec_is_erasure(v, io, want_digest, bbuf))
+ fio->erasures[(*neras)++] = i;
+ }
+
+ /*
+ * deinterleave and copy the bytes that fit into bufs,
+ * starting from block_offset
+ */
+ fec_for_each_buffer_rs_block(fio, n, j) {
+ k = fec_buffer_rs_index(n, j) + block_offset;
+
+ if (k >= 1 << v->data_dev_block_bits)
+ goto done;
+
+ rs_block = fec_buffer_rs_block(v, fio, n, j);
+ rs_block[i] = bbuf[k];
+ }
+done:
+ dm_bufio_release(buf);
+ }
+
+ return target_index;
+}
+
+/*
+ * Allocate RS control structure and FEC buffers from preallocated mempools,
+ * and attempt to allocate as many extra buffers as available.
+ */
+static int fec_alloc_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
+{
+ unsigned n;
+
+ if (!fio->rs)
+ fio->rs = mempool_alloc(v->fec->rs_pool, GFP_NOIO);
+
+ fec_for_each_prealloc_buffer(n) {
+ if (fio->bufs[n])
+ continue;
+
+ fio->bufs[n] = mempool_alloc(v->fec->prealloc_pool, GFP_NOWAIT);
+ if (unlikely(!fio->bufs[n])) {
+ DMERR("failed to allocate FEC buffer");
+ return -ENOMEM;
+ }
+ }
+
+ /* try to allocate the maximum number of buffers */
+ fec_for_each_extra_buffer(fio, n) {
+ if (fio->bufs[n])
+ continue;
+
+ fio->bufs[n] = mempool_alloc(v->fec->extra_pool, GFP_NOWAIT);
+ /* we can manage with even one buffer if necessary */
+ if (unlikely(!fio->bufs[n]))
+ break;
+ }
+ fio->nbufs = n;
+
+ if (!fio->output)
+ fio->output = mempool_alloc(v->fec->output_pool, GFP_NOIO);
+
+ return 0;
+}
+
+/*
+ * Initialize buffers and clear erasures. fec_read_bufs() assumes buffers are
+ * zeroed before deinterleaving.
+ */
+static void fec_init_bufs(struct dm_verity *v, struct dm_verity_fec_io *fio)
+{
+ unsigned n;
+
+ fec_for_each_buffer(fio, n)
+ memset(fio->bufs[n], 0, v->fec->rsn << DM_VERITY_FEC_BUF_RS_BITS);
+
+ memset(fio->erasures, 0, sizeof(fio->erasures));
+}
+
+/*
+ * Decode all RS blocks in a single data block and return the target block
+ * (indicated by @offset) in fio->output. If @use_erasures is non-zero, uses
+ * hashes to locate erasures.
+ */
+static int fec_decode_rsb(struct dm_verity *v, struct dm_verity_io *io,
+ struct dm_verity_fec_io *fio, u64 rsb, u64 offset,
+ bool use_erasures)
+{
+ int r, neras = 0;
+ unsigned pos;
+
+ r = fec_alloc_bufs(v, fio);
+ if (unlikely(r < 0))
+ return r;
+
+ for (pos = 0; pos < 1 << v->data_dev_block_bits; ) {
+ fec_init_bufs(v, fio);
+
+ r = fec_read_bufs(v, io, rsb, offset, pos,
+ use_erasures ? &neras : NULL);
+ if (unlikely(r < 0))
+ return r;
+
+ r = fec_decode_bufs(v, fio, rsb, r, pos, neras);
+ if (r < 0)
+ return r;
+
+ pos += fio->nbufs << DM_VERITY_FEC_BUF_RS_BITS;
+ }
+
+ /* Always re-validate the corrected block against the expected hash */
+ r = verity_hash(v, verity_io_hash_req(v, io), fio->output,
+ 1 << v->data_dev_block_bits,
+ verity_io_real_digest(v, io));
+ if (unlikely(r < 0))
+ return r;
+
+ if (memcmp(verity_io_real_digest(v, io), verity_io_want_digest(v, io),
+ v->digest_size)) {
+ DMERR_LIMIT("%s: FEC %llu: failed to correct (%d erasures)",
+ v->data_dev->name, (unsigned long long)rsb, neras);
+ return -EILSEQ;
+ }
+
+ return 0;
+}
+
+static int fec_bv_copy(struct dm_verity *v, struct dm_verity_io *io, u8 *data,
+ size_t len)
+{
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ memcpy(data, &fio->output[fio->output_pos], len);
+ fio->output_pos += len;
+
+ return 0;
+}
+
+/*
+ * Correct errors in a block. Copies corrected block to dest if non-NULL,
+ * otherwise to a bio_vec starting from iter.
+ */
+int verity_fec_decode(struct dm_verity *v, struct dm_verity_io *io,
+ enum verity_block_type type, sector_t block, u8 *dest,
+ struct bvec_iter *iter)
+{
+ int r;
+ struct dm_verity_fec_io *fio = fec_io(io);
+ u64 offset, res, rsb;
+
+ if (!verity_fec_is_enabled(v))
+ return -EOPNOTSUPP;
+
+ if (fio->level >= DM_VERITY_FEC_MAX_RECURSION) {
+ DMWARN_LIMIT("%s: FEC: recursion too deep", v->data_dev->name);
+ return -EIO;
+ }
+
+ fio->level++;
+
+ if (type == DM_VERITY_BLOCK_TYPE_METADATA)
+ block = block - v->hash_start + v->data_blocks;
+
+ /*
+ * For RS(M, N), the continuous FEC data is divided into blocks of N
+ * bytes. Since block size may not be divisible by N, the last block
+ * is zero padded when decoding.
+ *
+ * Each byte of the block is covered by a different RS(M, N) code,
+ * and each code is interleaved over N blocks to make it less likely
+ * that bursty corruption will leave us in unrecoverable state.
+ */
+
+ offset = block << v->data_dev_block_bits;
+ res = div64_u64(offset, v->fec->rounds << v->data_dev_block_bits);
+
+ /*
+ * The base RS block we can feed to the interleaver to find out all
+ * blocks required for decoding.
+ */
+ rsb = offset - res * (v->fec->rounds << v->data_dev_block_bits);
+
+ /*
+ * Locating erasures is slow, so attempt to recover the block without
+ * them first. Do a second attempt with erasures if the corruption is
+ * bad enough.
+ */
+ r = fec_decode_rsb(v, io, fio, rsb, offset, false);
+ if (r < 0) {
+ r = fec_decode_rsb(v, io, fio, rsb, offset, true);
+ if (r < 0)
+ goto done;
+ }
+
+ if (dest)
+ memcpy(dest, fio->output, 1 << v->data_dev_block_bits);
+ else if (iter) {
+ fio->output_pos = 0;
+ r = verity_for_bv_block(v, io, iter, fec_bv_copy);
+ }
+
+done:
+ fio->level--;
+ return r;
+}
+
+/*
+ * Clean up per-bio data.
+ */
+void verity_fec_finish_io(struct dm_verity_io *io)
+{
+ unsigned n;
+ struct dm_verity_fec *f = io->v->fec;
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ if (!verity_fec_is_enabled(io->v))
+ return;
+
+ mempool_free(fio->rs, f->rs_pool);
+
+ fec_for_each_prealloc_buffer(n)
+ mempool_free(fio->bufs[n], f->prealloc_pool);
+
+ fec_for_each_extra_buffer(fio, n)
+ mempool_free(fio->bufs[n], f->extra_pool);
+
+ mempool_free(fio->output, f->output_pool);
+}
+
+/*
+ * Initialize per-bio data.
+ */
+void verity_fec_init_io(struct dm_verity_io *io)
+{
+ struct dm_verity_fec_io *fio = fec_io(io);
+
+ if (!verity_fec_is_enabled(io->v))
+ return;
+
+ fio->rs = NULL;
+ memset(fio->bufs, 0, sizeof(fio->bufs));
+ fio->nbufs = 0;
+ fio->output = NULL;
+ fio->level = 0;
+}
+
+/*
+ * Append feature arguments and values to the status table.
+ */
+unsigned verity_fec_status_table(struct dm_verity *v, unsigned sz,
+ char *result, unsigned maxlen)
+{
+ if (!verity_fec_is_enabled(v))
+ return sz;
+
+ DMEMIT(" " DM_VERITY_OPT_FEC_DEV " %s "
+ DM_VERITY_OPT_FEC_BLOCKS " %llu "
+ DM_VERITY_OPT_FEC_START " %llu "
+ DM_VERITY_OPT_FEC_ROOTS " %d",
+ v->fec->dev->name,
+ (unsigned long long)v->fec->blocks,
+ (unsigned long long)v->fec->start,
+ v->fec->roots);
+
+ return sz;
+}
+
+void verity_fec_dtr(struct dm_verity *v)
+{
+ struct dm_verity_fec *f = v->fec;
+ struct kobject *kobj = &f->kobj_holder.kobj;
+
+ if (!verity_fec_is_enabled(v))
+ goto out;
+
+ mempool_destroy(f->rs_pool);
+ mempool_destroy(f->prealloc_pool);
+ mempool_destroy(f->extra_pool);
+ mempool_destroy(f->output_pool);
+ kmem_cache_destroy(f->cache);
+
+ if (f->data_bufio)
+ dm_bufio_client_destroy(f->data_bufio);
+ if (f->bufio)
+ dm_bufio_client_destroy(f->bufio);
+
+ if (f->dev)
+ dm_put_device(v->ti, f->dev);
+
+ if (kobj->state_initialized) {
+ kobject_put(kobj);
+ wait_for_completion(dm_get_completion_from_kobject(kobj));
+ }
+
+out:
+ kfree(f);
+ v->fec = NULL;
+}
+
+static void *fec_rs_alloc(gfp_t gfp_mask, void *pool_data)
+{
+ struct dm_verity *v = (struct dm_verity *)pool_data;
+
+ return init_rs(8, 0x11d, 0, 1, v->fec->roots);
+}
+
+static void fec_rs_free(void *element, void *pool_data)
+{
+ struct rs_control *rs = (struct rs_control *)element;
+
+ if (rs)
+ free_rs(rs);
+}
+
+bool verity_is_fec_opt_arg(const char *arg_name)
+{
+ return (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_START) ||
+ !strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS));
+}
+
+int verity_fec_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
+ unsigned *argc, const char *arg_name)
+{
+ int r;
+ struct dm_target *ti = v->ti;
+ const char *arg_value;
+ unsigned long long num_ll;
+ unsigned char num_c;
+ char dummy;
+
+ if (!*argc) {
+ ti->error = "FEC feature arguments require a value";
+ return -EINVAL;
+ }
+
+ arg_value = dm_shift_arg(as);
+ (*argc)--;
+
+ if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_DEV)) {
+ r = dm_get_device(ti, arg_value, FMODE_READ, &v->fec->dev);
+ if (r) {
+ ti->error = "FEC device lookup failed";
+ return r;
+ }
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_BLOCKS)) {
+ if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
+ ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT))
+ >> (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+ v->fec->blocks = num_ll;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_START)) {
+ if (sscanf(arg_value, "%llu%c", &num_ll, &dummy) != 1 ||
+ ((sector_t)(num_ll << (v->data_dev_block_bits - SECTOR_SHIFT)) >>
+ (v->data_dev_block_bits - SECTOR_SHIFT) != num_ll)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_START;
+ return -EINVAL;
+ }
+ v->fec->start = num_ll;
+
+ } else if (!strcasecmp(arg_name, DM_VERITY_OPT_FEC_ROOTS)) {
+ if (sscanf(arg_value, "%hhu%c", &num_c, &dummy) != 1 || !num_c ||
+ num_c < (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MAX_RSN) ||
+ num_c > (DM_VERITY_FEC_RSM - DM_VERITY_FEC_MIN_RSN)) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_ROOTS;
+ return -EINVAL;
+ }
+ v->fec->roots = num_c;
+
+ } else {
+ ti->error = "Unrecognized verity FEC feature request";
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static ssize_t corrected_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct dm_verity_fec *f = container_of(kobj, struct dm_verity_fec,
+ kobj_holder.kobj);
+
+ return sprintf(buf, "%d\n", atomic_read(&f->corrected));
+}
+
+static struct kobj_attribute attr_corrected = __ATTR_RO(corrected);
+
+static struct attribute *fec_attrs[] = {
+ &attr_corrected.attr,
+ NULL
+};
+
+static struct kobj_type fec_ktype = {
+ .sysfs_ops = &kobj_sysfs_ops,
+ .default_attrs = fec_attrs,
+ .release = dm_kobject_release
+};
+
+/*
+ * Allocate dm_verity_fec for v->fec. Must be called before verity_fec_ctr.
+ */
+int verity_fec_ctr_alloc(struct dm_verity *v)
+{
+ struct dm_verity_fec *f;
+
+ f = kzalloc(sizeof(struct dm_verity_fec), GFP_KERNEL);
+ if (!f) {
+ v->ti->error = "Cannot allocate FEC structure";
+ return -ENOMEM;
+ }
+ v->fec = f;
+
+ return 0;
+}
+
+/*
+ * Validate arguments and preallocate memory. Must be called after arguments
+ * have been parsed using verity_fec_parse_opt_args.
+ */
+int verity_fec_ctr(struct dm_verity *v)
+{
+ int r;
+ struct dm_verity_fec *f = v->fec;
+ struct dm_target *ti = v->ti;
+ struct mapped_device *md = dm_table_get_md(ti->table);
+ u64 hash_blocks;
+
+ if (!verity_fec_is_enabled(v)) {
+ verity_fec_dtr(v);
+ return 0;
+ }
+
+ /* Create a kobject and sysfs attributes */
+ init_completion(&f->kobj_holder.completion);
+
+ r = kobject_init_and_add(&f->kobj_holder.kobj, &fec_ktype,
+ &disk_to_dev(dm_disk(md))->kobj, "%s", "fec");
+ if (r) {
+ ti->error = "Cannot create kobject";
+ return r;
+ }
+
+ /*
+ * FEC is computed over data blocks, possible metadata, and
+ * hash blocks. In other words, FEC covers total of fec_blocks
+ * blocks consisting of the following:
+ *
+ * data blocks | hash blocks | metadata (optional)
+ *
+ * We allow metadata after hash blocks to support a use case
+ * where all data is stored on the same device and FEC covers
+ * the entire area.
+ *
+ * If metadata is included, we require it to be available on the
+ * hash device after the hash blocks.
+ */
+
+ hash_blocks = v->hash_blocks - v->hash_start;
+
+ /*
+ * Require matching block sizes for data and hash devices for
+ * simplicity.
+ */
+ if (v->data_dev_block_bits != v->hash_dev_block_bits) {
+ ti->error = "Block sizes must match to use FEC";
+ return -EINVAL;
+ }
+
+ if (!f->roots) {
+ ti->error = "Missing " DM_VERITY_OPT_FEC_ROOTS;
+ return -EINVAL;
+ }
+ f->rsn = DM_VERITY_FEC_RSM - f->roots;
+
+ if (!f->blocks) {
+ ti->error = "Missing " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+
+ f->rounds = f->blocks;
+ if (sector_div(f->rounds, f->rsn))
+ f->rounds++;
+
+ /*
+ * Due to optional metadata, f->blocks can be larger than
+ * data_blocks and hash_blocks combined.
+ */
+ if (f->blocks < v->data_blocks + hash_blocks || !f->rounds) {
+ ti->error = "Invalid " DM_VERITY_OPT_FEC_BLOCKS;
+ return -EINVAL;
+ }
+
+ /*
+ * Metadata is accessed through the hash device, so we require
+ * it to be large enough.
+ */
+ f->hash_blocks = f->blocks - v->data_blocks;
+ if (dm_bufio_get_device_size(v->bufio) < f->hash_blocks) {
+ ti->error = "Hash device is too small for "
+ DM_VERITY_OPT_FEC_BLOCKS;
+ return -E2BIG;
+ }
+
+ f->bufio = dm_bufio_client_create(f->dev->bdev,
+ 1 << v->data_dev_block_bits,
+ 1, 0, NULL, NULL);
+ if (IS_ERR(f->bufio)) {
+ ti->error = "Cannot initialize FEC bufio client";
+ return PTR_ERR(f->bufio);
+ }
+
+ if (dm_bufio_get_device_size(f->bufio) <
+ ((f->start + f->rounds * f->roots) >> v->data_dev_block_bits)) {
+ ti->error = "FEC device is too small";
+ return -E2BIG;
+ }
+
+ f->data_bufio = dm_bufio_client_create(v->data_dev->bdev,
+ 1 << v->data_dev_block_bits,
+ 1, 0, NULL, NULL);
+ if (IS_ERR(f->data_bufio)) {
+ ti->error = "Cannot initialize FEC data bufio client";
+ return PTR_ERR(f->data_bufio);
+ }
+
+ if (dm_bufio_get_device_size(f->data_bufio) < v->data_blocks) {
+ ti->error = "Data device is too small";
+ return -E2BIG;
+ }
+
+ /* Preallocate an rs_control structure for each worker thread */
+ f->rs_pool = mempool_create(num_online_cpus(), fec_rs_alloc,
+ fec_rs_free, (void *) v);
+ if (!f->rs_pool) {
+ ti->error = "Cannot allocate RS pool";
+ return -ENOMEM;
+ }
+
+ f->cache = kmem_cache_create("dm_verity_fec_buffers",
+ f->rsn << DM_VERITY_FEC_BUF_RS_BITS,
+ 0, 0, NULL);
+ if (!f->cache) {
+ ti->error = "Cannot create FEC buffer cache";
+ return -ENOMEM;
+ }
+
+ /* Preallocate DM_VERITY_FEC_BUF_PREALLOC buffers for each thread */
+ f->prealloc_pool = mempool_create_slab_pool(num_online_cpus() *
+ DM_VERITY_FEC_BUF_PREALLOC,
+ f->cache);
+ if (!f->prealloc_pool) {
+ ti->error = "Cannot allocate FEC buffer prealloc pool";
+ return -ENOMEM;
+ }
+
+ f->extra_pool = mempool_create_slab_pool(0, f->cache);
+ if (!f->extra_pool) {
+ ti->error = "Cannot allocate FEC buffer extra pool";
+ return -ENOMEM;
+ }
+
+ /* Preallocate an output buffer for each thread */
+ f->output_pool = mempool_create_kmalloc_pool(num_online_cpus(),
+ 1 << v->data_dev_block_bits);
+ if (!f->output_pool) {
+ ti->error = "Cannot allocate FEC output pool";
+ return -ENOMEM;
+ }
+
+ /* Reserve space for our per-bio data */
+ ti->per_io_data_size += sizeof(struct dm_verity_fec_io);
+
+ return 0;
+}