diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/md/dm-table.c | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 535fdaf2473d..e3bcfb8b15a1 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -724,6 +724,71 @@ static void check_for_valid_limits(struct io_restrictions *rs) rs->bounce_pfn = -1; } +/* + * Impose necessary and sufficient conditions on a devices's table such + * that any incoming bio which respects its logical_block_size can be + * processed successfully. If it falls across the boundary between + * two or more targets, the size of each piece it gets split into must + * be compatible with the logical_block_size of the target processing it. + */ +static int validate_hardware_logical_block_alignment(struct dm_table *table) +{ + /* + * This function uses arithmetic modulo the logical_block_size + * (in units of 512-byte sectors). + */ + unsigned short device_logical_block_size_sects = + table->limits.logical_block_size >> SECTOR_SHIFT; + + /* + * Offset of the start of the next table entry, mod logical_block_size. + */ + unsigned short next_target_start = 0; + + /* + * Given an aligned bio that extends beyond the end of a + * target, how many sectors must the next target handle? + */ + unsigned short remaining = 0; + + struct dm_target *uninitialized_var(ti); + unsigned i = 0; + + /* + * Check each entry in the table in turn. + */ + while (i < dm_table_get_num_targets(table)) { + ti = dm_table_get_target(table, i++); + + /* + * If the remaining sectors fall entirely within this + * table entry are they compatible with its logical_block_size? + */ + if (remaining < ti->len && + remaining & ((ti->limits.logical_block_size >> + SECTOR_SHIFT) - 1)) + break; /* Error */ + + next_target_start = + (unsigned short) ((next_target_start + ti->len) & + (device_logical_block_size_sects - 1)); + remaining = next_target_start ? + device_logical_block_size_sects - next_target_start : 0; + } + + if (remaining) { + DMWARN("%s: table line %u (start sect %llu len %llu) " + "not aligned to hardware logical block size %hu", + dm_device_name(table->md), i, + (unsigned long long) ti->begin, + (unsigned long long) ti->len, + table->limits.logical_block_size); + return -EINVAL; + } + + return 0; +} + int dm_table_add_target(struct dm_table *t, const char *type, sector_t start, sector_t len, char *params) { @@ -823,6 +888,10 @@ int dm_table_complete(struct dm_table *t) check_for_valid_limits(&t->limits); + r = validate_hardware_logical_block_alignment(t); + if (r) + return r; + /* how many indexes will the btree have ? */ leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE); t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE); |