1 files changed, 234 insertions, 0 deletions

diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
new file mode 100644
index 000000000000..ab89278a56bf
--- /dev/null
+++ b/drivers/md/dm-stripe.c
@@ -0,0 +1,234 @@
+/*
+ * Copyright (C) 2001-2003 Sistina Software (UK) Limited.
+ *
+ * This file is released under the GPL.
+ */
+
+#include "dm.h"
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+#include <linux/slab.h>
+
+struct stripe {
+        struct dm_dev *dev;
+        sector_t physical_start;
+};
+
+struct stripe_c {
+        uint32_t stripes;
+
+        /* The size of this target / num. stripes */
+        sector_t stripe_width;
+
+        /* stripe chunk size */
+        uint32_t chunk_shift;
+        sector_t chunk_mask;
+
+        struct stripe stripe[0];
+};
+
+static inline struct stripe_c *alloc_context(unsigned int stripes)
+{
+        size_t len;
+
+        if (array_too_big(sizeof(struct stripe_c), sizeof(struct stripe),
+                          stripes))
+                return NULL;
+
+        len = sizeof(struct stripe_c) + (sizeof(struct stripe) * stripes);
+
+        return kmalloc(len, GFP_KERNEL);
+}
+
+/*
+ * Parse a single <dev> <sector> pair
+ */
+static int get_stripe(struct dm_target *ti, struct stripe_c *sc,
+                      unsigned int stripe, char **argv)
+{
+        sector_t start;
+
+        if (sscanf(argv[1], SECTOR_FORMAT, &start) != 1)
+                return -EINVAL;
+
+        if (dm_get_device(ti, argv[0], start, sc->stripe_width,
+                          dm_table_get_mode(ti->table),
+                          &sc->stripe[stripe].dev))
+                return -ENXIO;
+
+        sc->stripe[stripe].physical_start = start;
+        return 0;
+}
+
+/*
+ * Construct a striped mapping.
+ * <number of stripes> <chunk size (2^^n)> [<dev_path> <offset>]+
+ */
+static int stripe_ctr(struct dm_target *ti, unsigned int argc, char **argv)
+{
+        struct stripe_c *sc;
+        sector_t width;
+        uint32_t stripes;
+        uint32_t chunk_size;
+        char *end;
+        int r;
+        unsigned int i;
+
+        if (argc < 2) {
+                ti->error = "dm-stripe: Not enough arguments";
+                return -EINVAL;
+        }
+
+        stripes = simple_strtoul(argv[0], &end, 10);
+        if (*end) {
+                ti->error = "dm-stripe: Invalid stripe count";
+                return -EINVAL;
+        }
+
+        chunk_size = simple_strtoul(argv[1], &end, 10);
+        if (*end) {
+                ti->error = "dm-stripe: Invalid chunk_size";
+                return -EINVAL;
+        }
+
+        /*
+         * chunk_size is a power of two
+         */
+        if (!chunk_size || (chunk_size & (chunk_size - 1)) ||
+            (chunk_size < (PAGE_SIZE >> SECTOR_SHIFT))) {
+                ti->error = "dm-stripe: Invalid chunk size";
+                return -EINVAL;
+        }
+
+        width = ti->len;
+        if (sector_div(width, stripes)) {
+                ti->error = "dm-stripe: Target length not divisable by "
+                    "number of stripes";
+                return -EINVAL;
+        }
+
+        /*
+         * Do we have enough arguments for that many stripes ?
+         */
+        if (argc != (2 + 2 * stripes)) {
+                ti->error = "dm-stripe: Not enough destinations "
+                        "specified";
+                return -EINVAL;
+        }
+
+        sc = alloc_context(stripes);
+        if (!sc) {
+                ti->error = "dm-stripe: Memory allocation for striped context "
+                    "failed";
+                return -ENOMEM;
+        }
+
+        sc->stripes = stripes;
+        sc->stripe_width = width;
+        ti->split_io = chunk_size;
+
+        sc->chunk_mask = ((sector_t) chunk_size) - 1;
+        for (sc->chunk_shift = 0; chunk_size; sc->chunk_shift++)
+                chunk_size >>= 1;
+        sc->chunk_shift--;
+
+        /*
+         * Get the stripe destinations.
+         */
+        for (i = 0; i < stripes; i++) {
+                argv += 2;
+
+                r = get_stripe(ti, sc, i, argv);
+                if (r < 0) {
+                        ti->error = "dm-stripe: Couldn't parse stripe "
+                                "destination";
+                        while (i--)
+                                dm_put_device(ti, sc->stripe[i].dev);
+                        kfree(sc);
+                        return r;
+                }
+        }
+
+        ti->private = sc;
+        return 0;
+}
+
+static void stripe_dtr(struct dm_target *ti)
+{
+        unsigned int i;
+        struct stripe_c *sc = (struct stripe_c *) ti->private;
+
+        for (i = 0; i < sc->stripes; i++)
+                dm_put_device(ti, sc->stripe[i].dev);
+
+        kfree(sc);
+}
+
+static int stripe_map(struct dm_target *ti, struct bio *bio,
+                      union map_info *map_context)
+{
+        struct stripe_c *sc = (struct stripe_c *) ti->private;
+
+        sector_t offset = bio->bi_sector - ti->begin;
+        sector_t chunk = offset >> sc->chunk_shift;
+        uint32_t stripe = sector_div(chunk, sc->stripes);
+
+        bio->bi_bdev = sc->stripe[stripe].dev->bdev;
+        bio->bi_sector = sc->stripe[stripe].physical_start +
+            (chunk << sc->chunk_shift) + (offset & sc->chunk_mask);
+        return 1;
+}
+
+static int stripe_status(struct dm_target *ti,
+                         status_type_t type, char *result, unsigned int maxlen)
+{
+        struct stripe_c *sc = (struct stripe_c *) ti->private;
+        unsigned int sz = 0;
+        unsigned int i;
+
+        switch (type) {
+        case STATUSTYPE_INFO:
+                result[0] = '\0';
+                break;
+
+        case STATUSTYPE_TABLE:
+                DMEMIT("%d " SECTOR_FORMAT, sc->stripes, sc->chunk_mask + 1);
+                for (i = 0; i < sc->stripes; i++)
+                        DMEMIT(" %s " SECTOR_FORMAT, sc->stripe[i].dev->name,
+                               sc->stripe[i].physical_start);
+                break;
+        }
+        return 0;
+}
+
+static struct target_type stripe_target = {
+        .name   = "striped",
+        .version= {1, 0, 2},
+        .module = THIS_MODULE,
+        .ctr    = stripe_ctr,
+        .dtr    = stripe_dtr,
+        .map    = stripe_map,
+        .status = stripe_status,
+};
+
+int __init dm_stripe_init(void)
+{
+        int r;
+
+        r = dm_register_target(&stripe_target);
+        if (r < 0)
+                DMWARN("striped target registration failed");
+
+        return r;
+}
+
+void dm_stripe_exit(void)
+{
+        if (dm_unregister_target(&stripe_target))
+                DMWARN("striped target unregistration failed");
+
+        return;
+}