libnvdimm, btt: consolidate arena validation

Use arena_is_valid as a common routine for checking the validity of an
info block from both discover_arenas, and nd_btt_probe.

As a result, don't check for validity of the BTT's UUID, and lbasize.
The checksum in the BTT info block guarantees self-consistency, and when
we're called from nd_btt_probe, we don't have a valid uuid or lbasize
available to check against.

Also cleanup to return a bool instead of an int.

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 87e6a96..6567746 100644 (file)
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -582,32 +582,6 @@ static void free_arenas(struct btt *btt)
        }
 }
 
-/*
- * This function checks if the metadata layout is valid and error free
- */
-static int arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
-{
-       u64 checksum;
-
-       if (memcmp(super->uuid, nd_btt->uuid, 16))
-               return 0;
-
-       checksum = le64_to_cpu(super->checksum);
-       super->checksum = 0;
-       if (checksum != nd_btt_sb_checksum(super))
-               return 0;
-       super->checksum = cpu_to_le64(checksum);
-
-       if (nd_btt->lbasize != le32_to_cpu(super->external_lbasize))
-               return 0;
-
-       /* TODO: figure out action for this */
-       if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)
-               dev_info(&nd_btt->dev, "Found arena with an error flag\n");
-
-       return 1;
-}
-
 /*
  * This function reads an existing valid btt superblock and
  * populates the corresponding arena_info struct
@@ -665,7 +639,7 @@ static int discover_arenas(struct btt *btt)
                if (ret)
                        goto out;
 
-               if (!arena_is_valid(btt->nd_btt, super)) {
+               if (!nd_btt_arena_is_valid(btt->nd_btt, super)) {
                        if (remaining == btt->rawsize) {
                                btt->init_state = INIT_NOTFOUND;
                                dev_info(to_dev(arena), "No existing arenas\n");

diff --git a/drivers/nvdimm/btt.h b/drivers/nvdimm/btt.h
index 75b0d80..b2f8651 100644 (file)
--- a/drivers/nvdimm/btt.h
+++ b/drivers/nvdimm/btt.h
@@ -182,4 +182,7 @@ struct btt {
        int init_state;
        int num_arenas;
 };
+
+bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super);
+
 #endif

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index 6ac8c0f..18e0663 100644 (file)
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -342,6 +342,38 @@ struct device *nd_btt_create(struct nd_region *nd_region)
        return dev;
 }
 
+/**
+ * nd_btt_arena_is_valid - check if the metadata layout is valid
+ * @nd_btt:    device with BTT geometry and backing device info
+ * @super:     pointer to the arena's info block being tested
+ *
+ * Check consistency of the btt info block with itself by validating
+ * the checksum.
+ *
+ * Returns:
+ * false for an invalid info block, true for a valid one
+ */
+bool nd_btt_arena_is_valid(struct nd_btt *nd_btt, struct btt_sb *super)
+{
+       u64 checksum;
+
+       if (memcmp(super->signature, BTT_SIG, BTT_SIG_LEN) != 0)
+               return false;
+
+       checksum = le64_to_cpu(super->checksum);
+       super->checksum = 0;
+       if (checksum != nd_btt_sb_checksum(super))
+               return false;
+       super->checksum = cpu_to_le64(checksum);
+
+       /* TODO: figure out action for this */
+       if ((le32_to_cpu(super->flags) & IB_FLAG_ERROR_MASK) != 0)
+               dev_info(&nd_btt->dev, "Found arena with an error flag\n");
+
+       return true;
+}
+EXPORT_SYMBOL(nd_btt_arena_is_valid);
+
 /*
  * nd_btt_sb_checksum: compute checksum for btt info block
  *
@@ -364,8 +396,6 @@ EXPORT_SYMBOL(nd_btt_sb_checksum);
 static int __nd_btt_probe(struct nd_btt *nd_btt,
                struct nd_namespace_common *ndns, struct btt_sb *btt_sb)
 {
-       u64 checksum;
-
        if (!btt_sb || !ndns || !nd_btt)
                return -ENODEV;
 
@@ -375,14 +405,8 @@ static int __nd_btt_probe(struct nd_btt *nd_btt,
        if (nvdimm_namespace_capacity(ndns) < SZ_16M)
                return -ENXIO;
 
-       if (memcmp(btt_sb->signature, BTT_SIG, BTT_SIG_LEN) != 0)
-               return -ENODEV;
-
-       checksum = le64_to_cpu(btt_sb->checksum);
-       btt_sb->checksum = 0;
-       if (checksum != nd_btt_sb_checksum(btt_sb))
+       if (!nd_btt_arena_is_valid(nd_btt, btt_sb))
                return -ENODEV;
-       btt_sb->checksum = cpu_to_le64(checksum);
 
        nd_btt->lbasize = le32_to_cpu(btt_sb->external_lbasize);
        nd_btt->uuid = kmemdup(btt_sb->uuid, 16, GFP_KERNEL);