Quoting from Linux kernel commit 9e694d9c18dd "libnvdimm, label: change
nvdimm_num_label_slots per UEFI 2.7":
sizeof_namespace_index() fails when NVDIMM devices have the minimum
1024 bytes label storage area. nvdimm_num_label_slots() returns 3
slots while the area is only big enough for 2 slots.
Change nvdimm_num_label_slots() to calculate a number of label slots
according to UEFI 2.7 spec.
Without this fix attempts to initialize labels on a small (1K) label
area results in the following:
libndctl: sizeof_namespace_index: nmem2: label area (1024) too small to host
(128 byte) labels
libndctl: sizeof_namespace_index: nmem2: label area (1024) too small to host
(256 byte) labels
Based on an original patch by Toshi Kani
Fixes: bdaec95463ca ("ndctl: introduce
ndctl_dimm_{validate_labels,init_labels}")
Reported-by: Sujith Pandel <sujith_pan...@dell.com>
Link: https://github.com/pmem/ndctl/issues/78
Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
---
ndctl/lib/dimm.c | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)
diff --git a/ndctl/lib/dimm.c b/ndctl/lib/dimm.c
index 79e2ca0aa5e2..beb67890a2df 100644
--- a/ndctl/lib/dimm.c
+++ b/ndctl/lib/dimm.c
@@ -66,9 +66,27 @@ static unsigned int sizeof_namespace_label(struct
nvdimm_data *ndd)
return ndctl_dimm_sizeof_namespace_label(to_dimm(ndd));
}
+static size_t __sizeof_namespace_index(u32 nslot)
+{
+ return ALIGN(sizeof(struct namespace_index) + DIV_ROUND_UP(nslot, 8),
+ NSINDEX_ALIGN);
+}
+
+static int __nvdimm_num_label_slots(struct nvdimm_data *ndd,
+ size_t index_size)
+{
+ return (ndd->config_size - index_size * 2) /
+ sizeof_namespace_label(ndd);
+}
+
static int nvdimm_num_label_slots(struct nvdimm_data *ndd)
{
- return ndd->config_size / (sizeof_namespace_label(ndd) + 1);
+ u32 tmp_nslot, n;
+
+ tmp_nslot = ndd->config_size / sizeof_namespace_label(ndd);
+ n = __sizeof_namespace_index(tmp_nslot) / NSINDEX_ALIGN;
+
+ return __nvdimm_num_label_slots(ndd, NSINDEX_ALIGN * n);
}
static unsigned int sizeof_namespace_index(struct nvdimm_data *ndd)
@@ -78,18 +96,15 @@ static unsigned int sizeof_namespace_index(struct
nvdimm_data *ndd)
struct ndctl_ctx *ctx = ndctl_dimm_get_ctx(dimm);
/*
- * The minimum index space is 512 bytes, with that amount of
- * index we can describe ~1400 labels which is less than a byte
- * of overhead per label. Round up to a byte of overhead per
- * label and determine the size of the index region. Yes, this
- * starts to waste space at larger config_sizes, but it's
- * unlikely we'll ever see anything but 128K.
+ * Per UEFI 2.7, the minimum size of the Label Storage Area is
+ * large enough to hold 2 index blocks and 2 labels. The
+ * minimum index block size is 256 bytes, and the minimum label
+ * size is 256 bytes.
*/
nslot = nvdimm_num_label_slots(ndd);
space = ndd->config_size - nslot * sizeof_namespace_label(ndd);
- size = ALIGN(sizeof(struct namespace_index) + DIV_ROUND_UP(nslot, 8),
- NSINDEX_ALIGN) * 2;
- if (size <= space)
+ size = __sizeof_namespace_index(nslot) * 2;
+ if (size <= space && nslot >= 2)
return size / 2;
err(ctx, "%s: label area (%ld) too small to host (%d byte) labels\n",
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