Re: btt ndctl question

On Tue, Jul 26, 2016 at 2:24 PM, Verma, Vishal L <vishal.l.verma(a)intel.com&gt; wrote: > On Tue, 2016-07-26 at 14:58 -0600, Vishal Verma wrote: >> On 07/26, Linda Knippers wrote: >> > >> > My system has 4 8G NVDIMMs and I have them configured in different >> > ways, as you can >> > see from the ndctl output: >> > >> > $ ndctl list >> > [ >> > { >> > "dev":"namespace3.0", >> > "mode":"raw", >> > "size":8589934592, >> > "blockdev":"pmem3" >> > }, >> > { >> > "dev":"namespace2.0", >> > "mode":"memory", >> > "size":8587837440, >> > "uuid":"2567d762-68ae-486b-a6eb-2d3ab1b9dca9", >> > "blockdev":"pmem2" >> > }, >> > { >> > "dev":"namespace1.0", >> > "mode":"sector", >> > "uuid":"44fb474e-7db8-4438-ad95-05ecb9f2075e", >> > "sector_size":4096, >> > "blockdev":"pmem1s" >> > }, >> > { >> > "dev":"namespace0.0", >> > "mode":"memory", >> > "size":8453619712, >> > "uuid":"933ed54b-5b64-47f1-8409-c88f7c846522", >> > "blockdev":"pmem0" >> > } >> > ] >> > >> > The two memory namespaces have different sizes because one is -- >> > map=dev and the other is --map=mem. >> > It would be nice if the map option was displayed but my question is >> > about the size value for the >> > btt device, or lack of one. >> > >> > All the namespaces show a size except for the btt. The btt only >> > shows a sector size. There >> > is no size value exposed by the btt sysfs information, which is >> > probably why it's not in ndctl. >> > >> > I know the size can be gotten from the block device but it looks >> > like an omission here. >> > Is this a bug or a feature? >> >> Probably an omission :) >> This patch should expose a size attribute in sysfs: >> >> $ cat /sys/bus/nd/devices/btt7.0/size >> 32440320 >> >> I can look at the 'ndctl list' enabling too if this looks good. >> >> 8<------ >> >> From fb119bf4380d1d65d82754e581bbd41161c2100f Mon Sep 17 00:00:00 2001 >> From: Vishal Verma <vishal.l.verma(a)intel.com&gt; >> Date: Tue, 26 Jul 2016 14:54:39 -0600 >> Subject: [PATCH] nvdimm, btt: add a size attribute for BTTs >> >> To be consistent with other namespaces, expose a 'size' attribute for >> BTT devices also. >> >> Cc: Dan Williams <dan.j.williams(a)intel.com&gt; >> Reported-by: Linda Knippers <linda.knippers(a)hpe.com&gt; >> Signed-off-by: Vishal Verma <vishal.l.verma(a)intel.com&gt; >> --- >> drivers/nvdimm/btt.c | 1 + >> drivers/nvdimm/btt_devs.c | 15 +++++++++++++++ >> drivers/nvdimm/nd.h | 1 + >> 3 files changed, 17 insertions(+) >> >> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c >> index 68a7c3c..71ce0dc 100644 >> --- a/drivers/nvdimm/btt.c >> +++ b/drivers/nvdimm/btt.c >> @@ -1270,6 +1270,7 @@ static int btt_blk_init(struct btt *btt) >> } >> } >> set_capacity(btt->btt_disk, btt->nlba * btt->sector_size >> >> 9); >> + btt->nd_btt->size = btt->nlba * btt->sector_size; > > Blargh, I think I was a bit hasty; I think this should be: > > + btt->nd_btt->size = btt->nlba * (u64)btt->sector_size; > > Right? (I always get bit by integer promotion rules...) ...but at this point we're identical to what the block layer is reporting. The other 'size' attributes are communicating the raw byte-aligned capacity of the namespace minus local driver overhead.