[PATCH 0/2] nvdimm deadcoding

[PATCH 0/2] nvdimm deadcoding

[linux]

From: "Dr. David Alan Gilbert" <linux@treblig.org>

Hi,
  A couple of nvdimm dead coding patches; they just
remove entirely unused functions.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>


Dr. David Alan Gilbert (2):
  libnvdimm: Remove unused nd_region_conflict
  libnvdimm: Remove unused nd_attach_ndns

 drivers/nvdimm/claim.c       | 11 ----------
 drivers/nvdimm/nd-core.h     |  4 ----
 drivers/nvdimm/region_devs.c | 41 ------------------------------------
 3 files changed, 56 deletions(-)

-- 
2.48.1

[PATCH 1/2] libnvdimm: Remove unused nd_region_conflict

[linux]

From: "Dr. David Alan Gilbert" <linux@treblig.org>

nd_region_conflict() has been unused since 2019's
commit a3619190d62e ("libnvdimm/pfn: stop padding pmem namespaces to
section alignment")

Remove it, and the region_confict() helper it uses, and the associated
struct conflict_context.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
---
 drivers/nvdimm/nd-core.h     |  2 --
 drivers/nvdimm/region_devs.c | 41 ------------------------------------
 2 files changed, 43 deletions(-)

diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 86976a9e8a15..2b37b7fc4fef 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -127,8 +127,6 @@ resource_size_t nd_region_allocatable_dpa(struct nd_region *nd_region);
 resource_size_t nd_pmem_available_dpa(struct nd_region *nd_region,
 				      struct nd_mapping *nd_mapping);
 resource_size_t nd_region_available_dpa(struct nd_region *nd_region);
-int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
-		resource_size_t size);
 resource_size_t nvdimm_allocated_dpa(struct nvdimm_drvdata *ndd,
 		struct nd_label_id *label_id);
 int nvdimm_num_label_slots(struct nvdimm_drvdata *ndd);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index 37417ce5ec7b..de1ee5ebc851 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1229,45 +1229,4 @@ bool is_nvdimm_sync(struct nd_region *nd_region)
 }
 EXPORT_SYMBOL_GPL(is_nvdimm_sync);
 
-struct conflict_context {
-	struct nd_region *nd_region;
-	resource_size_t start, size;
-};
-
-static int region_conflict(struct device *dev, void *data)
-{
-	struct nd_region *nd_region;
-	struct conflict_context *ctx = data;
-	resource_size_t res_end, region_end, region_start;
-
-	if (!is_memory(dev))
-		return 0;
-
-	nd_region = to_nd_region(dev);
-	if (nd_region == ctx->nd_region)
-		return 0;
-
-	res_end = ctx->start + ctx->size;
-	region_start = nd_region->ndr_start;
-	region_end = region_start + nd_region->ndr_size;
-	if (ctx->start >= region_start && ctx->start < region_end)
-		return -EBUSY;
-	if (res_end > region_start && res_end <= region_end)
-		return -EBUSY;
-	return 0;
-}
-
-int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
-		resource_size_t size)
-{
-	struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(&nd_region->dev);
-	struct conflict_context ctx = {
-		.nd_region = nd_region,
-		.start = start,
-		.size = size,
-	};
-
-	return device_for_each_child(&nvdimm_bus->dev, &ctx, region_conflict);
-}
-
 MODULE_IMPORT_NS("DEVMEM");
-- 
2.48.1

[PATCH 2/2] libnvdimm: Remove unused nd_attach_ndns

[linux]

From: "Dr. David Alan Gilbert" <linux@treblig.org>

nd_attach_ndns() hasn't been used since 2017's
commit 452bae0aede7 ("libnvdimm: fix nvdimm_bus_lock() vs device_lock()
ordering")

Remove it.

Note the __ version is still used and has been left.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
---
 drivers/nvdimm/claim.c   | 11 -----------
 drivers/nvdimm/nd-core.h |  2 --
 2 files changed, 13 deletions(-)

diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c
index 9e84ab411564..51614651d2e7 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -56,17 +56,6 @@ bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
 	return true;
 }
 
-bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
-		struct nd_namespace_common **_ndns)
-{
-	bool claimed;
-
-	nvdimm_bus_lock(&attach->dev);
-	claimed = __nd_attach_ndns(dev, attach, _ndns);
-	nvdimm_bus_unlock(&attach->dev);
-	return claimed;
-}
-
 static bool is_idle(struct device *dev, struct nd_namespace_common *ndns)
 {
 	struct nd_region *nd_region = to_nd_region(dev->parent);
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 2b37b7fc4fef..bfc6bfeb6e24 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -134,8 +134,6 @@ void get_ndd(struct nvdimm_drvdata *ndd);
 resource_size_t __nvdimm_namespace_capacity(struct nd_namespace_common *ndns);
 void nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
 void __nd_detach_ndns(struct device *dev, struct nd_namespace_common **_ndns);
-bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
-		struct nd_namespace_common **_ndns);
 bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
 		struct nd_namespace_common **_ndns);
 ssize_t nd_namespace_store(struct device *dev,
-- 
2.48.1

Re: [PATCH 0/2] nvdimm deadcoding

[Ira Weiny]

linux@ wrote:
> From: "Dr. David Alan Gilbert" <linux@treblig.org>
> 
> Hi,
>   A couple of nvdimm dead coding patches; they just
> remove entirely unused functions.
> 
> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>

For the series.

I'll pick these up for 6.15.

Reviewed-by: Ira Weiny <ira.weiny@intel.com>

> 
> 
> Dr. David Alan Gilbert (2):
>   libnvdimm: Remove unused nd_region_conflict
>   libnvdimm: Remove unused nd_attach_ndns
> 
>  drivers/nvdimm/claim.c       | 11 ----------
>  drivers/nvdimm/nd-core.h     |  4 ----
>  drivers/nvdimm/region_devs.c | 41 ------------------------------------
>  3 files changed, 56 deletions(-)
> 
> -- 
> 2.48.1
> 

Re: [PATCH 0/2] nvdimm deadcoding

[Alison Schofield]

On Thu, Feb 20, 2025 at 12:45:36AM +0000, linux@treblig.org wrote:
> From: "Dr. David Alan Gilbert" <linux@treblig.org>
> 
> Hi,
>   A couple of nvdimm dead coding patches; they just
> remove entirely unused functions.

I see you've been sending patches for dead code removal
for several months. What tool are you using for discovery?

Thanks,
Alison


> 
> Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
> 
> 
> Dr. David Alan Gilbert (2):
>   libnvdimm: Remove unused nd_region_conflict
>   libnvdimm: Remove unused nd_attach_ndns
> 
>  drivers/nvdimm/claim.c       | 11 ----------
>  drivers/nvdimm/nd-core.h     |  4 ----
>  drivers/nvdimm/region_devs.c | 41 ------------------------------------
>  3 files changed, 56 deletions(-)
> 
> -- 
> 2.48.1
> 
> 

Re: [PATCH 0/2] nvdimm deadcoding

[Dr. David Alan Gilbert]

* Alison Schofield (alison.schofield@intel.com) wrote:
> On Thu, Feb 20, 2025 at 12:45:36AM +0000, linux@treblig.org wrote:
> > From: "Dr. David Alan Gilbert" <linux@treblig.org>
> > 
> > Hi,
> >   A couple of nvdimm dead coding patches; they just
> > remove entirely unused functions.
> 
> I see you've been sending patches for dead code removal
> for several months. What tool are you using for discovery?

Hi Alison,
  Thanks for noticing.

  I'm using my own very very hacky scripts; notes below.
The problem is they generate lots of false-positives
so I've got this big output file from one run of the scripts
and I then have to go through finding the useful ones.
I start with an all-yes-config build on x86, then the
script dumps all the relocations using readelf and finds
symbols that are defined but don't have any apparent
use.
(Actually not quite all-yes-config, but close)

Then for each of those symbols I grep the whole tree
for the symbol and get myself a huge debug file.
That means that for each symbol I'm hopefully left where
it's defined and declared, and if there are actually any
uses that weren't built in my world they show up.

Then I gently work through these, look them up with git log -G
to find when they were added/stopped being used.

On one side there are false positives (stuff only in other
builds, so that's why I grep for the symbol name, also
symbols that are defined but only used locally in a .o
file)
There are lots of false negatives as well.
But then I have to second guess from the git output
  a) If it was recently added don't bother, someone is
probably about to use it.
  b) If it's actually a bug and it *should* be called.
  c) If it's a trivial one liner I don't bother
  d) If it looks like it's really a wrapper of every
firmware call for that device I leave it.
  e) Skip anything __init etc marked, or look magic
(bpf etc)

It's tricky because they're all over, so you fall
into the preferences of each maitainers oddities of
what they care about.

My debug file is alphabetically searched; I'm just near
the end of the n's - a while to go!

I'm hoping once I get to the end, then it'll be a bit
cleaner and I can tidy the scripts up and watch for
new entries in each release.

For reference for the nvdimm symbols my output file looks
like:
---- nd_attach_ndns[^A-Z_a-z] ----
drivers/nvdimm/claim.c:44:bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
drivers/nvdimm/claim.c:59:bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
drivers/nvdimm/claim.c:65:  claimed = __nd_attach_ndns(dev, attach, _ndns);
drivers/nvdimm/claim.c:216: if (!__nd_attach_ndns(dev, ndns, _ndns)) { 
drivers/nvdimm/nd-core.h:139:bool nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
drivers/nvdimm/nd-core.h:141:bool __nd_attach_ndns(struct device *dev, struct nd_namespace_common *attach,
drivers/nvdimm/btt_devs.c:211:  if (ndns && !__nd_attach_ndns(&nd_btt->dev, ndns, &nd_btt->ndns)) {
drivers/nvdimm/pfn_devs.c:311:  if (ndns && !__nd_attach_ndns(&nd_pfn->dev, ndns, &nd_pfn->ndns)) {
---- nd_region_conflict[^A-Z_a-z] ----
drivers/nvdimm/nd-core.h:130:int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,
drivers/nvdimm/region_devs.c:1260:int nd_region_conflict(struct nd_region *nd_region, resource_size_t start,


Scripts
  (Which I've not run for a few months, I'm still working through
the first main run)

I start with:
  find . -name \*.o -exec ~/sym/dosyms {} \;
of which dosyms is:
--------
  echo $1
  DIR=$(dirname $1)
  NEWN=$DIR/$(basename -s .o $1).x

  readelf -W -s -r $1 | awk -f ~/sym/relocs.awk |sort|uniq > $NEWN
--------
so that gets me a load of .x files, which I run through
  awk -f ~/sym/collate.awk $(find . -name \*.x) > col
of which collate.awk is:
--------
  { if (($1=="u") || ($1=="U")) {
      use[$2]=use[$2] "," FILENAME
      usecount[$2]++
    } else {
      def[$2]=def[$2] ",:" $1 ":" FILENAME
      defcount[$2]++
    }
  }
  END {
    for (s in def) {
      if (usecount[s] == 0) {
        printf("%s:%d: %s from %s\n", s, usecount[s], use[s], def[s]) 
      }
    }
  }
--------
Then the following magic:
  cut -d' ' -f1 col | sed -e 's/:.*/[^A-Z_a-z]/' | while read SYM; do echo $SYM; ag -s --ignore '*.x' --ignore col --ignore col2 "$SYM" < /dev/null; done > search.out

which gives the output shown above.
(ag is a fast parallel grep, 'the-silver-searcher' )

> Thanks,
> Alison

Have fun,

Dave
> 
> > 
> > Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
> > 
> > 
> > Dr. David Alan Gilbert (2):
> >   libnvdimm: Remove unused nd_region_conflict
> >   libnvdimm: Remove unused nd_attach_ndns
> > 
> >  drivers/nvdimm/claim.c       | 11 ----------
> >  drivers/nvdimm/nd-core.h     |  4 ----
> >  drivers/nvdimm/region_devs.c | 41 ------------------------------------
> >  3 files changed, 56 deletions(-)
> > 
> > -- 
> > 2.48.1
> > 
> > 
-- 
 -----Open up your eyes, open up your mind, open up your code -------   
/ Dr. David Alan Gilbert    |       Running GNU/Linux       | Happy  \ 
\        dave @ treblig.org |                               | In Hex /
 \ _________________________|_____ http://www.treblig.org   |_______/