[PATCH 1.5/3] Remove unused map-of-maps functions

[PATCH 1.5/3] Remove unused map-of-maps functions

[eugene.loh]

From: Eugene Loh <eugene.loh@oracle.com>

Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
---
 libdtrace/dt_bpf.c | 57 ----------------------------------------------
 libdtrace/dt_bpf.h |  5 ----
 2 files changed, 62 deletions(-)

diff --git a/libdtrace/dt_bpf.c b/libdtrace/dt_bpf.c
index 635780738..4e4b6eb87 100644
--- a/libdtrace/dt_bpf.c
+++ b/libdtrace/dt_bpf.c
@@ -341,63 +341,6 @@ dt_bpf_map_update(int fd, const void *key, const void *val)
 	return dt_bpf(BPF_MAP_UPDATE_ELEM, &attr);
 }
 
-/*
- * Retrieve the fd for a map-in-map, i.e. map[okey] which is the fd of a map.
- *
- * Note: the caller is responsible for closing the fd.
- */
-int
-dt_bpf_map_lookup_fd(int fd, const void *okey)
-{
-	uint32_t	id;
-
-	if (dt_bpf_map_lookup(fd, okey, &id) < 0)
-		return -1;
-
-	return dt_bpf_map_get_fd_by_id(id);
-}
-
-/*
- * Retrieve the value in a map-of-maps, i.e. map[okey][ikey].
- */
-int
-dt_bpf_map_lookup_inner(int fd, const void *okey, const void *ikey, void *val)
-{
-	int		rc;
-
-	fd = dt_bpf_map_lookup_fd(fd, okey);
-	if (fd < 0)
-		return -1;
-
-	rc = dt_bpf_map_lookup(fd, ikey, val);
-	close(fd);
-
-	return rc;
-}
-
-/*
- * Store the value in a map-of-maps, i.e. map[okey][ikey] = value.
- */
-int
-dt_bpf_map_update_inner(int fd, const void *okey, const void *ikey,
-			const void *val)
-{
-	uint32_t	id;
-	int		rc;
-
-	if (dt_bpf_map_lookup(fd, okey, &id) < 0)
-		return -1;
-
-	fd = dt_bpf_map_get_fd_by_id(id);
-	if (fd < 0)
-		return -1;
-
-	rc = dt_bpf_map_update(fd, ikey, val);
-	close(fd);
-
-	return rc;
-}
-
 /*
  * Associate a BPF program (by fd) with a raw tracepoint.
  */
diff --git a/libdtrace/dt_bpf.h b/libdtrace/dt_bpf.h
index e03c5c6d9..43fb2233e 100644
--- a/libdtrace/dt_bpf.h
+++ b/libdtrace/dt_bpf.h
@@ -80,11 +80,6 @@ extern int dt_bpf_map_next_key(int fd, const void *key, void *nxt);
 extern int dt_bpf_map_update(int fd, const void *key, const void *val);
 extern int dt_bpf_map_delete(int fd, const void *key);
 extern int dt_bpf_map_get_fd_by_id(uint32_t id);
-extern int dt_bpf_map_lookup_fd(int fd, const void *okey);
-extern int dt_bpf_map_lookup_inner(int fd, const void *okey, const void *ikey,
-				   void *val);
-extern int dt_bpf_map_update_inner(int fd, const void *okey, const void *ikey,
-				   const void *val);
 extern int dt_bpf_prog_attach(enum bpf_prog_type ptype,
 			      enum bpf_attach_type atype, int btf_fd,
 			      uint32_t btf_id, const dtrace_difo_t *dp,
-- 
2.43.5

Re: [DTrace-devel] [PATCH 1.5/3] Remove unused map-of-maps functions

[Nick Alcock]

On 1 May 2025, eugene loh outgrape:

> From: Eugene Loh <eugene.loh@oracle.com>
>
> Signed-off-by: Eugene Loh <eugene.loh@oracle.com>

Reviewed-by: Nick Alcock <nick.alcock@oracle.com>

-- 
NULL && (void)

Re: [DTrace-devel] [PATCH 1.5/3] Remove unused map-of-maps functions

[Kris Van Hees]

On Wed, Jul 16, 2025 at 02:50:08PM +0100, Nick Alcock wrote:
> On 1 May 2025, eugene loh outgrape:
> 
> > From: Eugene Loh <eugene.loh@oracle.com>
> >
> > Signed-off-by: Eugene Loh <eugene.loh@oracle.com>
> 
> Reviewed-by: Nick Alcock <nick.alcock@oracle.com>

While in general I am all for removing unused function, I would actually
prefer to keep these because they are part of our BPF library and likely
to be of use in the future.  Yes, we could always revert this, but it is
probably more likely that we would end up re-implementing them because
we forgot they ever existed.  Since we implement our own library to
interact with the BPF subsystem, having some extra functions around for
now for functionality that isn't immediately trivial to implement when
you deal with inner maps for the first time, can be useful.