[PATCH 1/3] staging: greybus: loopback.c: remove unused gb_loopback::lbid

From: Rasmus Villemoes
Date: Fri Oct 05 2018 - 10:28:34 EST


It's not obvious how the code prevents adding more than 31 elements to
the list and thus invoking undefined behaviour in the 1 << new_lbid
expression, and in practice causing ->lbid values to repeat every 32
elements.

But the definition of struct gb_loopback is local to loopback.c, and the
lbid field is entirely unused outside of this function, so it seems we
can just drop it entirely.

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
Since lbid isn't mentioned anywhere else in greybus/, it's hard to
figure out how it was meant to be used. It does seem like entirely
dead (write-only) code.

drivers/staging/greybus/loopback.c | 8 --------
1 file changed, 8 deletions(-)

diff --git a/drivers/staging/greybus/loopback.c b/drivers/staging/greybus/loopback.c
index 42f6f3de967c..7080294f705c 100644
--- a/drivers/staging/greybus/loopback.c
+++ b/drivers/staging/greybus/loopback.c
@@ -97,7 +97,6 @@ struct gb_loopback {
u32 timeout_min;
u32 timeout_max;
u32 outstanding_operations_max;
- u32 lbid;
u64 elapsed_nsecs;
u32 apbridge_latency_ts;
u32 gbphy_latency_ts;
@@ -1014,16 +1013,9 @@ static int gb_loopback_bus_id_compare(void *priv, struct list_head *lha,

static void gb_loopback_insert_id(struct gb_loopback *gb)
{
- struct gb_loopback *gb_list;
- u32 new_lbid = 0;
-
/* perform an insertion sort */
list_add_tail(&gb->entry, &gb_dev.list);
list_sort(NULL, &gb_dev.list, gb_loopback_bus_id_compare);
- list_for_each_entry(gb_list, &gb_dev.list, entry) {
- gb_list->lbid = 1 << new_lbid;
- new_lbid++;
- }
}

#define DEBUGFS_NAMELEN 32
--
2.19.0