Revert "ethtool: Fix mod state of verbose no_mask bitset"

This reverts commit 108a36d07c01edbc5942d27c92494d1c6e4d45a0.

It was reported that this fix breaks the possibility to remove existing WoL
flags. For example:
~$ ethtool lan2
...
        Supports Wake-on: pg
        Wake-on: d
...
~$ ethtool -s lan2 wol gp
~$ ethtool lan2
...
        Wake-on: pg
...
~$ ethtool -s lan2 wol d
~$ ethtool lan2
...
        Wake-on: pg
...

This worked correctly before this commit because we were always updating
a zero bitmap (since commit 6699170376ab ("ethtool: fix application of
verbose no_mask bitset"), that is) so that the rest was left zero
naturally. But now the 1->0 change (old_val is true, bit not present in
netlink nest) no longer works.

Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Closes: https://lore.kernel.org/netdev/20231019095140.l6fffnszraeb6iiw@lion.mk-sys.cz/
Cc: stable@vger.kernel.org
Fixes: 108a36d07c01 ("ethtool: Fix mod state of verbose no_mask bitset")
Signed-off-by: Kory Maincent <kory.maincent@bootlin.com>
Reviewed-by: Michal Kubecek <mkubecek@suse.cz>
Link: https://lore.kernel.org/r/20231019-feature_ptp_bitset_fix-v1-1-70f3c429a221@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/ethtool/bitset.c b/net/ethtool/bitset.c
index 883ed9b..0515d66 100644 (file)
--- a/net/ethtool/bitset.c
+++ b/net/ethtool/bitset.c
@@ -431,10 +431,8 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
                              ethnl_string_array_t names,
                              struct netlink_ext_ack *extack, bool *mod)
 {
-       u32 *orig_bitmap, *saved_bitmap = NULL;
        struct nlattr *bit_attr;
        bool no_mask;
-       bool dummy;
        int rem;
        int ret;
 
@@ -450,22 +448,8 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
        }
 
        no_mask = tb[ETHTOOL_A_BITSET_NOMASK];
-       if (no_mask) {
-               unsigned int nwords = DIV_ROUND_UP(nbits, 32);
-               unsigned int nbytes = nwords * sizeof(u32);
-
-               /* The bitmap size is only the size of the map part without
-                * its mask part.
-                */
-               saved_bitmap = kcalloc(nwords, sizeof(u32), GFP_KERNEL);
-               if (!saved_bitmap)
-                       return -ENOMEM;
-               memcpy(saved_bitmap, bitmap, nbytes);
-               ethnl_bitmap32_clear(bitmap, 0, nbits, &dummy);
-               orig_bitmap = saved_bitmap;
-       } else {
-               orig_bitmap = bitmap;
-       }
+       if (no_mask)
+               ethnl_bitmap32_clear(bitmap, 0, nbits, mod);
 
        nla_for_each_nested(bit_attr, tb[ETHTOOL_A_BITSET_BITS], rem) {
                bool old_val, new_val;
@@ -474,14 +458,13 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
                if (nla_type(bit_attr) != ETHTOOL_A_BITSET_BITS_BIT) {
                        NL_SET_ERR_MSG_ATTR(extack, bit_attr,
                                            "only ETHTOOL_A_BITSET_BITS_BIT allowed in ETHTOOL_A_BITSET_BITS");
-                       ret = -EINVAL;
-                       goto out;
+                       return -EINVAL;
                }
                ret = ethnl_parse_bit(&idx, &new_val, nbits, bit_attr, no_mask,
                                      names, extack);
                if (ret < 0)
-                       goto out;
-               old_val = orig_bitmap[idx / 32] & ((u32)1 << (idx % 32));
+                       return ret;
+               old_val = bitmap[idx / 32] & ((u32)1 << (idx % 32));
                if (new_val != old_val) {
                        if (new_val)
                                bitmap[idx / 32] |= ((u32)1 << (idx % 32));
@@ -491,10 +474,7 @@ ethnl_update_bitset32_verbose(u32 *bitmap, unsigned int nbits,
                }
        }
 
-       ret = 0;
-out:
-       kfree(saved_bitmap);
-       return ret;
+       return 0;
 }
 
 static int ethnl_compact_sanity_checks(unsigned int nbits,