Re: [PATCH] crash_dump: Constify struct configfs_item_operations and configfs_group_operations

[Christophe JAILLET]

Le 15/12/2025 à 03:13, Baoquan He a écrit :
On 12/14/25 at 06:57pm, Christophe JAILLET wrote:
'struct configfs_item_operations' and 'configfs_group_operations' are not
modified in this driver.
Constifying these structures moves some data to a read-only section, so
increases overall security, especially when the structure holds some
function pointers.

On a x86_64, with allmodconfig, as an example:
Before:
======
    text           data     bss     dec     hex filename
   16339          11001     384   27724    6c4c kernel/crash_dump_dm_crypt.o

After:
=====
    text           data     bss     dec     hex filename
   16499          10841     384   27724    6c4c kernel/crash_dump_dm_crypt.o

Signed-off-by: Christophe JAILLET <christophe.jail...@wanadoo.fr>

Sounds not bad, leave this to Coiby to test.

---
Compile tested only.

This change is possible since commits f2f36500a63b and f7f78098690d.

I don't follow here, why do these two commits have anything with this
patch?

Without these patches, it won't compile because "struct 
config_item_type" needs to be tweaked to accept some const field. It is 
what is done by these patches that have landed 2 weeks ago or so.


Without these 2 commits, you would get (with French messages, sorry):

  CC      kernel/crash_dump_dm_crypt.o
kernel/crash_dump_dm_crypt.c:231:24: erreur: l'initialisation abandonne 
le qualificatif « const » du type pointé [-Werror=discarded-qualifiers]
  231 |         .ct_item_ops = &config_key_item_ops,
      |                        ^
kernel/crash_dump_dm_crypt.c:306:25: erreur: l'initialisation abandonne 
le qualificatif « const » du type pointé [-Werror=discarded-qualifiers]
  306 |         .ct_group_ops = &config_keys_group_ops,
      |                         ^

CJ


---
  kernel/crash_dump_dm_crypt.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/crash_dump_dm_crypt.c b/kernel/crash_dump_dm_crypt.c
index 401423ba477d..0d23dc1de67c 100644
--- a/kernel/crash_dump_dm_crypt.c
+++ b/kernel/crash_dump_dm_crypt.c
@@ -223,7 +223,7 @@ static void config_key_release(struct config_item *item)
        key_count--;
  }
  
-static struct configfs_item_operations config_key_item_ops = {
+static const struct configfs_item_operations config_key_item_ops = {
        .release = config_key_release,
  };
  
@@ -298,7 +298,7 @@ static struct configfs_attribute *config_keys_attrs[] = {
   * Note that, since no extra work is required on ->drop_item(),
   * no ->drop_item() is provided.
   */
-static struct configfs_group_operations config_keys_group_ops = {
+static const struct configfs_group_operations config_keys_group_ops = {
        .make_item = config_keys_make_item,
  };
  
--
2.52.0