[PATCH v2 0/9] encode the values directly in the table entry

From: wenyang . linux
Date: Sat Mar 09 2024 - 05:33:06 EST


From: Wen Yang <wenyang.linux@xxxxxxxxxxx>

The boundary check of multiple modules uses these static variables (such as
two_five_five, n_65535, ue_int_max, etc), and they are also not changed.

Eric points out: "by turning .extra1 and .extra2 into longs instead of
keeping them as pointers and needing constants to be pointed at somewhere
.. The only people I can see who find a significant benefit by
consolidating all of the constants into one place are people who know how
to stomp kernel memory."

This patch series achieves direct encoding values in table entries and still
maintains compatibility with existing extra1/extra2 pointers.
Afterwards, we can remove these unnecessary static variables progressively and
also gradually kill the shared const array.

Wen Yang (9):
sysctl: support encoding values directly in the table entry
kernel/sysctl-test: add some kunit test cases for min/max detection
rxrpc: delete these unnecessary static variables n_65535, four,
max_500, etc
net: ipv6: delete these unnecessary static variables two_five_five and
minus_one
svcrdma: delete these unnecessary static variables min_ord, max_ord,
etc
sysctl: delete these unnecessary static variables i_zero and
i_one_hundred
epoll: delete these unnecessary static variables long_zero and
long_max
fs: inotify: delete these unnecessary static variables it_zero and
it_int_max
ucounts: delete these unnecessary static variables ue_zero and
ue_int_max

fs/eventpoll.c | 19 +-
fs/notify/inotify/inotify_user.c | 49 +++--
include/linux/sysctl.h | 108 ++++++++++-
kernel/sysctl-test.c | 300 +++++++++++++++++++++++++++++++
kernel/sysctl.c | 61 +++++--
kernel/ucount.c | 8 +-
lib/test_sysctl.c | 12 +-
net/ipv6/addrconf.c | 15 +-
net/rxrpc/sysctl.c | 169 ++++++++---------
net/sunrpc/xprtrdma/svc_rdma.c | 21 +--
10 files changed, 571 insertions(+), 191 deletions(-)

Cc: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Joel Granados <j.granados@xxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx

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