linux/fs/proc
Linus Torvalds f122a08b19 capability: just use a 'u64' instead of a 'u32[2]' array
Back in 2008 we extended the capability bits from 32 to 64, and we did
it by extending the single 32-bit capability word from one word to an
array of two words.  It was then obfuscated by hiding the "2" behind two
macro expansions, with the reasoning being that maybe it gets extended
further some day.

That reasoning may have been valid at the time, but the last thing we
want to do is to extend the capability set any more.  And the array of
values not only causes source code oddities (with loops to deal with
it), but also results in worse code generation.  It's a lose-lose
situation.

So just change the 'u32[2]' into a 'u64' and be done with it.

We still have to deal with the fact that the user space interface is
designed around an array of these 32-bit values, but that was the case
before too, since the array layouts were different (ie user space
doesn't use an array of 32-bit values for individual capability masks,
but an array of 32-bit slices of multiple masks).

So that marshalling of data is actually simplified too, even if it does
remain somewhat obscure and odd.

This was all triggered by my reaction to the new "cap_isidentical()"
introduced recently.  By just using a saner data structure, it went from

	unsigned __capi;
	CAP_FOR_EACH_U32(__capi) {
		if (a.cap[__capi] != b.cap[__capi])
			return false;
	}
	return true;

to just being

	return a.val == b.val;

instead.  Which is rather more obvious both to humans and to compilers.

Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: Serge Hallyn <serge@hallyn.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Moore <paul@paul-moore.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2023-03-01 10:01:22 -08:00
..
array.c capability: just use a 'u64' instead of a 'u32[2]' array 2023-03-01 10:01:22 -08:00
base.c fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00
bootconfig.c proc: bootconfig: Add null pointer check 2022-04-02 08:40:09 -04:00
cmdline.c proc: mark /proc/cmdline as permanent 2023-02-02 22:50:02 -08:00
consoles.c proc: consoles: use console_list_lock for list iteration 2022-12-02 11:25:02 +01:00
cpuinfo.c x86/aperfmperf: Replace aperfmperf_get_khz() 2022-04-27 20:22:19 +02:00
devices.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
fd.c fs.idmapped.v6.3 2023-02-20 11:53:11 -08:00
fd.h fs: port ->permission() to pass mnt_idmap 2023-01-19 09:24:28 +01:00
generic.c fs: port ->getattr() to pass mnt_idmap 2023-01-19 09:24:25 +01:00
inode.c take care to handle NULL ->proc_lseek() 2022-08-14 15:16:18 -04:00
internal.h fs: port ->getattr() to pass mnt_idmap 2023-01-19 09:24:25 +01:00
interrupts.c
Kconfig proc: make config PROC_CHILDREN depend on PROC_FS 2022-10-03 14:21:43 -07:00
kcore.c mm: remove kern_addr_valid() completely 2022-11-08 17:37:18 -08:00
kmsg.c printk changes for 6.1 2022-10-10 11:24:19 -07:00
loadavg.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
Makefile
meminfo.c proc/meminfo: fix spacing in SecPageTables 2022-11-22 18:50:44 -08:00
namespaces.c
nommu.c proc: delete unused <linux/uaccess.h> includes 2022-07-17 17:31:39 -07:00
page.c mm: Add PG_arch_3 page flag 2022-11-29 09:26:07 +00:00
proc_net.c fs: port ->getattr() to pass mnt_idmap 2023-01-19 09:24:25 +01:00
proc_sysctl.c sysctl: fix proc_dobool() usability 2023-02-21 13:34:07 -08:00
proc_tty.c proc: delete unused <linux/uaccess.h> includes 2022-07-17 17:31:39 -07:00
root.c fs: port ->getattr() to pass mnt_idmap 2023-01-19 09:24:25 +01:00
self.c
softirqs.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
stat.c
task_mmu.c mm: replace vma->vm_flags direct modifications with modifier calls 2023-02-09 16:51:39 -08:00
task_nommu.c mm/nommu: factor out check for NOMMU shared mappings into is_nommu_shared_mapping() 2023-01-18 17:12:56 -08:00
thread_self.c
uptime.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
util.c
version.c proc: mark more files as permanent 2022-10-03 14:21:45 -07:00
vmcore.c mm: replace vma->vm_flags direct modifications with modifier calls 2023-02-09 16:51:39 -08:00