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From: ebiederm@xmission.com (Eric W. Biederman)
To: Alexey Gladkov <legion@kernel.org>
Cc: Rune Kleveland <rune.kleveland@infomedia.dk>,
	Yu Zhao <yuzhao@google.com>,
	Jordan Glover <Golden_Miller83@protonmail.ch>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-mm@kvack.org, containers@lists.linux-foundation.org,
	Hillf Danton <hdanton@sina.com>
Subject: [PATCH 4/4] ucounts: Use atomic_long_sub_return for clarity
Date: Mon, 18 Oct 2021 12:57:24 -0500	[thread overview]
Message-ID: <87k0iaqkqj.fsf_-_@disp2133> (raw)
In-Reply-To: <877dearzfo.fsf_-_@disp2133> (Eric W. Biederman's message of "Mon, 18 Oct 2021 12:54:35 -0500")


Decrement ucounts using atomic_long_sub_return to make it
clear the point is for the ucount to decrease.

Not a big deal but it should make it easier to catch bugs.

Suggested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
 kernel/ucount.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/ucount.c b/kernel/ucount.c
index 133b6044fda4..4f5613dac227 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -282,7 +282,7 @@ bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v)
 	struct ucounts *iter;
 	long new = -1; /* Silence compiler warning */
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		long dec = atomic_long_add_return(-v, &iter->ucount[type]);
+		long dec = atomic_long_sub_return(v, &iter->ucount[type]);
 		WARN_ON_ONCE(dec < 0);
 		if (iter == ucounts)
 			new = dec;
@@ -295,7 +295,7 @@ static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
 {
 	struct ucounts *iter, *next;
 	for (iter = ucounts; iter != last; iter = next) {
-		long dec = atomic_long_add_return(-1, &iter->ucount[type]);
+		long dec = atomic_long_sub_return(1, &iter->ucount[type]);
 		WARN_ON_ONCE(dec < 0);
 		next = iter->ns->ucounts;
 		if (dec == 0)
@@ -332,7 +332,7 @@ long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum ucount_type type)
 	}
 	return ret;
 dec_unwind:
-	dec = atomic_long_add_return(-1, &iter->ucount[type]);
+	dec = atomic_long_sub_return(1, &iter->ucount[type]);
 	WARN_ON_ONCE(dec < 0);
 unwind:
 	do_dec_rlimit_put_ucounts(ucounts, iter, type);
-- 
2.20.1


  parent reply	other threads:[~2021-10-18 17:57 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-15 19:49 linux 5.14.3: free_user_ns causes NULL pointer dereference Jordan Glover
2021-09-15 21:02 ` Eric W. Biederman
2021-09-15 22:42   ` Jordan Glover
2021-09-15 23:44     ` Yu Zhao
2021-09-17 16:15       ` Eric W. Biederman
2021-09-17 18:45         ` Yu Zhao
2021-09-15 23:47     ` Jordan Glover
2021-09-16 17:30       ` Eric W. Biederman
2021-09-16 19:14         ` Alexey Gladkov
2021-09-28 13:40         ` Jordan Glover
2021-09-29 17:36           ` Alexey Gladkov
2021-09-29 21:39             ` Jordan Glover
2021-09-30 13:06               ` Alexey Gladkov
2021-09-30 22:27                 ` Yu Zhao
2021-10-04 17:10                   ` Eric W. Biederman
2021-10-04 17:19                     ` Eric W. Biederman
2021-10-04 21:34                       ` Yu Zhao
2021-10-11 13:39                       ` Alexey Gladkov
     [not found]                       ` <ccbccf82-dc50-00b2-1cfd-3da5e2c81dbf@infomedia.dk>
2021-10-12 17:31                         ` Eric W. Biederman
2021-10-15 22:10                         ` [CFT][PATCH] ucounts: Fix signal ucount refcounting Eric W. Biederman
2021-10-15 23:09                           ` Alexey Gladkov
2021-10-16 17:34                             ` Eric W. Biederman
2021-10-17 19:35                               ` Yu Zhao
2021-10-18 15:35                                 ` Eric W. Biederman
2021-10-17 16:47                           ` Rune Kleveland
2021-10-18  6:25                             ` Yu Zhao
2021-10-18 10:31                               ` Jordan Glover
2021-10-18 16:06                           ` [PATCH v2] " Eric W. Biederman
2021-10-18 17:21                             ` [PATCH 0/3] ucounts: misc fixes Eric W. Biederman
2021-10-18 17:23                               ` [PATCH 1/3] ucounts: Pair inc_rlimit_ucounts with dec_rlimit_ucoutns in commit_creds Eric W. Biederman
2021-10-18 17:23                               ` [PATCH 2/3] ucounts: Proper error handling in set_cred_ucounts Eric W. Biederman
2021-10-18 17:24                               ` [PATCH 3/3] ucounts: Move get_ucounts from cred_alloc_blank to key_change_session_keyring Eric W. Biederman
2021-10-18 17:54                               ` [PATCH 0/4] ucounts: misc cleanups Eric W. Biederman
2021-10-18 17:55                                 ` [PATCH 1/4] ucounts: In set_cred_ucounts assume new->ucounts is non-NULL Eric W. Biederman
2021-10-18 17:56                                 ` [PATCH 2/4] ucounts: Remove unnecessary test for NULL ucount in get_ucounts Eric W. Biederman
2021-10-18 17:56                                 ` [PATCH 3/4] ucounts: Add get_ucounts_or_wrap for clarity Eric W. Biederman
2021-10-18 17:57                                 ` Eric W. Biederman [this message]
2021-10-18 22:29                                 ` [PATCH 0/4] ucounts: misc cleanups Yu Zhao
2021-10-18 22:28                               ` [PATCH 0/3] ucounts: misc fixes Yu Zhao
2021-10-18 22:26                             ` [PATCH v2] ucounts: Fix signal ucount refcounting Yu Zhao
     [not found]                         ` <20211016020833.1538-1-hdanton@sina.com>
2021-10-16 18:00                           ` [CFT][PATCH] " Eric W. Biederman
     [not found]                   ` <20211006021219.2010-1-hdanton@sina.com>
2021-10-06  6:22                     ` linux 5.14.3: free_user_ns causes NULL pointer dereference Yu Zhao
2021-10-07 13:28                     ` Jordan Glover
2021-10-03 19:37             ` Jordan Glover

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