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From:   Alexey Gladkov <gladkov.alexey@gmail.com>
To:     LKML <linux-kernel@vger.kernel.org>,
        Linux Containers <containers@lists.linux-foundation.org>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc:     Alexey Gladkov <legion@kernel.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Kees Cook <keescook@chromium.org>,
        Christian Brauner <christian@brauner.io>,
        Linus Torvalds <torvalds@linux-foundation.org>
Subject: [RFC PATCH v2 3/8] Increase size of ucounts to atomic_long_t
Date:   Sun, 10 Jan 2021 18:33:42 +0100
Message-Id: <2868ed8e8f196ae6ff4de60934668483680df14d.1610299857.git.gladkov.alexey@gmail.com>
In-Reply-To: <cover.1610299857.git.gladkov.alexey@gmail.com>
References: <cover.1610299857.git.gladkov.alexey@gmail.com>
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This commit is preparation for migrating rlimits counters to ucounts.

Signed-off-by: Alexey Gladkov <gladkov.alexey@gmail.com>
---
 include/linux/user_namespace.h |  4 ++--
 kernel/ucount.c                | 14 +++++++-------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 483568a56f7f..24b850c7b70e 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -85,7 +85,7 @@ struct user_namespace {
 	struct ctl_table_header *sysctls;
 #endif
 	struct ucounts		*ucounts;
-	int ucount_max[UCOUNT_COUNTS];
+	long ucount_max[UCOUNT_COUNTS];
 } __randomize_layout;
 
 struct ucounts {
@@ -93,7 +93,7 @@ struct ucounts {
 	struct user_namespace *ns;
 	kuid_t uid;
 	atomic_t count;
-	atomic_t ucount[UCOUNT_COUNTS];
+	atomic_long_t ucount[UCOUNT_COUNTS];
 };
 
 extern struct user_namespace init_user_ns;
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 80a39073bcef..4c5825ffd2e9 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -185,14 +185,14 @@ void set_cred_ucounts(const struct cred *cred, struct user_namespace *ns, kuid_t
 	((struct cred *) cred)->ucounts = get_ucounts(ns, uid);
 }
 
-static inline bool atomic_inc_below(atomic_t *v, int u)
+static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
 {
-	int c, old;
-	c = atomic_read(v);
+	long c, old;
+	c = atomic_long_read(v);
 	for (;;) {
 		if (unlikely(c >= u))
 			return false;
-		old = atomic_cmpxchg(v, c, c+1);
+		old = atomic_long_cmpxchg(v, c, c+1);
 		if (likely(old == c))
 			return true;
 		c = old;
@@ -209,14 +209,14 @@ struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
 		int max;
 		tns = iter->ns;
 		max = READ_ONCE(tns->ucount_max[type]);
-		if (!atomic_inc_below(&iter->ucount[type], max))
+		if (!atomic_long_inc_below(&iter->ucount[type], max))
 			goto fail;
 	}
 	return ucounts;
 fail:
 	bad = iter;
 	for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
-		atomic_dec(&iter->ucount[type]);
+		atomic_long_dec(&iter->ucount[type]);
 
 	put_ucounts(ucounts);
 	return NULL;
@@ -226,7 +226,7 @@ void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
 {
 	struct ucounts *iter;
 	for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-		int dec = atomic_dec_if_positive(&iter->ucount[type]);
+		int dec = atomic_long_dec_if_positive(&iter->ucount[type]);
 		WARN_ON_ONCE(dec < 0);
 	}
 	put_ucounts(ucounts);
-- 
2.29.2