linux-kernel - [PATCH] fs/resctl: use for_each_bit_from() in __check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250719213424.403632-1-yury.norov@gmail.com>
Date: Sat, 19 Jul 2025 17:34:23 -0400
From: Yury Norov <yury.norov@...il.com>
To: Tony Luck <tony.luck@...el.com>,
	Reinette Chatre <reinette.chatre@...el.com>,
	Dave Martin <Dave.Martin@....com>,
	James Morse <james.morse@....com>,
	linux-kernel@...r.kernel.org
Cc: Yury Norov <yury.norov@...il.com>
Subject: [PATCH] fs/resctl: use for_each_bit_from() in __check_limbo()

From: Yury Norov (NVIDIA) <yury.norov@...il.com>

The function opencodes for_each_set_bit_from(). Switch to the dedicated
macro, and drop some housekeeping code.

While there, switch to non-atomic __clear_bit(), because atomicity is
not possible in this context, and that may confuse readers.

Signed-off-by: Yury Norov (NVIDIA) <yury.norov@...il.com>
---
 fs/resctrl/monitor.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/fs/resctrl/monitor.c b/fs/resctrl/monitor.c
index f5637855c3ac..3e1c14214ea8 100644
--- a/fs/resctrl/monitor.c
+++ b/fs/resctrl/monitor.c
@@ -135,7 +135,7 @@ void __check_limbo(struct rdt_mon_domain *d, bool force_free)
 	struct rdt_resource *r = resctrl_arch_get_resource(RDT_RESOURCE_L3);
 	u32 idx_limit = resctrl_arch_system_num_rmid_idx();
 	struct rmid_entry *entry;
-	u32 idx, cur_idx = 1;
+	u32 idx = 1;
 	void *arch_mon_ctx;
 	bool rmid_dirty;
 	u64 val = 0;
@@ -153,11 +153,7 @@ void __check_limbo(struct rdt_mon_domain *d, bool force_free)
 	 * is less than the threshold decrement the busy counter of the
 	 * RMID and move it to the free list when the counter reaches 0.
 	 */
-	for (;;) {
-		idx = find_next_bit(d->rmid_busy_llc, idx_limit, cur_idx);
-		if (idx >= idx_limit)
-			break;
-
+	for_each_set_bit_from(idx, d->rmid_busy_llc, idx_limit) {
 		entry = __rmid_entry(idx);
 		if (resctrl_arch_rmid_read(r, d, entry->closid, entry->rmid,
 					   QOS_L3_OCCUP_EVENT_ID, &val,
@@ -178,11 +174,10 @@ void __check_limbo(struct rdt_mon_domain *d, bool force_free)
 		}
 
 		if (force_free || !rmid_dirty) {
-			clear_bit(idx, d->rmid_busy_llc);
+			__clear_bit(idx, d->rmid_busy_llc);
 			if (!--entry->busy)
 				limbo_release_entry(entry);
 		}
-		cur_idx = idx + 1;
 	}
 
 	resctrl_arch_mon_ctx_free(r, QOS_L3_OCCUP_EVENT_ID, arch_mon_ctx);
-- 
2.43.0