From: "Paul E. McKenney" <paulmck@linux.ibm.com>
To: rcu@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
jiangshanlai@gmail.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
fweisbec@gmail.com, oleg@redhat.com, joel@joelfernandes.org,
"Paul E . McKenney" <paulmck@linux.ibm.com>
Subject: [PATCH tip/core/rcu 7/8] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator
Date: Thu, 1 Aug 2019 15:42:57 -0700 [thread overview]
Message-ID: <20190801224258.16679-7-paulmck@linux.ibm.com> (raw)
In-Reply-To: <20190801224240.GA16092@linux.ibm.com>
From: "Joel Fernandes (Google)" <joel@joelfernandes.org>
The pcm_mmcfg_list is traversed by list_for_each_entry_rcu() outside
of an RCU read-side critical section, which is safe because the
pci_mmcfg_lock is held. This commit therefore adds a lockdep expression
to list_for_each_entry_rcu() in order t avoid lockdep warnings.
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
---
arch/x86/pci/mmconfig-shared.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
index 7389db538c30..6fa42e9c4e6f 100644
--- a/arch/x86/pci/mmconfig-shared.c
+++ b/arch/x86/pci/mmconfig-shared.c
@@ -29,6 +29,7 @@
static bool pci_mmcfg_running_state;
static bool pci_mmcfg_arch_init_failed;
static DEFINE_MUTEX(pci_mmcfg_lock);
+#define pci_mmcfg_lock_held() lock_is_held(&(pci_mmcfg_lock).dep_map)
LIST_HEAD(pci_mmcfg_list);
@@ -54,7 +55,7 @@ static void list_add_sorted(struct pci_mmcfg_region *new)
struct pci_mmcfg_region *cfg;
/* keep list sorted by segment and starting bus number */
- list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list) {
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list, pci_mmcfg_lock_held()) {
if (cfg->segment > new->segment ||
(cfg->segment == new->segment &&
cfg->start_bus >= new->start_bus)) {
@@ -118,7 +119,7 @@ struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus)
{
struct pci_mmcfg_region *cfg;
- list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
+ list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list, pci_mmcfg_lock_held())
if (cfg->segment == segment &&
cfg->start_bus <= bus && bus <= cfg->end_bus)
return cfg;
--
2.17.1
next prev parent reply other threads:[~2019-08-01 22:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-01 22:42 [PATCH tip/core/rcu 0/8] RCU list-traversal lockdep updates for v5.4 Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 1/8] treewide: Rename rcu_dereference_raw_notrace() to _check() Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 2/8] rcu: Remove redundant debug_locks check in rcu_read_lock_sched_held() Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 3/8] rcu: Add support for consolidated-RCU reader checking Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 4/8] rcu/sync: Remove custom check for RCU readers Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 5/8] ipv4: Add lockdep condition to fix for_each_entry() Paul E. McKenney
2019-08-01 22:42 ` [PATCH tip/core/rcu 6/8] driver/core: Convert to use built-in RCU list checking Paul E. McKenney
2019-08-01 22:42 ` Paul E. McKenney [this message]
2019-08-01 22:42 ` [PATCH tip/core/rcu 8/8] acpi: Use built-in RCU list checking for acpi_ioremaps list Paul E. McKenney
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