diff mbox series

[net-next,8/9] page_pool: add a lockdep check for recycling in hardirq

Message ID 20230727144336.1646454-9-aleksander.lobakin@intel.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series page_pool: a couple of assorted optimizations | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 15861 this patch: 15861
netdev/cc_maintainers warning 5 maintainers not CCed: boqun.feng@gmail.com longman@redhat.com mingo@redhat.com peterz@infradead.org will@kernel.org
netdev/build_clang success Errors and warnings before: 4799 this patch: 4799
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 16898 this patch: 16898
netdev/checkpatch warning WARNING: Single statement macros should not use a do {} while (0) loop
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Alexander Lobakin July 27, 2023, 2:43 p.m. UTC 
From: Jakub Kicinski <kuba@kernel.org>

Page pool use in hardirq is prohibited, add debug checks
to catch misuses. IIRC we previously discussed using
DEBUG_NET_WARN_ON_ONCE() for this, but there were concerns
that people will have DEBUG_NET enabled in perf testing.
I don't think anyone enables lockdep in perf testing,
so use lockdep to avoid pushback and arguing :)

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexander Lobakin <aleksander.lobakin@intel.com>
---
 include/linux/lockdep.h | 7 +++++++
 net/core/page_pool.c    | 2 ++
 2 files changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 310f85903c91..dc2844b071c2 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -625,6 +625,12 @@  do {									\
 	WARN_ON_ONCE(__lockdep_enabled && !this_cpu_read(hardirq_context)); \
 } while (0)
 
+#define lockdep_assert_no_hardirq()					\
+do {									\
+	WARN_ON_ONCE(__lockdep_enabled && (this_cpu_read(hardirq_context) || \
+					   !this_cpu_read(hardirqs_enabled))); \
+} while (0)
+
 #define lockdep_assert_preemption_enabled()				\
 do {									\
 	WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_COUNT)	&&		\
@@ -659,6 +665,7 @@  do {									\
 # define lockdep_assert_irqs_enabled() do { } while (0)
 # define lockdep_assert_irqs_disabled() do { } while (0)
 # define lockdep_assert_in_irq() do { } while (0)
+# define lockdep_assert_no_hardirq() do { } while (0)
 
 # define lockdep_assert_preemption_enabled() do { } while (0)
 # define lockdep_assert_preemption_disabled() do { } while (0)
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 529e4b41e9eb..be9371cd9ac7 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -579,6 +579,8 @@  static __always_inline struct page *
 __page_pool_put_page(struct page_pool *pool, struct page *page,
 		     unsigned int dma_sync_size, bool allow_direct)
 {
+	lockdep_assert_no_hardirq();
+
 	/* This allocator is optimized for the XDP mode that uses
 	 * one-frame-per-page, but have fallbacks that act like the
 	 * regular page allocator APIs.