Merge tag 'mlx5-shared-2017-08-07' of git://git.kernel.org/pub/scm/linux/kernel/git/mellanox/linux

Saeed Mahameed says:

====================
mlx5-shared-2017-08-07

This series includes some mlx5 updates for both net-next and rdma trees.

From Saeed,
Core driver updates to allow selectively building the driver with
or without some large driver components, such as
	- E-Switch (Ethernet SRIOV support).
	- Multi-Physical Function Switch (MPFs) support.
For that we split E-Switch and MPFs functionalities into separate files.

From Erez,
Delay mlx5_core events when mlx5 interfaces, namely mlx5_ib, registration
is taking place and until it completes.

From Rabie,
Increase the maximum supported flow counters.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 2 deletions

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 119a3f9604b0..898cfe2eeb42 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -18,6 +18,19 @@
 
 #ifdef CONFIG_CPUSETS
 
+/*
+ * Static branch rewrites can happen in an arbitrary order for a given
+ * key. In code paths where we need to loop with read_mems_allowed_begin() and
+ * read_mems_allowed_retry() to get a consistent view of mems_allowed, we need
+ * to ensure that begin() always gets rewritten before retry() in the
+ * disabled -> enabled transition. If not, then if local irqs are disabled
+ * around the loop, we can deadlock since retry() would always be
+ * comparing the latest value of the mems_allowed seqcount against 0 as
+ * begin() still would see cpusets_enabled() as false. The enabled -> disabled
+ * transition should happen in reverse order for the same reasons (want to stop
+ * looking at real value of mems_allowed.sequence in retry() first).
+ */
+extern struct static_key_false cpusets_pre_enable_key;
 extern struct static_key_false cpusets_enabled_key;
 static inline bool cpusets_enabled(void)
 {
@@ -32,12 +45,14 @@ static inline int nr_cpusets(void)
 
 static inline void cpuset_inc(void)
 {
+	static_branch_inc(&cpusets_pre_enable_key);
 	static_branch_inc(&cpusets_enabled_key);
 }
 
 static inline void cpuset_dec(void)
 {
 	static_branch_dec(&cpusets_enabled_key);
+	static_branch_dec(&cpusets_pre_enable_key);
 }
 
 extern int cpuset_init(void);
@@ -115,7 +130,7 @@ extern void cpuset_print_current_mems_allowed(void);
  */
 static inline unsigned int read_mems_allowed_begin(void)
 {
-	if (!cpusets_enabled())
+	if (!static_branch_unlikely(&cpusets_pre_enable_key))
 		return 0;
 
 	return read_seqcount_begin(&current->mems_allowed_seq);
@@ -129,7 +144,7 @@ static inline unsigned int read_mems_allowed_begin(void)
  */
 static inline bool read_mems_allowed_retry(unsigned int seq)
 {
-	if (!cpusets_enabled())
+	if (!static_branch_unlikely(&cpusets_enabled_key))
 		return false;
 
 	return read_seqcount_retry(&current->mems_allowed_seq, seq);