[dpdk-stable] patch 'power: fix thread-safety environment modification' has been queued to LTS release 18.11.2

[Kevin Traynor]

Hi,

FYI, your patch has been queued to LTS release 18.11.2

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/13/19. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Queued patches are on a temporary branch at:
https://github.com/kevintraynor/dpdk-stable-queue

This queued commit can be viewed at:
https://github.com/kevintraynor/dpdk-stable-queue/commit/3c2019093661e477b4b01753b9d0ad0b545b13e2

Thanks.

Kevin Traynor

---
>From 3c2019093661e477b4b01753b9d0ad0b545b13e2 Mon Sep 17 00:00:00 2001
From: Marcin Hajkowski <marcinx.hajkowski at intel.com>
Date: Fri, 5 Apr 2019 16:35:35 +0200
Subject: [PATCH] power: fix thread-safety environment modification

[ upstream commit 92433e347326c4d438c69093bbfa6212b8b59d60 ]

Due to lack of thread safety in exisiting solution
use spinlock mechanism for atomic
modification of power environment related data.

Fixes: 445c6528b5 ("power: common interface for guest and host")

Signed-off-by: Marcin Hajkowski <marcinx.hajkowski at intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov at intel.com>
---
 lib/librte_power/rte_power.c | 30 +++++++++++++++++++++---------
 lib/librte_power/rte_power.h |  2 +-
 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/lib/librte_power/rte_power.c b/lib/librte_power/rte_power.c
index 208b79195..cc05b0faf 100644
--- a/lib/librte_power/rte_power.c
+++ b/lib/librte_power/rte_power.c
@@ -3,5 +3,5 @@
  */
 
-#include <rte_atomic.h>
+#include <rte_spinlock.h>
 
 #include "rte_power.h"
@@ -12,5 +12,5 @@
 enum power_management_env global_default_env = PM_ENV_NOT_SET;
 
-volatile uint32_t global_env_cfg_status = 0;
+static rte_spinlock_t global_env_cfg_lock = RTE_SPINLOCK_INITIALIZER;
 
 /* function pointers */
@@ -30,7 +30,13 @@ int
 rte_power_set_env(enum power_management_env env)
 {
-	if (rte_atomic32_cmpset(&global_env_cfg_status, 0, 1) == 0) {
+	rte_spinlock_lock(&global_env_cfg_lock);
+
+	if (global_default_env != PM_ENV_NOT_SET) {
+		rte_spinlock_unlock(&global_env_cfg_lock);
 		return 0;
 	}
+
+	int ret = 0;
+
 	if (env == PM_ENV_ACPI_CPUFREQ) {
 		rte_power_freqs = power_acpi_cpufreq_freqs;
@@ -60,9 +66,14 @@ rte_power_set_env(enum power_management_env env)
 		RTE_LOG(ERR, POWER, "Invalid Power Management Environment(%d) set\n",
 				env);
-		rte_power_unset_env();
-		return -1;
+		ret = -1;
 	}
-	global_default_env = env;
-	return 0;
+
+	if (ret == 0)
+		global_default_env = env;
+	else
+		global_default_env = PM_ENV_NOT_SET;
+
+	rte_spinlock_unlock(&global_env_cfg_lock);
+	return ret;
 
 }
@@ -71,6 +82,7 @@ void
 rte_power_unset_env(void)
 {
-	if (rte_atomic32_cmpset(&global_env_cfg_status, 1, 0) != 0)
-		global_default_env = PM_ENV_NOT_SET;
+	rte_spinlock_lock(&global_env_cfg_lock);
+	global_default_env = PM_ENV_NOT_SET;
+	rte_spinlock_unlock(&global_env_cfg_lock);
 }
 
diff --git a/lib/librte_power/rte_power.h b/lib/librte_power/rte_power.h
index d70bc0b33..d7542c3fa 100644
--- a/lib/librte_power/rte_power.h
+++ b/lib/librte_power/rte_power.h
@@ -26,5 +26,5 @@ enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM};
  * Set the default power management implementation. If this is not called prior
  * to rte_power_init(), then auto-detect of the environment will take place.
- * It is not thread safe.
+ * It is thread safe.
  *
  * @param env
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2019-05-08 11:05:07.230076661 +0100
+++ 0028-power-fix-thread-safety-environment-modification.patch	2019-05-08 11:05:05.812933117 +0100
@@ -1 +1 @@
-From 92433e347326c4d438c69093bbfa6212b8b59d60 Mon Sep 17 00:00:00 2001
+From 3c2019093661e477b4b01753b9d0ad0b545b13e2 Mon Sep 17 00:00:00 2001
@@ -5,0 +6,2 @@
+[ upstream commit 92433e347326c4d438c69093bbfa6212b8b59d60 ]
+
@@ -11 +12,0 @@
-Cc: stable at dpdk.org
@@ -16,4 +17,3 @@
- doc/guides/rel_notes/release_19_05.rst |  3 +++
- lib/librte_power/rte_power.c           | 30 ++++++++++++++++++--------
- lib/librte_power/rte_power.h           |  2 +-
- 3 files changed, 25 insertions(+), 10 deletions(-)
+ lib/librte_power/rte_power.c | 30 +++++++++++++++++++++---------
+ lib/librte_power/rte_power.h |  2 +-
+ 2 files changed, 22 insertions(+), 10 deletions(-)
@@ -21,12 +20,0 @@
-diff --git a/doc/guides/rel_notes/release_19_05.rst b/doc/guides/rel_notes/release_19_05.rst
-index 3c388da66..d5ed564ab 100644
---- a/doc/guides/rel_notes/release_19_05.rst
-+++ b/doc/guides/rel_notes/release_19_05.rst
-@@ -230,4 +230,7 @@ API Changes
-   request mapping or un-mapping to the default vfio container fd.
- 
-+* power: ``rte_power_set_env`` and ``rte_power_unset_env`` functions
-+  have been modified to be thread safe.
-+
- 
- ABI Changes
@@ -34 +22 @@
-index a05fbef94..540d69be7 100644
+index 208b79195..cc05b0faf 100644
@@ -44 +32 @@
-@@ -13,5 +13,5 @@
+@@ -12,5 +12,5 @@
@@ -51 +39 @@
-@@ -31,7 +31,13 @@ int
+@@ -30,7 +30,13 @@ int
@@ -66 +54 @@
-@@ -74,9 +80,14 @@ rte_power_set_env(enum power_management_env env)
+@@ -60,9 +66,14 @@ rte_power_set_env(enum power_management_env env)
@@ -83 +70,0 @@
- }
@@ -85 +72,2 @@
-@@ -84,6 +95,7 @@ void
+ }
+@@ -71,6 +82,7 @@ void
@@ -96 +84 @@
-index dee7af345..47db69f33 100644
+index d70bc0b33..d7542c3fa 100644
@@ -99 +87 @@
-@@ -27,5 +27,5 @@ enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM,
+@@ -26,5 +26,5 @@ enum power_management_env {PM_ENV_NOT_SET, PM_ENV_ACPI_CPUFREQ, PM_ENV_KVM_VM};