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authorPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>2021-08-18 10:49:52 +0800
committerVinod Koul <vkoul@kernel.org>2021-08-23 17:40:33 +0530
commitea6942dad4b2a7e1735aa0f10f3d0b04b847750f (patch)
treef6c41ea740884ada64ea62aaf39c4ab9562e3094 /drivers/soundwire
parentdd81e7c3f0bb4fbe48b770b389ab6ccb95058dab (diff)
soundwire: intel: fix potential race condition during power down
The power down sequence sets the link_up flag as false outside of the mutex_lock. This is potentially unsafe. In additional the flow in that sequence can be improved by first testing if the link was powered, setting the link_up flag as false and proceeding with the power down. In case the CPA bits cannot be cleared, we only flag an error since we cannot deal with interrupts any longer. Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@linux.intel.com> Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Link: https://lore.kernel.org/r/20210818024954.16873-2-yung-chuan.liao@linux.intel.com Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'drivers/soundwire')
-rw-r--r--drivers/soundwire/intel.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/drivers/soundwire/intel.c b/drivers/soundwire/intel.c
index 9794bc222fb5..808dda1380c2 100644
--- a/drivers/soundwire/intel.c
+++ b/drivers/soundwire/intel.c
@@ -538,12 +538,14 @@ static int intel_link_power_down(struct sdw_intel *sdw)
mutex_lock(sdw->link_res->shim_lock);
- intel_shim_master_ip_to_glue(sdw);
-
if (!(*shim_mask & BIT(link_id)))
dev_err(sdw->cdns.dev,
"%s: Unbalanced power-up/down calls\n", __func__);
+ sdw->cdns.link_up = false;
+
+ intel_shim_master_ip_to_glue(sdw);
+
*shim_mask &= ~BIT(link_id);
if (!*shim_mask) {
@@ -560,18 +562,19 @@ static int intel_link_power_down(struct sdw_intel *sdw)
link_control &= spa_mask;
ret = intel_clear_bit(shim, SDW_SHIM_LCTL, link_control, cpa_mask);
+ if (ret < 0) {
+ dev_err(sdw->cdns.dev, "%s: could not power down link\n", __func__);
+
+ /*
+ * we leave the sdw->cdns.link_up flag as false since we've disabled
+ * the link at this point and cannot handle interrupts any longer.
+ */
+ }
}
mutex_unlock(sdw->link_res->shim_lock);
- if (ret < 0) {
- dev_err(sdw->cdns.dev, "%s: could not power down link\n", __func__);
-
- return ret;
- }
-
- sdw->cdns.link_up = false;
- return 0;
+ return ret;
}
static void intel_shim_sync_arm(struct sdw_intel *sdw)