summaryrefslogtreecommitdiff
path: root/drivers/remoteproc
diff options
context:
space:
mode:
authorBjorn Andersson <bjorn.andersson@linaro.org>2020-03-24 08:29:01 +0300
committerBjorn Andersson <bjorn.andersson@linaro.org>2020-03-26 08:29:44 +0300
commitc0abe2ca3605e4c4fb25bf69d0218c63baf71d2b (patch)
tree200afc104f4c75b015d53ed481b020eea129d485 /drivers/remoteproc
parent791c13b709dd51eb37330f2a5837434e90c87c27 (diff)
downloadlinux-c0abe2ca3605e4c4fb25bf69d0218c63baf71d2b.tar.xz
remoteproc: Traverse rproc_list under RCU read lock
In order to be able to traverse the mostly read-only rproc_list without locking during panic migrate traversal to be done under rcu_read_lock(). Mutual exclusion for modifications of the list continues to be handled by the rproc_list_mutex and a synchronization point is added before releasing objects that are popped from the list. Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200324052904.738594-2-bjorn.andersson@linaro.org Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Diffstat (limited to 'drivers/remoteproc')
-rw-r--r--drivers/remoteproc/remoteproc_core.c14
1 files changed, 9 insertions, 5 deletions
diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index a9ac1d01e09b..7ee976ee2044 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -26,6 +26,7 @@
#include <linux/string.h>
#include <linux/debugfs.h>
#include <linux/devcoredump.h>
+#include <linux/rculist.h>
#include <linux/remoteproc.h>
#include <linux/iommu.h>
#include <linux/idr.h>
@@ -1868,8 +1869,8 @@ struct rproc *rproc_get_by_phandle(phandle phandle)
if (!np)
return NULL;
- mutex_lock(&rproc_list_mutex);
- list_for_each_entry(r, &rproc_list, node) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(r, &rproc_list, node) {
if (r->dev.parent && r->dev.parent->of_node == np) {
/* prevent underlying implementation from being removed */
if (!try_module_get(r->dev.parent->driver->owner)) {
@@ -1882,7 +1883,7 @@ struct rproc *rproc_get_by_phandle(phandle phandle)
break;
}
}
- mutex_unlock(&rproc_list_mutex);
+ rcu_read_unlock();
of_node_put(np);
@@ -1939,7 +1940,7 @@ int rproc_add(struct rproc *rproc)
/* expose to rproc_get_by_phandle users */
mutex_lock(&rproc_list_mutex);
- list_add(&rproc->node, &rproc_list);
+ list_add_rcu(&rproc->node, &rproc_list);
mutex_unlock(&rproc_list_mutex);
return 0;
@@ -2156,9 +2157,12 @@ int rproc_del(struct rproc *rproc)
/* the rproc is downref'ed as soon as it's removed from the klist */
mutex_lock(&rproc_list_mutex);
- list_del(&rproc->node);
+ list_del_rcu(&rproc->node);
mutex_unlock(&rproc_list_mutex);
+ /* Ensure that no readers of rproc_list are still active */
+ synchronize_rcu();
+
device_del(&rproc->dev);
return 0;