diff options
| author | Bjorn Andersson <bjorn.andersson@linaro.org> | 2020-03-24 08:29:01 +0300 |
|---|---|---|
| committer | Bjorn Andersson <bjorn.andersson@linaro.org> | 2020-03-26 08:29:44 +0300 |
| commit | c0abe2ca3605e4c4fb25bf69d0218c63baf71d2b (patch) | |
| tree | 200afc104f4c75b015d53ed481b020eea129d485 /drivers/remoteproc | |
| parent | 791c13b709dd51eb37330f2a5837434e90c87c27 (diff) | |
| download | linux-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.c | 14 |
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; |