nvmem: core: Fix cell lookup when no cell is found

If the cell list is not empty and nvmem_find_cell_by_node/name() is
called for a cell that is not present in the list they will return an
invalid pointer instead of NULL. This happen because
list_for_each_entry() stop once it reach the list head again, but as
the list head is not contained in a struct nvmem_cell the iteration
variable then contains an invalid value.

This is easily solved by using a variable to iterate over the list and
one to return the cell found.

Signed-off-by: Alban Bedel <albeu@free.fr>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
index f8c43da..a2ad441 100644 (file)
--- a/drivers/nvmem/core.c
+++ b/drivers/nvmem/core.c
@@ -525,12 +525,14 @@ out:
 static struct nvmem_cell *
 nvmem_find_cell_by_name(struct nvmem_device *nvmem, const char *cell_id)
 {
-       struct nvmem_cell *cell = NULL;
+       struct nvmem_cell *iter, *cell = NULL;
 
        mutex_lock(&nvmem_mutex);
-       list_for_each_entry(cell, &nvmem->cells, node) {
-               if (strcmp(cell_id, cell->name) == 0)
+       list_for_each_entry(iter, &nvmem->cells, node) {
+               if (strcmp(cell_id, iter->name) == 0) {
+                       cell = iter;
                        break;
+               }
        }
        mutex_unlock(&nvmem_mutex);
 
@@ -994,12 +996,14 @@ out:
 static struct nvmem_cell *
 nvmem_find_cell_by_node(struct nvmem_device *nvmem, struct device_node *np)
 {
-       struct nvmem_cell *cell = NULL;
+       struct nvmem_cell *iter, *cell = NULL;
 
        mutex_lock(&nvmem_mutex);
-       list_for_each_entry(cell, &nvmem->cells, node) {
-               if (np == cell->np)
+       list_for_each_entry(iter, &nvmem->cells, node) {
+               if (np == iter->np) {
+                       cell = iter;
                        break;
+               }
        }
        mutex_unlock(&nvmem_mutex);