@@ -46,7 +46,7 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
end = new_range->hw_start + new_range->size;
mutex_lock(&io_range_mutex);
- list_for_each_entry_rcu(range, &io_range_list, list) {
+ list_for_each_entry(range, &io_range_list, list) {
if (range->fwnode == new_range->fwnode) {
/* range already there */
goto end_register;
@@ -108,26 +108,38 @@ int logic_pio_register_range(struct logic_pio_hwaddr *new_range)
*/
struct logic_pio_hwaddr *find_io_range_by_fwnode(struct fwnode_handle *fwnode)
{
- struct logic_pio_hwaddr *range;
+ struct logic_pio_hwaddr *range, *found_range = NULL;
+ rcu_read_lock();
list_for_each_entry_rcu(range, &io_range_list, list) {
- if (range->fwnode == fwnode)
- return range;
+ if (range->fwnode == fwnode) {
+ found_range = range;
+ break;
+ }
}
- return NULL;
+ rcu_read_unlock();
+
+ return found_range;
}
/* Return a registered range given an input PIO token */
static struct logic_pio_hwaddr *find_io_range(unsigned long pio)
{
- struct logic_pio_hwaddr *range;
+ struct logic_pio_hwaddr *range, *found_range = NULL;
+ rcu_read_lock();
list_for_each_entry_rcu(range, &io_range_list, list) {
- if (in_range(pio, range->io_start, range->size))
- return range;
+ if (in_range(pio, range->io_start, range->size)) {
+ found_range = range;
+ break;
+ }
}
- pr_err("PIO entry token %lx invalid\n", pio);
- return NULL;
+ rcu_read_unlock();
+
+ if (!found_range)
+ pr_err("PIO entry token 0x%lx invalid\n", pio);
+
+ return found_range;
}
/**
@@ -180,14 +192,23 @@ unsigned long logic_pio_trans_cpuaddr(resource_size_t addr)
{
struct logic_pio_hwaddr *range;
+ rcu_read_lock();
list_for_each_entry_rcu(range, &io_range_list, list) {
if (range->flags != LOGIC_PIO_CPU_MMIO)
continue;
- if (in_range(addr, range->hw_start, range->size))
- return addr - range->hw_start + range->io_start;
+ if (in_range(addr, range->hw_start, range->size)) {
+ unsigned long cpuaddr;
+
+ cpuaddr = addr - range->hw_start + range->io_start;
+
+ rcu_read_unlock();
+ return cpuaddr;
+ }
}
- pr_err("addr %llx not registered in io_range_list\n",
- (unsigned long long) addr);
+ rcu_read_unlock();
+
+ pr_err("addr %pa not registered in io_range_list\n", &addr);
+
return ~0UL;
}
The traversing of io_range_list with list_for_each_entry_rcu() is not properly protected by rcu_read_lock() and rcu_read_unlock(), so add them. These functions mark the critical section scope where the list is protected for the reader, it cannot be "reclaimed". Any updater - in this case, the logical PIO registration functions - cannot update the list until the reader exits this critical section. In addition, the list traversing used in logic_pio_register_range() does not need to use the rcu variant. This is because we are already using io_range_mutex to guarantee mutual exclusion from mutating the list. Fixes: 031e3601869c ("lib: Add generic PIO mapping method") Signed-off-by: John Garry <john.garry@huawei.com> --- lib/logic_pio.c | 49 +++++++++++++++++++++++++++++++++++-------------- 1 file changed, 35 insertions(+), 14 deletions(-) -- 2.17.1