2020-01-04 14:43:58

by Madhuparna Bhowmik

Subject: [PATCH] drivers: firewire: core-transaction: Pass lockdep condition to address_handler_list iterator

From: Madhuparna Bhowmik <[email protected]>

The address_handler_list is traversed with list_for_each_entry_rcu
with address_handler_list_lock held.
list_for_each_entry_rcu has built-in RCU and lock checking.
Use it for address_handler_list traversal.

Signed-off-by: Madhuparna Bhowmik <[email protected]>
---
drivers/firewire/core-transaction.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index 404a035f104d..a15e70027932 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -61,6 +61,11 @@
#define PHY_CONFIG_ROOT_ID(node_id) ((((node_id) & 0x3f) << 24) | (1 << 23))
#define PHY_IDENTIFIER(id) ((id) << 30)

+static DEFINE_SPINLOCK(address_handler_list_lock);
+static LIST_HEAD(address_handler_list);
+
+#define address_handler_list_lock_held() lock_is_held(&(address_handler_list_lock).dep_map)
+
/* returns 0 if the split timeout handler is already running */
static int try_cancel_split_timeout(struct fw_transaction *t)
{
@@ -485,7 +490,7 @@ static struct fw_address_handler *lookup_overlapping_address_handler(
{
struct fw_address_handler *handler;

- list_for_each_entry_rcu(handler, list, link) {
+ list_for_each_entry_rcu(handler, list, link, address_handler_list_lock_held()) {
if (handler->offset < offset + length &&
offset < handler->offset + handler->length)
return handler;
@@ -514,8 +519,6 @@ static struct fw_address_handler *lookup_enclosing_address_handler(
return NULL;
}

-static DEFINE_SPINLOCK(address_handler_list_lock);
-static LIST_HEAD(address_handler_list);

const struct fw_address_region fw_high_memory_region =
{ .start = FW_MAX_PHYSICAL_RANGE, .end = 0xffffe0000000ULL, };
--
2.17.1

2020-01-04 21:22:23

by Joel Fernandes

Subject: Re: [PATCH] drivers: firewire: core-transaction: Pass lockdep condition to address_handler_list iterator

On Sat, Jan 04, 2020 at 08:12:15PM +0530, [email protected] wrote:
> From: Madhuparna Bhowmik <[email protected]>
>
> The address_handler_list is traversed with list_for_each_entry_rcu
> with address_handler_list_lock held.
> list_for_each_entry_rcu has built-in RCU and lock checking.
> Use it for address_handler_list traversal.
>
> Signed-off-by: Madhuparna Bhowmik <[email protected]>

Reviewed-by: Joel Fernandes (Google) <[email protected]>

thanks,

- Joel

> ---
> drivers/firewire/core-transaction.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
> index 404a035f104d..a15e70027932 100644
> --- a/drivers/firewire/core-transaction.c
> +++ b/drivers/firewire/core-transaction.c
> @@ -61,6 +61,11 @@
> #define PHY_CONFIG_ROOT_ID(node_id) ((((node_id) & 0x3f) << 24) | (1 << 23))
> #define PHY_IDENTIFIER(id) ((id) << 30)
>
> +static DEFINE_SPINLOCK(address_handler_list_lock);
> +static LIST_HEAD(address_handler_list);
> +
> +#define address_handler_list_lock_held() lock_is_held(&(address_handler_list_lock).dep_map)
> +
> /* returns 0 if the split timeout handler is already running */
> static int try_cancel_split_timeout(struct fw_transaction *t)
> {
> @@ -485,7 +490,7 @@ static struct fw_address_handler *lookup_overlapping_address_handler(
> {
> struct fw_address_handler *handler;
>
> - list_for_each_entry_rcu(handler, list, link) {
> + list_for_each_entry_rcu(handler, list, link, address_handler_list_lock_held()) {
> if (handler->offset < offset + length &&
> offset < handler->offset + handler->length)
> return handler;
> @@ -514,8 +519,6 @@ static struct fw_address_handler *lookup_enclosing_address_handler(
> return NULL;
> }
>
> -static DEFINE_SPINLOCK(address_handler_list_lock);
> -static LIST_HEAD(address_handler_list);
>
> const struct fw_address_region fw_high_memory_region =
> { .start = FW_MAX_PHYSICAL_RANGE, .end = 0xffffe0000000ULL, };
> --
> 2.17.1
>