On Mon, May 18, 2020 at 08:00:25PM -0700, Saravana Kannan wrote:
When SYNC_STATE_ONLY support was added in commit 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag"), device_link_add() incorrectly skipped adding the new SYNC_STATE_ONLY device link to the supplier's and consumer's "device link" list.
This causes multiple issues:
- The device link is lost forever from driver core if the caller didn't keep track of it (caller typically isn't expected to). This is a memory leak.
- The device link is also never visible to any other code path after device_link_add() returns.
If we fix the "device link" list handling, that exposes a bunch of issues.
- The device link "status" state management code rightfully doesn't
handle the case where a DL_FLAG_MANAGED device link exists between a supplier and consumer, but the consumer manages to probe successfully before the supplier. The addition of DL_FLAG_SYNC_STATE_ONLY links break this assumption. This causes device_links_driver_bound() to throw a warning when this happens.
Since DL_FLAG_SYNC_STATE_ONLY device links are mainly used for creating proxy device links for child device dependencies and aren't useful once the consumer device probes successfully, this patch just deletes DL_FLAG_SYNC_STATE_ONLY device links once its consumer device probes. This way, we avoid the warning, free up some memory and avoid complicating the device links "status" state management code.
- Creating a DL_FLAG_STATELESS device link between two devices that
already have a DL_FLAG_SYNC_STATE_ONLY device link will result in the DL_FLAG_STATELESS flag not getting set correctly. This patch also fixes this.
Lastly, this patch also fixes minor whitespace issues.
Cc: stable@vger.kernel.org Fixes: 05ef983e0d65 ("driver core: Add device link support for SYNC_STATE_ONLY flag") Signed-off-by: Saravana Kannan saravanak@google.com
drivers/base/core.c | 61 +++++++++++++++++++++++++++++---------------- 1 file changed, 39 insertions(+), 22 deletions(-)
If this is v2, what changed from v1?
That always goes below the --- line, you know this :)
v3 please?
thanks,
greg k-h