firmware: arm_ffa: Skip Rx buffer ownership release if not acquired

JIRA: https://issues.redhat.com/browse/RHEL-102691

commit 4567bda
Author: Sudeep Holla <[email protected]>
Date: Fri, 21 Mar 2025 11:57:00 +0000

    Completion of the FFA_PARTITION_INFO_GET ABI transfers the ownership of
    the caller’s Rx buffer from the producer(typically partition mnager) to
    the consumer(this driver/OS). FFA_RX_RELEASE transfers the ownership
    from the consumer back to the producer.

    However, when we set the flag to just return the count of partitions
    deployed in the system corresponding to the specified UUID while
    invoking FFA_PARTITION_INFO_GET, the Rx buffer ownership shouldn't be
    transferred to this driver. We must be able to skip transferring back
    the ownership to the partition manager when we request just to get the
    count of the partitions as the buffers are not acquired in this case.

    Firmware may return FFA_RET_DENIED or other error for the ffa_rx_release()
    in such cases.

    Fixes: bb1be74 ("firmware: arm_ffa: Add v1.1 get_partition_info support")
    Message-Id: <[email protected]>
    Signed-off-by: Sudeep Holla <[email protected]>

Signed-off-by: Marcin Juszkiewicz <[email protected]>

Author: hrw

drivers/firmware/arm_ffa/driver.c

@@ -299,7 +299,8 @@ __ffa_partition_info_get(u32 uuid0, u32 uuid1, u32 uuid2, u32 uuid3,
 				import_uuid(&buf->uuid, (u8 *)&rx_buf->uuid);
 		}
 
-	ffa_rx_release();
+	if (!(flags & PARTITION_INFO_GET_RETURN_COUNT_ONLY))
+		ffa_rx_release();
 
 	mutex_unlock(&drv_info->rx_lock);