[PATCH AUTOSEL for 4.9 290/293] locking/qspinlock: Ensure node->count is updated before initialising node

From: Will Deacon [ Upstream commit 11dc13224c975efcec96647a4768a6f1bb7a19a8 ] When queuing on the qspinlock, the count field for the current CPU's head node is incremented. This needn't be atomic because locking in e.g. IRQ context is balanced and so an IRQ will return

[PATCH AUTOSEL for 4.9 290/293] locking/qspinlock: Ensure node->count is updated before initialising node

From: Will Deacon [ Upstream commit 11dc13224c975efcec96647a4768a6f1bb7a19a8 ] When queuing on the qspinlock, the count field for the current CPU's head node is incremented. This needn't be atomic because locking in e.g. IRQ context is balanced and so an IRQ will return with node->count as it