mm/vmalloc: eliminated the lock contention from twice to once

When allocating a new memory area where the mapping address range is
known, it is observed that the vmap_node->busy.lock is acquired twice.

The first acquisition occurs in the alloc_vmap_area() function when
inserting the vm area into the vm mapping red-black tree.  The second
acquisition occurs in the setup_vmalloc_vm() function when updating the
properties of the vm, such as flags and address, etc.

Combine these two operations together in alloc_vmap_area(), which improves
scalability when the vmap_node->busy.lock is contended.  By doing so, the
need to acquire the lock twice can also be eliminated to once.

With the above change, tested on intel sapphire rapids platform(224 vcpu),
a 4% performance improvement is gained on
stress-ng/pthread(https://github.com/ColinIanKing/stress-ng), which is the
stress test of thread creations.

Link: https://lkml.kernel.org/r/[email protected]
Co-developed-by: "Chen, Tim C" <[email protected]>
Signed-off-by: "Chen, Tim C" <[email protected]>
Co-developed-by: "King, Colin" <[email protected]>
Signed-off-by: "King, Colin" <[email protected]>
Signed-off-by: rulinhuang <[email protected]>
Reviewed-by: Baoquan He <[email protected]>
Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>
Cc: Tim Chen <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Wangyang Guo <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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