net/ipv5/tcp: use vma_lookup() in tcp_zerocopy_receive()

Use vma_lookup() to find the VMA at a specific address.  As vma_lookup()
will return NULL if the address is not within any VMA, the start address
no longer needs to be validated.

Link: https://lkml.kernel.org/r/20210521174745.2219620-13-Liam.Howlett@Oracle.comSigned-off-by: NLiam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: NLaurent Dufour <ldufour@linux.ibm.com>
Acked-by: NDavid Hildenbrand <david@redhat.com>
Acked-by: NDavidlohr Bueso <dbueso@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

net/ipv4/tcp.c

@@ -2095,8 +2095,8 @@ static int tcp_zerocopy_receive(struct sock *sk,
 
 	mmap_read_lock(current->mm);
 
-	vma = find_vma(current->mm, address);
-	if (!vma || vma->vm_start > address || vma->vm_ops != &tcp_vm_ops) {
+	vma = vma_lookup(current->mm, address);
+	if (!vma || vma->vm_ops != &tcp_vm_ops) {
 		mmap_read_unlock(current->mm);
 		return -EINVAL;
 	}