The patch series "Mitigate a vmap lock contention" removes vmap_area_list,
which will break the gdb vmallocinfo command:

(gdb) lx-vmallocinfo
Python Exception <class 'gdb.error'>: No symbol "vmap_area_list" in current context.
Error occurred in Python: No symbol "vmap_area_list" in current context.

So we can instead use vmap_nodes to iterate all vmallocinfo.

Link: https://lkml.kernel.org/r/20240207085856.11190-1-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: Casper Li <casper.li@mediatek.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

vmap_area does not exist on no-MMU, therefore the GDB scripts fail to
load:

Traceback (most recent call last):
  File "<...>/vmlinux-gdb.py", line 51, in <module>
    import linux.vmalloc
  File "<...>/scripts/gdb/linux/vmalloc.py", line 14, in <module>
    vmap_area_ptr_type = vmap_area_type.get_type().pointer()
                         ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<...>/scripts/gdb/linux/utils.py", line 28, in get_type
    self._type = gdb.lookup_type(self._name)
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
gdb.error: No struct type named vmap_area.

To fix this, disable the command and add an informative error message if
CONFIG_MMU is not defined, following the example of lx-slabinfo.

Link: https://lkml.kernel.org/r/20231031202235.2655333-2-ben.wolsieffer@hefring.com
Fixes: 852622bf3616 ("scripts/gdb/vmalloc: add vmallocinfo support")
Signed-off-by: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This GDB script shows the vmallocinfo for user to
analyze the vmalloc memory usage.

Example output:
0xffff800008000000-0xffff800008009000      36864 <start_kernel+372> pages=8 vmalloc
0xffff800008009000-0xffff80000800b000       8192 <gicv2m_init_one+400> phys=0x8020000 ioremap
0xffff80000800b000-0xffff80000800d000       8192 <bpf_prog_alloc_no_stats+72> pages=1 vmalloc
0xffff80000800d000-0xffff80000800f000       8192 <bpf_jit_alloc_exec+16> pages=1 vmalloc
0xffff800008010000-0xffff80000ad30000   47316992 <paging_init+452> phys=0x40210000 vmap
0xffff80000ad30000-0xffff80000c1c0000   21561344 <paging_init+556> phys=0x42f30000 vmap
0xffff80000c1c0000-0xffff80000c370000    1769472 <paging_init+592> phys=0x443c0000 vmap
0xffff80000c370000-0xffff80000de90000   28442624 <paging_init+692> phys=0x44570000 vmap
0xffff80000de90000-0xffff80000f4c1000   23269376 <paging_init+788> phys=0x46090000 vmap
0xffff80000f4c1000-0xffff80000f4c3000       8192 <gen_pool_add_owner+112> pages=1 vmalloc
0xffff80000f4c3000-0xffff80000f4c5000       8192 <gen_pool_add_owner+112> pages=1 vmalloc
0xffff80000f4c5000-0xffff80000f4c7000       8192 <gen_pool_add_owner+112> pages=1 vmalloc

Link: https://lkml.kernel.org/r/20230808083020.22254-9-Kuan-Ying.Lee@mediatek.com
Signed-off-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Cc: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: Chinwen Chang <chinwen.chang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Qun-Wei Lin <qun-wei.lin@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>