mm/vmalloc.c: allow vread() to read out vm_map_ram areas

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Currently, vread can read out vmalloc areas which is associated with a
vm_struct.  While this doesn't work for areas created by vm_map_ram()
interface because it doesn't have an associated vm_struct.  Then in
vread(), these areas are all skipped.

Here, add a new function vmap_ram_vread() to read out vm_map_ram areas. 
The area created with vmap_ram_vread() interface directly can be handled
like the other normal vmap areas with aligned_vread().  While areas which
will be further subdivided and managed with vmap_block need carefully read
out page-aligned small regions and zero fill holes.

Link: https://lkml.kernel.org/r/20230206084020.174506-4-bhe@redhat.com
Reported-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Tested-by: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

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Baoquan He 2023-02-06 16:40:16 +08:00 • committed by Andrew Morton

parent 869176a096

commit 06c8994626

1 changed files with 81 additions and 7 deletions

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mm/vmalloc.c

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