linux.git/kernel/memremap.c, branch v4.16-rc2

mm: Fix devm_memremap_pages() collision handling

2018-01-20T00:29:56+00:00

If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.

Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.

Cc: 
Fixes: 9476df7d80df ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr 
Signed-off-by: Dan Williams

mm: Fix memory size alignment in devm_memremap_pages_release()

2018-01-20T00:29:48+00:00

The functions devm_memremap_pages() and devm_memremap_pages_release() use
different ways to calculate the section-aligned amount of memory. The
latter function may use an incorrect size if the memory region is small
but straddles a section border.

Use the same code for both.

Cc: 
Fixes: 5f29a77cd957 ("mm: fix mixed zone detection in devm_memremap_pages")
Signed-off-by: Jan H. Schönherr 
Signed-off-by: Dan Williams

memremap: merge find_dev_pagemap into get_dev_pagemap

2018-01-08T19:46:23+00:00

There is only one caller of the trivial function find_dev_pagemap left,
so just merge it into the caller.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Dan Williams

memremap: change devm_memremap_pages interface to use struct dev_pagemap

2018-01-08T19:46:23+00:00

This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.

This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).

Signed-off-by: Logan Gunthorpe 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Dan Williams

memremap: drop private struct page_map

2018-01-08T19:46:23+00:00

'struct page_map' is a private structure of 'struct dev_pagemap' but the
latter replicates all the same fields as the former so there isn't much
value in it. Thus drop it in favour of a completely public struct.

This is a clean up in preperation for a more generally useful
'devm_memeremap_pages' interface.

Signed-off-by: Logan Gunthorpe 
Signed-off-by: Christoph Hellwig 
Signed-off-by: Dan Williams

memremap: simplify duplicate region handling in devm_memremap_pages

2018-01-08T19:46:23+00:00

__radix_tree_insert already checks for duplicates and returns -EEXIST in
that case, so remove the duplicate (and racy) duplicates check.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Logan Gunthorpe 
Signed-off-by: Dan Williams

memremap: remove to_vmem_altmap

2018-01-08T19:46:23+00:00

All callers are gone now.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Dan Williams

mm: optimize dev_pagemap reference counting around get_dev_pagemap

2018-01-08T19:46:23+00:00

Change the calling convention so that get_dev_pagemap always consumes the
previous reference instead of doing this using an explicit earlier call to
put_dev_pagemap in the callers.

The callers will still need to put the final reference after finishing the
loop over the pages.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Logan Gunthorpe 
Signed-off-by: Dan Williams

mm: move get_dev_pagemap out of line

2018-01-08T19:46:23+00:00

This is a pretty big function, which should be out of line in general,
and a no-op stub if CONFIG_ZONE_DEVICЕ is not set.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Logan Gunthorpe 
Signed-off-by: Dan Williams

mm: pass the vmem_altmap to memmap_init_zone

2018-01-08T19:46:23+00:00

Pass the vmem_altmap two levels down instead of needing a lookup.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Dan Williams