dlan17/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

mm: move get_dev_pagemap out of line

Browse Source 
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 <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Christoph Hellwig
2018-01-08 11:46:23 -08:00
committed by Dan Williams
parent eb8045335c
commit 0822acb86c
2 changed files with 38 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/memremap.c
+34 -2
View File
@@ -314,7 +314,7 @@ static void devm_memremap_pages_release(struct device *dev, void *data)
}
/* assumes rcu_read_lock() held at entry */
struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
static struct dev_pagemap *find_dev_pagemap(resource_size_t phys)
{
struct page_map *page_map;
@@ -501,8 +501,40 @@ struct vmem_altmap *to_vmem_altmap(unsigned long memmap_start)
return pgmap ? pgmap->altmap : NULL;
}
#endif /* CONFIG_ZONE_DEVICE */
/**
* get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
* @pfn: page frame number to lookup page_map
* @pgmap: optional known pgmap that already has a reference
*
* @pgmap allows the overhead of a lookup to be bypassed when @pfn lands in the
* same mapping.
*/
struct dev_pagemap *get_dev_pagemap(unsigned long pfn,
struct dev_pagemap *pgmap)
{
const struct resource *res = pgmap ? pgmap->res : NULL;
resource_size_t phys = PFN_PHYS(pfn);
/*
* In the cached case we're already holding a live reference so
* we can simply do a blind increment
*/
if (res && phys >= res->start && phys <= res->end) {
percpu_ref_get(pgmap->ref);
return pgmap;
}
/* fall back to slow path lookup */
rcu_read_lock();
pgmap = find_dev_pagemap(phys);
if (pgmap && !percpu_ref_tryget_live(pgmap->ref))
pgmap = NULL;
rcu_read_unlock();
return pgmap;
}
#endif /* CONFIG_ZONE_DEVICE */
#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) || IS_ENABLED(CONFIG_DEVICE_PUBLIC)
void put_zone_device_private_or_public_page(struct page *page)