Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
mm/page_ext: Add page_ext_get_from_phys()
The IOMMU code operates on physical addresses which can be outside
of system RAM.
Add a new function page_ext_get_from_phys() to abstract the logic of
checking the address and returning the page_ext.
Signed-off-by: Mostafa Saleh <smostafa@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
authored by
Mostafa Saleh
and committed by
Joerg Roedel
d414b83d
2e2f6b0e
+29
+6
include/linux/page_ext.h
+6
include/linux/page_ext.h
···
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#endif
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extern struct page_ext *page_ext_get(const struct page *page);
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extern struct page_ext *page_ext_from_phys(phys_addr_t phys);
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extern void page_ext_put(struct page_ext *page_ext);
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extern struct page_ext *page_ext_lookup(unsigned long pfn);
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···
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}
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static inline struct page_ext *page_ext_get(const struct page *page)
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{
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return NULL;
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}
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static inline struct page_ext *page_ext_from_phys(phys_addr_t phys)
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{
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return NULL;
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}
+23
mm/page_ext.c
+23
mm/page_ext.c
···
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}
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/**
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* page_ext_from_phys() - Get the page_ext structure for a physical address.
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* @phys: The physical address to query.
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*
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* This function safely gets the `struct page_ext` associated with a given
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* physical address. It performs validation to ensure the address corresponds
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* to a valid, online struct page before attempting to access it.
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* It returns NULL for MMIO, ZONE_DEVICE, holes and offline memory.
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*
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* Return: NULL if no page_ext exists for this physical address.
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* Context: Any context. Caller may not sleep until they have called
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* page_ext_put().
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*/
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struct page_ext *page_ext_from_phys(phys_addr_t phys)
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{
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struct page *page = pfn_to_online_page(__phys_to_pfn(phys));
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if (!page)
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return NULL;
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return page_ext_get(page);
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}
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/**
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* page_ext_put() - Working with page extended information is done.
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* @page_ext: Page extended information received from page_ext_get().
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*