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    Subject[PATCH v6 03/38] mm: Add generic flush_icache_pages() and documentation
    Date
    flush_icache_page() is deprecated but not yet removed, so add
    a range version of it. Change the documentation to refer to
    update_mmu_cache_range() instead of update_mmu_cache().

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
    Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
    ---
    Documentation/core-api/cachetlb.rst | 39 ++++++++++++++++-------------
    include/asm-generic/cacheflush.h | 5 ++++
    2 files changed, 27 insertions(+), 17 deletions(-)

    diff --git a/Documentation/core-api/cachetlb.rst b/Documentation/core-api/cachetlb.rst
    index 5c0552e78c58..b645947954fb 100644
    --- a/Documentation/core-api/cachetlb.rst
    +++ b/Documentation/core-api/cachetlb.rst
    @@ -88,13 +88,17 @@ changes occur:

    This is used primarily during fault processing.

    -5) ``void update_mmu_cache(struct vm_area_struct *vma,
    - unsigned long address, pte_t *ptep)``
    +5) ``void update_mmu_cache_range(struct vm_fault *vmf,
    + struct vm_area_struct *vma, unsigned long address, pte_t *ptep,
    + unsigned int nr)``

    - At the end of every page fault, this routine is invoked to
    - tell the architecture specific code that a translation
    - now exists at virtual address "address" for address space
    - "vma->vm_mm", in the software page tables.
    + At the end of every page fault, this routine is invoked to tell
    + the architecture specific code that translations now exists
    + in the software page tables for address space "vma->vm_mm"
    + at virtual address "address" for "nr" consecutive pages.
    +
    + This routine is also invoked in various other places which pass
    + a NULL "vmf".

    A port may use this information in any way it so chooses.
    For example, it could use this event to pre-load TLB
    @@ -306,17 +310,18 @@ maps this page at its virtual address.
    private". The kernel guarantees that, for pagecache pages, it will
    clear this bit when such a page first enters the pagecache.

    - This allows these interfaces to be implemented much more efficiently.
    - It allows one to "defer" (perhaps indefinitely) the actual flush if
    - there are currently no user processes mapping this page. See sparc64's
    - flush_dcache_page and update_mmu_cache implementations for an example
    - of how to go about doing this.
    + This allows these interfaces to be implemented much more
    + efficiently. It allows one to "defer" (perhaps indefinitely) the
    + actual flush if there are currently no user processes mapping this
    + page. See sparc64's flush_dcache_page and update_mmu_cache_range
    + implementations for an example of how to go about doing this.

    - The idea is, first at flush_dcache_page() time, if page_file_mapping()
    - returns a mapping, and mapping_mapped on that mapping returns %false,
    - just mark the architecture private page flag bit. Later, in
    - update_mmu_cache(), a check is made of this flag bit, and if set the
    - flush is done and the flag bit is cleared.
    + The idea is, first at flush_dcache_page() time, if
    + page_file_mapping() returns a mapping, and mapping_mapped on that
    + mapping returns %false, just mark the architecture private page
    + flag bit. Later, in update_mmu_cache_range(), a check is made
    + of this flag bit, and if set the flush is done and the flag bit
    + is cleared.

    .. important::

    @@ -369,7 +374,7 @@ maps this page at its virtual address.
    ``void flush_icache_page(struct vm_area_struct *vma, struct page *page)``

    All the functionality of flush_icache_page can be implemented in
    - flush_dcache_page and update_mmu_cache. In the future, the hope
    + flush_dcache_page and update_mmu_cache_range. In the future, the hope
    is to remove this interface completely.

    The final category of APIs is for I/O to deliberately aliased address
    diff --git a/include/asm-generic/cacheflush.h b/include/asm-generic/cacheflush.h
    index f46258d1a080..09d51a680765 100644
    --- a/include/asm-generic/cacheflush.h
    +++ b/include/asm-generic/cacheflush.h
    @@ -78,6 +78,11 @@ static inline void flush_icache_range(unsigned long start, unsigned long end)
    #endif

    #ifndef flush_icache_page
    +static inline void flush_icache_pages(struct vm_area_struct *vma,
    + struct page *page, unsigned int nr)
    +{
    +}
    +
    static inline void flush_icache_page(struct vm_area_struct *vma,
    struct page *page)
    {
    --
    2.40.1
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