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    device-dax: add a range mapping allocation attribute · 8490e2e2
    Joao Martins 提交于
    Add a sysfs attribute which denotes a range from the dax region to be
    allocated.  It's an write only @mapping sysfs attribute in the format of
    '<start>-<end>' to allocate a range.  @start and @end use hexadecimal
    values and the @pgoff is implicitly ordered wrt to previous writes to
    @mapping sysfs e.g.  a write of a range of length 1G the pgoff is
    0..1G(-4K), a second write will use @pgoff for 1G+4K..<size>.
    
    This range mapping interface is useful for:
    
     1) Application which want to implement its own allocation logic, and
        thus pick the desired ranges from dax_region.
    
     2) For use cases like VMM fast restart[0] where after kexec we want
        to the same gpa<->phys mappings (as originally created before kexec).
    
    [0] https://static.sched.com/hosted_files/kvmforum2019/66/VMM-fast-restart_kvmforum2019.pdfSigned-off-by: NJoao Martins <joao.m.martins@oracle.com>
    Signed-off-by: NDan Williams <dan.j.williams@intel.com>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Cc: Andy Lutomirski <luto@kernel.org>
    Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: Ard Biesheuvel <ardb@kernel.org>
    Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
    Cc: Ben Skeggs <bskeggs@redhat.com>
    Cc: Bjorn Helgaas <bhelgaas@google.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
    Cc: Brice Goglin <Brice.Goglin@inria.fr>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: Daniel Vetter <daniel@ffwll.ch>
    Cc: Dave Hansen <dave.hansen@linux.intel.com>
    Cc: Dave Jiang <dave.jiang@intel.com>
    Cc: David Airlie <airlied@linux.ie>
    Cc: David Hildenbrand <david@redhat.com>
    Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    Cc: "H. Peter Anvin" <hpa@zytor.com>
    Cc: Hulk Robot <hulkci@huawei.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Ira Weiny <ira.weiny@intel.com>
    Cc: Jason Gunthorpe <jgg@mellanox.com>
    Cc: Jason Yan <yanaijie@huawei.com>
    Cc: Jeff Moyer <jmoyer@redhat.com>
    Cc: "Jérôme Glisse" <jglisse@redhat.com>
    Cc: Jia He <justin.he@arm.com>
    Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
    Cc: Juergen Gross <jgross@suse.com>
    Cc: kernel test robot <lkp@intel.com>
    Cc: Michael Ellerman <mpe@ellerman.id.au>
    Cc: Mike Rapoport <rppt@linux.ibm.com>
    Cc: Paul Mackerras <paulus@ozlabs.org>
    Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
    Cc: Randy Dunlap <rdunlap@infradead.org>
    Cc: Stefano Stabellini <sstabellini@kernel.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Tom Lendacky <thomas.lendacky@amd.com>
    Cc: Vishal Verma <vishal.l.verma@intel.com>
    Cc: Vivek Goyal <vgoyal@redhat.com>
    Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
    Cc: Will Deacon <will@kernel.org>
    Link: https://lkml.kernel.org/r/159643106970.4062302.10402616567780784722.stgit@dwillia2-desk3.amr.corp.intel.com
    Link: https://lore.kernel.org/r/20200716172913.19658-5-joao.m.martins@oracle.com
    Link: https://lkml.kernel.org/r/160106119570.30709.4548889722645210610.stgit@dwillia2-desk3.amr.corp.intel.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    8490e2e2
bus.c 34.5 KB