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    f542b8e5
    mm/page_poison: replace kmap_atomic() with kmap_local_page() · f542b8e5
    Fabio M. De Francesco authored
    kmap_atomic() has been deprecated in favor of kmap_local_page().
    
    Therefore, replace kmap_atomic() with kmap_local_page().
    
    kmap_atomic() is implemented like a kmap_local_page() which also disables
    page-faults and preemption (the latter only in !PREEMPT_RT kernels).  The
    kernel virtual addresses returned by these two API are only valid in the
    context of the callers (i.e., they cannot be handed to other threads).
    
    With kmap_local_page() the mappings are per thread and CPU local like in
    kmap_atomic(); however, they can handle page-faults and can be called from
    any context (including interrupts).  The tasks that call kmap_local_page()
    can be preempted and, when they are scheduled to run again, the kernel
    virtual addresses are restored and are still valid.
    
    The code blocks between the mappings and un-mappings do not rely on the
    above-mentioned side effects of kmap_atomic(), so that mere replacements
    of the old API with the new one is all that they require (i.e., there is
    no need to explicitly call pagefault_disable() and/or preempt_disable()).
    
    Link: https://lkml.kernel.org/r/20231120142836.7219-1-fabio.maria.de.francesco@linux.intel.com
    
    
    Signed-off-by: default avatarFabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
    Cc: Ira Weiny <ira.weiny@intel.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    f542b8e5
    History
    mm/page_poison: replace kmap_atomic() with kmap_local_page()
    Fabio M. De Francesco authored
    kmap_atomic() has been deprecated in favor of kmap_local_page().
    
    Therefore, replace kmap_atomic() with kmap_local_page().
    
    kmap_atomic() is implemented like a kmap_local_page() which also disables
    page-faults and preemption (the latter only in !PREEMPT_RT kernels).  The
    kernel virtual addresses returned by these two API are only valid in the
    context of the callers (i.e., they cannot be handed to other threads).
    
    With kmap_local_page() the mappings are per thread and CPU local like in
    kmap_atomic(); however, they can handle page-faults and can be called from
    any context (including interrupts).  The tasks that call kmap_local_page()
    can be preempted and, when they are scheduled to run again, the kernel
    virtual addresses are restored and are still valid.
    
    The code blocks between the mappings and un-mappings do not rely on the
    above-mentioned side effects of kmap_atomic(), so that mere replacements
    of the old API with the new one is all that they require (i.e., there is
    no need to explicitly call pagefault_disable() and/or preempt_disable()).
    
    Link: https://lkml.kernel.org/r/20231120142836.7219-1-fabio.maria.de.francesco@linux.intel.com
    
    
    Signed-off-by: default avatarFabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
    Cc: Ira Weiny <ira.weiny@intel.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>