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author | Dan Williams <dan.j.williams@intel.com> | 2018-12-28 00:39:46 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-12-28 12:11:52 -0800 |
commit | 063a7d1d3623db31ca5d2309cab6030ebf93b72f (patch) | |
tree | db21d6e0f9a623faa40bc2d9ac2dc1f43f5ba9a5 /include/linux/hmm.h | |
parent | c86aa7bbfd5568ba8a82d3635d8f7b8a8e06fe54 (diff) | |
download | linux-stable-063a7d1d3623db31ca5d2309cab6030ebf93b72f.tar.gz linux-stable-063a7d1d3623db31ca5d2309cab6030ebf93b72f.tar.bz2 linux-stable-063a7d1d3623db31ca5d2309cab6030ebf93b72f.zip |
mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
The kbuild robot reported the following on a development branch that used
memremap.h in a new path:
In file included from arch/m68k/include/asm/pgtable_mm.h:148:0,
from arch/m68k/include/asm/pgtable.h:5,
from include/linux/memremap.h:7,
from drivers//dax/bus.c:3:
arch/m68k/include/asm/motorola_pgtable.h: In function 'pgd_offset':
>> arch/m68k/include/asm/motorola_pgtable.h:199:11: error: dereferencing pointer to incomplete type 'const struct mm_struct'
return mm->pgd + pgd_index(address);
^~
The ->page_fault() callback is specific to HMM. Move it to 'struct
hmm_devmem' where the unusual asm/pgtable.h dependency can be contained in
include/linux/hmm.h. Longer term refactoring this dependency out of HMM
is recommended, but in the meantime memremap.h remains generic.
Link: http://lkml.kernel.org/r/154534090899.3120190.6652620807617715272.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 5042db43cc26 ("mm/ZONE_DEVICE: new type of ZONE_DEVICE memory...")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/hmm.h')
-rw-r--r-- | include/linux/hmm.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/include/linux/hmm.h b/include/linux/hmm.h index ed89fbc525d2..66f9ebbb1df3 100644 --- a/include/linux/hmm.h +++ b/include/linux/hmm.h @@ -69,6 +69,7 @@ #define LINUX_HMM_H #include <linux/kconfig.h> +#include <asm/pgtable.h> #if IS_ENABLED(CONFIG_HMM) @@ -486,6 +487,7 @@ struct hmm_devmem_ops { * @device: device to bind resource to * @ops: memory operations callback * @ref: per CPU refcount + * @page_fault: callback when CPU fault on an unaddressable device page * * This an helper structure for device drivers that do not wish to implement * the gory details related to hotplugging new memoy and allocating struct @@ -493,7 +495,28 @@ struct hmm_devmem_ops { * * Device drivers can directly use ZONE_DEVICE memory on their own if they * wish to do so. + * + * The page_fault() callback must migrate page back, from device memory to + * system memory, so that the CPU can access it. This might fail for various + * reasons (device issues, device have been unplugged, ...). When such error + * conditions happen, the page_fault() callback must return VM_FAULT_SIGBUS and + * set the CPU page table entry to "poisoned". + * + * Note that because memory cgroup charges are transferred to the device memory, + * this should never fail due to memory restrictions. However, allocation + * of a regular system page might still fail because we are out of memory. If + * that happens, the page_fault() callback must return VM_FAULT_OOM. + * + * The page_fault() callback can also try to migrate back multiple pages in one + * chunk, as an optimization. It must, however, prioritize the faulting address + * over all the others. */ +typedef int (*dev_page_fault_t)(struct vm_area_struct *vma, + unsigned long addr, + const struct page *page, + unsigned int flags, + pmd_t *pmdp); + struct hmm_devmem { struct completion completion; unsigned long pfn_first; @@ -503,6 +526,7 @@ struct hmm_devmem { struct dev_pagemap pagemap; const struct hmm_devmem_ops *ops; struct percpu_ref ref; + dev_page_fault_t page_fault; }; /* |