Merge branch 'hmm-devmem-cleanup.4' into rdma.git hmm

Christoph Hellwig says:

====================
Below is a series that cleans up the dev_pagemap interface so that it is
more easily usable, which removes the need to wrap it in hmm and thus
allowing to kill a lot of code

Changes since v3:
 - pull in "mm/swap: Fix release_pages() when releasing devmap pages" and
   rebase the other patches on top of that
 - fold the hmm_devmem_add_resource into the DEVICE_PUBLIC memory removal
   patch
 - remove _vm_normal_page as it isn't needed without DEVICE_PUBLIC memory
 - pick up various ACKs

Changes since v2:
 - fix nvdimm kunit build
 - add a new memory type for device dax
 - fix a few issues in intermediate patches that didn't show up in the end
   result
 - incorporate feedback from Michal Hocko, including killing of
   the DEVICE_PUBLIC memory type entirely

Changes since v1:
 - rebase
 - also switch p2pdma to the internal refcount
 - add type checking for pgmap->type
 - rename the migrate method to migrate_to_ram
 - cleanup the altmap_valid flag
 - various tidbits from the reviews
====================

Conflicts resolved by:
 - Keeping Ira's version of the code in swap.c
 - Using the delete for the section in hmm.rst
 - Using the delete for the devmap code in hmm.c and .h

* branch 'hmm-devmem-cleanup.4': (24 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...

Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 1 insertions, 197 deletions

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 0fa8ea34ccef..b8a08b2a10ca 100644
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -62,7 +62,7 @@
 #include <linux/kconfig.h>
 #include <asm/pgtable.h>
 
-#if IS_ENABLED(CONFIG_HMM)
+#ifdef CONFIG_HMM_MIRROR
 
 #include <linux/device.h>
 #include <linux/migrate.h>
@@ -324,9 +324,6 @@ static inline uint64_t hmm_pfn_from_pfn(const struct hmm_range *range,
 	return hmm_device_entry_from_pfn(range, pfn);
 }
 
-
-
-#if IS_ENABLED(CONFIG_HMM_MIRROR)
 /*
  * Mirroring: how to synchronize device page table with CPU page table.
  *
@@ -550,197 +547,4 @@ static inline void hmm_mm_init(struct mm_struct *mm)
 static inline void hmm_mm_init(struct mm_struct *mm) {}
 #endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
 
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) ||  IS_ENABLED(CONFIG_DEVICE_PUBLIC)
-struct hmm_devmem;
-
-struct page *hmm_vma_alloc_locked_page(struct vm_area_struct *vma,
-				       unsigned long addr);
-
-/*
- * struct hmm_devmem_ops - callback for ZONE_DEVICE memory events
- *
- * @free: call when refcount on page reach 1 and thus is no longer use
- * @fault: call when there is a page fault to unaddressable memory
- *
- * Both callback happens from page_free() and page_fault() callback of struct
- * dev_pagemap respectively. See include/linux/memremap.h for more details on
- * those.
- *
- * The hmm_devmem_ops callback are just here to provide a coherent and
- * uniq API to device driver and device driver should not register their
- * own page_free() or page_fault() but rely on the hmm_devmem_ops call-
- * back.
- */
-struct hmm_devmem_ops {
-	/*
-	 * free() - free a device page
-	 * @devmem: device memory structure (see struct hmm_devmem)
-	 * @page: pointer to struct page being freed
-	 *
-	 * Call back occurs whenever a device page refcount reach 1 which
-	 * means that no one is holding any reference on the page anymore
-	 * (ZONE_DEVICE page have an elevated refcount of 1 as default so
-	 * that they are not release to the general page allocator).
-	 *
-	 * Note that callback has exclusive ownership of the page (as no
-	 * one is holding any reference).
-	 */
-	void (*free)(struct hmm_devmem *devmem, struct page *page);
-	/*
-	 * fault() - CPU page fault or get user page (GUP)
-	 * @devmem: device memory structure (see struct hmm_devmem)
-	 * @vma: virtual memory area containing the virtual address
-	 * @addr: virtual address that faulted or for which there is a GUP
-	 * @page: pointer to struct page backing virtual address (unreliable)
-	 * @flags: FAULT_FLAG_* (see include/linux/mm.h)
-	 * @pmdp: page middle directory
-	 * Return: VM_FAULT_MINOR/MAJOR on success or one of VM_FAULT_ERROR
-	 *   on error
-	 *
-	 * The callback occurs whenever there is a CPU page fault or GUP on a
-	 * virtual address. This means that the device driver must migrate the
-	 * page back to regular memory (CPU accessible).
-	 *
-	 * The device driver is free to migrate more than one page from the
-	 * fault() callback as an optimization. However if the device decides
-	 * to migrate more than one page it must always priotirize the faulting
-	 * address over the others.
-	 *
-	 * The struct page pointer is only given as a hint to allow quick
-	 * lookup of internal device driver data. A concurrent migration
-	 * might have already freed that page and the virtual address might
-	 * no longer be backed by it. So it should not be modified by the
-	 * callback.
-	 *
-	 * Note that mmap semaphore is held in read mode at least when this
-	 * callback occurs, hence the vma is valid upon callback entry.
-	 */
-	vm_fault_t (*fault)(struct hmm_devmem *devmem,
-		     struct vm_area_struct *vma,
-		     unsigned long addr,
-		     const struct page *page,
-		     unsigned int flags,
-		     pmd_t *pmdp);
-};
-
-/*
- * struct hmm_devmem - track device memory
- *
- * @completion: completion object for device memory
- * @pfn_first: first pfn for this resource (set by hmm_devmem_add())
- * @pfn_last: last pfn for this resource (set by hmm_devmem_add())
- * @resource: IO resource reserved for this chunk of memory
- * @pagemap: device page map for that chunk
- * @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 is a helper structure for device drivers that do not wish to implement
- * the gory details related to hotplugging new memoy and allocating struct
- * pages.
- *
- * 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 vm_fault_t (*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;
-	unsigned long			pfn_last;
-	struct resource			*resource;
-	struct device			*device;
-	struct dev_pagemap		pagemap;
-	const struct hmm_devmem_ops	*ops;
-	struct percpu_ref		ref;
-	dev_page_fault_t		page_fault;
-};
-
-/*
- * To add (hotplug) device memory, HMM assumes that there is no real resource
- * that reserves a range in the physical address space (this is intended to be
- * use by unaddressable device memory). It will reserve a physical range big
- * enough and allocate struct page for it.
- *
- * The device driver can wrap the hmm_devmem struct inside a private device
- * driver struct.
- */
-struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops,
-				  struct device *device,
-				  unsigned long size);
-struct hmm_devmem *hmm_devmem_add_resource(const struct hmm_devmem_ops *ops,
-					   struct device *device,
-					   struct resource *res);
-
-/*
- * hmm_devmem_page_set_drvdata - set per-page driver data field
- *
- * @page: pointer to struct page
- * @data: driver data value to set
- *
- * Because page can not be on lru we have an unsigned long that driver can use
- * to store a per page field. This just a simple helper to do that.
- */
-static inline void hmm_devmem_page_set_drvdata(struct page *page,
-					       unsigned long data)
-{
-	page->hmm_data = data;
-}
-
-/*
- * hmm_devmem_page_get_drvdata - get per page driver data field
- *
- * @page: pointer to struct page
- * Return: driver data value
- */
-static inline unsigned long hmm_devmem_page_get_drvdata(const struct page *page)
-{
-	return page->hmm_data;
-}
-
-
-/*
- * struct hmm_device - fake device to hang device memory onto
- *
- * @device: device struct
- * @minor: device minor number
- */
-struct hmm_device {
-	struct device		device;
-	unsigned int		minor;
-};
-
-/*
- * A device driver that wants to handle multiple devices memory through a
- * single fake device can use hmm_device to do so. This is purely a helper and
- * it is not strictly needed, in order to make use of any HMM functionality.
- */
-struct hmm_device *hmm_device_new(void *drvdata);
-void hmm_device_put(struct hmm_device *hmm_device);
-#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
-#else /* IS_ENABLED(CONFIG_HMM) */
-static inline void hmm_mm_destroy(struct mm_struct *mm) {}
-static inline void hmm_mm_init(struct mm_struct *mm) {}
-#endif /* IS_ENABLED(CONFIG_HMM) */
-
 #endif /* LINUX_HMM_H */