Commit 82b0f8c3 authored by Jan Kara's avatar Jan Kara Committed by Linus Torvalds
Browse files

mm: join struct fault_env and vm_fault 

Currently we have two different structures for passing fault information
around - struct vm_fault and struct fault_env.  DAX will need more
information in struct vm_fault to handle its faults so the content of
that structure would become event closer to fault_env.  Furthermore it
would need to generate struct fault_env to be able to call some of the
generic functions.  So at this point I don't think there's much use in
keeping these two structures separate.  Just embed into struct vm_fault
all that is needed to use it for both purposes.

Link: http://lkml.kernel.org/r/1479460644-25076-2-git-send-email-jack@suse.cz


Signed-off-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8b7457ef

Documentation/filesystems/Locking

+1 −1
Original line number Diff line number Diff line
@@ -556,7 +556,7 @@ till "end_pgoff". ->map_pages() is called with page table locked and must 
not block.  If it's not possible to reach a page without blocking,

filesystem should skip it. Filesystem should use do_set_pte() to setup

page table entry. Pointer to entry associated with the page is passed in

"pte" field in fault_env structure. Pointers to entries for other offsets

"pte" field in vm_fault structure. Pointers to entries for other offsets

should be calculated relative to "pte".



	->page_mkwrite() is called when a previously read-only pte is

fs/userfaultfd.c

+12 −10
Original line number Diff line number Diff line
@@ -257,9 +257,9 @@ out: 
 * fatal_signal_pending()s, and the mmap_sem must be released before

 * returning it.

 */

int handle_userfault(struct fault_env *fe, unsigned long reason)

int handle_userfault(struct vm_fault *vmf, unsigned long reason)

{

	struct mm_struct *mm = fe->vma->vm_mm;

	struct mm_struct *mm = vmf->vma->vm_mm;

	struct userfaultfd_ctx *ctx;

	struct userfaultfd_wait_queue uwq;

	int ret;
@@ -268,7 +268,7 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) 
	BUG_ON(!rwsem_is_locked(&mm->mmap_sem));



	ret = VM_FAULT_SIGBUS;

	ctx = fe->vma->vm_userfaultfd_ctx.ctx;

	ctx = vmf->vma->vm_userfaultfd_ctx.ctx;

	if (!ctx)

		goto out;
@@ -301,17 +301,18 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) 
	 * without first stopping userland access to the memory. For

	 * VM_UFFD_MISSING userfaults this is enough for now.

	 */

	if (unlikely(!(fe->flags & FAULT_FLAG_ALLOW_RETRY))) {

	if (unlikely(!(vmf->flags & FAULT_FLAG_ALLOW_RETRY))) {

		/*

		 * Validate the invariant that nowait must allow retry

		 * to be sure not to return SIGBUS erroneously on

		 * nowait invocations.

		 */

		BUG_ON(fe->flags & FAULT_FLAG_RETRY_NOWAIT);

		BUG_ON(vmf->flags & FAULT_FLAG_RETRY_NOWAIT);

#ifdef CONFIG_DEBUG_VM

		if (printk_ratelimit()) {

			printk(KERN_WARNING

			       "FAULT_FLAG_ALLOW_RETRY missing %x\n", fe->flags);

			       "FAULT_FLAG_ALLOW_RETRY missing %x\n",

			       vmf->flags);

			dump_stack();

		}

#endif
@@ -323,7 +324,7 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) 
	 * and wait.

	 */

	ret = VM_FAULT_RETRY;

	if (fe->flags & FAULT_FLAG_RETRY_NOWAIT)

	if (vmf->flags & FAULT_FLAG_RETRY_NOWAIT)

		goto out;



	/* take the reference before dropping the mmap_sem */
@@ -331,11 +332,11 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) 


	init_waitqueue_func_entry(&uwq.wq, userfaultfd_wake_function);

	uwq.wq.private = current;

	uwq.msg = userfault_msg(fe->address, fe->flags, reason);

	uwq.msg = userfault_msg(vmf->address, vmf->flags, reason);

	uwq.ctx = ctx;



	return_to_userland =

		(fe->flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) ==

		(vmf->flags & (FAULT_FLAG_USER|FAULT_FLAG_KILLABLE)) ==

		(FAULT_FLAG_USER|FAULT_FLAG_KILLABLE);



	spin_lock(&ctx->fault_pending_wqh.lock);
@@ -353,7 +354,8 @@ int handle_userfault(struct fault_env *fe, unsigned long reason) 
			  TASK_KILLABLE);

	spin_unlock(&ctx->fault_pending_wqh.lock);



	must_wait = userfaultfd_must_wait(ctx, fe->address, fe->flags, reason);

	must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags,

					  reason);

	up_read(&mm->mmap_sem);



	if (likely(must_wait && !ACCESS_ONCE(ctx->released) &&

include/linux/huge_mm.h

+5 −5
Original line number Diff line number Diff line 
#ifndef _LINUX_HUGE_MM_H

#define _LINUX_HUGE_MM_H



extern int do_huge_pmd_anonymous_page(struct fault_env *fe);

extern int do_huge_pmd_anonymous_page(struct vm_fault *vmf);

extern int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,

			 pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,

			 struct vm_area_struct *vma);

extern void huge_pmd_set_accessed(struct fault_env *fe, pmd_t orig_pmd);

extern int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd);

extern void huge_pmd_set_accessed(struct vm_fault *vmf, pmd_t orig_pmd);

extern int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd);

extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,

					  unsigned long addr,

					  pmd_t *pmd,
@@ -142,7 +142,7 @@ static inline int hpage_nr_pages(struct page *page) 
	return 1;

}



extern int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t orig_pmd);

extern int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);



extern struct page *huge_zero_page;
@@ -212,7 +212,7 @@ static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd, 
	return NULL;

}



static inline int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t orig_pmd)

static inline int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd)

{

	return 0;

}

include/linux/mm.h

+11 −17
Original line number Diff line number Diff line
@@ -292,10 +292,16 @@ extern pgprot_t protection_map[16]; 
 * pgoff should be used in favour of virtual_address, if possible.

 */

struct vm_fault {

	struct vm_area_struct *vma;	/* Target VMA */

	unsigned int flags;		/* FAULT_FLAG_xxx flags */

	gfp_t gfp_mask;			/* gfp mask to be used for allocations */

	pgoff_t pgoff;			/* Logical page offset based on vma */

	void __user *virtual_address;	/* Faulting virtual address */

	unsigned long address;		/* Faulting virtual address */

	void __user *virtual_address;	/* Faulting virtual address masked by

					 * PAGE_MASK */

	pmd_t *pmd;			/* Pointer to pmd entry matching

					 * the 'address'

					 */



	struct page *cow_page;		/* Handler may choose to COW */

	struct page *page;		/* ->fault handlers should return a
@@ -309,19 +315,7 @@ struct vm_fault { 
					 * VM_FAULT_DAX_LOCKED and fill in

					 * entry here.

					 */

};



/*

 * Page fault context: passes though page fault handler instead of endless list

 * of function arguments.

 */

struct fault_env {

	struct vm_area_struct *vma;	/* Target VMA */

	unsigned long address;		/* Faulting virtual address */

	unsigned int flags;		/* FAULT_FLAG_xxx flags */

	pmd_t *pmd;			/* Pointer to pmd entry matching

					 * the 'address'

					 */

	/* These three entries are valid only while holding ptl lock */

	pte_t *pte;			/* Pointer to pte entry matching

					 * the 'address'. NULL if the page

					 * table hasn't been allocated.
@@ -351,7 +345,7 @@ struct vm_operations_struct { 
	int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);

	int (*pmd_fault)(struct vm_area_struct *, unsigned long address,

						pmd_t *, unsigned int flags);

	void (*map_pages)(struct fault_env *fe,

	void (*map_pages)(struct vm_fault *vmf,

			pgoff_t start_pgoff, pgoff_t end_pgoff);



	/* notification that a previously read-only page is about to become
@@ -625,7 +619,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 
	return pte;

}



int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg,

int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,

		struct page *page);

#endif
@@ -2094,7 +2088,7 @@ extern void truncate_inode_pages_final(struct address_space *); 


/* generic vm_area_ops exported for stackable file systems */

extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);

extern void filemap_map_pages(struct fault_env *fe,

extern void filemap_map_pages(struct vm_fault *vmf,

		pgoff_t start_pgoff, pgoff_t end_pgoff);

extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);

include/linux/userfaultfd_k.h

+2 −2
Original line number Diff line number Diff line
@@ -27,7 +27,7 @@ 
#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)

#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)



extern int handle_userfault(struct fault_env *fe, unsigned long reason);

extern int handle_userfault(struct vm_fault *vmf, unsigned long reason);



extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,

			    unsigned long src_start, unsigned long len);
@@ -55,7 +55,7 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma) 
#else /* CONFIG_USERFAULTFD */



/* mm helpers */

static inline int handle_userfault(struct fault_env *fe, unsigned long reason)

static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)

{

	return VM_FAULT_SIGBUS;

}

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