Commit 4a55c5b4 authored by ZhangPeng's avatar ZhangPeng Committed by Ma Wupeng
Browse files

userswap: move userswap feature code into mm/userswap.c 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6CAIM



--------------------------------

This patch moves the code related to enable_userswap and CONFIG_USERSWAP
to mm/userswap.c. This allows for better encapsulation and easier
maintenance.

Signed-off-by: default avatarZhangPeng <zhangpeng362@huawei.com>
parent 2ca987f1

fs/userfaultfd.c

+4 −33
Original line number Diff line number Diff line
@@ -335,8 +335,7 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx, 
	 * changes under us.

	 */

#ifdef CONFIG_USERSWAP

	if ((reason & VM_USWAP) && (!pte_present(*pte)))

		ret = true;

	uswap_must_wait(reason, *pte, &ret);

#endif

	if (pte_none(*pte))

		ret = true;
@@ -875,8 +874,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file) 
	for (vma = mm->mmap; vma; vma = vma->vm_next) {

		userfault_flags = VM_UFFD_MISSING | VM_UFFD_WP;

#ifdef CONFIG_USERSWAP

		if (enable_userswap)

			userfault_flags |= VM_USWAP;

		uswap_release(&userfault_flags);

#endif

		cond_resched();

		BUG_ON(!!vma->vm_userfaultfd_ctx.ctx ^
@@ -1297,26 +1295,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, 
		goto out;

	vm_flags = 0;

#ifdef CONFIG_USERSWAP

	/*

	 * register the whole vma overlapping with the address range to avoid

	 * splitting the vma.

	 */

	if (enable_userswap && (uffdio_register.mode & UFFDIO_REGISTER_MODE_USWAP)) {

		uffdio_register.mode &= ~UFFDIO_REGISTER_MODE_USWAP;

		if (!uffdio_register.mode)

	if (!uswap_register(&uffdio_register, &vm_flags, mm))

		goto out;

		vm_flags |= VM_USWAP;

		end = uffdio_register.range.start + uffdio_register.range.len - 1;

		vma = find_vma(mm, uffdio_register.range.start);

		if (!vma)

			goto out;

		uffdio_register.range.start = vma->vm_start;



		vma = find_vma(mm, end);

		if (!vma)

			goto out;

		uffdio_register.range.len = vma->vm_end - uffdio_register.range.start;

	}

#endif

	if (uffdio_register.mode & ~(UFFDIO_REGISTER_MODE_MISSING|

				     UFFDIO_REGISTER_MODE_WP))
@@ -2041,15 +2021,6 @@ SYSCALL_DEFINE1(userfaultfd, int, flags) 
	return fd;

}



#ifdef CONFIG_USERSWAP

static int __init enable_userswap_setup(char *str)

{

	enable_userswap = true;

	return 1;

}

__setup("enable_userswap", enable_userswap_setup);

#endif



static int __init userfaultfd_init(void)

{

	userfaultfd_ctx_cachep = kmem_cache_create("userfaultfd_ctx_cache",

include/linux/userswap.h

+18 −0
Original line number Diff line number Diff line
@@ -28,6 +28,12 @@ int mfill_atomic_pte_nocopy(struct mm_struct *dst_mm, 
unsigned long uswap_mremap(unsigned long old_addr, unsigned long old_len,

			   unsigned long new_addr, unsigned long new_len);



bool uswap_register(struct uffdio_register *uffdio_register,

		    unsigned long *vm_flags, struct mm_struct *mm);



bool do_uswap_page(swp_entry_t entry, struct vm_fault *vmf,

		   struct vm_area_struct *vma, vm_fault_t *ret);



static inline bool uswap_check_copy_mode(struct vm_area_struct *vma, __u64 mode)

{

	if (!(vma->vm_flags & VM_USWAP) && (mode & UFFDIO_COPY_MODE_DIRECT_MAP))
@@ -72,6 +78,18 @@ static inline void uswap_get_cpu_id(unsigned long reason, struct uffd_msg *msg) 
		msg->reserved3 = smp_processor_id();

}



static inline void uswap_release(unsigned long *userfault_flags)

{

	if (enable_userswap)

		*userfault_flags |= VM_USWAP;

}



static inline void uswap_must_wait(unsigned long reason, pte_t pte, bool *ret)

{

	if ((reason & VM_USWAP) && (!pte_present(pte)))

		*ret = true;

}



#endif /* CONFIG_USERSWAP */



#endif /* _LINUX_USERSWAP_H */

mm/memory.c

+1 −15
Original line number Diff line number Diff line
@@ -3396,22 +3396,8 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) 


	entry = pte_to_swp_entry(vmf->orig_pte);

#ifdef CONFIG_USERSWAP

	if (swp_type(entry) == SWP_USERSWAP_ENTRY) {

		/* print error if we come across a nested fault */

		if (!strncmp(current->comm, "uswap", 5)) {

			pr_err("USWAP: fault %lx is triggered by %s\n",

					vmf->address, current->comm);

			return VM_FAULT_SIGBUS;

		}

		if (!(vma->vm_flags & VM_UFFD_MISSING)) {

			pr_err("USWAP: addr %lx flags %lx is not a user swap page",

					vmf->address, vma->vm_flags);

			goto skip_uswap;

		}

		ret = handle_userfault(vmf, VM_UFFD_MISSING | VM_USWAP);

	if (!do_uswap_page(entry, vmf, vma, &ret))

		return ret;

	}

skip_uswap:

#endif

	if (unlikely(non_swap_entry(entry))) {

		if (is_migration_entry(entry)) {

mm/userswap.c

+65 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/rmap.h>

#include <linux/mmu_notifier.h>

#include <linux/userswap.h>

#include <linux/userfaultfd_k.h>



#include "internal.h"
@@ -458,3 +459,67 @@ int mfill_atomic_pte_nocopy(struct mm_struct *mm, 
	put_page(page);

	return ret;

}



/*

 * register the whole vma overlapping with the address range to avoid splitting

 * the vma.

 */

bool uswap_register(struct uffdio_register *uffdio_register,

		    unsigned long *vm_flags, struct mm_struct *mm)

{

	struct vm_area_struct *vma;

	unsigned long end;



	if (!enable_userswap)

		return true;

	if (!(uffdio_register->mode & UFFDIO_REGISTER_MODE_USWAP))

		return true;

	uffdio_register->mode &= ~UFFDIO_REGISTER_MODE_USWAP;

	if (!uffdio_register->mode)

		return false;



	end = uffdio_register->range.start + uffdio_register->range.len - 1;

	vma = find_vma(mm, uffdio_register->range.start);

	if (!vma)

		return false;

	uffdio_register->range.start = vma->vm_start;

	vma = find_vma(mm, end);

	if (!vma)

		return false;

	uffdio_register->range.len = vma->vm_end - uffdio_register->range.start;



	*vm_flags |= VM_USWAP;



	return true;

}



bool do_uswap_page(swp_entry_t entry, struct vm_fault *vmf,

		   struct vm_area_struct *vma, vm_fault_t *ret)

{

	if (swp_type(entry) != SWP_USERSWAP_ENTRY)

		return true;



	/* print error if we come across a nested fault */

	if (!strncmp(current->comm, "uswap", 5)) {

		pr_err("USWAP: fault %lx is triggered by %s\n", vmf->address,

		       current->comm);

		*ret = VM_FAULT_SIGBUS;

		return false;

	}



	if (!(vma->vm_flags & VM_UFFD_MISSING)) {

		pr_err("USWAP: addr %lx flags %lx is not a user swap page",

				vmf->address, vma->vm_flags);

		return true;

	}



	*ret = handle_userfault(vmf, VM_UFFD_MISSING | VM_USWAP);

	return false;

}



static int __init enable_userswap_setup(char *str)

{

	enable_userswap = true;

	return 1;

}

__setup("enable_userswap", enable_userswap_setup);