mm: reorder code blocks in gup.c
This moves the actually exported functions towards the end of the file, and reorders some functions to be in more logical blocks as a preparation for moving various stubs inline into the main functionality using IS_ENABLED(). Link: http://lkml.kernel.org/r/20190625143715.1689-12-hch@lst.de Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: James Hogan <jhogan@kernel.org> Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Khalid Aziz <khalid.aziz@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Rich Felker <dalias@libc.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig
Linus Torvalds
parent
67a929e097
commit
d3649f68b4
410
mm/gup.c
410
mm/gup.c
@ -1100,86 +1100,6 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
|
||||
return pages_done;
|
||||
}
|
||||
|
||||
/*
|
||||
* We can leverage the VM_FAULT_RETRY functionality in the page fault
|
||||
* paths better by using either get_user_pages_locked() or
|
||||
* get_user_pages_unlocked().
|
||||
*
|
||||
* get_user_pages_locked() is suitable to replace the form:
|
||||
*
|
||||
* down_read(&mm->mmap_sem);
|
||||
* do_something()
|
||||
* get_user_pages(tsk, mm, ..., pages, NULL);
|
||||
* up_read(&mm->mmap_sem);
|
||||
*
|
||||
* to:
|
||||
*
|
||||
* int locked = 1;
|
||||
* down_read(&mm->mmap_sem);
|
||||
* do_something()
|
||||
* get_user_pages_locked(tsk, mm, ..., pages, &locked);
|
||||
* if (locked)
|
||||
* up_read(&mm->mmap_sem);
|
||||
*/
|
||||
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
|
||||
unsigned int gup_flags, struct page **pages,
|
||||
int *locked)
|
||||
{
|
||||
/*
|
||||
* FIXME: Current FOLL_LONGTERM behavior is incompatible with
|
||||
* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
|
||||
* vmas. As there are no users of this flag in this call we simply
|
||||
* disallow this option for now.
|
||||
*/
|
||||
if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
|
||||
return -EINVAL;
|
||||
|
||||
return __get_user_pages_locked(current, current->mm, start, nr_pages,
|
||||
pages, NULL, locked,
|
||||
gup_flags | FOLL_TOUCH);
|
||||
}
|
||||
EXPORT_SYMBOL(get_user_pages_locked);
|
||||
|
||||
/*
|
||||
* get_user_pages_unlocked() is suitable to replace the form:
|
||||
*
|
||||
* down_read(&mm->mmap_sem);
|
||||
* get_user_pages(tsk, mm, ..., pages, NULL);
|
||||
* up_read(&mm->mmap_sem);
|
||||
*
|
||||
* with:
|
||||
*
|
||||
* get_user_pages_unlocked(tsk, mm, ..., pages);
|
||||
*
|
||||
* It is functionally equivalent to get_user_pages_fast so
|
||||
* get_user_pages_fast should be used instead if specific gup_flags
|
||||
* (e.g. FOLL_FORCE) are not required.
|
||||
*/
|
||||
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
|
||||
struct page **pages, unsigned int gup_flags)
|
||||
{
|
||||
struct mm_struct *mm = current->mm;
|
||||
int locked = 1;
|
||||
long ret;
|
||||
|
||||
/*
|
||||
* FIXME: Current FOLL_LONGTERM behavior is incompatible with
|
||||
* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
|
||||
* vmas. As there are no users of this flag in this call we simply
|
||||
* disallow this option for now.
|
||||
*/
|
||||
if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
|
||||
return -EINVAL;
|
||||
|
||||
down_read(&mm->mmap_sem);
|
||||
ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
|
||||
&locked, gup_flags | FOLL_TOUCH);
|
||||
if (locked)
|
||||
up_read(&mm->mmap_sem);
|
||||
return ret;
|
||||
}
|
||||
EXPORT_SYMBOL(get_user_pages_unlocked);
|
||||
|
||||
/*
|
||||
* get_user_pages_remote() - pin user pages in memory
|
||||
* @tsk: the task_struct to use for page fault accounting, or
|
||||
@ -1256,6 +1176,153 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
|
||||
}
|
||||
EXPORT_SYMBOL(get_user_pages_remote);
|
||||
|
||||
/**
|
||||
* populate_vma_page_range() - populate a range of pages in the vma.
|
||||
* @vma: target vma
|
||||
* @start: start address
|
||||
* @end: end address
|
||||
* @nonblocking:
|
||||
*
|
||||
* This takes care of mlocking the pages too if VM_LOCKED is set.
|
||||
*
|
||||
* return 0 on success, negative error code on error.
|
||||
*
|
||||
* vma->vm_mm->mmap_sem must be held.
|
||||
*
|
||||
* If @nonblocking is NULL, it may be held for read or write and will
|
||||
* be unperturbed.
|
||||
*
|
||||
* If @nonblocking is non-NULL, it must held for read only and may be
|
||||
* released. If it's released, *@nonblocking will be set to 0.
|
||||
*/
|
||||
long populate_vma_page_range(struct vm_area_struct *vma,
|
||||
unsigned long start, unsigned long end, int *nonblocking)
|
||||
{
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
unsigned long nr_pages = (end - start) / PAGE_SIZE;
|
||||
int gup_flags;
|
||||
|
||||
VM_BUG_ON(start & ~PAGE_MASK);
|
||||
VM_BUG_ON(end & ~PAGE_MASK);
|
||||
VM_BUG_ON_VMA(start < vma->vm_start, vma);
|
||||
VM_BUG_ON_VMA(end > vma->vm_end, vma);
|
||||
VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
|
||||
|
||||
gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
|
||||
if (vma->vm_flags & VM_LOCKONFAULT)
|
||||
gup_flags &= ~FOLL_POPULATE;
|
||||
/*
|
||||
* We want to touch writable mappings with a write fault in order
|
||||
* to break COW, except for shared mappings because these don't COW
|
||||
* and we would not want to dirty them for nothing.
|
||||
*/
|
||||
if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
|
||||
gup_flags |= FOLL_WRITE;
|
||||
|
||||
/*
|
||||
* We want mlock to succeed for regions that have any permissions
|
||||
* other than PROT_NONE.
|
||||
*/
|
||||
if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
|
||||
gup_flags |= FOLL_FORCE;
|
||||
|
||||
/*
|
||||
* We made sure addr is within a VMA, so the following will
|
||||
* not result in a stack expansion that recurses back here.
|
||||
*/
|
||||
return __get_user_pages(current, mm, start, nr_pages, gup_flags,
|
||||
NULL, NULL, nonblocking);
|
||||
}
|
||||
|
||||
/*
|
||||
* __mm_populate - populate and/or mlock pages within a range of address space.
|
||||
*
|
||||
* This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
|
||||
* flags. VMAs must be already marked with the desired vm_flags, and
|
||||
* mmap_sem must not be held.
|
||||
*/
|
||||
int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
|
||||
{
|
||||
struct mm_struct *mm = current->mm;
|
||||
unsigned long end, nstart, nend;
|
||||
struct vm_area_struct *vma = NULL;
|
||||
int locked = 0;
|
||||
long ret = 0;
|
||||
|
||||
end = start + len;
|
||||
|
||||
for (nstart = start; nstart < end; nstart = nend) {
|
||||
/*
|
||||
* We want to fault in pages for [nstart; end) address range.
|
||||
* Find first corresponding VMA.
|
||||
*/
|
||||
if (!locked) {
|
||||
locked = 1;
|
||||
down_read(&mm->mmap_sem);
|
||||
vma = find_vma(mm, nstart);
|
||||
} else if (nstart >= vma->vm_end)
|
||||
vma = vma->vm_next;
|
||||
if (!vma || vma->vm_start >= end)
|
||||
break;
|
||||
/*
|
||||
* Set [nstart; nend) to intersection of desired address
|
||||
* range with the first VMA. Also, skip undesirable VMA types.
|
||||
*/
|
||||
nend = min(end, vma->vm_end);
|
||||
if (vma->vm_flags & (VM_IO | VM_PFNMAP))
|
||||
continue;
|
||||
if (nstart < vma->vm_start)
|
||||
nstart = vma->vm_start;
|
||||
/*
|
||||
* Now fault in a range of pages. populate_vma_page_range()
|
||||
* double checks the vma flags, so that it won't mlock pages
|
||||
* if the vma was already munlocked.
|
||||
*/
|
||||
ret = populate_vma_page_range(vma, nstart, nend, &locked);
|
||||
if (ret < 0) {
|
||||
if (ignore_errors) {
|
||||
ret = 0;
|
||||
continue; /* continue at next VMA */
|
||||
}
|
||||
break;
|
||||
}
|
||||
nend = nstart + ret * PAGE_SIZE;
|
||||
ret = 0;
|
||||
}
|
||||
if (locked)
|
||||
up_read(&mm->mmap_sem);
|
||||
return ret; /* 0 or negative error code */
|
||||
}
|
||||
|
||||
/**
|
||||
* get_dump_page() - pin user page in memory while writing it to core dump
|
||||
* @addr: user address
|
||||
*
|
||||
* Returns struct page pointer of user page pinned for dump,
|
||||
* to be freed afterwards by put_page().
|
||||
*
|
||||
* Returns NULL on any kind of failure - a hole must then be inserted into
|
||||
* the corefile, to preserve alignment with its headers; and also returns
|
||||
* NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
|
||||
* allowing a hole to be left in the corefile to save diskspace.
|
||||
*
|
||||
* Called without mmap_sem, but after all other threads have been killed.
|
||||
*/
|
||||
#ifdef CONFIG_ELF_CORE
|
||||
struct page *get_dump_page(unsigned long addr)
|
||||
{
|
||||
struct vm_area_struct *vma;
|
||||
struct page *page;
|
||||
|
||||
if (__get_user_pages(current, current->mm, addr, 1,
|
||||
FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
|
||||
NULL) < 1)
|
||||
return NULL;
|
||||
flush_cache_page(vma, addr, page_to_pfn(page));
|
||||
return page;
|
||||
}
|
||||
#endif /* CONFIG_ELF_CORE */
|
||||
|
||||
#if defined(CONFIG_FS_DAX) || defined (CONFIG_CMA)
|
||||
static bool check_dax_vmas(struct vm_area_struct **vmas, long nr_pages)
|
||||
{
|
||||
@ -1503,152 +1570,85 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
|
||||
}
|
||||
EXPORT_SYMBOL(get_user_pages);
|
||||
|
||||
/**
|
||||
* populate_vma_page_range() - populate a range of pages in the vma.
|
||||
* @vma: target vma
|
||||
* @start: start address
|
||||
* @end: end address
|
||||
* @nonblocking:
|
||||
/*
|
||||
* We can leverage the VM_FAULT_RETRY functionality in the page fault
|
||||
* paths better by using either get_user_pages_locked() or
|
||||
* get_user_pages_unlocked().
|
||||
*
|
||||
* This takes care of mlocking the pages too if VM_LOCKED is set.
|
||||
* get_user_pages_locked() is suitable to replace the form:
|
||||
*
|
||||
* return 0 on success, negative error code on error.
|
||||
* down_read(&mm->mmap_sem);
|
||||
* do_something()
|
||||
* get_user_pages(tsk, mm, ..., pages, NULL);
|
||||
* up_read(&mm->mmap_sem);
|
||||
*
|
||||
* vma->vm_mm->mmap_sem must be held.
|
||||
* to:
|
||||
*
|
||||
* If @nonblocking is NULL, it may be held for read or write and will
|
||||
* be unperturbed.
|
||||
*
|
||||
* If @nonblocking is non-NULL, it must held for read only and may be
|
||||
* released. If it's released, *@nonblocking will be set to 0.
|
||||
* int locked = 1;
|
||||
* down_read(&mm->mmap_sem);
|
||||
* do_something()
|
||||
* get_user_pages_locked(tsk, mm, ..., pages, &locked);
|
||||
* if (locked)
|
||||
* up_read(&mm->mmap_sem);
|
||||
*/
|
||||
long populate_vma_page_range(struct vm_area_struct *vma,
|
||||
unsigned long start, unsigned long end, int *nonblocking)
|
||||
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
|
||||
unsigned int gup_flags, struct page **pages,
|
||||
int *locked)
|
||||
{
|
||||
struct mm_struct *mm = vma->vm_mm;
|
||||
unsigned long nr_pages = (end - start) / PAGE_SIZE;
|
||||
int gup_flags;
|
||||
|
||||
VM_BUG_ON(start & ~PAGE_MASK);
|
||||
VM_BUG_ON(end & ~PAGE_MASK);
|
||||
VM_BUG_ON_VMA(start < vma->vm_start, vma);
|
||||
VM_BUG_ON_VMA(end > vma->vm_end, vma);
|
||||
VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_sem), mm);
|
||||
|
||||
gup_flags = FOLL_TOUCH | FOLL_POPULATE | FOLL_MLOCK;
|
||||
if (vma->vm_flags & VM_LOCKONFAULT)
|
||||
gup_flags &= ~FOLL_POPULATE;
|
||||
/*
|
||||
* We want to touch writable mappings with a write fault in order
|
||||
* to break COW, except for shared mappings because these don't COW
|
||||
* and we would not want to dirty them for nothing.
|
||||
* FIXME: Current FOLL_LONGTERM behavior is incompatible with
|
||||
* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
|
||||
* vmas. As there are no users of this flag in this call we simply
|
||||
* disallow this option for now.
|
||||
*/
|
||||
if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
|
||||
gup_flags |= FOLL_WRITE;
|
||||
if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
|
||||
return -EINVAL;
|
||||
|
||||
/*
|
||||
* We want mlock to succeed for regions that have any permissions
|
||||
* other than PROT_NONE.
|
||||
*/
|
||||
if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
|
||||
gup_flags |= FOLL_FORCE;
|
||||
|
||||
/*
|
||||
* We made sure addr is within a VMA, so the following will
|
||||
* not result in a stack expansion that recurses back here.
|
||||
*/
|
||||
return __get_user_pages(current, mm, start, nr_pages, gup_flags,
|
||||
NULL, NULL, nonblocking);
|
||||
return __get_user_pages_locked(current, current->mm, start, nr_pages,
|
||||
pages, NULL, locked,
|
||||
gup_flags | FOLL_TOUCH);
|
||||
}
|
||||
EXPORT_SYMBOL(get_user_pages_locked);
|
||||
|
||||
/*
|
||||
* __mm_populate - populate and/or mlock pages within a range of address space.
|
||||
* get_user_pages_unlocked() is suitable to replace the form:
|
||||
*
|
||||
* This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
|
||||
* flags. VMAs must be already marked with the desired vm_flags, and
|
||||
* mmap_sem must not be held.
|
||||
* down_read(&mm->mmap_sem);
|
||||
* get_user_pages(tsk, mm, ..., pages, NULL);
|
||||
* up_read(&mm->mmap_sem);
|
||||
*
|
||||
* with:
|
||||
*
|
||||
* get_user_pages_unlocked(tsk, mm, ..., pages);
|
||||
*
|
||||
* It is functionally equivalent to get_user_pages_fast so
|
||||
* get_user_pages_fast should be used instead if specific gup_flags
|
||||
* (e.g. FOLL_FORCE) are not required.
|
||||
*/
|
||||
int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
|
||||
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
|
||||
struct page **pages, unsigned int gup_flags)
|
||||
{
|
||||
struct mm_struct *mm = current->mm;
|
||||
unsigned long end, nstart, nend;
|
||||
struct vm_area_struct *vma = NULL;
|
||||
int locked = 0;
|
||||
long ret = 0;
|
||||
int locked = 1;
|
||||
long ret;
|
||||
|
||||
end = start + len;
|
||||
/*
|
||||
* FIXME: Current FOLL_LONGTERM behavior is incompatible with
|
||||
* FAULT_FLAG_ALLOW_RETRY because of the FS DAX check requirement on
|
||||
* vmas. As there are no users of this flag in this call we simply
|
||||
* disallow this option for now.
|
||||
*/
|
||||
if (WARN_ON_ONCE(gup_flags & FOLL_LONGTERM))
|
||||
return -EINVAL;
|
||||
|
||||
for (nstart = start; nstart < end; nstart = nend) {
|
||||
/*
|
||||
* We want to fault in pages for [nstart; end) address range.
|
||||
* Find first corresponding VMA.
|
||||
*/
|
||||
if (!locked) {
|
||||
locked = 1;
|
||||
down_read(&mm->mmap_sem);
|
||||
vma = find_vma(mm, nstart);
|
||||
} else if (nstart >= vma->vm_end)
|
||||
vma = vma->vm_next;
|
||||
if (!vma || vma->vm_start >= end)
|
||||
break;
|
||||
/*
|
||||
* Set [nstart; nend) to intersection of desired address
|
||||
* range with the first VMA. Also, skip undesirable VMA types.
|
||||
*/
|
||||
nend = min(end, vma->vm_end);
|
||||
if (vma->vm_flags & (VM_IO | VM_PFNMAP))
|
||||
continue;
|
||||
if (nstart < vma->vm_start)
|
||||
nstart = vma->vm_start;
|
||||
/*
|
||||
* Now fault in a range of pages. populate_vma_page_range()
|
||||
* double checks the vma flags, so that it won't mlock pages
|
||||
* if the vma was already munlocked.
|
||||
*/
|
||||
ret = populate_vma_page_range(vma, nstart, nend, &locked);
|
||||
if (ret < 0) {
|
||||
if (ignore_errors) {
|
||||
ret = 0;
|
||||
continue; /* continue at next VMA */
|
||||
}
|
||||
break;
|
||||
}
|
||||
nend = nstart + ret * PAGE_SIZE;
|
||||
ret = 0;
|
||||
}
|
||||
down_read(&mm->mmap_sem);
|
||||
ret = __get_user_pages_locked(current, mm, start, nr_pages, pages, NULL,
|
||||
&locked, gup_flags | FOLL_TOUCH);
|
||||
if (locked)
|
||||
up_read(&mm->mmap_sem);
|
||||
return ret; /* 0 or negative error code */
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* get_dump_page() - pin user page in memory while writing it to core dump
|
||||
* @addr: user address
|
||||
*
|
||||
* Returns struct page pointer of user page pinned for dump,
|
||||
* to be freed afterwards by put_page().
|
||||
*
|
||||
* Returns NULL on any kind of failure - a hole must then be inserted into
|
||||
* the corefile, to preserve alignment with its headers; and also returns
|
||||
* NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
|
||||
* allowing a hole to be left in the corefile to save diskspace.
|
||||
*
|
||||
* Called without mmap_sem, but after all other threads have been killed.
|
||||
*/
|
||||
#ifdef CONFIG_ELF_CORE
|
||||
struct page *get_dump_page(unsigned long addr)
|
||||
{
|
||||
struct vm_area_struct *vma;
|
||||
struct page *page;
|
||||
|
||||
if (__get_user_pages(current, current->mm, addr, 1,
|
||||
FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
|
||||
NULL) < 1)
|
||||
return NULL;
|
||||
flush_cache_page(vma, addr, page_to_pfn(page));
|
||||
return page;
|
||||
}
|
||||
#endif /* CONFIG_ELF_CORE */
|
||||
EXPORT_SYMBOL(get_user_pages_unlocked);
|
||||
|
||||
/*
|
||||
* Fast GUP
|
||||
|
||||
Loading…
Reference in New Issue
Block a user