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mm/gup.c: convert to use get_user_{page|pages}_fast_only() 

API __get_user_pages_fast() renamed to get_user_pages_fast_only() to
align with pin_user_pages_fast_only().

As part of this we will get rid of write parameter.  Instead caller will
pass FOLL_WRITE to get_user_pages_fast_only().  This will not change any
existing functionality of the API.

All the callers are changed to pass FOLL_WRITE.

Also introduce get_user_page_fast_only(), and use it in a few places
that hard-code nr_pages to 1.

Updated the documentation of the API.

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Paul Mackerras <paulus@ozlabs.org>		[arch/powerpc/kvm]
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michal Suchanek <msuchanek@suse.de>
Link: http://lkml.kernel.org/r/1590396812-31277-1-git-send-email-jrdr.linux@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alistair/sunxi64-5.8
Souptick Joarder 2020-06-07 21:40:55 -07:00 committed by Linus Torvalds
parent e77132e758
commit dadbb612f6
7 changed files with 32 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@ -581,7 +581,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
* We always ask for write permission since the common case
* is that the page is writable.
*/
if (__get_user_pages_fast(hva, 1, 1, &page) == 1) {
if (get_user_page_fast_only(hva, FOLL_WRITE, &page)) {
write_ok = true;
} else {
/* Call KVM generic code to do the slow-path check */

2
arch/powerpc/kvm/book3s_64_mmu_radix.c
View File

@ -795,7 +795,7 @@ int kvmppc_book3s_instantiate_page(struct kvm_vcpu *vcpu,
* is that the page is writable.
*/
hva = gfn_to_hva_memslot(memslot, gfn);
if (!kvm_ro && __get_user_pages_fast(hva, 1, 1, &page) == 1) {
if (!kvm_ro && get_user_page_fast_only(hva, FOLL_WRITE, &page)) {
upgrade_write = true;
} else {
unsigned long pfn;

4
arch/powerpc/perf/callchain_64.c
View File

@ -30,11 +30,9 @@ int read_user_stack_slow(void __user *ptr, void *buf, int nb)
unsigned long addr = (unsigned long) ptr;
unsigned long offset;
struct page *page;
int nrpages;
void *kaddr;
nrpages = __get_user_pages_fast(addr, 1, 1, &page);
if (nrpages == 1) {
if (get_user_page_fast_only(addr, FOLL_WRITE, &page)) {
kaddr = page_address(page);
/* align address to page boundary */

10
include/linux/mm.h
View File

@ -1824,10 +1824,16 @@ extern int mprotect_fixup(struct vm_area_struct *vma,
/*
* doesn't attempt to fault and will return short.
*/
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);
int get_user_pages_fast_only(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages);
int pin_user_pages_fast_only(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages);
static inline bool get_user_page_fast_only(unsigned long addr,
unsigned int gup_flags, struct page **pagep)
{
return get_user_pages_fast_only(addr, 1, gup_flags, pagep) == 1;
}
/*
* per-process(per-mm_struct) statistics.
*/

4
kernel/events/core.c
View File

@ -6934,12 +6934,12 @@ static u64 perf_virt_to_phys(u64 virt)
* Walking the pages tables for user address.
* Interrupts are disabled, so it prevents any tear down
* of the page tables.
* Try IRQ-safe __get_user_pages_fast first.
* Try IRQ-safe get_user_page_fast_only first.
* If failed, leave phys_addr as 0.
*/
if (current->mm != NULL) {
pagefault_disable();
if (__get_user_pages_fast(virt, 1, 0, &p) == 1)
if (get_user_page_fast_only(virt, 0, &p))
phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
pagefault_enable();
}

29
mm/gup.c
View File

@ -2294,7 +2294,7 @@ pte_unmap:
* to be special.
*
* For a futex to be placed on a THP tail page, get_futex_key requires a
* __get_user_pages_fast implementation that can pin pages. Thus it's still
* get_user_pages_fast_only implementation that can pin pages. Thus it's still
* useful to have gup_huge_pmd even if we can't operate on ptes.
*/
static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
@ -2699,7 +2699,7 @@ static inline void gup_pgd_range(unsigned long addr, unsigned long end,
#ifndef gup_fast_permitted
/*
* Check if it's allowed to use __get_user_pages_fast() for the range, or
* Check if it's allowed to use get_user_pages_fast_only() for the range, or
* we need to fall back to the slow version:
*/
static bool gup_fast_permitted(unsigned long start, unsigned long end)
@ -2811,8 +2811,14 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
return ret;
}
/*
/**
* get_user_pages_fast_only() - pin user pages in memory
* @start: starting user address
* @nr_pages: number of pages from start to pin
* @gup_flags: flags modifying pin behaviour
* @pages: array that receives pointers to the pages pinned.
* Should be at least nr_pages long.
*
* Like get_user_pages_fast() except it's IRQ-safe in that it won't fall back to
* the regular GUP.
* Note a difference with get_user_pages_fast: this always returns the
@ -2825,8 +2831,8 @@ static int internal_get_user_pages_fast(unsigned long start, int nr_pages,
* access can get ambiguous page results. If you call this function without
* 'write' set, you'd better be sure that you're ok with that ambiguity.
*/
int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages)
int get_user_pages_fast_only(unsigned long start, int nr_pages,
unsigned int gup_flags, struct page **pages)
{
int nr_pinned;
/*
@ -2836,10 +2842,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
* FOLL_FAST_ONLY is required in order to match the API description of
* this routine: no fall back to regular ("slow") GUP.
*/
unsigned int gup_flags = FOLL_GET | FOLL_FAST_ONLY;
if (write)
gup_flags |= FOLL_WRITE;
gup_flags |= FOLL_GET | FOLL_FAST_ONLY;
nr_pinned = internal_get_user_pages_fast(start, nr_pages, gup_flags,
pages);
@ -2855,7 +2858,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
return nr_pinned;
}
EXPORT_SYMBOL_GPL(__get_user_pages_fast);
EXPORT_SYMBOL_GPL(get_user_pages_fast_only);
/**
* get_user_pages_fast() - pin user pages in memory
@ -2926,8 +2929,8 @@ int pin_user_pages_fast(unsigned long start, int nr_pages,
EXPORT_SYMBOL_GPL(pin_user_pages_fast);
/*
* This is the FOLL_PIN equivalent of __get_user_pages_fast(). Behavior is the
* same, except that this one sets FOLL_PIN instead of FOLL_GET.
* This is the FOLL_PIN equivalent of get_user_pages_fast_only(). Behavior
* is the same, except that this one sets FOLL_PIN instead of FOLL_GET.
*
* The API rules are the same, too: no negative values may be returned.
*/

8
virt/kvm/kvm_main.c
View File

@ -1740,7 +1740,6 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
bool *writable, kvm_pfn_t *pfn)
{
struct page *page[1];
int npages;
/*
* Fast pin a writable pfn only if it is a write fault request
@ -1750,8 +1749,7 @@ static bool hva_to_pfn_fast(unsigned long addr, bool write_fault,
if (!(write_fault || writable))
return false;
npages = __get_user_pages_fast(addr, 1, 1, page);
if (npages == 1) {
if (get_user_page_fast_only(addr, FOLL_WRITE, page)) {
*pfn = page_to_pfn(page[0]);
if (writable)
@ -1791,7 +1789,7 @@ static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
if (unlikely(!write_fault) && writable) {
struct page *wpage;
if (__get_user_pages_fast(addr, 1, 1, &wpage) == 1) {
if (get_user_page_fast_only(addr, FOLL_WRITE, &wpage)) {
*writable = true;
put_page(page);
page = wpage;
@ -2003,7 +2001,7 @@ int gfn_to_page_many_atomic(struct kvm_memory_slot *slot, gfn_t gfn,
if (entry < nr_pages)
return 0;
return __get_user_pages_fast(addr, nr_pages, 1, pages);
return get_user_pages_fast_only(addr, nr_pages, FOLL_WRITE, pages);
}
EXPORT_SYMBOL_GPL(gfn_to_page_many_atomic);