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Merge branch 'work.get_user_pages_fast' of git://git.kernel.org/pub/s…
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…cm/linux/kernel/git/viro/vfs

Pull get_user_pages_fast updates from Al Viro:
 "A bit more get_user_pages work"

* 'work.get_user_pages_fast' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  kvm: switch get_user_page_nowait() to get_user_pages_unlocked()
  __get_user_pages_locked(): get rid of notify_drop argument
  get_user_pages_unlocked(): pass true to __get_user_pages_locked() notify_drop
  cris: switch to get_user_pages_fast()
  fold __get_user_pages_unlocked() into its sole remaining caller
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@torvalds
torvalds committed Jan 31, 2018
2 parents 19e7b5f + ce53053 commit 5a87e37
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Showing 3 changed files with 34 additions and 78 deletions.
23 changes: 7 additions & 16 deletions arch/cris/arch-v32/drivers/cryptocop.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2717,37 +2717,28 @@ static int cryptocop_ioctl_process(struct inode *inode, struct file *filp, unsig
}
}

/* Acquire the mm page semaphore. */
down_read(&current->mm->mmap_sem);

err = get_user_pages((unsigned long int)(oper.indata + prev_ix),
err = get_user_pages_fast((unsigned long)(oper.indata + prev_ix),
noinpages,
0, /* read access only for in data */
inpages,
NULL);
false, /* read access only for in data */
inpages);

if (err < 0) {
up_read(&current->mm->mmap_sem);
nooutpages = noinpages = 0;
DEBUG_API(printk("cryptocop_ioctl_process: get_user_pages indata\n"));
goto error_cleanup;
}
noinpages = err;
if (oper.do_cipher){
err = get_user_pages((unsigned long int)oper.cipher_outdata,
if (oper.do_cipher) {
err = get_user_pages_fast((unsigned long)oper.cipher_outdata,
nooutpages,
FOLL_WRITE, /* write access for out data */
outpages,
NULL);
up_read(&current->mm->mmap_sem);
true, /* write access for out data */
outpages);
if (err < 0) {
nooutpages = 0;
DEBUG_API(printk("cryptocop_ioctl_process: get_user_pages outdata\n"));
goto error_cleanup;
}
nooutpages = err;
} else {
up_read(&current->mm->mmap_sem);
}

/* Add 6 to nooutpages to make room for possibly inserted buffers for storing digest and
Expand Down
46 changes: 15 additions & 31 deletions mm/gup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -848,7 +848,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
unsigned long nr_pages,
struct page **pages,
struct vm_area_struct **vmas,
int *locked, bool notify_drop,
int *locked,
unsigned int flags)
{
long ret, pages_done;
Expand Down Expand Up @@ -922,7 +922,7 @@ static __always_inline long __get_user_pages_locked(struct task_struct *tsk,
pages++;
start += PAGE_SIZE;
}
if (notify_drop && lock_dropped && *locked) {
if (lock_dropped && *locked) {
/*
* We must let the caller know we temporarily dropped the lock
* and so the critical section protected by it was lost.
Expand Down Expand Up @@ -959,35 +959,11 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
int *locked)
{
return __get_user_pages_locked(current, current->mm, start, nr_pages,
pages, NULL, locked, true,
pages, NULL, locked,
gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages_locked);

/*
* Same as get_user_pages_unlocked(...., FOLL_TOUCH) but it allows for
* tsk, mm to be specified.
*
* NOTE: here FOLL_TOUCH is not set implicitly and must be set by the
* caller if required (just like with __get_user_pages). "FOLL_GET"
* is set implicitly if "pages" is non-NULL.
*/
static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk,
struct mm_struct *mm, unsigned long start,
unsigned long nr_pages, struct page **pages,
unsigned int gup_flags)
{
long ret;
int locked = 1;

down_read(&mm->mmap_sem);
ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, NULL,
&locked, false, gup_flags);
if (locked)
up_read(&mm->mmap_sem);
return ret;
}

/*
* get_user_pages_unlocked() is suitable to replace the form:
*
Expand All @@ -1006,8 +982,16 @@ static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk,
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags)
{
return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
pages, gup_flags | FOLL_TOUCH);
struct mm_struct *mm = current->mm;
int locked = 1;
long ret;

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);

Expand Down Expand Up @@ -1073,7 +1057,7 @@ long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
struct vm_area_struct **vmas, int *locked)
{
return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas,
locked, true,
locked,
gup_flags | FOLL_TOUCH | FOLL_REMOTE);
}
EXPORT_SYMBOL(get_user_pages_remote);
Expand All @@ -1090,7 +1074,7 @@ long get_user_pages(unsigned long start, unsigned long nr_pages,
struct vm_area_struct **vmas)
{
return __get_user_pages_locked(current, current->mm, start, nr_pages,
pages, vmas, NULL, false,
pages, vmas, NULL,
gup_flags | FOLL_TOUCH);
}
EXPORT_SYMBOL(get_user_pages);
Expand Down
43 changes: 12 additions & 31 deletions virt/kvm/kvm_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1322,17 +1322,6 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w
return gfn_to_hva_memslot_prot(slot, gfn, writable);
}

static int get_user_page_nowait(unsigned long start, int write,
struct page **page)
{
int flags = FOLL_NOWAIT | FOLL_HWPOISON;

if (write)
flags |= FOLL_WRITE;

return get_user_pages(start, 1, flags, page, NULL);
}

static inline int check_user_page_hwpoison(unsigned long addr)
{
int rc, flags = FOLL_HWPOISON | FOLL_WRITE;
Expand Down Expand Up @@ -1381,43 +1370,35 @@ static bool hva_to_pfn_fast(unsigned long addr, bool atomic, bool *async,
static int hva_to_pfn_slow(unsigned long addr, bool *async, bool write_fault,
bool *writable, kvm_pfn_t *pfn)
{
struct page *page[1];
unsigned int flags = FOLL_HWPOISON;
struct page *page;
int npages = 0;

might_sleep();

if (writable)
*writable = write_fault;

if (async) {
down_read(&current->mm->mmap_sem);
npages = get_user_page_nowait(addr, write_fault, page);
up_read(&current->mm->mmap_sem);
} else {
unsigned int flags = FOLL_HWPOISON;

if (write_fault)
flags |= FOLL_WRITE;
if (write_fault)
flags |= FOLL_WRITE;
if (async)
flags |= FOLL_NOWAIT;

npages = get_user_pages_unlocked(addr, 1, page, flags);
}
npages = get_user_pages_unlocked(addr, 1, &page, flags);
if (npages != 1)
return npages;

/* map read fault as writable if possible */
if (unlikely(!write_fault) && writable) {
struct page *wpage[1];
struct page *wpage;

npages = __get_user_pages_fast(addr, 1, 1, wpage);
if (npages == 1) {
if (__get_user_pages_fast(addr, 1, 1, &wpage) == 1) {
*writable = true;
put_page(page[0]);
page[0] = wpage[0];
put_page(page);
page = wpage;
}

npages = 1;
}
*pfn = page_to_pfn(page[0]);
*pfn = page_to_pfn(page);
return npages;
}

Expand Down

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