From: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Subject: mm: unexport __get_user_pages_unlocked()
Unexport the low-level __get_user_pages_unlocked() function and replaces
invocations with calls to more appropriate higher-level functions.
In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked()
with get_user_pages_unlocked() since we can now pass gup_flags.
In async_pf_execute() and process_vm_rw_single_vec() we need to pass
different tsk, mm arguments so get_user_pages_remote() is the sane
replacement in these cases (having added manual acquisition and release of
mmap_sem.)
Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH
flag. However, this flag was originally silently dropped by 1e9877902dc7e
("mm/gup: Introduce get_user_pages_remote()"), so this appears to have
been unintentional and reintroducing it is therefore not an issue.
[akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes]
Link: http://lkml.kernel.org/r/20161027095141.2569-3-lstoakes@xxxxxxxxx
Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim Krcmar <rkrcmar@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 3 ---
mm/gup.c | 8 ++++----
mm/nommu.c | 8 ++++----
mm/process_vm_access.c | 12 ++++++++----
virt/kvm/async_pf.c | 10 +++++++---
virt/kvm/kvm_main.c | 5 ++---
6 files changed, 25 insertions(+), 21 deletions(-)
diff -puN include/linux/mm.h~mm-unexport-__get_user_pages_unlocked include/linux/mm.h
--- a/include/linux/mm.h~mm-unexport-__get_user_pages_unlocked
+++ a/include/linux/mm.h
@@ -1280,9 +1280,6 @@ long get_user_pages(unsigned long start,
struct vm_area_struct **vmas);
long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages, int *locked);
-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 get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags);
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
diff -puN mm/gup.c~mm-unexport-__get_user_pages_unlocked mm/gup.c
--- a/mm/gup.c~mm-unexport-__get_user_pages_unlocked
+++ a/mm/gup.c
@@ -865,9 +865,10 @@ EXPORT_SYMBOL(get_user_pages_locked);
* caller if required (just like with __get_user_pages). "FOLL_GET"
* is set implicitly if "pages" is non-NULL.
*/
-__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)
+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;
@@ -879,7 +880,6 @@ __always_inline long __get_user_pages_un
up_read(&mm->mmap_sem);
return ret;
}
-EXPORT_SYMBOL(__get_user_pages_unlocked);
/*
* get_user_pages_unlocked() is suitable to replace the form:
diff -puN mm/nommu.c~mm-unexport-__get_user_pages_unlocked mm/nommu.c
--- a/mm/nommu.c~mm-unexport-__get_user_pages_unlocked
+++ a/mm/nommu.c
@@ -176,9 +176,10 @@ long get_user_pages_locked(unsigned long
}
EXPORT_SYMBOL(get_user_pages_locked);
-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)
+static 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;
down_read(&mm->mmap_sem);
@@ -187,7 +188,6 @@ long __get_user_pages_unlocked(struct ta
up_read(&mm->mmap_sem);
return ret;
}
-EXPORT_SYMBOL(__get_user_pages_unlocked);
long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
struct page **pages, unsigned int gup_flags)
diff -puN mm/process_vm_access.c~mm-unexport-__get_user_pages_unlocked mm/process_vm_access.c
--- a/mm/process_vm_access.c~mm-unexport-__get_user_pages_unlocked
+++ a/mm/process_vm_access.c
@@ -88,7 +88,7 @@ static int process_vm_rw_single_vec(unsi
ssize_t rc = 0;
unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
/ sizeof(struct pages *);
- unsigned int flags = FOLL_REMOTE;
+ unsigned int flags = 0;
/* Work out address and page range required */
if (len == 0)
@@ -100,15 +100,19 @@ static int process_vm_rw_single_vec(unsi
while (!rc && nr_pages && iov_iter_count(iter)) {
int pages = min(nr_pages, max_pages_per_loop);
+ int locked = 1;
size_t bytes;
/*
* Get the pages we're interested in. We must
- * add FOLL_REMOTE because task/mm might not
+ * access remotely because task/mm might not
* current/current->mm
*/
- pages = __get_user_pages_unlocked(task, mm, pa, pages,
- process_pages, flags);
+ down_read(&mm->mmap_sem);
+ pages = get_user_pages_remote(task, mm, pa, pages, flags,
+ process_pages, NULL, &locked);
+ if (locked)
+ up_read(&mm->mmap_sem);
if (pages <= 0)
return -EFAULT;
diff -puN virt/kvm/async_pf.c~mm-unexport-__get_user_pages_unlocked virt/kvm/async_pf.c
--- a/virt/kvm/async_pf.c~mm-unexport-__get_user_pages_unlocked
+++ a/virt/kvm/async_pf.c
@@ -76,16 +76,20 @@ static void async_pf_execute(struct work
struct kvm_vcpu *vcpu = apf->vcpu;
unsigned long addr = apf->addr;
gva_t gva = apf->gva;
+ int locked = 1;
might_sleep();
/*
* This work is run asynchromously to the task which owns
* mm and might be done in another context, so we must
- * use FOLL_REMOTE.
+ * access remotely.
*/
- __get_user_pages_unlocked(NULL, mm, addr, 1, NULL,
- FOLL_WRITE | FOLL_REMOTE);
+ down_read(&mm->mmap_sem);
+ get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL,
+ &locked);
+ if (locked)
+ up_read(&mm->mmap_sem);
kvm_async_page_present_sync(vcpu, apf);
diff -puN virt/kvm/kvm_main.c~mm-unexport-__get_user_pages_unlocked virt/kvm/kvm_main.c
--- a/virt/kvm/kvm_main.c~mm-unexport-__get_user_pages_unlocked
+++ a/virt/kvm/kvm_main.c
@@ -1418,13 +1418,12 @@ static int hva_to_pfn_slow(unsigned long
npages = get_user_page_nowait(addr, write_fault, page);
up_read(¤t->mm->mmap_sem);
} else {
- unsigned int flags = FOLL_TOUCH | FOLL_HWPOISON;
+ unsigned int flags = FOLL_HWPOISON;
if (write_fault)
flags |= FOLL_WRITE;
- npages = __get_user_pages_unlocked(current, current->mm, addr, 1,
- page, flags);
+ npages = get_user_pages_unlocked(addr, 1, page, flags);
}
if (npages != 1)
return npages;
_
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
