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Message-Id: <20161027203403.31708-2-lstoakes@gmail.com>
Date: Thu, 27 Oct 2016 21:34:02 +0100
From: Lorenzo Stoakes <lstoakes@...il.com>
To: linux-mm@...ck.org
Cc: Michal Hocko <mhocko@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Jan Kara <jack@...e.cz>, Hugh Dickins <hughd@...gle.com>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Rik van Riel <riel@...hat.com>,
Mel Gorman <mgorman@...hsingularity.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Paolo Bonzini <pbonzini@...hat.com>,
Radim Krčmář <rkrcmar@...hat.com>,
kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-security-module@...r.kernel.org, linux-rdma@...r.kernel.org,
dri-devel@...ts.freedesktop.org, linux-fsdevel@...r.kernel.org,
Lorenzo Stoakes <lstoakes@...il.com>
Subject: [PATCH v2 1/2] mm: add locked parameter to get_user_pages_remote()
This patch adds an int *locked parameter to get_user_pages_remote() to allow
VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked().
It additionally clears the way for __get_user_pages_unlocked() to be unexported
as its sole remaining useful characteristic was to allow for VM_FAULT_RETRY
behaviour when faulting in pages.
It should not introduce any functional changes, however it does allow for
subsequent changes to get_user_pages_remote() callers to take advantage of
VM_FAULT_RETRY.
Signed-off-by: Lorenzo Stoakes <lstoakes@...il.com>
---
v2: updated description
drivers/gpu/drm/etnaviv/etnaviv_gem.c | 2 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/infiniband/core/umem_odp.c | 2 +-
fs/exec.c | 2 +-
include/linux/mm.h | 2 +-
kernel/events/uprobes.c | 4 ++--
mm/gup.c | 12 ++++++++----
mm/memory.c | 2 +-
security/tomoyo/domain.c | 2 +-
9 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index 0370b84..0c69a97f 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -763,7 +763,7 @@ static struct page **etnaviv_gem_userptr_do_get_pages(
down_read(&mm->mmap_sem);
while (pinned < npages) {
ret = get_user_pages_remote(task, mm, ptr, npages - pinned,
- flags, pvec + pinned, NULL);
+ flags, pvec + pinned, NULL, NULL);
if (ret < 0)
break;
diff --git a/drivers/gpu/drm/i915/i915_gem_userptr.c b/drivers/gpu/drm/i915/i915_gem_userptr.c
index c6f780f..836b525 100644
--- a/drivers/gpu/drm/i915/i915_gem_userptr.c
+++ b/drivers/gpu/drm/i915/i915_gem_userptr.c
@@ -522,7 +522,7 @@ __i915_gem_userptr_get_pages_worker(struct work_struct *_work)
obj->userptr.ptr + pinned * PAGE_SIZE,
npages - pinned,
flags,
- pvec + pinned, NULL);
+ pvec + pinned, NULL, NULL);
if (ret < 0)
break;
diff --git a/drivers/infiniband/core/umem_odp.c b/drivers/infiniband/core/umem_odp.c
index 1f0fe32..6b079a3 100644
--- a/drivers/infiniband/core/umem_odp.c
+++ b/drivers/infiniband/core/umem_odp.c
@@ -578,7 +578,7 @@ int ib_umem_odp_map_dma_pages(struct ib_umem *umem, u64 user_virt, u64 bcnt,
*/
npages = get_user_pages_remote(owning_process, owning_mm,
user_virt, gup_num_pages,
- flags, local_page_list, NULL);
+ flags, local_page_list, NULL, NULL);
up_read(&owning_mm->mmap_sem);
if (npages < 0)
diff --git a/fs/exec.c b/fs/exec.c
index 4e497b9..2cf049d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -209,7 +209,7 @@ static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
* doing the exec and bprm->mm is the new process's mm.
*/
ret = get_user_pages_remote(current, bprm->mm, pos, 1, gup_flags,
- &page, NULL);
+ &page, NULL, NULL);
if (ret <= 0)
return NULL;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a92c8d7..cc15445 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1274,7 +1274,7 @@ extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas);
+ struct vm_area_struct **vmas, int *locked);
long get_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
struct vm_area_struct **vmas);
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index f9ec9ad..215871b 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -301,7 +301,7 @@ int uprobe_write_opcode(struct mm_struct *mm, unsigned long vaddr,
retry:
/* Read the page with vaddr into memory */
ret = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &old_page,
- &vma);
+ &vma, NULL);
if (ret <= 0)
return ret;
@@ -1712,7 +1712,7 @@ static int is_trap_at_addr(struct mm_struct *mm, unsigned long vaddr)
* essentially a kernel access to the memory.
*/
result = get_user_pages_remote(NULL, mm, vaddr, 1, FOLL_FORCE, &page,
- NULL);
+ NULL, NULL);
if (result < 0)
return result;
diff --git a/mm/gup.c b/mm/gup.c
index ec4f827..0567851 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -920,6 +920,9 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
* only intends to ensure the pages are faulted in.
* @vmas: array of pointers to vmas corresponding to each page.
* Or NULL if the caller does not require them.
+ * @locked: pointer to lock flag indicating whether lock is held and
+ * subsequently whether VM_FAULT_RETRY functionality can be
+ * utilised. Lock must initially be held.
*
* Returns number of pages pinned. This may be fewer than the number
* requested. If nr_pages is 0 or negative, returns 0. If no pages
@@ -963,10 +966,10 @@ EXPORT_SYMBOL(get_user_pages_unlocked);
long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
- struct vm_area_struct **vmas)
+ struct vm_area_struct **vmas, int *locked)
{
return __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas,
- NULL, false,
+ locked, true,
gup_flags | FOLL_TOUCH | FOLL_REMOTE);
}
EXPORT_SYMBOL(get_user_pages_remote);
@@ -974,8 +977,9 @@ EXPORT_SYMBOL(get_user_pages_remote);
/*
* This is the same as get_user_pages_remote(), just with a
* less-flexible calling convention where we assume that the task
- * and mm being operated on are the current task's. We also
- * obviously don't pass FOLL_REMOTE in here.
+ * and mm being operated on are the current task's and don't allow
+ * passing of a locked parameter. We also obviously don't pass
+ * FOLL_REMOTE in here.
*/
long get_user_pages(unsigned long start, unsigned long nr_pages,
unsigned int gup_flags, struct page **pages,
diff --git a/mm/memory.c b/mm/memory.c
index e18c57b..2f3949b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3883,7 +3883,7 @@ static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
struct page *page = NULL;
ret = get_user_pages_remote(tsk, mm, addr, 1,
- gup_flags, &page, &vma);
+ gup_flags, &page, &vma, NULL);
if (ret <= 0) {
#ifndef CONFIG_HAVE_IOREMAP_PROT
break;
diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index 682b73a..838ffa7 100644
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -881,7 +881,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
* the execve().
*/
if (get_user_pages_remote(current, bprm->mm, pos, 1,
- FOLL_FORCE, &page, NULL) <= 0)
+ FOLL_FORCE, &page, NULL, NULL) <= 0)
return false;
#else
page = bprm->page[pos / PAGE_SIZE];
--
2.10.1
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