Permalink
Browse files

mm: add locked parameter to get_user_pages_remote()

Patch series "mm: unexport __get_user_pages_unlocked()".

This patch series continues the cleanup of get_user_pages*() functions
taking advantage of the fact we can now pass gup_flags as we please.

It firstly adds an additional 'locked' parameter to
get_user_pages_remote() to allow for its callers to utilise
VM_FAULT_RETRY functionality.  This is necessary as the invocation of
__get_user_pages_unlocked() in process_vm_rw_single_vec() makes use of
this and no other existing higher level function would allow it to do
so.

Secondly existing callers of __get_user_pages_unlocked() are replaced
with the appropriate higher-level replacement -
get_user_pages_unlocked() if the current task and memory descriptor are
referenced, or get_user_pages_remote() if other task/memory descriptors
are referenced (having acquiring mmap_sem.)

This patch (of 2):

Add a int *locked parameter to get_user_pages_remote() to allow
VM_FAULT_RETRY faulting behaviour similar to get_user_pages_[un]locked().

Taking into account the previous adjustments to get_user_pages*()
functions allowing for the passing of gup_flags, we are now in a
position where __get_user_pages_unlocked() need only be exported for his
ability to allow VM_FAULT_RETRY behaviour, this adjustment allows us to
subsequently unexport __get_user_pages_unlocked() as well as allowing
for future flexibility in the use of get_user_pages_remote().

[sfr@canb.auug.org.au: merge fix for get_user_pages_remote API change]
  Link: http://lkml.kernel.org/r/20161122210511.024ec341@canb.auug.org.au
Link: http://lkml.kernel.org/r/20161027095141.2569-2-lstoakes@gmail.com
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  • Loading branch information...
lorenzo-stoakes authored and torvalds committed Dec 14, 2016
1 parent 370b262 commit 5b56d49fc31dbb0487e14ead790fc81ca9fb2c99
@@ -759,7 +759,7 @@ 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;
@@ -515,7 +515,7 @@ __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;
@@ -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)
@@ -362,7 +362,7 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
down_read(&mm->mmap_sem);
ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
NULL);
NULL, NULL);
up_read(&mm->mmap_sem);
}
@@ -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;
@@ -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);
@@ -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;
@@ -917,6 +917,9 @@ 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
@@ -960,19 +963,20 @@ 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);
/*
* 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,
@@ -3919,7 +3919,7 @@ 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;
@@ -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];

0 comments on commit 5b56d49

Please sign in to comment.