mm: add locked parameter to get_user_pages_remote()
authorLorenzo Stoakes <lstoakes@gmail.com>
Wed, 14 Dec 2016 23:06:52 +0000 (15:06 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 15 Dec 2016 00:04:08 +0000 (16:04 -0800)
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>
drivers/gpu/drm/etnaviv/etnaviv_gem.c
drivers/gpu/drm/i915/i915_gem_userptr.c
drivers/infiniband/core/umem_odp.c
drivers/vfio/vfio_iommu_type1.c
fs/exec.c
include/linux/mm.h
kernel/events/uprobes.c
mm/gup.c
mm/memory.c
security/tomoyo/domain.c

index 7d066a91d7784f628590e829f306ea8dfe0699c8..6f5dfabb3096999726adffbc882332c487ba1fd9 100644 (file)
@@ -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;
 
index 107ddf51065e50be5c810180084f035f06c0dfcd..d068af2ec3a3a9597d5e9fb8553ecc7cf7596d86 100644 (file)
@@ -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;
 
index 1f0fe3217f2386e03caf4b7e14cd228bddac2020..6b079a31dceda1e56a6a9ee5112539ade36dcd08 100644 (file)
@@ -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)
index 9815e45c23c4515b1acee531e0cb0643a88ad35c..f3726ba12aa6ceccff8a0c96523aa683537be8f4 100644 (file)
@@ -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);
        }
 
index 923c57d96899f821f65a68359e8657c576691fdf..eac60886b0ab42c87ccb61f64a0d43caa484dc93 100644 (file)
--- 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;
 
index a92c8d73aeafc5f5bafa551eacc284f86bad50d0..cc154454675ad79b7de1b816e7df25e4211fb7e0 100644 (file)
@@ -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);
index f9ec9add21647fb4b60c3be08f515112b4bf4a25..215871bda3a20150e88e001f364ecfa9ae052e64 100644 (file)
@@ -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;
 
index e50178c58b9707398efeae7c9ba66704d69ef9eb..b64c907aa4f06e14ce8eb3ed54d16749a273e80c 100644 (file)
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -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
@@ -960,10 +963,10 @@ 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);
@@ -971,8 +974,9 @@ 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,
index c264f7cd3e47f146d0b9fe61df32c9f874cb6c1f..3a6a1239c42b3af2e00e343edd361295e03d5354 100644 (file)
@@ -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;
index 682b73af77661a4c6260b9f450e015d86c453ede..838ffa78cfdac17e117a1a617d78a883971bb8f6 100644 (file)
@@ -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];