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authorAxel Rasmussen2023-03-14 15:12:49 -0700
committerAndrew Morton2023-04-05 19:42:48 -0700
commitd9712937037e0ce887920f321429826e9dbfd960 (patch)
tree6471b4a9899a53bc761f464ba7d89d05e594b25d /mm
parent61c5004022f56c443b86800e8985d8803f3a22aa (diff)
mm: userfaultfd: combine 'mode' and 'wp_copy' arguments
Many userfaultfd ioctl functions take both a 'mode' and a 'wp_copy' argument. In future commits we plan to plumb the flags through to more places, so we'd be proliferating the very long argument list even further. Let's take the time to simplify the argument list. Combine the two arguments into one - and generalize, so when we add more flags in the future, it doesn't imply more function arguments. Since the modes (copy, zeropage, continue) are mutually exclusive, store them as an integer value (0, 1, 2) in the low bits. Place combine-able flag bits in the high bits. This is quite similar to an earlier patch proposed by Nadav Amit ("userfaultfd: introduce uffd_flags" [1]). The main difference is that patch only handled flags, whereas this patch *also* combines the "mode" argument into the same type to shorten the argument list. [1]: https://lore.kernel.org/all/20220619233449.181323-2-namit@vmware.com/ Link: https://lkml.kernel.org/r/20230314221250.682452-4-axelrasmussen@google.com Signed-off-by: Axel Rasmussen <axelrasmussen@google.com> Acked-by: James Houghton <jthoughton@google.com> Acked-by: Peter Xu <peterx@redhat.com> Acked-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Shuah Khan <shuah@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c12
-rw-r--r--mm/shmem.c7
-rw-r--r--mm/userfaultfd.c76
3 files changed, 43 insertions, 52 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6dc32cccbd9b..8bfd07f4c143 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6163,12 +6163,12 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
- enum mcopy_atomic_mode mode,
- struct page **pagep,
- bool wp_copy)
+ uffd_flags_t flags,
+ struct page **pagep)
{
struct mm_struct *dst_mm = dst_vma->vm_mm;
- bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
+ bool is_continue = uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE);
+ bool wp_enabled = (flags & MFILL_ATOMIC_WP);
struct hstate *h = hstate_vma(dst_vma);
struct address_space *mapping = dst_vma->vm_file->f_mapping;
pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
@@ -6303,7 +6303,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
* For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY
* with wp flag set, don't set pte write bit.
*/
- if (wp_copy || (is_continue && !vm_shared))
+ if (wp_enabled || (is_continue && !vm_shared))
writable = 0;
else
writable = dst_vma->vm_flags & VM_WRITE;
@@ -6318,7 +6318,7 @@ int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
_dst_pte = huge_pte_mkdirty(_dst_pte);
_dst_pte = pte_mkyoung(_dst_pte);
- if (wp_copy)
+ if (wp_enabled)
_dst_pte = huge_pte_mkuffd_wp(_dst_pte);
set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
diff --git a/mm/shmem.c b/mm/shmem.c
index 9d13b9a64144..b185c1db3009 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -76,7 +76,6 @@ static struct vfsmount *shm_mnt;
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <uapi/linux/memfd.h>
-#include <linux/userfaultfd_k.h>
#include <linux/rmap.h>
#include <linux/uuid.h>
@@ -2433,7 +2432,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
- bool zeropage, bool wp_copy,
+ uffd_flags_t flags,
struct page **pagep)
{
struct inode *inode = file_inode(dst_vma->vm_file);
@@ -2465,7 +2464,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
if (!folio)
goto out_unacct_blocks;
- if (!zeropage) { /* COPY */
+ if (uffd_flags_mode_is(flags, MFILL_ATOMIC_COPY)) {
page_kaddr = kmap_local_folio(folio, 0);
/*
* The read mmap_lock is held here. Despite the
@@ -2524,7 +2523,7 @@ int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
goto out_release;
ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
- &folio->page, true, wp_copy);
+ &folio->page, true, flags);
if (ret)
goto out_delete_from_cache;
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index c3cc6cb04548..a9b19b39413d 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -58,7 +58,7 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,
int mfill_atomic_install_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr, struct page *page,
- bool newly_allocated, bool wp_copy)
+ bool newly_allocated, uffd_flags_t flags)
{
int ret;
struct mm_struct *dst_mm = dst_vma->vm_mm;
@@ -77,7 +77,7 @@ int mfill_atomic_install_pte(pmd_t *dst_pmd,
writable = false;
if (writable)
_dst_pte = pte_mkwrite(_dst_pte);
- if (wp_copy)
+ if (flags & MFILL_ATOMIC_WP)
_dst_pte = pte_mkuffd_wp(_dst_pte);
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
@@ -132,8 +132,8 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
- struct page **pagep,
- bool wp_copy)
+ uffd_flags_t flags,
+ struct page **pagep)
{
void *page_kaddr;
int ret;
@@ -194,7 +194,7 @@ static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
goto out_release;
ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
- page, true, wp_copy);
+ page, true, flags);
if (ret)
goto out_release;
out:
@@ -242,7 +242,7 @@ out_unlock:
static int mfill_atomic_pte_continue(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
- bool wp_copy)
+ uffd_flags_t flags)
{
struct inode *inode = file_inode(dst_vma->vm_file);
pgoff_t pgoff = linear_page_index(dst_vma, dst_addr);
@@ -268,7 +268,7 @@ static int mfill_atomic_pte_continue(pmd_t *dst_pmd,
}
ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
- page, false, wp_copy);
+ page, false, flags);
if (ret)
goto out_release;
@@ -313,8 +313,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- enum mcopy_atomic_mode mode,
- bool wp_copy)
+ uffd_flags_t flags)
{
struct mm_struct *dst_mm = dst_vma->vm_mm;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
@@ -334,7 +333,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(
* by THP. Since we can not reliably insert a zero page, this
* feature is not supported.
*/
- if (mode == MCOPY_ATOMIC_ZEROPAGE) {
+ if (uffd_flags_mode_is(flags, MFILL_ATOMIC_ZEROPAGE)) {
mmap_read_unlock(dst_mm);
return -EINVAL;
}
@@ -402,7 +401,7 @@ retry:
goto out_unlock;
}
- if (mode != MCOPY_ATOMIC_CONTINUE &&
+ if (!uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE) &&
!huge_pte_none_mostly(huge_ptep_get(dst_pte))) {
err = -EEXIST;
hugetlb_vma_unlock_read(dst_vma);
@@ -410,9 +409,8 @@ retry:
goto out_unlock;
}
- err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma,
- dst_addr, src_addr, mode, &page,
- wp_copy);
+ err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma, dst_addr,
+ src_addr, flags, &page);
hugetlb_vma_unlock_read(dst_vma);
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
@@ -466,23 +464,21 @@ extern ssize_t mfill_atomic_hugetlb(struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- enum mcopy_atomic_mode mode,
- bool wp_copy);
+ uffd_flags_t flags);
#endif /* CONFIG_HUGETLB_PAGE */
static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
- struct page **page,
- enum mcopy_atomic_mode mode,
- bool wp_copy)
+ uffd_flags_t flags,
+ struct page **pagep)
{
ssize_t err;
- if (mode == MCOPY_ATOMIC_CONTINUE) {
+ if (uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE)) {
return mfill_atomic_pte_continue(dst_pmd, dst_vma,
- dst_addr, wp_copy);
+ dst_addr, flags);
}
/*
@@ -496,18 +492,17 @@ static __always_inline ssize_t mfill_atomic_pte(pmd_t *dst_pmd,
* and not in the radix tree.
*/
if (!(dst_vma->vm_flags & VM_SHARED)) {
- if (mode == MCOPY_ATOMIC_NORMAL)
+ if (uffd_flags_mode_is(flags, MFILL_ATOMIC_COPY))
err = mfill_atomic_pte_copy(dst_pmd, dst_vma,
- dst_addr, src_addr, page,
- wp_copy);
+ dst_addr, src_addr,
+ flags, pagep);
else
err = mfill_atomic_pte_zeropage(dst_pmd,
dst_vma, dst_addr);
} else {
err = shmem_mfill_atomic_pte(dst_pmd, dst_vma,
dst_addr, src_addr,
- mode != MCOPY_ATOMIC_NORMAL,
- wp_copy, page);
+ flags, pagep);
}
return err;
@@ -517,9 +512,8 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
unsigned long dst_start,
unsigned long src_start,
unsigned long len,
- enum mcopy_atomic_mode mcopy_mode,
atomic_t *mmap_changing,
- __u64 mode)
+ uffd_flags_t flags)
{
struct vm_area_struct *dst_vma;
ssize_t err;
@@ -527,7 +521,6 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
unsigned long src_addr, dst_addr;
long copied;
struct page *page;
- bool wp_copy;
/*
* Sanitize the command parameters:
@@ -577,8 +570,7 @@ retry:
* validate 'mode' now that we know the dst_vma: don't allow
* a wrprotect copy if the userfaultfd didn't register as WP.
*/
- wp_copy = mode & UFFDIO_COPY_MODE_WP;
- if (wp_copy && !(dst_vma->vm_flags & VM_UFFD_WP))
+ if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP))
goto out_unlock;
/*
@@ -586,12 +578,12 @@ retry:
*/
if (is_vm_hugetlb_page(dst_vma))
return mfill_atomic_hugetlb(dst_vma, dst_start,
- src_start, len, mcopy_mode,
- wp_copy);
+ src_start, len, flags);
if (!vma_is_anonymous(dst_vma) && !vma_is_shmem(dst_vma))
goto out_unlock;
- if (!vma_is_shmem(dst_vma) && mcopy_mode == MCOPY_ATOMIC_CONTINUE)
+ if (!vma_is_shmem(dst_vma) &&
+ uffd_flags_mode_is(flags, MFILL_ATOMIC_CONTINUE))
goto out_unlock;
/*
@@ -639,7 +631,7 @@ retry:
BUG_ON(pmd_trans_huge(*dst_pmd));
err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr,
- src_addr, &page, mcopy_mode, wp_copy);
+ src_addr, flags, &page);
cond_resched();
if (unlikely(err == -ENOENT)) {
@@ -687,24 +679,24 @@ out:
ssize_t mfill_atomic_copy(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long src_start, unsigned long len,
- atomic_t *mmap_changing, __u64 mode)
+ atomic_t *mmap_changing, uffd_flags_t flags)
{
- return mfill_atomic(dst_mm, dst_start, src_start, len,
- MCOPY_ATOMIC_NORMAL, mmap_changing, mode);
+ return mfill_atomic(dst_mm, dst_start, src_start, len, mmap_changing,
+ uffd_flags_set_mode(flags, MFILL_ATOMIC_COPY));
}
ssize_t mfill_atomic_zeropage(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, atomic_t *mmap_changing)
{
- return mfill_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_ZEROPAGE,
- mmap_changing, 0);
+ return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
+ uffd_flags_set_mode(0, MFILL_ATOMIC_ZEROPAGE));
}
ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, atomic_t *mmap_changing)
{
- return mfill_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_CONTINUE,
- mmap_changing, 0);
+ return mfill_atomic(dst_mm, start, 0, len, mmap_changing,
+ uffd_flags_set_mode(0, MFILL_ATOMIC_CONTINUE));
}
long uffd_wp_range(struct vm_area_struct *dst_vma,