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Message-ID: <20230308221932.1548827-3-axelrasmussen@google.com>
Date: Wed, 8 Mar 2023 14:19:30 -0800
From: Axel Rasmussen <axelrasmussen@...gle.com>
To: Alexander Viro <viro@...iv.linux.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Hugh Dickins <hughd@...gle.com>, Jan Kara <jack@...e.cz>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Matthew Wilcox <willy@...radead.org>,
Mike Kravetz <mike.kravetz@...cle.com>,
Mike Rapoport <rppt@...nel.org>,
Muchun Song <muchun.song@...ux.dev>,
Nadav Amit <namit@...are.com>, Peter Xu <peterx@...hat.com>,
Shuah Khan <shuah@...nel.org>
Cc: James Houghton <jthoughton@...gle.com>,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
Axel Rasmussen <axelrasmussen@...gle.com>
Subject: [PATCH v4 2/4] mm: userfaultfd: don't pass around both mm and vma
Quite a few userfaultfd functions took both mm and vma pointers as
arguments. Since the mm is trivially accessible via vma->vm_mm, there's
no reason to pass both; it just needlessly extends the already long
argument list.
Get rid of the mm pointer, where possible, to shorten the argument list.
Acked-by: Peter Xu <peterx@...hat.com>
Signed-off-by: Axel Rasmussen <axelrasmussen@...gle.com>
---
fs/userfaultfd.c | 2 +-
include/linux/hugetlb.h | 5 ++-
include/linux/shmem_fs.h | 4 +--
include/linux/userfaultfd_k.h | 4 +--
mm/hugetlb.c | 4 +--
mm/shmem.c | 7 ++--
mm/userfaultfd.c | 61 +++++++++++++++++------------------
7 files changed, 41 insertions(+), 46 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 365bf00dd8dd..84d5d402214a 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1629,7 +1629,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
/* Reset ptes for the whole vma range if wr-protected */
if (userfaultfd_wp(vma))
- uffd_wp_range(mm, vma, start, vma_end - start, false);
+ uffd_wp_range(vma, start, vma_end - start, false);
new_flags = vma->vm_flags & ~__VM_UFFD_FLAGS;
prev = vma_merge(&vmi, mm, prev, start, vma_end, new_flags,
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 8f0467bf1cbd..8b9325f77ac3 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -158,7 +158,7 @@ unsigned long hugetlb_total_pages(void);
vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags);
#ifdef CONFIG_USERFAULTFD
-int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
+int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
@@ -393,8 +393,7 @@ static inline void hugetlb_free_pgd_range(struct mmu_gather *tlb,
}
#ifdef CONFIG_USERFAULTFD
-static inline int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm,
- pte_t *dst_pte,
+static inline int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 103d1000a5a2..b82916c25e61 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -151,14 +151,14 @@ extern void shmem_uncharge(struct inode *inode, long pages);
#ifdef CONFIG_USERFAULTFD
#ifdef CONFIG_SHMEM
-extern int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
+extern 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,
struct page **pagep);
#else /* !CONFIG_SHMEM */
-#define shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr, \
+#define shmem_mfill_atomic_pte(dst_pmd, dst_vma, dst_addr, \
src_addr, zeropage, wp_copy, pagep) ({ BUG(); 0; })
#endif /* CONFIG_SHMEM */
#endif /* CONFIG_USERFAULTFD */
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 468080125612..ba79e296fcc7 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -56,7 +56,7 @@ enum mcopy_atomic_mode {
MCOPY_ATOMIC_CONTINUE,
};
-extern int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
+extern 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);
@@ -73,7 +73,7 @@ extern ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long dst
extern int mwriteprotect_range(struct mm_struct *dst_mm,
unsigned long start, unsigned long len,
bool enable_wp, atomic_t *mmap_changing);
-extern long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma,
+extern long uffd_wp_range(struct vm_area_struct *vma,
unsigned long start, unsigned long len, bool enable_wp);
/* mm helpers */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4c9276549394..fe043034ab46 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6157,8 +6157,7 @@ vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
* Used by userfaultfd UFFDIO_* ioctls. Based on userfaultfd's mfill_atomic_pte
* with modifications for hugetlb pages.
*/
-int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm,
- pte_t *dst_pte,
+int hugetlb_mfill_atomic_pte(pte_t *dst_pte,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
@@ -6166,6 +6165,7 @@ int hugetlb_mfill_atomic_pte(struct mm_struct *dst_mm,
struct page **pagep,
bool wp_copy)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
struct hstate *h = hstate_vma(dst_vma);
struct address_space *mapping = dst_vma->vm_file->f_mapping;
diff --git a/mm/shmem.c b/mm/shmem.c
index 448f393d8ab2..1d751b6cf1ac 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2415,8 +2415,7 @@ static struct inode *shmem_get_inode(struct mnt_idmap *idmap, struct super_block
}
#ifdef CONFIG_USERFAULTFD
-int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
- pmd_t *dst_pmd,
+int shmem_mfill_atomic_pte(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
@@ -2506,11 +2505,11 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
goto out_release;
ret = shmem_add_to_page_cache(folio, mapping, pgoff, NULL,
- gfp & GFP_RECLAIM_MASK, dst_mm);
+ gfp & GFP_RECLAIM_MASK, dst_vma->vm_mm);
if (ret)
goto out_release;
- ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
+ ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
&folio->page, true, wp_copy);
if (ret)
goto out_delete_from_cache;
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 84db5b2fad3a..4fc373476739 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -55,12 +55,13 @@ struct vm_area_struct *find_dst_vma(struct mm_struct *dst_mm,
* This function handles both MCOPY_ATOMIC_NORMAL and _CONTINUE for both shmem
* and anon, and for both shared and private VMAs.
*/
-int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
+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)
{
int ret;
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
pte_t _dst_pte, *dst_pte;
bool writable = dst_vma->vm_flags & VM_WRITE;
bool vm_shared = dst_vma->vm_flags & VM_SHARED;
@@ -127,8 +128,7 @@ int mfill_atomic_install_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd,
return ret;
}
-static int mfill_atomic_pte_copy(struct mm_struct *dst_mm,
- pmd_t *dst_pmd,
+static int mfill_atomic_pte_copy(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
unsigned long src_addr,
@@ -190,10 +190,10 @@ static int mfill_atomic_pte_copy(struct mm_struct *dst_mm,
__SetPageUptodate(page);
ret = -ENOMEM;
- if (mem_cgroup_charge(page_folio(page), dst_mm, GFP_KERNEL))
+ if (mem_cgroup_charge(page_folio(page), dst_vma->vm_mm, GFP_KERNEL))
goto out_release;
- ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
+ ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
page, true, wp_copy);
if (ret)
goto out_release;
@@ -204,8 +204,7 @@ static int mfill_atomic_pte_copy(struct mm_struct *dst_mm,
goto out;
}
-static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm,
- pmd_t *dst_pmd,
+static int mfill_atomic_pte_zeropage(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr)
{
@@ -217,7 +216,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm,
_dst_pte = pte_mkspecial(pfn_pte(my_zero_pfn(dst_addr),
dst_vma->vm_page_prot));
- dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
+ dst_pte = pte_offset_map_lock(dst_vma->vm_mm, dst_pmd, dst_addr, &ptl);
if (dst_vma->vm_file) {
/* the shmem MAP_PRIVATE case requires checking the i_size */
inode = dst_vma->vm_file->f_inode;
@@ -230,7 +229,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm,
ret = -EEXIST;
if (!pte_none(*dst_pte))
goto out_unlock;
- set_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
+ set_pte_at(dst_vma->vm_mm, dst_addr, dst_pte, _dst_pte);
/* No need to invalidate - it was non-present before */
update_mmu_cache(dst_vma, dst_addr, dst_pte);
ret = 0;
@@ -240,8 +239,7 @@ static int mfill_atomic_pte_zeropage(struct mm_struct *dst_mm,
}
/* Handles UFFDIO_CONTINUE for all shmem VMAs (shared or private). */
-static int mfill_atomic_pte_continue(struct mm_struct *dst_mm,
- pmd_t *dst_pmd,
+static int mfill_atomic_pte_continue(pmd_t *dst_pmd,
struct vm_area_struct *dst_vma,
unsigned long dst_addr,
bool wp_copy)
@@ -269,7 +267,7 @@ static int mfill_atomic_pte_continue(struct mm_struct *dst_mm,
goto out_release;
}
- ret = mfill_atomic_install_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
+ ret = mfill_atomic_install_pte(dst_pmd, dst_vma, dst_addr,
page, false, wp_copy);
if (ret)
goto out_release;
@@ -310,7 +308,7 @@ static pmd_t *mm_alloc_pmd(struct mm_struct *mm, unsigned long address)
* mfill_atomic processing for HUGETLB vmas. Note that this routine is
* called with mmap_lock held, it will release mmap_lock before returning.
*/
-static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm,
+static __always_inline ssize_t mfill_atomic_hugetlb(
struct vm_area_struct *dst_vma,
unsigned long dst_start,
unsigned long src_start,
@@ -318,6 +316,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm,
enum mcopy_atomic_mode mode,
bool wp_copy)
{
+ struct mm_struct *dst_mm = dst_vma->vm_mm;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
ssize_t err;
pte_t *dst_pte;
@@ -411,7 +410,7 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm,
goto out_unlock;
}
- err = hugetlb_mfill_atomic_pte(dst_mm, dst_pte, dst_vma,
+ err = hugetlb_mfill_atomic_pte(dst_pte, dst_vma,
dst_addr, src_addr, mode, &page,
wp_copy);
@@ -463,17 +462,15 @@ static __always_inline ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm,
}
#else /* !CONFIG_HUGETLB_PAGE */
/* fail at build time if gcc attempts to use this */
-extern ssize_t mfill_atomic_hugetlb(struct mm_struct *dst_mm,
- 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);
+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);
#endif /* CONFIG_HUGETLB_PAGE */
-static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
- pmd_t *dst_pmd,
+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,
@@ -484,7 +481,7 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
ssize_t err;
if (mode == MCOPY_ATOMIC_CONTINUE) {
- return mfill_atomic_pte_continue(dst_mm, dst_pmd, dst_vma,
+ return mfill_atomic_pte_continue(dst_pmd, dst_vma,
dst_addr, wp_copy);
}
@@ -500,14 +497,14 @@ static __always_inline ssize_t mfill_atomic_pte(struct mm_struct *dst_mm,
*/
if (!(dst_vma->vm_flags & VM_SHARED)) {
if (mode == MCOPY_ATOMIC_NORMAL)
- err = mfill_atomic_pte_copy(dst_mm, dst_pmd, dst_vma,
+ err = mfill_atomic_pte_copy(dst_pmd, dst_vma,
dst_addr, src_addr, page,
wp_copy);
else
- err = mfill_atomic_pte_zeropage(dst_mm, dst_pmd,
+ err = mfill_atomic_pte_zeropage(dst_pmd,
dst_vma, dst_addr);
} else {
- err = shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma,
+ err = shmem_mfill_atomic_pte(dst_pmd, dst_vma,
dst_addr, src_addr,
mode != MCOPY_ATOMIC_NORMAL,
wp_copy, page);
@@ -588,7 +585,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
* If this is a HUGETLB vma, pass off to appropriate routine
*/
if (is_vm_hugetlb_page(dst_vma))
- return mfill_atomic_hugetlb(dst_mm, dst_vma, dst_start,
+ return mfill_atomic_hugetlb(dst_vma, dst_start,
src_start, len, mcopy_mode,
wp_copy);
@@ -641,7 +638,7 @@ static __always_inline ssize_t mfill_atomic(struct mm_struct *dst_mm,
BUG_ON(pmd_none(*dst_pmd));
BUG_ON(pmd_trans_huge(*dst_pmd));
- err = mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, dst_addr,
+ err = mfill_atomic_pte(dst_pmd, dst_vma, dst_addr,
src_addr, &page, mcopy_mode, wp_copy);
cond_resched();
@@ -710,7 +707,7 @@ ssize_t mfill_atomic_continue(struct mm_struct *dst_mm, unsigned long start,
mmap_changing, 0);
}
-long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
+long uffd_wp_range(struct vm_area_struct *dst_vma,
unsigned long start, unsigned long len, bool enable_wp)
{
unsigned int mm_cp_flags;
@@ -730,7 +727,7 @@ long uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
*/
if (!enable_wp && vma_wants_manual_pte_write_upgrade(dst_vma))
mm_cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
- tlb_gather_mmu(&tlb, dst_mm);
+ tlb_gather_mmu(&tlb, dst_vma->vm_mm);
ret = change_protection(&tlb, dst_vma, start, start + len, mm_cp_flags);
tlb_finish_mmu(&tlb);
@@ -782,7 +779,7 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
goto out_unlock;
}
- err = uffd_wp_range(dst_mm, dst_vma, start, len, enable_wp);
+ err = uffd_wp_range(dst_vma, start, len, enable_wp);
/* Return 0 on success, <0 on failures */
if (err > 0)
--
2.40.0.rc1.284.g88254d51c5-goog
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