diff options
| -rw-r--r-- | include/linux/shmem_fs.h | 6 | ||||
| -rw-r--r-- | mm/shmem.c | 62 |
2 files changed, 51 insertions, 17 deletions
diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h index a7d6bd2a918f..b6c3540e07bc 100644 --- a/include/linux/shmem_fs.h +++ b/include/linux/shmem_fs.h @@ -137,9 +137,15 @@ extern int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, pmd_t *dst_pmd, unsigned long dst_addr, unsigned long src_addr, struct page **pagep); +extern int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, + pmd_t *dst_pmd, + struct vm_area_struct *dst_vma, + unsigned long dst_addr); #else #define shmem_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \ src_addr, pagep) ({ BUG(); 0; }) +#define shmem_mfill_zeropage_pte(dst_mm, dst_pmd, dst_vma, \ + dst_addr) ({ BUG(); 0; }) #endif #endif diff --git a/mm/shmem.c b/mm/shmem.c index b7d84c4f2a5c..64bdc91187f7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2207,12 +2207,13 @@ bool shmem_mapping(struct address_space *mapping) return mapping->a_ops == &shmem_aops; } -int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, - pmd_t *dst_pmd, - struct vm_area_struct *dst_vma, - unsigned long dst_addr, - unsigned long src_addr, - struct page **pagep) +static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm, + pmd_t *dst_pmd, + struct vm_area_struct *dst_vma, + unsigned long dst_addr, + unsigned long src_addr, + bool zeropage, + struct page **pagep) { struct inode *inode = file_inode(dst_vma->vm_file); struct shmem_inode_info *info = SHMEM_I(inode); @@ -2235,17 +2236,22 @@ int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, if (!page) goto out_unacct_blocks; - page_kaddr = kmap_atomic(page); - ret = copy_from_user(page_kaddr, (const void __user *)src_addr, - PAGE_SIZE); - kunmap_atomic(page_kaddr); - - /* fallback to copy_from_user outside mmap_sem */ - if (unlikely(ret)) { - *pagep = page; - shmem_inode_unacct_blocks(inode, 1); - /* don't free the page */ - return -EFAULT; + if (!zeropage) { /* mcopy_atomic */ + page_kaddr = kmap_atomic(page); + ret = copy_from_user(page_kaddr, + (const void __user *)src_addr, + PAGE_SIZE); + kunmap_atomic(page_kaddr); + + /* fallback to copy_from_user outside mmap_sem */ + if (unlikely(ret)) { + *pagep = page; + shmem_inode_unacct_blocks(inode, 1); + /* don't free the page */ + return -EFAULT; + } + } else { /* mfill_zeropage_atomic */ + clear_highpage(page); } } else { page = *pagep; @@ -2311,6 +2317,28 @@ out_unacct_blocks: goto out; } +int shmem_mcopy_atomic_pte(struct mm_struct *dst_mm, + pmd_t *dst_pmd, + struct vm_area_struct *dst_vma, + unsigned long dst_addr, + unsigned long src_addr, + struct page **pagep) +{ + return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, + dst_addr, src_addr, false, pagep); +} + +int shmem_mfill_zeropage_pte(struct mm_struct *dst_mm, + pmd_t *dst_pmd, + struct vm_area_struct *dst_vma, + unsigned long dst_addr) +{ + struct page *page = NULL; + + return shmem_mfill_atomic_pte(dst_mm, dst_pmd, dst_vma, + dst_addr, 0, true, &page); +} + #ifdef CONFIG_TMPFS static const struct inode_operations shmem_symlink_inode_operations; static const struct inode_operations shmem_short_symlink_operations; |