shmem: get_unmapped_area align huge page

[linux-2.6-microblaze.git] / mm / shmem.c

diff --git a/mm/shmem.c b/mm/shmem.c
index fd374f7..ab02b5b 100644 (file)
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1513,6 +1513,94 @@ static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
        return ret;
 }
 
+unsigned long shmem_get_unmapped_area(struct file *file,
+                                     unsigned long uaddr, unsigned long len,
+                                     unsigned long pgoff, unsigned long flags)
+{
+       unsigned long (*get_area)(struct file *,
+               unsigned long, unsigned long, unsigned long, unsigned long);
+       unsigned long addr;
+       unsigned long offset;
+       unsigned long inflated_len;
+       unsigned long inflated_addr;
+       unsigned long inflated_offset;
+
+       if (len > TASK_SIZE)
+               return -ENOMEM;
+
+       get_area = current->mm->get_unmapped_area;
+       addr = get_area(file, uaddr, len, pgoff, flags);
+
+       if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+               return addr;
+       if (IS_ERR_VALUE(addr))
+               return addr;
+       if (addr & ~PAGE_MASK)
+               return addr;
+       if (addr > TASK_SIZE - len)
+               return addr;
+
+       if (shmem_huge == SHMEM_HUGE_DENY)
+               return addr;
+       if (len < HPAGE_PMD_SIZE)
+               return addr;
+       if (flags & MAP_FIXED)
+               return addr;
+       /*
+        * Our priority is to support MAP_SHARED mapped hugely;
+        * and support MAP_PRIVATE mapped hugely too, until it is COWed.
+        * But if caller specified an address hint, respect that as before.
+        */
+       if (uaddr)
+               return addr;
+
+       if (shmem_huge != SHMEM_HUGE_FORCE) {
+               struct super_block *sb;
+
+               if (file) {
+                       VM_BUG_ON(file->f_op != &shmem_file_operations);
+                       sb = file_inode(file)->i_sb;
+               } else {
+                       /*
+                        * Called directly from mm/mmap.c, or drivers/char/mem.c
+                        * for "/dev/zero", to create a shared anonymous object.
+                        */
+                       if (IS_ERR(shm_mnt))
+                               return addr;
+                       sb = shm_mnt->mnt_sb;
+               }
+               if (SHMEM_SB(sb)->huge != SHMEM_HUGE_NEVER)
+                       return addr;
+       }
+
+       offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1);
+       if (offset && offset + len < 2 * HPAGE_PMD_SIZE)
+               return addr;
+       if ((addr & (HPAGE_PMD_SIZE-1)) == offset)
+               return addr;
+
+       inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE;
+       if (inflated_len > TASK_SIZE)
+               return addr;
+       if (inflated_len < len)
+               return addr;
+
+       inflated_addr = get_area(NULL, 0, inflated_len, 0, flags);
+       if (IS_ERR_VALUE(inflated_addr))
+               return addr;
+       if (inflated_addr & ~PAGE_MASK)
+               return addr;
+
+       inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1);
+       inflated_addr += offset - inflated_offset;
+       if (inflated_offset > offset)
+               inflated_addr += HPAGE_PMD_SIZE;
+
+       if (inflated_addr > TASK_SIZE - len)
+               return addr;
+       return inflated_addr;
+}
+
 #ifdef CONFIG_NUMA
 static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol)
 {
@@ -3261,6 +3349,7 @@ static const struct address_space_operations shmem_aops = {
 
 static const struct file_operations shmem_file_operations = {
        .mmap           = shmem_mmap,
+       .get_unmapped_area = shmem_get_unmapped_area,
 #ifdef CONFIG_TMPFS
        .llseek         = shmem_file_llseek,
        .read_iter      = shmem_file_read_iter,
@@ -3496,6 +3585,15 @@ void shmem_unlock_mapping(struct address_space *mapping)
 {
 }
 
+#ifdef CONFIG_MMU
+unsigned long shmem_get_unmapped_area(struct file *file,
+                                     unsigned long addr, unsigned long len,
+                                     unsigned long pgoff, unsigned long flags)
+{
+       return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+}
+#endif
+
 void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
 {
        truncate_inode_pages_range(inode->i_mapping, lstart, lend);