Merge branch 'master'
[pandora-kernel.git] / mm / msync.c
1 /*
2  *      linux/mm/msync.c
3  *
4  * Copyright (C) 1994-1999  Linus Torvalds
5  */
6
7 /*
8  * The msync() system call.
9  */
10 #include <linux/slab.h>
11 #include <linux/pagemap.h>
12 #include <linux/mm.h>
13 #include <linux/mman.h>
14 #include <linux/hugetlb.h>
15 #include <linux/syscalls.h>
16
17 #include <asm/pgtable.h>
18 #include <asm/tlbflush.h>
19
20 static void msync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
21                                 unsigned long addr, unsigned long end)
22 {
23         pte_t *pte;
24         spinlock_t *ptl;
25         int progress = 0;
26
27 again:
28         pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
29         do {
30                 struct page *page;
31
32                 if (progress >= 64) {
33                         progress = 0;
34                         if (need_resched() || need_lockbreak(ptl))
35                                 break;
36                 }
37                 progress++;
38                 if (!pte_present(*pte))
39                         continue;
40                 if (!pte_maybe_dirty(*pte))
41                         continue;
42                 page = vm_normal_page(vma, addr, *pte);
43                 if (!page)
44                         continue;
45                 if (ptep_clear_flush_dirty(vma, addr, pte) ||
46                     page_test_and_clear_dirty(page))
47                         set_page_dirty(page);
48                 progress += 3;
49         } while (pte++, addr += PAGE_SIZE, addr != end);
50         pte_unmap_unlock(pte - 1, ptl);
51         cond_resched();
52         if (addr != end)
53                 goto again;
54 }
55
56 static inline void msync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
57                                 unsigned long addr, unsigned long end)
58 {
59         pmd_t *pmd;
60         unsigned long next;
61
62         pmd = pmd_offset(pud, addr);
63         do {
64                 next = pmd_addr_end(addr, end);
65                 if (pmd_none_or_clear_bad(pmd))
66                         continue;
67                 msync_pte_range(vma, pmd, addr, next);
68         } while (pmd++, addr = next, addr != end);
69 }
70
71 static inline void msync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
72                                 unsigned long addr, unsigned long end)
73 {
74         pud_t *pud;
75         unsigned long next;
76
77         pud = pud_offset(pgd, addr);
78         do {
79                 next = pud_addr_end(addr, end);
80                 if (pud_none_or_clear_bad(pud))
81                         continue;
82                 msync_pmd_range(vma, pud, addr, next);
83         } while (pud++, addr = next, addr != end);
84 }
85
86 static void msync_page_range(struct vm_area_struct *vma,
87                                 unsigned long addr, unsigned long end)
88 {
89         pgd_t *pgd;
90         unsigned long next;
91
92         /* For hugepages we can't go walking the page table normally,
93          * but that's ok, hugetlbfs is memory based, so we don't need
94          * to do anything more on an msync().
95          */
96         if (vma->vm_flags & VM_HUGETLB)
97                 return;
98
99         BUG_ON(addr >= end);
100         pgd = pgd_offset(vma->vm_mm, addr);
101         flush_cache_range(vma, addr, end);
102         do {
103                 next = pgd_addr_end(addr, end);
104                 if (pgd_none_or_clear_bad(pgd))
105                         continue;
106                 msync_pud_range(vma, pgd, addr, next);
107         } while (pgd++, addr = next, addr != end);
108 }
109
110 /*
111  * MS_SYNC syncs the entire file - including mappings.
112  *
113  * MS_ASYNC does not start I/O (it used to, up to 2.5.67).  Instead, it just
114  * marks the relevant pages dirty.  The application may now run fsync() to
115  * write out the dirty pages and wait on the writeout and check the result.
116  * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
117  * async writeout immediately.
118  * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to
119  * applications.
120  */
121 static int msync_interval(struct vm_area_struct *vma,
122                         unsigned long addr, unsigned long end, int flags)
123 {
124         int ret = 0;
125         struct file *file = vma->vm_file;
126
127         if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
128                 return -EBUSY;
129
130         if (file && (vma->vm_flags & VM_SHARED)) {
131                 msync_page_range(vma, addr, end);
132
133                 if (flags & MS_SYNC) {
134                         struct address_space *mapping = file->f_mapping;
135                         int err;
136
137                         ret = filemap_fdatawrite(mapping);
138                         if (file->f_op && file->f_op->fsync) {
139                                 /*
140                                  * We don't take i_sem here because mmap_sem
141                                  * is already held.
142                                  */
143                                 err = file->f_op->fsync(file,file->f_dentry,1);
144                                 if (err && !ret)
145                                         ret = err;
146                         }
147                         err = filemap_fdatawait(mapping);
148                         if (!ret)
149                                 ret = err;
150                 }
151         }
152         return ret;
153 }
154
155 asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
156 {
157         unsigned long end;
158         struct vm_area_struct *vma;
159         int unmapped_error, error = -EINVAL;
160
161         if (flags & MS_SYNC)
162                 current->flags |= PF_SYNCWRITE;
163
164         down_read(&current->mm->mmap_sem);
165         if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
166                 goto out;
167         if (start & ~PAGE_MASK)
168                 goto out;
169         if ((flags & MS_ASYNC) && (flags & MS_SYNC))
170                 goto out;
171         error = -ENOMEM;
172         len = (len + ~PAGE_MASK) & PAGE_MASK;
173         end = start + len;
174         if (end < start)
175                 goto out;
176         error = 0;
177         if (end == start)
178                 goto out;
179         /*
180          * If the interval [start,end) covers some unmapped address ranges,
181          * just ignore them, but return -ENOMEM at the end.
182          */
183         vma = find_vma(current->mm, start);
184         unmapped_error = 0;
185         for (;;) {
186                 /* Still start < end. */
187                 error = -ENOMEM;
188                 if (!vma)
189                         goto out;
190                 /* Here start < vma->vm_end. */
191                 if (start < vma->vm_start) {
192                         unmapped_error = -ENOMEM;
193                         start = vma->vm_start;
194                 }
195                 /* Here vma->vm_start <= start < vma->vm_end. */
196                 if (end <= vma->vm_end) {
197                         if (start < end) {
198                                 error = msync_interval(vma, start, end, flags);
199                                 if (error)
200                                         goto out;
201                         }
202                         error = unmapped_error;
203                         goto out;
204                 }
205                 /* Here vma->vm_start <= start < vma->vm_end < end. */
206                 error = msync_interval(vma, start, vma->vm_end, flags);
207                 if (error)
208                         goto out;
209                 start = vma->vm_end;
210                 vma = vma->vm_next;
211         }
212 out:
213         up_read(&current->mm->mmap_sem);
214         current->flags &= ~PF_SYNCWRITE;
215         return error;
216 }