[PATCH] USB: MODALIAS change for bcdDevice
[linux-2.6] / 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 /*
21  * Called with mm->page_table_lock held to protect against other
22  * threads/the swapper from ripping pte's out from under us.
23  */
24
25 static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
26                                 unsigned long addr, unsigned long end)
27 {
28         pte_t *pte;
29
30         pte = pte_offset_map(pmd, addr);
31         do {
32                 unsigned long pfn;
33                 struct page *page;
34
35                 if (!pte_present(*pte))
36                         continue;
37                 pfn = pte_pfn(*pte);
38                 if (!pfn_valid(pfn))
39                         continue;
40                 page = pfn_to_page(pfn);
41                 if (PageReserved(page))
42                         continue;
43
44                 if (ptep_clear_flush_dirty(vma, addr, pte) ||
45                     page_test_and_clear_dirty(page))
46                         set_page_dirty(page);
47         } while (pte++, addr += PAGE_SIZE, addr != end);
48         pte_unmap(pte - 1);
49 }
50
51 static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
52                                 unsigned long addr, unsigned long end)
53 {
54         pmd_t *pmd;
55         unsigned long next;
56
57         pmd = pmd_offset(pud, addr);
58         do {
59                 next = pmd_addr_end(addr, end);
60                 if (pmd_none_or_clear_bad(pmd))
61                         continue;
62                 sync_pte_range(vma, pmd, addr, next);
63         } while (pmd++, addr = next, addr != end);
64 }
65
66 static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
67                                 unsigned long addr, unsigned long end)
68 {
69         pud_t *pud;
70         unsigned long next;
71
72         pud = pud_offset(pgd, addr);
73         do {
74                 next = pud_addr_end(addr, end);
75                 if (pud_none_or_clear_bad(pud))
76                         continue;
77                 sync_pmd_range(vma, pud, addr, next);
78         } while (pud++, addr = next, addr != end);
79 }
80
81 static void sync_page_range(struct vm_area_struct *vma,
82                                 unsigned long addr, unsigned long end)
83 {
84         struct mm_struct *mm = vma->vm_mm;
85         pgd_t *pgd;
86         unsigned long next;
87
88         /* For hugepages we can't go walking the page table normally,
89          * but that's ok, hugetlbfs is memory based, so we don't need
90          * to do anything more on an msync() */
91         if (is_vm_hugetlb_page(vma))
92                 return;
93
94         BUG_ON(addr >= end);
95         pgd = pgd_offset(mm, addr);
96         flush_cache_range(vma, addr, end);
97         spin_lock(&mm->page_table_lock);
98         do {
99                 next = pgd_addr_end(addr, end);
100                 if (pgd_none_or_clear_bad(pgd))
101                         continue;
102                 sync_pud_range(vma, pgd, addr, next);
103         } while (pgd++, addr = next, addr != end);
104         spin_unlock(&mm->page_table_lock);
105 }
106
107 #ifdef CONFIG_PREEMPT
108 static inline void filemap_sync(struct vm_area_struct *vma,
109                                 unsigned long addr, unsigned long end)
110 {
111         const size_t chunk = 64 * 1024; /* bytes */
112         unsigned long next;
113
114         do {
115                 next = addr + chunk;
116                 if (next > end || next < addr)
117                         next = end;
118                 sync_page_range(vma, addr, next);
119                 cond_resched();
120         } while (addr = next, addr != end);
121 }
122 #else
123 static inline void filemap_sync(struct vm_area_struct *vma,
124                                 unsigned long addr, unsigned long end)
125 {
126         sync_page_range(vma, addr, end);
127 }
128 #endif
129
130 /*
131  * MS_SYNC syncs the entire file - including mappings.
132  *
133  * MS_ASYNC does not start I/O (it used to, up to 2.5.67).  Instead, it just
134  * marks the relevant pages dirty.  The application may now run fsync() to
135  * write out the dirty pages and wait on the writeout and check the result.
136  * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
137  * async writeout immediately.
138  * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to
139  * applications.
140  */
141 static int msync_interval(struct vm_area_struct *vma,
142                         unsigned long addr, unsigned long end, int flags)
143 {
144         int ret = 0;
145         struct file *file = vma->vm_file;
146
147         if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
148                 return -EBUSY;
149
150         if (file && (vma->vm_flags & VM_SHARED)) {
151                 filemap_sync(vma, addr, end);
152
153                 if (flags & MS_SYNC) {
154                         struct address_space *mapping = file->f_mapping;
155                         int err;
156
157                         ret = filemap_fdatawrite(mapping);
158                         if (file->f_op && file->f_op->fsync) {
159                                 /*
160                                  * We don't take i_sem here because mmap_sem
161                                  * is already held.
162                                  */
163                                 err = file->f_op->fsync(file,file->f_dentry,1);
164                                 if (err && !ret)
165                                         ret = err;
166                         }
167                         err = filemap_fdatawait(mapping);
168                         if (!ret)
169                                 ret = err;
170                 }
171         }
172         return ret;
173 }
174
175 asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
176 {
177         unsigned long end;
178         struct vm_area_struct *vma;
179         int unmapped_error, error = -EINVAL;
180
181         if (flags & MS_SYNC)
182                 current->flags |= PF_SYNCWRITE;
183
184         down_read(&current->mm->mmap_sem);
185         if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
186                 goto out;
187         if (start & ~PAGE_MASK)
188                 goto out;
189         if ((flags & MS_ASYNC) && (flags & MS_SYNC))
190                 goto out;
191         error = -ENOMEM;
192         len = (len + ~PAGE_MASK) & PAGE_MASK;
193         end = start + len;
194         if (end < start)
195                 goto out;
196         error = 0;
197         if (end == start)
198                 goto out;
199         /*
200          * If the interval [start,end) covers some unmapped address ranges,
201          * just ignore them, but return -ENOMEM at the end.
202          */
203         vma = find_vma(current->mm, start);
204         unmapped_error = 0;
205         for (;;) {
206                 /* Still start < end. */
207                 error = -ENOMEM;
208                 if (!vma)
209                         goto out;
210                 /* Here start < vma->vm_end. */
211                 if (start < vma->vm_start) {
212                         unmapped_error = -ENOMEM;
213                         start = vma->vm_start;
214                 }
215                 /* Here vma->vm_start <= start < vma->vm_end. */
216                 if (end <= vma->vm_end) {
217                         if (start < end) {
218                                 error = msync_interval(vma, start, end, flags);
219                                 if (error)
220                                         goto out;
221                         }
222                         error = unmapped_error;
223                         goto out;
224                 }
225                 /* Here vma->vm_start <= start < vma->vm_end < end. */
226                 error = msync_interval(vma, start, vma->vm_end, flags);
227                 if (error)
228                         goto out;
229                 start = vma->vm_end;
230                 vma = vma->vm_next;
231         }
232 out:
233         up_read(&current->mm->mmap_sem);
234         current->flags &= ~PF_SYNCWRITE;
235         return error;
236 }