[PATCH] Remove unnecessary BUG_ON in irq.c
[linux/fpc-iii.git] / mm / msync.c
blobd0f5a1bce7cb14ecd7b74b960e87c8b079024020
1 /*
2 * linux/mm/msync.c
4 * Copyright (C) 1994-1999 Linus Torvalds
5 */
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>
17 #include <asm/pgtable.h>
18 #include <asm/tlbflush.h>
21 * Called with mm->page_table_lock held to protect against other
22 * threads/the swapper from ripping pte's out from under us.
25 static void sync_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
26 unsigned long addr, unsigned long end)
28 pte_t *pte;
30 pte = pte_offset_map(pmd, addr);
31 do {
32 unsigned long pfn;
33 struct page *page;
35 if (!pte_present(*pte))
36 continue;
37 if (!pte_maybe_dirty(*pte))
38 continue;
39 pfn = pte_pfn(*pte);
40 if (!pfn_valid(pfn))
41 continue;
42 page = pfn_to_page(pfn);
43 if (PageReserved(page))
44 continue;
46 if (ptep_clear_flush_dirty(vma, addr, pte) ||
47 page_test_and_clear_dirty(page))
48 set_page_dirty(page);
49 } while (pte++, addr += PAGE_SIZE, addr != end);
50 pte_unmap(pte - 1);
53 static inline void sync_pmd_range(struct vm_area_struct *vma, pud_t *pud,
54 unsigned long addr, unsigned long end)
56 pmd_t *pmd;
57 unsigned long next;
59 pmd = pmd_offset(pud, addr);
60 do {
61 next = pmd_addr_end(addr, end);
62 if (pmd_none_or_clear_bad(pmd))
63 continue;
64 sync_pte_range(vma, pmd, addr, next);
65 } while (pmd++, addr = next, addr != end);
68 static inline void sync_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
69 unsigned long addr, unsigned long end)
71 pud_t *pud;
72 unsigned long next;
74 pud = pud_offset(pgd, addr);
75 do {
76 next = pud_addr_end(addr, end);
77 if (pud_none_or_clear_bad(pud))
78 continue;
79 sync_pmd_range(vma, pud, addr, next);
80 } while (pud++, addr = next, addr != end);
83 static void sync_page_range(struct vm_area_struct *vma,
84 unsigned long addr, unsigned long end)
86 struct mm_struct *mm = vma->vm_mm;
87 pgd_t *pgd;
88 unsigned long next;
90 /* For hugepages we can't go walking the page table normally,
91 * but that's ok, hugetlbfs is memory based, so we don't need
92 * to do anything more on an msync() */
93 if (is_vm_hugetlb_page(vma))
94 return;
96 BUG_ON(addr >= end);
97 pgd = pgd_offset(mm, addr);
98 flush_cache_range(vma, addr, end);
99 spin_lock(&mm->page_table_lock);
100 do {
101 next = pgd_addr_end(addr, end);
102 if (pgd_none_or_clear_bad(pgd))
103 continue;
104 sync_pud_range(vma, pgd, addr, next);
105 } while (pgd++, addr = next, addr != end);
106 spin_unlock(&mm->page_table_lock);
109 #ifdef CONFIG_PREEMPT
110 static inline void filemap_sync(struct vm_area_struct *vma,
111 unsigned long addr, unsigned long end)
113 const size_t chunk = 64 * 1024; /* bytes */
114 unsigned long next;
116 do {
117 next = addr + chunk;
118 if (next > end || next < addr)
119 next = end;
120 sync_page_range(vma, addr, next);
121 cond_resched();
122 } while (addr = next, addr != end);
124 #else
125 static inline void filemap_sync(struct vm_area_struct *vma,
126 unsigned long addr, unsigned long end)
128 sync_page_range(vma, addr, end);
130 #endif
133 * MS_SYNC syncs the entire file - including mappings.
135 * MS_ASYNC does not start I/O (it used to, up to 2.5.67). Instead, it just
136 * marks the relevant pages dirty. The application may now run fsync() to
137 * write out the dirty pages and wait on the writeout and check the result.
138 * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
139 * async writeout immediately.
140 * So my _not_ starting I/O in MS_ASYNC we provide complete flexibility to
141 * applications.
143 static int msync_interval(struct vm_area_struct *vma,
144 unsigned long addr, unsigned long end, int flags)
146 int ret = 0;
147 struct file *file = vma->vm_file;
149 if ((flags & MS_INVALIDATE) && (vma->vm_flags & VM_LOCKED))
150 return -EBUSY;
152 if (file && (vma->vm_flags & VM_SHARED)) {
153 filemap_sync(vma, addr, end);
155 if (flags & MS_SYNC) {
156 struct address_space *mapping = file->f_mapping;
157 int err;
159 ret = filemap_fdatawrite(mapping);
160 if (file->f_op && file->f_op->fsync) {
162 * We don't take i_sem here because mmap_sem
163 * is already held.
165 err = file->f_op->fsync(file,file->f_dentry,1);
166 if (err && !ret)
167 ret = err;
169 err = filemap_fdatawait(mapping);
170 if (!ret)
171 ret = err;
174 return ret;
177 asmlinkage long sys_msync(unsigned long start, size_t len, int flags)
179 unsigned long end;
180 struct vm_area_struct *vma;
181 int unmapped_error, error = -EINVAL;
183 if (flags & MS_SYNC)
184 current->flags |= PF_SYNCWRITE;
186 down_read(&current->mm->mmap_sem);
187 if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
188 goto out;
189 if (start & ~PAGE_MASK)
190 goto out;
191 if ((flags & MS_ASYNC) && (flags & MS_SYNC))
192 goto out;
193 error = -ENOMEM;
194 len = (len + ~PAGE_MASK) & PAGE_MASK;
195 end = start + len;
196 if (end < start)
197 goto out;
198 error = 0;
199 if (end == start)
200 goto out;
202 * If the interval [start,end) covers some unmapped address ranges,
203 * just ignore them, but return -ENOMEM at the end.
205 vma = find_vma(current->mm, start);
206 unmapped_error = 0;
207 for (;;) {
208 /* Still start < end. */
209 error = -ENOMEM;
210 if (!vma)
211 goto out;
212 /* Here start < vma->vm_end. */
213 if (start < vma->vm_start) {
214 unmapped_error = -ENOMEM;
215 start = vma->vm_start;
217 /* Here vma->vm_start <= start < vma->vm_end. */
218 if (end <= vma->vm_end) {
219 if (start < end) {
220 error = msync_interval(vma, start, end, flags);
221 if (error)
222 goto out;
224 error = unmapped_error;
225 goto out;
227 /* Here vma->vm_start <= start < vma->vm_end < end. */
228 error = msync_interval(vma, start, vma->vm_end, flags);
229 if (error)
230 goto out;
231 start = vma->vm_end;
232 vma = vma->vm_next;
234 out:
235 up_read(&current->mm->mmap_sem);
236 current->flags &= ~PF_SYNCWRITE;
237 return error;