mm, hotplug: fix error handling in mem_online_node()
[linux-2.6.git] / mm / pagewalk.c
1 #include <linux/mm.h>
2 #include <linux/highmem.h>
3 #include <linux/sched.h>
4 #include <linux/hugetlb.h>
5
6 static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
7                           struct mm_walk *walk)
8 {
9         pte_t *pte;
10         int err = 0;
11
12         pte = pte_offset_map(pmd, addr);
13         for (;;) {
14                 err = walk->pte_entry(pte, addr, addr + PAGE_SIZE, walk);
15                 if (err)
16                        break;
17                 addr += PAGE_SIZE;
18                 if (addr == end)
19                         break;
20                 pte++;
21         }
22
23         pte_unmap(pte);
24         return err;
25 }
26
27 static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end,
28                           struct mm_walk *walk)
29 {
30         pmd_t *pmd;
31         unsigned long next;
32         int err = 0;
33
34         pmd = pmd_offset(pud, addr);
35         do {
36 again:
37                 next = pmd_addr_end(addr, end);
38                 if (pmd_none(*pmd)) {
39                         if (walk->pte_hole)
40                                 err = walk->pte_hole(addr, next, walk);
41                         if (err)
42                                 break;
43                         continue;
44                 }
45                 /*
46                  * This implies that each ->pmd_entry() handler
47                  * needs to know about pmd_trans_huge() pmds
48                  */
49                 if (walk->pmd_entry)
50                         err = walk->pmd_entry(pmd, addr, next, walk);
51                 if (err)
52                         break;
53
54                 /*
55                  * Check this here so we only break down trans_huge
56                  * pages when we _need_ to
57                  */
58                 if (!walk->pte_entry)
59                         continue;
60
61                 split_huge_page_pmd(walk->mm, pmd);
62                 if (pmd_none_or_clear_bad(pmd))
63                         goto again;
64                 err = walk_pte_range(pmd, addr, next, walk);
65                 if (err)
66                         break;
67         } while (pmd++, addr = next, addr != end);
68
69         return err;
70 }
71
72 static int walk_pud_range(pgd_t *pgd, unsigned long addr, unsigned long end,
73                           struct mm_walk *walk)
74 {
75         pud_t *pud;
76         unsigned long next;
77         int err = 0;
78
79         pud = pud_offset(pgd, addr);
80         do {
81                 next = pud_addr_end(addr, end);
82                 if (pud_none_or_clear_bad(pud)) {
83                         if (walk->pte_hole)
84                                 err = walk->pte_hole(addr, next, walk);
85                         if (err)
86                                 break;
87                         continue;
88                 }
89                 if (walk->pud_entry)
90                         err = walk->pud_entry(pud, addr, next, walk);
91                 if (!err && (walk->pmd_entry || walk->pte_entry))
92                         err = walk_pmd_range(pud, addr, next, walk);
93                 if (err)
94                         break;
95         } while (pud++, addr = next, addr != end);
96
97         return err;
98 }
99
100 #ifdef CONFIG_HUGETLB_PAGE
101 static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
102                                        unsigned long end)
103 {
104         unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
105         return boundary < end ? boundary : end;
106 }
107
108 static int walk_hugetlb_range(struct vm_area_struct *vma,
109                               unsigned long addr, unsigned long end,
110                               struct mm_walk *walk)
111 {
112         struct hstate *h = hstate_vma(vma);
113         unsigned long next;
114         unsigned long hmask = huge_page_mask(h);
115         pte_t *pte;
116         int err = 0;
117
118         do {
119                 next = hugetlb_entry_end(h, addr, end);
120                 pte = huge_pte_offset(walk->mm, addr & hmask);
121                 if (pte && walk->hugetlb_entry)
122                         err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
123                 if (err)
124                         return err;
125         } while (addr = next, addr != end);
126
127         return 0;
128 }
129 #endif
130
131 /**
132  * walk_page_range - walk a memory map's page tables with a callback
133  * @mm: memory map to walk
134  * @addr: starting address
135  * @end: ending address
136  * @walk: set of callbacks to invoke for each level of the tree
137  *
138  * Recursively walk the page table for the memory area in a VMA,
139  * calling supplied callbacks. Callbacks are called in-order (first
140  * PGD, first PUD, first PMD, first PTE, second PTE... second PMD,
141  * etc.). If lower-level callbacks are omitted, walking depth is reduced.
142  *
143  * Each callback receives an entry pointer and the start and end of the
144  * associated range, and a copy of the original mm_walk for access to
145  * the ->private or ->mm fields.
146  *
147  * No locks are taken, but the bottom level iterator will map PTE
148  * directories from highmem if necessary.
149  *
150  * If any callback returns a non-zero value, the walk is aborted and
151  * the return value is propagated back to the caller. Otherwise 0 is returned.
152  */
153 int walk_page_range(unsigned long addr, unsigned long end,
154                     struct mm_walk *walk)
155 {
156         pgd_t *pgd;
157         unsigned long next;
158         int err = 0;
159
160         if (addr >= end)
161                 return err;
162
163         if (!walk->mm)
164                 return -EINVAL;
165
166         pgd = pgd_offset(walk->mm, addr);
167         do {
168                 struct vm_area_struct *uninitialized_var(vma);
169
170                 next = pgd_addr_end(addr, end);
171
172 #ifdef CONFIG_HUGETLB_PAGE
173                 /*
174                  * handle hugetlb vma individually because pagetable walk for
175                  * the hugetlb page is dependent on the architecture and
176                  * we can't handled it in the same manner as non-huge pages.
177                  */
178                 vma = find_vma(walk->mm, addr);
179                 if (vma && is_vm_hugetlb_page(vma)) {
180                         if (vma->vm_end < next)
181                                 next = vma->vm_end;
182                         /*
183                          * Hugepage is very tightly coupled with vma, so
184                          * walk through hugetlb entries within a given vma.
185                          */
186                         err = walk_hugetlb_range(vma, addr, next, walk);
187                         if (err)
188                                 break;
189                         pgd = pgd_offset(walk->mm, next);
190                         continue;
191                 }
192 #endif
193                 if (pgd_none_or_clear_bad(pgd)) {
194                         if (walk->pte_hole)
195                                 err = walk->pte_hole(addr, next, walk);
196                         if (err)
197                                 break;
198                         pgd++;
199                         continue;
200                 }
201                 if (walk->pgd_entry)
202                         err = walk->pgd_entry(pgd, addr, next, walk);
203                 if (!err &&
204                     (walk->pud_entry || walk->pmd_entry || walk->pte_entry))
205                         err = walk_pud_range(pgd, addr, next, walk);
206                 if (err)
207                         break;
208                 pgd++;
209         } while (addr = next, addr != end);
210
211         return err;
212 }