Commit 06090e8ed89ea2113a236befb41f71d51f100e60
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ef3e035c3a
Exists in
ti-lsk-linux-4.1.y
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sparc64: Implement __get_user_pages_fast().
It is not sufficient to only implement get_user_pages_fast(), you must also implement the atomic version __get_user_pages_fast() otherwise you end up using the weak symbol fallback implementation which simply returns zero. This is dangerous, because it causes the futex code to loop forever if transparent hugepages are supported (see get_futex_key()). Signed-off-by: David S. Miller <davem@davemloft.net>
Showing 1 changed file with 30 additions and 0 deletions Side-by-side Diff
arch/sparc/mm/gup.c
| ... | ... | @@ -160,6 +160,36 @@ |
| 160 | 160 | return 1; |
| 161 | 161 | } |
| 162 | 162 | |
| 163 | +int __get_user_pages_fast(unsigned long start, int nr_pages, int write, | |
| 164 | + struct page **pages) | |
| 165 | +{ | |
| 166 | + struct mm_struct *mm = current->mm; | |
| 167 | + unsigned long addr, len, end; | |
| 168 | + unsigned long next, flags; | |
| 169 | + pgd_t *pgdp; | |
| 170 | + int nr = 0; | |
| 171 | + | |
| 172 | + start &= PAGE_MASK; | |
| 173 | + addr = start; | |
| 174 | + len = (unsigned long) nr_pages << PAGE_SHIFT; | |
| 175 | + end = start + len; | |
| 176 | + | |
| 177 | + local_irq_save(flags); | |
| 178 | + pgdp = pgd_offset(mm, addr); | |
| 179 | + do { | |
| 180 | + pgd_t pgd = *pgdp; | |
| 181 | + | |
| 182 | + next = pgd_addr_end(addr, end); | |
| 183 | + if (pgd_none(pgd)) | |
| 184 | + break; | |
| 185 | + if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) | |
| 186 | + break; | |
| 187 | + } while (pgdp++, addr = next, addr != end); | |
| 188 | + local_irq_restore(flags); | |
| 189 | + | |
| 190 | + return nr; | |
| 191 | +} | |
| 192 | + | |
| 163 | 193 | int get_user_pages_fast(unsigned long start, int nr_pages, int write, |
| 164 | 194 | struct page **pages) |
| 165 | 195 | { |
