diff options
-rw-r--r-- | mm/shmem.c | 109 |
1 files changed, 3 insertions, 106 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 43d071922b81..5dfe79048f6d 100644 --- a/mm/shmem.c +++ b/mm/shmem.c | |||
@@ -1106,7 +1106,7 @@ static int shmem_getpage(struct inode *inode, unsigned long idx, | |||
1106 | * Normally, filepage is NULL on entry, and either found | 1106 | * Normally, filepage is NULL on entry, and either found |
1107 | * uptodate immediately, or allocated and zeroed, or read | 1107 | * uptodate immediately, or allocated and zeroed, or read |
1108 | * in under swappage, which is then assigned to filepage. | 1108 | * in under swappage, which is then assigned to filepage. |
1109 | * But shmem_readpage and shmem_write_begin pass in a locked | 1109 | * But shmem_readpage (required for splice) passes in a locked |
1110 | * filepage, which may be found not uptodate by other callers | 1110 | * filepage, which may be found not uptodate by other callers |
1111 | * too, and may need to be copied from the swappage read in. | 1111 | * too, and may need to be copied from the swappage read in. |
1112 | */ | 1112 | */ |
@@ -1476,110 +1476,6 @@ shmem_write_end(struct file *file, struct address_space *mapping, | |||
1476 | return copied; | 1476 | return copied; |
1477 | } | 1477 | } |
1478 | 1478 | ||
1479 | static ssize_t | ||
1480 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | ||
1481 | { | ||
1482 | struct inode *inode = file->f_path.dentry->d_inode; | ||
1483 | loff_t pos; | ||
1484 | unsigned long written; | ||
1485 | ssize_t err; | ||
1486 | |||
1487 | if ((ssize_t) count < 0) | ||
1488 | return -EINVAL; | ||
1489 | |||
1490 | if (!access_ok(VERIFY_READ, buf, count)) | ||
1491 | return -EFAULT; | ||
1492 | |||
1493 | mutex_lock(&inode->i_mutex); | ||
1494 | |||
1495 | pos = *ppos; | ||
1496 | written = 0; | ||
1497 | |||
1498 | err = generic_write_checks(file, &pos, &count, 0); | ||
1499 | if (err || !count) | ||
1500 | goto out; | ||
1501 | |||
1502 | err = remove_suid(file->f_path.dentry); | ||
1503 | if (err) | ||
1504 | goto out; | ||
1505 | |||
1506 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | ||
1507 | |||
1508 | do { | ||
1509 | struct page *page = NULL; | ||
1510 | unsigned long bytes, index, offset; | ||
1511 | char *kaddr; | ||
1512 | int left; | ||
1513 | |||
1514 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | ||
1515 | index = pos >> PAGE_CACHE_SHIFT; | ||
1516 | bytes = PAGE_CACHE_SIZE - offset; | ||
1517 | if (bytes > count) | ||
1518 | bytes = count; | ||
1519 | |||
1520 | /* | ||
1521 | * We don't hold page lock across copy from user - | ||
1522 | * what would it guard against? - so no deadlock here. | ||
1523 | * But it still may be a good idea to prefault below. | ||
1524 | */ | ||
1525 | |||
1526 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | ||
1527 | if (err) | ||
1528 | break; | ||
1529 | |||
1530 | unlock_page(page); | ||
1531 | left = bytes; | ||
1532 | if (PageHighMem(page)) { | ||
1533 | volatile unsigned char dummy; | ||
1534 | __get_user(dummy, buf); | ||
1535 | __get_user(dummy, buf + bytes - 1); | ||
1536 | |||
1537 | kaddr = kmap_atomic(page, KM_USER0); | ||
1538 | left = __copy_from_user_inatomic(kaddr + offset, | ||
1539 | buf, bytes); | ||
1540 | kunmap_atomic(kaddr, KM_USER0); | ||
1541 | } | ||
1542 | if (left) { | ||
1543 | kaddr = kmap(page); | ||
1544 | left = __copy_from_user(kaddr + offset, buf, bytes); | ||
1545 | kunmap(page); | ||
1546 | } | ||
1547 | |||
1548 | written += bytes; | ||
1549 | count -= bytes; | ||
1550 | pos += bytes; | ||
1551 | buf += bytes; | ||
1552 | if (pos > inode->i_size) | ||
1553 | i_size_write(inode, pos); | ||
1554 | |||
1555 | flush_dcache_page(page); | ||
1556 | set_page_dirty(page); | ||
1557 | mark_page_accessed(page); | ||
1558 | page_cache_release(page); | ||
1559 | |||
1560 | if (left) { | ||
1561 | pos -= left; | ||
1562 | written -= left; | ||
1563 | err = -EFAULT; | ||
1564 | break; | ||
1565 | } | ||
1566 | |||
1567 | /* | ||
1568 | * Our dirty pages are not counted in nr_dirty, | ||
1569 | * and we do not attempt to balance dirty pages. | ||
1570 | */ | ||
1571 | |||
1572 | cond_resched(); | ||
1573 | } while (count); | ||
1574 | |||
1575 | *ppos = pos; | ||
1576 | if (written) | ||
1577 | err = written; | ||
1578 | out: | ||
1579 | mutex_unlock(&inode->i_mutex); | ||
1580 | return err; | ||
1581 | } | ||
1582 | |||
1583 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | 1479 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1584 | { | 1480 | { |
1585 | struct inode *inode = filp->f_path.dentry->d_inode; | 1481 | struct inode *inode = filp->f_path.dentry->d_inode; |
@@ -2354,7 +2250,8 @@ static const struct file_operations shmem_file_operations = { | |||
2354 | #ifdef CONFIG_TMPFS | 2250 | #ifdef CONFIG_TMPFS |
2355 | .llseek = generic_file_llseek, | 2251 | .llseek = generic_file_llseek, |
2356 | .read = shmem_file_read, | 2252 | .read = shmem_file_read, |
2357 | .write = shmem_file_write, | 2253 | .write = do_sync_write, |
2254 | .aio_write = generic_file_aio_write, | ||
2358 | .fsync = simple_sync_file, | 2255 | .fsync = simple_sync_file, |
2359 | .splice_read = generic_file_splice_read, | 2256 | .splice_read = generic_file_splice_read, |
2360 | .splice_write = generic_file_splice_write, | 2257 | .splice_write = generic_file_splice_write, |