The part of __swap_duplicate() with lock held is separated into a new function __swap_duplicate_locked(). Because we will add more logic about the PMD swap mapping into __swap_duplicate() and keep the most PTE swap mapping related logic in __swap_duplicate_locked().
Just mechanical code refactoring, there is no any functional change in this patch. Signed-off-by: "Huang, Ying" <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Shaohua Li <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Naoya Horiguchi <[email protected]> Cc: Zi Yan <[email protected]> Cc: Daniel Jordan <[email protected]> --- mm/swapfile.c | 63 +++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 35 insertions(+), 28 deletions(-) diff --git a/mm/swapfile.c b/mm/swapfile.c index 1996dcd732b6..532de6f8ff39 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3436,32 +3436,12 @@ void si_swapinfo(struct sysinfo *val) spin_unlock(&swap_lock); } -/* - * Verify that a swap entry is valid and increment its swap map count. - * - * Returns error code in following case. - * - success -> 0 - * - swp_entry is invalid -> EINVAL - * - swp_entry is migration entry -> EINVAL - * - swap-cache reference is requested but there is already one. -> EEXIST - * - swap-cache reference is requested but the entry is not used. -> ENOENT - * - swap-mapped reference requested but needs continued swap count. -> ENOMEM - */ -static int __swap_duplicate(swp_entry_t entry, unsigned char usage) +static int __swap_duplicate_locked(struct swap_info_struct *p, + unsigned long offset, unsigned char usage) { - struct swap_info_struct *p; - struct swap_cluster_info *ci; - unsigned long offset; unsigned char count; unsigned char has_cache; - int err = -EINVAL; - - p = get_swap_device(entry); - if (!p) - goto out; - - offset = swp_offset(entry); - ci = lock_cluster_or_swap_info(p, offset); + int err = 0; count = p->swap_map[offset]; @@ -3471,12 +3451,11 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) */ if (unlikely(swap_count(count) == SWAP_MAP_BAD)) { err = -ENOENT; - goto unlock_out; + goto out; } has_cache = count & SWAP_HAS_CACHE; count &= ~SWAP_HAS_CACHE; - err = 0; if (usage == SWAP_HAS_CACHE) { @@ -3503,11 +3482,39 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage) p->swap_map[offset] = count | has_cache; -unlock_out: +out: + return err; +} + +/* + * Verify that a swap entry is valid and increment its swap map count. + * + * Returns error code in following case. + * - success -> 0 + * - swp_entry is invalid -> EINVAL + * - swp_entry is migration entry -> EINVAL + * - swap-cache reference is requested but there is already one. -> EEXIST + * - swap-cache reference is requested but the entry is not used. -> ENOENT + * - swap-mapped reference requested but needs continued swap count. -> ENOMEM + */ +static int __swap_duplicate(swp_entry_t entry, unsigned char usage) +{ + struct swap_info_struct *p; + struct swap_cluster_info *ci; + unsigned long offset; + int err = -EINVAL; + + p = get_swap_device(entry); + if (!p) + goto out; + + offset = swp_offset(entry); + ci = lock_cluster_or_swap_info(p, offset); + err = __swap_duplicate_locked(p, offset, usage); unlock_cluster_or_swap_info(p, ci); + + put_swap_device(p); out: - if (p) - put_swap_device(p); return err; } -- 2.16.4
