mm/swapfile.c: tmp is always smaller than max

[thirdparty/linux.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5871a2aa86a57d4a43d2edb8d76fa083265cfde0..c74c9e1dc50d5864cf62ed211e350eeef38a805a 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -601,7 +601,6 @@ static bool scan_swap_map_try_ssd_cluster(struct swap_info_struct *si,
 {
        struct percpu_cluster *cluster;
        struct swap_cluster_info *ci;
-       bool found_free;
        unsigned long tmp, max;
 
 new_cluster:
@@ -623,8 +622,6 @@ new_cluster:
                        return false;
        }
 
-       found_free = false;
-
        /*
         * Other CPUs can use our cluster if they can't find a free cluster,
         * check if there is still free entry in the cluster
@@ -638,21 +635,19 @@ new_cluster:
        }
        ci = lock_cluster(si, tmp);
        while (tmp < max) {
-               if (!si->swap_map[tmp]) {
-                       found_free = true;
+               if (!si->swap_map[tmp])
                        break;
-               }
                tmp++;
        }
        unlock_cluster(ci);
-       if (!found_free) {
+       if (tmp >= max) {
                cluster_set_null(&cluster->index);
                goto new_cluster;
        }
        cluster->next = tmp + 1;
        *offset = tmp;
        *scan_base = tmp;
-       return found_free;
+       return true;
 }
 
 static void __del_from_avail_list(struct swap_info_struct *p)
@@ -740,9 +735,6 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
        int latency_ration = LATENCY_LIMIT;
        int n_ret = 0;
 
-       if (nr > SWAP_BATCH)
-               nr = SWAP_BATCH;
-
        /*
         * We try to cluster swap pages by allocating them sequentially
         * in swap.  Once we've allocated SWAPFILE_CLUSTER pages this
@@ -759,13 +751,9 @@ static int scan_swap_map_slots(struct swap_info_struct *si,
 
        /* SSD algorithm */
        if (si->cluster_info) {
-               if (scan_swap_map_try_ssd_cluster(si, &offset, &scan_base))
-                       goto checks;
-               else
+               if (!scan_swap_map_try_ssd_cluster(si, &offset, &scan_base))
                        goto scan;
-       }
-
-       if (unlikely(!si->cluster_nr--)) {
+       } else if (unlikely(!si->cluster_nr--)) {
                if (si->pages - si->inuse_pages < SWAPFILE_CLUSTER) {
                        si->cluster_nr = SWAPFILE_CLUSTER - 1;
                        goto checks;
@@ -871,14 +859,8 @@ checks:
        if (si->cluster_info) {
                if (scan_swap_map_try_ssd_cluster(si, &offset, &scan_base))
                        goto checks;
-               else
-                       goto done;
-       }
-       /* non-ssd case */
-       ++offset;
-
-       /* non-ssd case, still more slots in cluster? */
-       if (si->cluster_nr && !si->swap_map[offset]) {
+       } else if (si->cluster_nr && !si->swap_map[++offset]) {
+               /* non-ssd case, still more slots in cluster? */
                --si->cluster_nr;
                goto checks;
        }
@@ -1004,11 +986,7 @@ int get_swap_pages(int n_goal, swp_entry_t swp_entries[], int entry_size)
        if (avail_pgs <= 0)
                goto noswap;
 
-       if (n_goal > SWAP_BATCH)
-               n_goal = SWAP_BATCH;
-
-       if (n_goal > avail_pgs)
-               n_goal = avail_pgs;
+       n_goal = min3((long)n_goal, (long)SWAP_BATCH, avail_pgs);
 
        atomic_long_sub(n_goal * size, &nr_swap_pages);
 
@@ -1937,10 +1915,14 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 
                pte_unmap(pte);
                swap_map = &si->swap_map[offset];
-               vmf.vma = vma;
-               vmf.address = addr;
-               vmf.pmd = pmd;
-               page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE, &vmf);
+               page = lookup_swap_cache(entry, vma, addr);
+               if (!page) {
+                       vmf.vma = vma;
+                       vmf.address = addr;
+                       vmf.pmd = pmd;
+                       page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
+                                               &vmf);
+               }
                if (!page) {
                        if (*swap_map == 0 || *swap_map == SWAP_MAP_BAD)
                                goto try_next;
@@ -3654,7 +3636,7 @@ static bool swap_count_continued(struct swap_info_struct *si,
 
        spin_lock(&si->cont_lock);
        offset &= ~PAGE_MASK;
-       page = list_entry(head->lru.next, struct page, lru);
+       page = list_next_entry(head, lru);
        map = kmap_atomic(page) + offset;
 
        if (count == SWAP_MAP_MAX)      /* initial increment from swap_map */
@@ -3666,13 +3648,13 @@ static bool swap_count_continued(struct swap_info_struct *si,
                 */
                while (*map == (SWAP_CONT_MAX | COUNT_CONTINUED)) {
                        kunmap_atomic(map);
-                       page = list_entry(page->lru.next, struct page, lru);
+                       page = list_next_entry(page, lru);
                        BUG_ON(page == head);
                        map = kmap_atomic(page) + offset;
                }
                if (*map == SWAP_CONT_MAX) {
                        kunmap_atomic(map);
-                       page = list_entry(page->lru.next, struct page, lru);
+                       page = list_next_entry(page, lru);
                        if (page == head) {
                                ret = false;    /* add count continuation */
                                goto out;
@@ -3682,12 +3664,10 @@ init_map:               *map = 0;               /* we didn't zero the page */
                }
                *map += 1;
                kunmap_atomic(map);
-               page = list_entry(page->lru.prev, struct page, lru);
-               while (page != head) {
+               while ((page = list_prev_entry(page, lru)) != head) {
                        map = kmap_atomic(page) + offset;
                        *map = COUNT_CONTINUED;
                        kunmap_atomic(map);
-                       page = list_entry(page->lru.prev, struct page, lru);
                }
                ret = true;                     /* incremented */
 
@@ -3698,7 +3678,7 @@ init_map:         *map = 0;               /* we didn't zero the page */
                BUG_ON(count != COUNT_CONTINUED);
                while (*map == COUNT_CONTINUED) {
                        kunmap_atomic(map);
-                       page = list_entry(page->lru.next, struct page, lru);
+                       page = list_next_entry(page, lru);
                        BUG_ON(page == head);
                        map = kmap_atomic(page) + offset;
                }
@@ -3707,13 +3687,11 @@ init_map:               *map = 0;               /* we didn't zero the page */
                if (*map == 0)
                        count = 0;
                kunmap_atomic(map);
-               page = list_entry(page->lru.prev, struct page, lru);
-               while (page != head) {
+               while ((page = list_prev_entry(page, lru)) != head) {
                        map = kmap_atomic(page) + offset;
                        *map = SWAP_CONT_MAX | count;
                        count = COUNT_CONTINUED;
                        kunmap_atomic(map);
-                       page = list_entry(page->lru.prev, struct page, lru);
                }
                ret = count == COUNT_CONTINUED;
        }