swap_info: note SWAP_MAP_SHMEM

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index cc5e7ebf2d2c5105328688045080bcc6ce5a983f..58bec66001673dbd6dd58dd4d7bf8fa1fc53b135 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -548,6 +548,12 @@ static unsigned char swap_entry_free(struct swap_info_struct *p,
        if (usage == SWAP_HAS_CACHE) {
                VM_BUG_ON(!has_cache);
                has_cache = 0;
+       } else if (count == SWAP_MAP_SHMEM) {
+               /*
+                * Or we could insist on shmem.c using a special
+                * swap_shmem_free() and free_shmem_swap_and_cache()...
+                */
+               count = 0;
        } else if ((count & ~COUNT_CONTINUED) <= SWAP_MAP_MAX) {
                if (count == COUNT_CONTINUED) {
                        if (swap_count_continued(p, offset, count))
@@ -1031,7 +1037,6 @@ static int try_to_unuse(unsigned int type)
        swp_entry_t entry;
        unsigned int i = 0;
        int retval = 0;
-       int shmem;
 
        /*
         * When searching mms for an entry, a good strategy is to
@@ -1107,17 +1112,18 @@ static int try_to_unuse(unsigned int type)
 
                /*
                 * Remove all references to entry.
-                * Whenever we reach init_mm, there's no address space
-                * to search, but use it as a reminder to search shmem.
                 */
-               shmem = 0;
                swcount = *swap_map;
-               if (swap_count(swcount)) {
-                       if (start_mm == &init_mm)
-                               shmem = shmem_unuse(entry, page);
-                       else
-                               retval = unuse_mm(start_mm, entry, page);
+               if (swap_count(swcount) == SWAP_MAP_SHMEM) {
+                       retval = shmem_unuse(entry, page);
+                       /* page has already been unlocked and released */
+                       if (retval < 0)
+                               break;
+                       continue;
                }
+               if (swap_count(swcount) && start_mm != &init_mm)
+                       retval = unuse_mm(start_mm, entry, page);
+
                if (swap_count(*swap_map)) {
                        int set_start_mm = (*swap_map >= swcount);
                        struct list_head *p = &start_mm->mmlist;
@@ -1128,7 +1134,7 @@ static int try_to_unuse(unsigned int type)
                        atomic_inc(&new_start_mm->mm_users);
                        atomic_inc(&prev_mm->mm_users);
                        spin_lock(&mmlist_lock);
-                       while (swap_count(*swap_map) && !retval && !shmem &&
+                       while (swap_count(*swap_map) && !retval &&
                                        (p = p->next) != &start_mm->mmlist) {
                                mm = list_entry(p, struct mm_struct, mmlist);
                                if (!atomic_inc_not_zero(&mm->mm_users))
@@ -1142,10 +1148,9 @@ static int try_to_unuse(unsigned int type)
                                swcount = *swap_map;
                                if (!swap_count(swcount)) /* any usage ? */
                                        ;
-                               else if (mm == &init_mm) {
+                               else if (mm == &init_mm)
                                        set_start_mm = 1;
-                                       shmem = shmem_unuse(entry, page);
-                               } else
+                               else
                                        retval = unuse_mm(mm, entry, page);
 
                                if (set_start_mm && *swap_map < swcount) {
@@ -1161,13 +1166,6 @@ static int try_to_unuse(unsigned int type)
                        mmput(start_mm);
                        start_mm = new_start_mm;
                }
-               if (shmem) {
-                       /* page has already been unlocked and released */
-                       if (shmem > 0)
-                               continue;
-                       retval = shmem;
-                       break;
-               }
                if (retval) {
                        unlock_page(page);
                        page_cache_release(page);
@@ -2126,6 +2124,15 @@ bad_file:
        goto out;
 }
 
+/*
+ * Help swapoff by noting that swap entry belongs to shmem/tmpfs
+ * (in which case its reference count is never incremented).
+ */
+void swap_shmem_alloc(swp_entry_t entry)
+{
+       __swap_duplicate(entry, SWAP_MAP_SHMEM);
+}
+
 /*
  * increase reference count of swap entry by 1.
  */