cifs: fail i/o on soft mounts if sessionsetup errors out

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / mm / swapfile.c

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 5887731..8e25ff2 100644 (file)
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2206,6 +2206,35 @@ static int claim_swapfile(struct swap_info_struct *p, struct inode *inode)
        return 0;
 }
 
+
+/*
+ * Find out how many pages are allowed for a single swap device. There
+ * are two limiting factors:
+ * 1) the number of bits for the swap offset in the swp_entry_t type, and
+ * 2) the number of bits in the swap pte, as defined by the different
+ * architectures.
+ *
+ * In order to find the largest possible bit mask, a swap entry with
+ * swap type 0 and swap offset ~0UL is created, encoded to a swap pte,
+ * decoded to a swp_entry_t again, and finally the swap offset is
+ * extracted.
+ *
+ * This will mask all the bits from the initial ~0UL mask that can't
+ * be encoded in either the swp_entry_t or the architecture definition
+ * of a swap pte.
+ */
+unsigned long generic_max_swapfile_size(void)
+{
+       return swp_offset(pte_to_swp_entry(
+                       swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+}
+
+/* Can be overridden by an architecture for additional checks. */
+__weak unsigned long max_swapfile_size(void)
+{
+       return generic_max_swapfile_size();
+}
+
 static unsigned long read_swap_header(struct swap_info_struct *p,
                                        union swap_header *swap_header,
                                        struct inode *inode)
@@ -2225,6 +2254,8 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
                swab32s(&swap_header->info.version);
                swab32s(&swap_header->info.last_page);
                swab32s(&swap_header->info.nr_badpages);
+               if (swap_header->info.nr_badpages > MAX_SWAP_BADPAGES)
+                       return 0;
                for (i = 0; i < swap_header->info.nr_badpages; i++)
                        swab32s(&swap_header->info.badpages[i]);
        }
@@ -2239,23 +2270,12 @@ static unsigned long read_swap_header(struct swap_info_struct *p,
        p->cluster_next = 1;
        p->cluster_nr = 0;
 
-       /*
-        * Find out how many pages are allowed for a single swap
-        * device. There are two limiting factors: 1) the number
-        * of bits for the swap offset in the swp_entry_t type, and
-        * 2) the number of bits in the swap pte as defined by the
-        * different architectures. In order to find the
-        * largest possible bit mask, a swap entry with swap type 0
-        * and swap offset ~0UL is created, encoded to a swap pte,
-        * decoded to a swp_entry_t again, and finally the swap
-        * offset is extracted. This will mask all the bits from
-        * the initial ~0UL mask that can't be encoded in either
-        * the swp_entry_t or the architecture definition of a
-        * swap pte.
-        */
-       maxpages = swp_offset(pte_to_swp_entry(
-                       swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1;
+       maxpages = max_swapfile_size();
        last_page = swap_header->info.last_page;
+       if (!last_page) {
+               pr_warn("Empty swap-file\n");
+               return 0;
+       }
        if (last_page > maxpages) {
                pr_warn("Truncating oversized swap area, only using %luk out of %luk\n",
                        maxpages << (PAGE_SHIFT - 10),