xtensa: keep sysmem banks ordered in mem_reserve

Rewrite mem_reserve so that it keeps bank order.
Also make its return code more traditional.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

2 files changed, 51 insertions, 33 deletions

diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index df2b1d6fc843..017c06aba9b2 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -462,7 +462,7 @@ void __init setup_arch(char **cmdline_p)
 #ifdef CONFIG_BLK_DEV_INITRD
         if (initrd_start < initrd_end) {
                 initrd_is_mapped = mem_reserve(__pa(initrd_start),
-                                               __pa(initrd_end), 0);
+                                               __pa(initrd_end), 0) == 0;
                 initrd_below_start_ok = 1;
         } else {
                 initrd_start = 0;
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 79c0c3d52ae3..5d23697957bf 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c
@@ -142,6 +142,8 @@ int __init add_sysmem_bank(unsigned long start, unsigned long end)
  * mem_reserve(start, end, must_exist)
  *
  * Reserve some memory from the memory pool.
+ * If must_exist is set and a part of the region being reserved does not exist
+ * memory map is not altered.
  *
  * Parameters:
  *  start       Start of region,
@@ -149,53 +151,69 @@ int __init add_sysmem_bank(unsigned long start, unsigned long end)
  *  must_exist  Must exist in memory pool.
  *
  * Returns:
- *  0 (memory area couldn't be mapped)
- * -1 (success)
+ *  0 (success)
+ *  < 0 (error)
  */
 
 int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
 {
-        int i;
-
-        if (start == end)
-                return 0;
+        struct meminfo *it;
+        struct meminfo *rm = NULL;
+        unsigned long sz;
+        unsigned long bank_sz = 0;
 
         start = start & PAGE_MASK;
         end = PAGE_ALIGN(end);
+        sz = end - start;
+        if (!sz)
+                return -EINVAL;
 
-        for (i = 0; i < sysmem.nr_banks; i++)
-                if (start < sysmem.bank[i].end
-                    && end >= sysmem.bank[i].start)
-                        break;
+        it = find_bank(start);
+
+        if (it)
+                bank_sz = it->end - it->start;
 
-        if (i == sysmem.nr_banks) {
-                if (must_exist)
-                        printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
-                                "not in any region!\n", start, end);
-                return 0;
+        if ((!it || end - it->start > bank_sz) && must_exist) {
+                pr_warn("mem_reserve: [0x%0lx, 0x%0lx) not in any region!\n",
+                        start, end);
+                return -EINVAL;
         }
 
-        if (start > sysmem.bank[i].start) {
-                if (end < sysmem.bank[i].end) {
-                        /* split entry */
-                        if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
-                                panic("meminfo overflow\n");
-                        sysmem.bank[sysmem.nr_banks].start = end;
-                        sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
-                        sysmem.nr_banks++;
+        if (it && start - it->start < bank_sz) {
+                if (start == it->start) {
+                        if (end - it->start < bank_sz) {
+                                it->start = end;
+                                return 0;
+                        } else {
+                                rm = it;
+                        }
+                } else {
+                        it->end = start;
+                        if (end - it->start < bank_sz)
+                                return add_sysmem_bank(end,
+                                                       it->start + bank_sz);
+                        ++it;
                 }
-                sysmem.bank[i].end = start;
+        }
 
-        } else if (end < sysmem.bank[i].end) {
-                sysmem.bank[i].start = end;
+        if (!it)
+                it = sysmem.bank;
 
-        } else {
-                /* remove entry */
-                sysmem.nr_banks--;
-                sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
-                sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
+        for (; it < sysmem.bank + sysmem.nr_banks; ++it) {
+                if (it->end - start <= sz) {
+                        if (!rm)
+                                rm = it;
+                } else {
+                        if (it->start - start < sz)
+                                it->start = end;
+                        break;
+                }
         }
-        return -1;
+
+        if (rm)
+                move_banks(rm, it);
+
+        return 0;
 }