x86: change early_ioremap to use slots instead of nesting

so we could remove the requirement that one needs to call
early_iounmap() in exactly reverse order of early_ioremap().

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 57 insertions, 20 deletions

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index 8876220d906b..e4c43ec71b29 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -616,16 +616,22 @@ static inline void __init early_clear_fixmap(enum fixed_addresses idx)
                 __early_set_fixmap(idx, 0, __pgprot(0));
 }
 
-
-static int __initdata early_ioremap_nested;
-
+static void *prev_map[FIX_BTMAPS_SLOTS] __initdata;
+static unsigned long prev_size[FIX_BTMAPS_SLOTS] __initdata;
 static int __init check_early_ioremap_leak(void)
 {
-        if (!early_ioremap_nested)
+        int count = 0;
+        int i;
+
+        for (i = 0; i < FIX_BTMAPS_SLOTS; i++)
+                if (prev_map[i])
+                        count++;
+
+        if (!count)
                 return 0;
         WARN(1, KERN_WARNING
                "Debug warning: early ioremap leak of %d areas detected.\n",
-                early_ioremap_nested);
+                count);
         printk(KERN_WARNING
                 "please boot with early_ioremap_debug and report the dmesg.\n");
 
@@ -636,15 +642,30 @@ late_initcall(check_early_ioremap_leak);
 static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size, pgprot_t prot)
 {
         unsigned long offset, last_addr;
-        unsigned int nrpages, nesting;
+        unsigned int nrpages;
         enum fixed_addresses idx0, idx;
+        int i, slot;
 
         WARN_ON(system_state != SYSTEM_BOOTING);
 
-        nesting = early_ioremap_nested;
+        slot = -1;
+        for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+                if (!prev_map[i]) {
+                        slot = i;
+                        break;
+                }
+        }
+
+        if (slot < 0) {
+                printk(KERN_INFO "early_iomap(%08lx, %08lx) not found slot\n",
+                         phys_addr, size);
+                WARN_ON(1);
+                return NULL;
+        }
+
         if (early_ioremap_debug) {
                 printk(KERN_INFO "early_ioremap(%08lx, %08lx) [%d] => ",
-                       phys_addr, size, nesting);
+                       phys_addr, size, slot);
                 dump_stack();
         }
 
@@ -655,11 +676,7 @@ static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size,
                 return NULL;
         }
 
-        if (nesting >= FIX_BTMAPS_NESTING) {
-                WARN_ON(1);
-                return NULL;
-        }
-        early_ioremap_nested++;
+        prev_size[slot] = size;
         /*
          * Mappings have to be page-aligned
          */
@@ -679,7 +696,7 @@ static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size,
         /*
          * Ok, go for it..
          */
-        idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
+        idx0 = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
         idx = idx0;
         while (nrpages > 0) {
                 early_set_fixmap(idx, phys_addr, prot);
@@ -690,7 +707,8 @@ static void __init *__early_ioremap(unsigned long phys_addr, unsigned long size,
         if (early_ioremap_debug)
                 printk(KERN_CONT "%08lx + %08lx\n", offset, fix_to_virt(idx0));
 
-        return (void *) (offset + fix_to_virt(idx0));
+        prev_map[slot] = (void *) (offset + fix_to_virt(idx0));
+        return prev_map[slot];
 }
 
 /* Remap an IO device */
@@ -711,15 +729,33 @@ void __init early_iounmap(void *addr, unsigned long size)
         unsigned long offset;
         unsigned int nrpages;
         enum fixed_addresses idx;
-        int nesting;
+        int i, slot;
+
+        slot = -1;
+        for (i = 0; i < FIX_BTMAPS_SLOTS; i++) {
+                if (prev_map[i] == addr) {
+                        slot = i;
+                        break;
+                }
+        }
 
-        nesting = --early_ioremap_nested;
-        if (WARN_ON(nesting < 0))
+        if (slot < 0) {
+                printk(KERN_INFO "early_iounmap(%p, %08lx) not found slot\n",
+                         addr, size);
+                WARN_ON(1);
+                return;
+        }
+
+        if (prev_size[slot] != size) {
+                printk(KERN_INFO "early_iounmap(%p, %08lx) [%d] size not consistent %08lx\n",
+                         addr, size, slot, prev_size[slot]);
+                WARN_ON(1);
                 return;
+        }
 
         if (early_ioremap_debug) {
                 printk(KERN_INFO "early_iounmap(%p, %08lx) [%d]\n", addr,
-                       size, nesting);
+                       size, slot);
                 dump_stack();
         }
 
@@ -731,12 +767,13 @@ void __init early_iounmap(void *addr, unsigned long size)
         offset = virt_addr & ~PAGE_MASK;
         nrpages = PAGE_ALIGN(offset + size - 1) >> PAGE_SHIFT;
 
-        idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*nesting;
+        idx = FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*slot;
         while (nrpages > 0) {
                 early_clear_fixmap(idx);
                 --idx;
                 --nrpages;
         }
+        prev_map[slot] = 0;
 }
 
 void __this_fixmap_does_not_exist(void)