sparsemem: Fix compilation on PowerPC
[linux-2.6.git] / mm / percpu.c
index ec158bb..083e7c9 100644 (file)
@@ -72,6 +72,7 @@
 #include <asm/cacheflush.h>
 #include <asm/sections.h>
 #include <asm/tlbflush.h>
+#include <asm/io.h>
 
 #define PCPU_SLOT_BASE_SHIFT           5       /* 1-31 shares the same slot */
 #define PCPU_DFL_MAP_ALLOC             16      /* start a map with 16 ents */
@@ -151,7 +152,10 @@ static int pcpu_reserved_chunk_limit;
  *
  * During allocation, pcpu_alloc_mutex is kept locked all the time and
  * pcpu_lock is grabbed and released as necessary.  All actual memory
- * allocations are done using GFP_KERNEL with pcpu_lock released.
+ * allocations are done using GFP_KERNEL with pcpu_lock released.  In
+ * general, percpu memory can't be allocated with irq off but
+ * irqsave/restore are still used in alloc path so that it can be used
+ * from early init path - sched_init() specifically.
  *
  * Free path accesses and alters only the index data structures, so it
  * can be safely called from atomic context.  When memory needs to be
@@ -350,62 +354,86 @@ static struct pcpu_chunk *pcpu_chunk_addr_search(void *addr)
 }
 
 /**
- * pcpu_extend_area_map - extend area map for allocation
- * @chunk: target chunk
+ * pcpu_need_to_extend - determine whether chunk area map needs to be extended
+ * @chunk: chunk of interest
  *
- * Extend area map of @chunk so that it can accomodate an allocation.
- * A single allocation can split an area into three areas, so this
- * function makes sure that @chunk->map has at least two extra slots.
+ * Determine whether area map of @chunk needs to be extended to
+ * accomodate a new allocation.
  *
  * CONTEXT:
- * pcpu_alloc_mutex, pcpu_lock.  pcpu_lock is released and reacquired
- * if area map is extended.
+ * pcpu_lock.
  *
  * RETURNS:
- * 0 if noop, 1 if successfully extended, -errno on failure.
+ * New target map allocation length if extension is necessary, 0
+ * otherwise.
  */
-static int pcpu_extend_area_map(struct pcpu_chunk *chunk)
+static int pcpu_need_to_extend(struct pcpu_chunk *chunk)
 {
        int new_alloc;
-       int *new;
-       size_t size;
 
-       /* has enough? */
        if (chunk->map_alloc >= chunk->map_used + 2)
                return 0;
 
-       spin_unlock_irq(&pcpu_lock);
-
        new_alloc = PCPU_DFL_MAP_ALLOC;
        while (new_alloc < chunk->map_used + 2)
                new_alloc *= 2;
 
-       new = pcpu_mem_alloc(new_alloc * sizeof(new[0]));
-       if (!new) {
-               spin_lock_irq(&pcpu_lock);
+       return new_alloc;
+}
+
+/**
+ * pcpu_extend_area_map - extend area map of a chunk
+ * @chunk: chunk of interest
+ * @new_alloc: new target allocation length of the area map
+ *
+ * Extend area map of @chunk to have @new_alloc entries.
+ *
+ * CONTEXT:
+ * Does GFP_KERNEL allocation.  Grabs and releases pcpu_lock.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+static int pcpu_extend_area_map(struct pcpu_chunk *chunk, int new_alloc)
+{
+       int *old = NULL, *new = NULL;
+       size_t old_size = 0, new_size = new_alloc * sizeof(new[0]);
+       unsigned long flags;
+
+       new = pcpu_mem_alloc(new_size);
+       if (!new)
                return -ENOMEM;
-       }
 
-       /*
-        * Acquire pcpu_lock and switch to new area map.  Only free
-        * could have happened inbetween, so map_used couldn't have
-        * grown.
-        */
-       spin_lock_irq(&pcpu_lock);
-       BUG_ON(new_alloc < chunk->map_used + 2);
+       /* acquire pcpu_lock and switch to new area map */
+       spin_lock_irqsave(&pcpu_lock, flags);
+
+       if (new_alloc <= chunk->map_alloc)
+               goto out_unlock;
 
-       size = chunk->map_alloc * sizeof(chunk->map[0]);
-       memcpy(new, chunk->map, size);
+       old_size = chunk->map_alloc * sizeof(chunk->map[0]);
+       memcpy(new, chunk->map, old_size);
 
        /*
         * map_alloc < PCPU_DFL_MAP_ALLOC indicates that the chunk is
         * one of the first chunks and still using static map.
         */
        if (chunk->map_alloc >= PCPU_DFL_MAP_ALLOC)
-               pcpu_mem_free(chunk->map, size);
+               old = chunk->map;
 
        chunk->map_alloc = new_alloc;
        chunk->map = new;
+       new = NULL;
+
+out_unlock:
+       spin_unlock_irqrestore(&pcpu_lock, flags);
+
+       /*
+        * pcpu_mem_free() might end up calling vfree() which uses
+        * IRQ-unsafe lock and thus can't be called under pcpu_lock.
+        */
+       pcpu_mem_free(old, old_size);
+       pcpu_mem_free(new, new_size);
+
        return 0;
 }
 
@@ -1044,7 +1072,8 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved)
        static int warn_limit = 10;
        struct pcpu_chunk *chunk;
        const char *err;
-       int slot, off;
+       int slot, off, new_alloc;
+       unsigned long flags;
 
        if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
                WARN(true, "illegal size (%zu) or align (%zu) for "
@@ -1053,19 +1082,30 @@ static void *pcpu_alloc(size_t size, size_t align, bool reserved)
        }
 
        mutex_lock(&pcpu_alloc_mutex);
-       spin_lock_irq(&pcpu_lock);
+       spin_lock_irqsave(&pcpu_lock, flags);
 
        /* serve reserved allocations from the reserved chunk if available */
        if (reserved && pcpu_reserved_chunk) {
                chunk = pcpu_reserved_chunk;
-               if (size > chunk->contig_hint ||
-                   pcpu_extend_area_map(chunk) < 0) {
-                       err = "failed to extend area map of reserved chunk";
+
+               if (size > chunk->contig_hint) {
+                       err = "alloc from reserved chunk failed";
                        goto fail_unlock;
                }
+
+               while ((new_alloc = pcpu_need_to_extend(chunk))) {
+                       spin_unlock_irqrestore(&pcpu_lock, flags);
+                       if (pcpu_extend_area_map(chunk, new_alloc) < 0) {
+                               err = "failed to extend area map of reserved chunk";
+                               goto fail_unlock_mutex;
+                       }
+                       spin_lock_irqsave(&pcpu_lock, flags);
+               }
+
                off = pcpu_alloc_area(chunk, size, align);
                if (off >= 0)
                        goto area_found;
+
                err = "alloc from reserved chunk failed";
                goto fail_unlock;
        }
@@ -1077,14 +1117,20 @@ restart:
                        if (size > chunk->contig_hint)
                                continue;
 
-                       switch (pcpu_extend_area_map(chunk)) {
-                       case 0:
-                               break;
-                       case 1:
-                               goto restart;   /* pcpu_lock dropped, restart */
-                       default:
-                               err = "failed to extend area map";
-                               goto fail_unlock;
+                       new_alloc = pcpu_need_to_extend(chunk);
+                       if (new_alloc) {
+                               spin_unlock_irqrestore(&pcpu_lock, flags);
+                               if (pcpu_extend_area_map(chunk,
+                                                        new_alloc) < 0) {
+                                       err = "failed to extend area map";
+                                       goto fail_unlock_mutex;
+                               }
+                               spin_lock_irqsave(&pcpu_lock, flags);
+                               /*
+                                * pcpu_lock has been dropped, need to
+                                * restart cpu_slot list walking.
+                                */
+                               goto restart;
                        }
 
                        off = pcpu_alloc_area(chunk, size, align);
@@ -1094,7 +1140,7 @@ restart:
        }
 
        /* hmmm... no space left, create a new chunk */
-       spin_unlock_irq(&pcpu_lock);
+       spin_unlock_irqrestore(&pcpu_lock, flags);
 
        chunk = alloc_pcpu_chunk();
        if (!chunk) {
@@ -1102,16 +1148,16 @@ restart:
                goto fail_unlock_mutex;
        }
 
-       spin_lock_irq(&pcpu_lock);
+       spin_lock_irqsave(&pcpu_lock, flags);
        pcpu_chunk_relocate(chunk, -1);
        goto restart;
 
 area_found:
-       spin_unlock_irq(&pcpu_lock);
+       spin_unlock_irqrestore(&pcpu_lock, flags);
 
        /* populate, map and clear the area */
        if (pcpu_populate_chunk(chunk, off, size)) {
-               spin_lock_irq(&pcpu_lock);
+               spin_lock_irqsave(&pcpu_lock, flags);
                pcpu_free_area(chunk, off);
                err = "failed to populate";
                goto fail_unlock;
@@ -1123,7 +1169,7 @@ area_found:
        return __addr_to_pcpu_ptr(chunk->base_addr + off);
 
 fail_unlock:
-       spin_unlock_irq(&pcpu_lock);
+       spin_unlock_irqrestore(&pcpu_lock, flags);
 fail_unlock_mutex:
        mutex_unlock(&pcpu_alloc_mutex);
        if (warn_limit) {
@@ -1225,7 +1271,7 @@ static void pcpu_reclaim(struct work_struct *work)
  */
 void free_percpu(void *ptr)
 {
-       void *addr = __pcpu_ptr_to_addr(ptr);
+       void *addr;
        struct pcpu_chunk *chunk;
        unsigned long flags;
        int off;
@@ -1233,6 +1279,8 @@ void free_percpu(void *ptr)
        if (!ptr)
                return;
 
+       addr = __pcpu_ptr_to_addr(ptr);
+
        spin_lock_irqsave(&pcpu_lock, flags);
 
        chunk = pcpu_chunk_addr_search(addr);
@@ -1255,6 +1303,27 @@ void free_percpu(void *ptr)
 }
 EXPORT_SYMBOL_GPL(free_percpu);
 
+/**
+ * per_cpu_ptr_to_phys - convert translated percpu address to physical address
+ * @addr: the address to be converted to physical address
+ *
+ * Given @addr which is dereferenceable address obtained via one of
+ * percpu access macros, this function translates it into its physical
+ * address.  The caller is responsible for ensuring @addr stays valid
+ * until this function finishes.
+ *
+ * RETURNS:
+ * The physical address for @addr.
+ */
+phys_addr_t per_cpu_ptr_to_phys(void *addr)
+{
+       if ((unsigned long)addr < VMALLOC_START ||
+                       (unsigned long)addr >= VMALLOC_END)
+               return __pa(addr);
+       else
+               return page_to_phys(vmalloc_to_page(addr));
+}
+
 static inline size_t pcpu_calc_fc_sizes(size_t static_size,
                                        size_t reserved_size,
                                        ssize_t *dyn_sizep)