1 files changed, 447 insertions, 77 deletions

diff --git a/lib/genalloc.c b/lib/genalloc.c
index f6d276db2d58..26cf20be72b7 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -1,8 +1,26 @@
 /*
- * Basic general purpose allocator for managing special purpose memory
- * not managed by the regular kmalloc/kfree interface.
- * Uses for this includes on-device special memory, uncached memory
- * etc.
+ * Basic general purpose allocator for managing special purpose
+ * memory, for example, memory that is not managed by the regular
+ * kmalloc/kfree interface.  Uses for this includes on-device special
+ * memory, uncached memory etc.
+ *
+ * It is safe to use the allocator in NMI handlers and other special
+ * unblockable contexts that could otherwise deadlock on locks.  This
+ * is implemented by using atomic operations and retries on any
+ * conflicts.  The disadvantage is that there may be livelocks in
+ * extreme cases.  For better scalability, one allocator can be used
+ * for each CPU.
+ *
+ * The lockless operation only works if there is enough memory
+ * available.  If new memory is added to the pool a lock has to be
+ * still taken.  So any user relying on locklessness has to ensure
+ * that sufficient memory is preallocated.
+ *
+ * The basic atomic operation of this allocator is cmpxchg on long.
+ * On architectures that don't have NMI-safe cmpxchg implementation,
+ * the allocator can NOT be used in NMI handler.  So code uses the
+ * allocator in NMI handler should depend on
+ * CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG.
  *
  * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
  *
@@ -10,9 +28,119 @@
  * Version 2.  See the file COPYING for more details.
  */
 
-#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+#include <linux/bitmap.h>
+#include <linux/rculist.h>
+#include <linux/interrupt.h>
 #include <linux/genalloc.h>
+#include <linux/of_address.h>
+#include <linux/of_device.h>
+
+static inline size_t chunk_size(const struct gen_pool_chunk *chunk)
+{
+	return chunk->end_addr - chunk->start_addr + 1;
+}
+
+static int set_bits_ll(unsigned long *addr, unsigned long mask_to_set)
+{
+	unsigned long val, nval;
+
+	nval = *addr;
+	do {
+		val = nval;
+		if (val & mask_to_set)
+			return -EBUSY;
+		cpu_relax();
+	} while ((nval = cmpxchg(addr, val, val | mask_to_set)) != val);
+
+	return 0;
+}
+
+static int clear_bits_ll(unsigned long *addr, unsigned long mask_to_clear)
+{
+	unsigned long val, nval;
+
+	nval = *addr;
+	do {
+		val = nval;
+		if ((val & mask_to_clear) != mask_to_clear)
+			return -EBUSY;
+		cpu_relax();
+	} while ((nval = cmpxchg(addr, val, val & ~mask_to_clear)) != val);
+
+	return 0;
+}
 
+/*
+ * bitmap_set_ll - set the specified number of bits at the specified position
+ * @map: pointer to a bitmap
+ * @start: a bit position in @map
+ * @nr: number of bits to set
+ *
+ * Set @nr bits start from @start in @map lock-lessly. Several users
+ * can set/clear the same bitmap simultaneously without lock. If two
+ * users set the same bit, one user will return remain bits, otherwise
+ * return 0.
+ */
+static int bitmap_set_ll(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_set >= 0) {
+		if (set_bits_ll(p, mask_to_set))
+			return nr;
+		nr -= bits_to_set;
+		bits_to_set = BITS_PER_LONG;
+		mask_to_set = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+		if (set_bits_ll(p, mask_to_set))
+			return nr;
+	}
+
+	return 0;
+}
+
+/*
+ * bitmap_clear_ll - clear the specified number of bits at the specified position
+ * @map: pointer to a bitmap
+ * @start: a bit position in @map
+ * @nr: number of bits to set
+ *
+ * Clear @nr bits start from @start in @map lock-lessly. Several users
+ * can set/clear the same bitmap simultaneously without lock. If two
+ * users clear the same bit, one user will return remain bits,
+ * otherwise return 0.
+ */
+static int bitmap_clear_ll(unsigned long *map, int start, int nr)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const int size = start + nr;
+	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+	while (nr - bits_to_clear >= 0) {
+		if (clear_bits_ll(p, mask_to_clear))
+			return nr;
+		nr -= bits_to_clear;
+		bits_to_clear = BITS_PER_LONG;
+		mask_to_clear = ~0UL;
+		p++;
+	}
+	if (nr) {
+		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+		if (clear_bits_ll(p, mask_to_clear))
+			return nr;
+	}
+
+	return 0;
+}
 
 /**
  * gen_pool_create - create a new special memory pool
@@ -28,47 +156,78 @@ struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
 
 	pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
 	if (pool != NULL) {
-		rwlock_init(&pool->lock);
+		spin_lock_init(&pool->lock);
 		INIT_LIST_HEAD(&pool->chunks);
 		pool->min_alloc_order = min_alloc_order;
+		pool->algo = gen_pool_first_fit;
+		pool->data = NULL;
 	}
 	return pool;
 }
 EXPORT_SYMBOL(gen_pool_create);
 
 /**
- * gen_pool_add - add a new chunk of special memory to the pool
+ * gen_pool_add_virt - add a new chunk of special memory to the pool
  * @pool: pool to add new memory chunk to
- * @addr: starting address of memory chunk to add to pool
+ * @virt: virtual starting address of memory chunk to add to pool
+ * @phys: physical starting address of memory chunk to add to pool
  * @size: size in bytes of the memory chunk to add to pool
  * @nid: node id of the node the chunk structure and bitmap should be
  *       allocated on, or -1
  *
  * Add a new chunk of special memory to the specified pool.
+ *
+ * Returns 0 on success or a -ve errno on failure.
  */
-int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
-		 int nid)
+int gen_pool_add_virt(struct gen_pool *pool, unsigned long virt, phys_addr_t phys,
+		 size_t size, int nid)
 {
 	struct gen_pool_chunk *chunk;
 	int nbits = size >> pool->min_alloc_order;
 	int nbytes = sizeof(struct gen_pool_chunk) +
-				(nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
+				BITS_TO_LONGS(nbits) * sizeof(long);
 
-	chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
+	chunk = kzalloc_node(nbytes, GFP_KERNEL, nid);
 	if (unlikely(chunk == NULL))
-		return -1;
+		return -ENOMEM;
 
-	spin_lock_init(&chunk->lock);
-	chunk->start_addr = addr;
-	chunk->end_addr = addr + size;
+	chunk->phys_addr = phys;
+	chunk->start_addr = virt;
+	chunk->end_addr = virt + size - 1;
+	atomic_set(&chunk->avail, size);
 
-	write_lock(&pool->lock);
-	list_add(&chunk->next_chunk, &pool->chunks);
-	write_unlock(&pool->lock);
+	spin_lock(&pool->lock);
+	list_add_rcu(&chunk->next_chunk, &pool->chunks);
+	spin_unlock(&pool->lock);
 
 	return 0;
 }
-EXPORT_SYMBOL(gen_pool_add);
+EXPORT_SYMBOL(gen_pool_add_virt);
+
+/**
+ * gen_pool_virt_to_phys - return the physical address of memory
+ * @pool: pool to allocate from
+ * @addr: starting address of memory
+ *
+ * Returns the physical address on success, or -1 on error.
+ */
+phys_addr_t gen_pool_virt_to_phys(struct gen_pool *pool, unsigned long addr)
+{
+	struct gen_pool_chunk *chunk;
+	phys_addr_t paddr = -1;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
+		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
+			paddr = chunk->phys_addr + (addr - chunk->start_addr);
+			break;
+		}
+	}
+	rcu_read_unlock();
+
+	return paddr;
+}
+EXPORT_SYMBOL(gen_pool_virt_to_phys);
 
 /**
  * gen_pool_destroy - destroy a special memory pool
@@ -84,13 +243,11 @@ void gen_pool_destroy(struct gen_pool *pool)
 	int order = pool->min_alloc_order;
 	int bit, end_bit;
 
-
-	write_lock(&pool->lock);
 	list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
 		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
 		list_del(&chunk->next_chunk);
 
-		end_bit = (chunk->end_addr - chunk->start_addr) >> order;
+		end_bit = chunk_size(chunk) >> order;
 		bit = find_next_bit(chunk->bits, end_bit, 0);
 		BUG_ON(bit < end_bit);
 
@@ -107,55 +264,51 @@ EXPORT_SYMBOL(gen_pool_destroy);
  * @size: number of bytes to allocate from the pool
  *
  * Allocate the requested number of bytes from the specified pool.
- * Uses a first-fit algorithm.
+ * Uses the pool allocation function (with first-fit algorithm by default).
+ * Can not be used in NMI handler on architectures without
+ * NMI-safe cmpxchg implementation.
  */
 unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
 {
-	struct list_head *_chunk;
 	struct gen_pool_chunk *chunk;
-	unsigned long addr, flags;
+	unsigned long addr = 0;
 	int order = pool->min_alloc_order;
-	int nbits, bit, start_bit, end_bit;
+	int nbits, start_bit = 0, end_bit, remain;
+
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+	BUG_ON(in_nmi());
+#endif
 
 	if (size == 0)
 		return 0;
 
 	nbits = (size + (1UL << order) - 1) >> order;
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
+		if (size > atomic_read(&chunk->avail))
+			continue;
 
-	read_lock(&pool->lock);
-	list_for_each(_chunk, &pool->chunks) {
-		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
-
-		end_bit = (chunk->end_addr - chunk->start_addr) >> order;
-		end_bit -= nbits + 1;
-
-		spin_lock_irqsave(&chunk->lock, flags);
-		bit = -1;
-		while (bit + 1 < end_bit) {
-			bit = find_next_zero_bit(chunk->bits, end_bit, bit + 1);
-			if (bit >= end_bit)
-				break;
-
-			start_bit = bit;
-			if (nbits > 1) {
-				bit = find_next_bit(chunk->bits, bit + nbits,
-							bit + 1);
-				if (bit - start_bit < nbits)
-					continue;
-			}
-
-			addr = chunk->start_addr +
-					    ((unsigned long)start_bit << order);
-			while (nbits--)
-				__set_bit(start_bit++, chunk->bits);
-			spin_unlock_irqrestore(&chunk->lock, flags);
-			read_unlock(&pool->lock);
-			return addr;
+		end_bit = chunk_size(chunk) >> order;
+retry:
+		start_bit = pool->algo(chunk->bits, end_bit, start_bit, nbits,
+				pool->data);
+		if (start_bit >= end_bit)
+			continue;
+		remain = bitmap_set_ll(chunk->bits, start_bit, nbits);
+		if (remain) {
+			remain = bitmap_clear_ll(chunk->bits, start_bit,
+						 nbits - remain);
+			BUG_ON(remain);
+			goto retry;
 		}
-		spin_unlock_irqrestore(&chunk->lock, flags);
+
+		addr = chunk->start_addr + ((unsigned long)start_bit << order);
+		size = nbits << order;
+		atomic_sub(size, &chunk->avail);
+		break;
 	}
-	read_unlock(&pool->lock);
-	return 0;
+	rcu_read_unlock();
+	return addr;
 }
 EXPORT_SYMBOL(gen_pool_alloc);
 
@@ -165,33 +318,250 @@ EXPORT_SYMBOL(gen_pool_alloc);
  * @addr: starting address of memory to free back to pool
  * @size: size in bytes of memory to free
  *
- * Free previously allocated special memory back to the specified pool.
+ * Free previously allocated special memory back to the specified
+ * pool.  Can not be used in NMI handler on architectures without
+ * NMI-safe cmpxchg implementation.
  */
 void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
 {
-	struct list_head *_chunk;
 	struct gen_pool_chunk *chunk;
-	unsigned long flags;
 	int order = pool->min_alloc_order;
-	int bit, nbits;
+	int start_bit, nbits, remain;
+
+#ifndef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+	BUG_ON(in_nmi());
+#endif
 
 	nbits = (size + (1UL << order) - 1) >> order;
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
+		if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
+			BUG_ON(addr + size - 1 > chunk->end_addr);
+			start_bit = (addr - chunk->start_addr) >> order;
+			remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
+			BUG_ON(remain);
+			size = nbits << order;
+			atomic_add(size, &chunk->avail);
+			rcu_read_unlock();
+			return;
+		}
+	}
+	rcu_read_unlock();
+	BUG();
+}
+EXPORT_SYMBOL(gen_pool_free);
 
-	read_lock(&pool->lock);
-	list_for_each(_chunk, &pool->chunks) {
-		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
+/**
+ * gen_pool_for_each_chunk - call func for every chunk of generic memory pool
+ * @pool:	the generic memory pool
+ * @func:	func to call
+ * @data:	additional data used by @func
+ *
+ * Call @func for every chunk of generic memory pool.  The @func is
+ * called with rcu_read_lock held.
+ */
+void gen_pool_for_each_chunk(struct gen_pool *pool,
+	void (*func)(struct gen_pool *pool, struct gen_pool_chunk *chunk, void *data),
+	void *data)
+{
+	struct gen_pool_chunk *chunk;
 
-		if (addr >= chunk->start_addr && addr < chunk->end_addr) {
-			BUG_ON(addr + size > chunk->end_addr);
-			spin_lock_irqsave(&chunk->lock, flags);
-			bit = (addr - chunk->start_addr) >> order;
-			while (nbits--)
-				__clear_bit(bit++, chunk->bits);
-			spin_unlock_irqrestore(&chunk->lock, flags);
-			break;
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &(pool)->chunks, next_chunk)
+		func(pool, chunk, data);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(gen_pool_for_each_chunk);
+
+/**
+ * gen_pool_avail - get available free space of the pool
+ * @pool: pool to get available free space
+ *
+ * Return available free space of the specified pool.
+ */
+size_t gen_pool_avail(struct gen_pool *pool)
+{
+	struct gen_pool_chunk *chunk;
+	size_t avail = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
+		avail += atomic_read(&chunk->avail);
+	rcu_read_unlock();
+	return avail;
+}
+EXPORT_SYMBOL_GPL(gen_pool_avail);
+
+/**
+ * gen_pool_size - get size in bytes of memory managed by the pool
+ * @pool: pool to get size
+ *
+ * Return size in bytes of memory managed by the pool.
+ */
+size_t gen_pool_size(struct gen_pool *pool)
+{
+	struct gen_pool_chunk *chunk;
+	size_t size = 0;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk)
+		size += chunk_size(chunk);
+	rcu_read_unlock();
+	return size;
+}
+EXPORT_SYMBOL_GPL(gen_pool_size);
+
+/**
+ * gen_pool_set_algo - set the allocation algorithm
+ * @pool: pool to change allocation algorithm
+ * @algo: custom algorithm function
+ * @data: additional data used by @algo
+ *
+ * Call @algo for each memory allocation in the pool.
+ * If @algo is NULL use gen_pool_first_fit as default
+ * memory allocation function.
+ */
+void gen_pool_set_algo(struct gen_pool *pool, genpool_algo_t algo, void *data)
+{
+	rcu_read_lock();
+
+	pool->algo = algo;
+	if (!pool->algo)
+		pool->algo = gen_pool_first_fit;
+
+	pool->data = data;
+
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(gen_pool_set_algo);
+
+/**
+ * gen_pool_first_fit - find the first available region
+ * of memory matching the size requirement (no alignment constraint)
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @data: additional data - unused
+ */
+unsigned long gen_pool_first_fit(unsigned long *map, unsigned long size,
+		unsigned long start, unsigned int nr, void *data)
+{
+	return bitmap_find_next_zero_area(map, size, start, nr, 0);
+}
+EXPORT_SYMBOL(gen_pool_first_fit);
+
+/**
+ * gen_pool_best_fit - find the best fitting region of memory
+ * macthing the size requirement (no alignment constraint)
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @data: additional data - unused
+ *
+ * Iterate over the bitmap to find the smallest free region
+ * which we can allocate the memory.
+ */
+unsigned long gen_pool_best_fit(unsigned long *map, unsigned long size,
+		unsigned long start, unsigned int nr, void *data)
+{
+	unsigned long start_bit = size;
+	unsigned long len = size + 1;
+	unsigned long index;
+
+	index = bitmap_find_next_zero_area(map, size, start, nr, 0);
+
+	while (index < size) {
+		int next_bit = find_next_bit(map, size, index + nr);
+		if ((next_bit - index) < len) {
+			len = next_bit - index;
+			start_bit = index;
+			if (len == nr)
+				return start_bit;
 		}
+		index = bitmap_find_next_zero_area(map, size,
+						   next_bit + 1, nr, 0);
 	}
-	BUG_ON(nbits > 0);
-	read_unlock(&pool->lock);
+
+	return start_bit;
 }
-EXPORT_SYMBOL(gen_pool_free);
+EXPORT_SYMBOL(gen_pool_best_fit);
+
+static void devm_gen_pool_release(struct device *dev, void *res)
+{
+	gen_pool_destroy(*(struct gen_pool **)res);
+}
+
+/**
+ * devm_gen_pool_create - managed gen_pool_create
+ * @dev: device that provides the gen_pool
+ * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
+ * @nid: node id of the node the pool structure should be allocated on, or -1
+ *
+ * Create a new special memory pool that can be used to manage special purpose
+ * memory not managed by the regular kmalloc/kfree interface. The pool will be
+ * automatically destroyed by the device management code.
+ */
+struct gen_pool *devm_gen_pool_create(struct device *dev, int min_alloc_order,
+		int nid)
+{
+	struct gen_pool **ptr, *pool;
+
+	ptr = devres_alloc(devm_gen_pool_release, sizeof(*ptr), GFP_KERNEL);
+
+	pool = gen_pool_create(min_alloc_order, nid);
+	if (pool) {
+		*ptr = pool;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return pool;
+}
+
+/**
+ * dev_get_gen_pool - Obtain the gen_pool (if any) for a device
+ * @dev: device to retrieve the gen_pool from
+ *
+ * Returns the gen_pool for the device if one is present, or NULL.
+ */
+struct gen_pool *dev_get_gen_pool(struct device *dev)
+{
+	struct gen_pool **p = devres_find(dev, devm_gen_pool_release, NULL,
+					NULL);
+
+	if (!p)
+		return NULL;
+	return *p;
+}
+EXPORT_SYMBOL_GPL(dev_get_gen_pool);
+
+#ifdef CONFIG_OF
+/**
+ * of_get_named_gen_pool - find a pool by phandle property
+ * @np: device node
+ * @propname: property name containing phandle(s)
+ * @index: index into the phandle array
+ *
+ * Returns the pool that contains the chunk starting at the physical
+ * address of the device tree node pointed at by the phandle property,
+ * or NULL if not found.
+ */
+struct gen_pool *of_get_named_gen_pool(struct device_node *np,
+	const char *propname, int index)
+{
+	struct platform_device *pdev;
+	struct device_node *np_pool;
+
+	np_pool = of_parse_phandle(np, propname, index);
+	if (!np_pool)
+		return NULL;
+	pdev = of_find_device_by_node(np_pool);
+	if (!pdev)
+		return NULL;
+	return dev_get_gen_pool(&pdev->dev);
+}
+EXPORT_SYMBOL_GPL(of_get_named_gen_pool);
+#endif /* CONFIG_OF */