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![Al Viro](/assets/img/avatar_default.png)
- added typedef unsigned int __nocast gfp_t; - replaced __nocast uses for gfp flags with gfp_t - it gives exactly the same warnings as far as sparse is concerned, doesn't change generated code (from gcc point of view we replaced unsigned int with typedef) and documents what's going on far better. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
414 lines
10 KiB
C
414 lines
10 KiB
C
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#include <linux/device.h>
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#include <linux/mm.h>
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#include <asm/io.h> /* Needed for i386 to build */
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#include <asm/scatterlist.h> /* Needed for i386 to build */
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#include <linux/dma-mapping.h>
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#include <linux/dmapool.h>
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#include <linux/slab.h>
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#include <linux/module.h>
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/*
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* Pool allocator ... wraps the dma_alloc_coherent page allocator, so
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* small blocks are easily used by drivers for bus mastering controllers.
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* This should probably be sharing the guts of the slab allocator.
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*/
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struct dma_pool { /* the pool */
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struct list_head page_list;
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spinlock_t lock;
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size_t blocks_per_page;
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size_t size;
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struct device *dev;
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size_t allocation;
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char name [32];
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wait_queue_head_t waitq;
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struct list_head pools;
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};
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struct dma_page { /* cacheable header for 'allocation' bytes */
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struct list_head page_list;
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void *vaddr;
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dma_addr_t dma;
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unsigned in_use;
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unsigned long bitmap [0];
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};
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#define POOL_TIMEOUT_JIFFIES ((100 /* msec */ * HZ) / 1000)
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#define POOL_POISON_FREED 0xa7 /* !inuse */
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#define POOL_POISON_ALLOCATED 0xa9 /* !initted */
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static DECLARE_MUTEX (pools_lock);
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static ssize_t
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show_pools (struct device *dev, struct device_attribute *attr, char *buf)
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{
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unsigned temp;
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unsigned size;
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char *next;
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struct dma_page *page;
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struct dma_pool *pool;
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next = buf;
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size = PAGE_SIZE;
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temp = scnprintf(next, size, "poolinfo - 0.1\n");
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size -= temp;
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next += temp;
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down (&pools_lock);
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list_for_each_entry(pool, &dev->dma_pools, pools) {
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unsigned pages = 0;
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unsigned blocks = 0;
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list_for_each_entry(page, &pool->page_list, page_list) {
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pages++;
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blocks += page->in_use;
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}
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/* per-pool info, no real statistics yet */
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temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",
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pool->name,
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blocks, pages * pool->blocks_per_page,
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pool->size, pages);
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size -= temp;
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next += temp;
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}
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up (&pools_lock);
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return PAGE_SIZE - size;
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}
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static DEVICE_ATTR (pools, S_IRUGO, show_pools, NULL);
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/**
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* dma_pool_create - Creates a pool of consistent memory blocks, for dma.
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* @name: name of pool, for diagnostics
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* @dev: device that will be doing the DMA
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* @size: size of the blocks in this pool.
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* @align: alignment requirement for blocks; must be a power of two
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* @allocation: returned blocks won't cross this boundary (or zero)
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* Context: !in_interrupt()
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*
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* Returns a dma allocation pool with the requested characteristics, or
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* null if one can't be created. Given one of these pools, dma_pool_alloc()
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* may be used to allocate memory. Such memory will all have "consistent"
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* DMA mappings, accessible by the device and its driver without using
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* cache flushing primitives. The actual size of blocks allocated may be
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* larger than requested because of alignment.
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*
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* If allocation is nonzero, objects returned from dma_pool_alloc() won't
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* cross that size boundary. This is useful for devices which have
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* addressing restrictions on individual DMA transfers, such as not crossing
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* boundaries of 4KBytes.
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*/
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struct dma_pool *
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dma_pool_create (const char *name, struct device *dev,
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size_t size, size_t align, size_t allocation)
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{
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struct dma_pool *retval;
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if (align == 0)
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align = 1;
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if (size == 0)
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return NULL;
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else if (size < align)
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size = align;
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else if ((size % align) != 0) {
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size += align + 1;
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size &= ~(align - 1);
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}
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if (allocation == 0) {
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if (PAGE_SIZE < size)
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allocation = size;
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else
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allocation = PAGE_SIZE;
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// FIXME: round up for less fragmentation
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} else if (allocation < size)
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return NULL;
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if (!(retval = kmalloc (sizeof *retval, SLAB_KERNEL)))
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return retval;
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strlcpy (retval->name, name, sizeof retval->name);
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retval->dev = dev;
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INIT_LIST_HEAD (&retval->page_list);
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spin_lock_init (&retval->lock);
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retval->size = size;
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retval->allocation = allocation;
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retval->blocks_per_page = allocation / size;
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init_waitqueue_head (&retval->waitq);
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if (dev) {
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down (&pools_lock);
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if (list_empty (&dev->dma_pools))
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device_create_file (dev, &dev_attr_pools);
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/* note: not currently insisting "name" be unique */
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list_add (&retval->pools, &dev->dma_pools);
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up (&pools_lock);
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} else
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INIT_LIST_HEAD (&retval->pools);
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return retval;
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}
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static struct dma_page *
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pool_alloc_page (struct dma_pool *pool, gfp_t mem_flags)
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{
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struct dma_page *page;
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int mapsize;
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mapsize = pool->blocks_per_page;
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mapsize = (mapsize + BITS_PER_LONG - 1) / BITS_PER_LONG;
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mapsize *= sizeof (long);
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page = (struct dma_page *) kmalloc (mapsize + sizeof *page, mem_flags);
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if (!page)
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return NULL;
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page->vaddr = dma_alloc_coherent (pool->dev,
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pool->allocation,
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&page->dma,
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mem_flags);
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if (page->vaddr) {
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memset (page->bitmap, 0xff, mapsize); // bit set == free
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#ifdef CONFIG_DEBUG_SLAB
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memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
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#endif
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list_add (&page->page_list, &pool->page_list);
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page->in_use = 0;
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} else {
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kfree (page);
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page = NULL;
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}
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return page;
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}
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static inline int
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is_page_busy (int blocks, unsigned long *bitmap)
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{
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while (blocks > 0) {
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if (*bitmap++ != ~0UL)
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return 1;
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blocks -= BITS_PER_LONG;
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}
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return 0;
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}
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static void
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pool_free_page (struct dma_pool *pool, struct dma_page *page)
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{
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dma_addr_t dma = page->dma;
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#ifdef CONFIG_DEBUG_SLAB
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memset (page->vaddr, POOL_POISON_FREED, pool->allocation);
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#endif
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dma_free_coherent (pool->dev, pool->allocation, page->vaddr, dma);
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list_del (&page->page_list);
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kfree (page);
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}
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/**
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* dma_pool_destroy - destroys a pool of dma memory blocks.
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* @pool: dma pool that will be destroyed
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* Context: !in_interrupt()
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*
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* Caller guarantees that no more memory from the pool is in use,
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* and that nothing will try to use the pool after this call.
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*/
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void
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dma_pool_destroy (struct dma_pool *pool)
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{
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down (&pools_lock);
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list_del (&pool->pools);
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if (pool->dev && list_empty (&pool->dev->dma_pools))
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device_remove_file (pool->dev, &dev_attr_pools);
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up (&pools_lock);
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while (!list_empty (&pool->page_list)) {
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struct dma_page *page;
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page = list_entry (pool->page_list.next,
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struct dma_page, page_list);
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if (is_page_busy (pool->blocks_per_page, page->bitmap)) {
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if (pool->dev)
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dev_err(pool->dev, "dma_pool_destroy %s, %p busy\n",
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pool->name, page->vaddr);
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else
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printk (KERN_ERR "dma_pool_destroy %s, %p busy\n",
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pool->name, page->vaddr);
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/* leak the still-in-use consistent memory */
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list_del (&page->page_list);
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kfree (page);
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} else
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pool_free_page (pool, page);
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}
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kfree (pool);
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}
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/**
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* dma_pool_alloc - get a block of consistent memory
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* @pool: dma pool that will produce the block
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* @mem_flags: GFP_* bitmask
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* @handle: pointer to dma address of block
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*
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* This returns the kernel virtual address of a currently unused block,
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* and reports its dma address through the handle.
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* If such a memory block can't be allocated, null is returned.
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*/
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void *
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dma_pool_alloc (struct dma_pool *pool, gfp_t mem_flags, dma_addr_t *handle)
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{
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unsigned long flags;
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struct dma_page *page;
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int map, block;
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size_t offset;
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void *retval;
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restart:
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spin_lock_irqsave (&pool->lock, flags);
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list_for_each_entry(page, &pool->page_list, page_list) {
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int i;
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/* only cachable accesses here ... */
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for (map = 0, i = 0;
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i < pool->blocks_per_page;
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i += BITS_PER_LONG, map++) {
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if (page->bitmap [map] == 0)
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continue;
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block = ffz (~ page->bitmap [map]);
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if ((i + block) < pool->blocks_per_page) {
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clear_bit (block, &page->bitmap [map]);
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offset = (BITS_PER_LONG * map) + block;
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offset *= pool->size;
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goto ready;
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}
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}
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}
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if (!(page = pool_alloc_page (pool, SLAB_ATOMIC))) {
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if (mem_flags & __GFP_WAIT) {
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DECLARE_WAITQUEUE (wait, current);
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current->state = TASK_INTERRUPTIBLE;
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add_wait_queue (&pool->waitq, &wait);
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spin_unlock_irqrestore (&pool->lock, flags);
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schedule_timeout (POOL_TIMEOUT_JIFFIES);
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remove_wait_queue (&pool->waitq, &wait);
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goto restart;
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}
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retval = NULL;
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goto done;
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}
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clear_bit (0, &page->bitmap [0]);
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offset = 0;
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ready:
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page->in_use++;
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retval = offset + page->vaddr;
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*handle = offset + page->dma;
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#ifdef CONFIG_DEBUG_SLAB
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memset (retval, POOL_POISON_ALLOCATED, pool->size);
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#endif
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done:
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spin_unlock_irqrestore (&pool->lock, flags);
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return retval;
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}
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static struct dma_page *
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pool_find_page (struct dma_pool *pool, dma_addr_t dma)
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{
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unsigned long flags;
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struct dma_page *page;
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spin_lock_irqsave (&pool->lock, flags);
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list_for_each_entry(page, &pool->page_list, page_list) {
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if (dma < page->dma)
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continue;
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if (dma < (page->dma + pool->allocation))
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goto done;
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}
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page = NULL;
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done:
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spin_unlock_irqrestore (&pool->lock, flags);
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return page;
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}
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/**
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* dma_pool_free - put block back into dma pool
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* @pool: the dma pool holding the block
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* @vaddr: virtual address of block
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* @dma: dma address of block
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*
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* Caller promises neither device nor driver will again touch this block
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* unless it is first re-allocated.
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*/
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void
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dma_pool_free (struct dma_pool *pool, void *vaddr, dma_addr_t dma)
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{
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struct dma_page *page;
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unsigned long flags;
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int map, block;
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if ((page = pool_find_page (pool, dma)) == 0) {
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if (pool->dev)
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dev_err(pool->dev, "dma_pool_free %s, %p/%lx (bad dma)\n",
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pool->name, vaddr, (unsigned long) dma);
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else
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printk (KERN_ERR "dma_pool_free %s, %p/%lx (bad dma)\n",
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pool->name, vaddr, (unsigned long) dma);
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return;
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}
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block = dma - page->dma;
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block /= pool->size;
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map = block / BITS_PER_LONG;
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block %= BITS_PER_LONG;
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#ifdef CONFIG_DEBUG_SLAB
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if (((dma - page->dma) + (void *)page->vaddr) != vaddr) {
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if (pool->dev)
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dev_err(pool->dev, "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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pool->name, vaddr, (unsigned long long) dma);
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else
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printk (KERN_ERR "dma_pool_free %s, %p (bad vaddr)/%Lx\n",
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pool->name, vaddr, (unsigned long long) dma);
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return;
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}
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if (page->bitmap [map] & (1UL << block)) {
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if (pool->dev)
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dev_err(pool->dev, "dma_pool_free %s, dma %Lx already free\n",
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pool->name, (unsigned long long)dma);
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else
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printk (KERN_ERR "dma_pool_free %s, dma %Lx already free\n",
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pool->name, (unsigned long long)dma);
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return;
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}
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memset (vaddr, POOL_POISON_FREED, pool->size);
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#endif
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spin_lock_irqsave (&pool->lock, flags);
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page->in_use--;
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set_bit (block, &page->bitmap [map]);
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if (waitqueue_active (&pool->waitq))
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wake_up (&pool->waitq);
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/*
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* Resist a temptation to do
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* if (!is_page_busy(bpp, page->bitmap)) pool_free_page(pool, page);
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* Better have a few empty pages hang around.
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*/
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spin_unlock_irqrestore (&pool->lock, flags);
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}
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EXPORT_SYMBOL (dma_pool_create);
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EXPORT_SYMBOL (dma_pool_destroy);
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EXPORT_SYMBOL (dma_pool_alloc);
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EXPORT_SYMBOL (dma_pool_free);
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