[net-next-2.6.git] / mm / highmem.c

/*
 * High memory handling common code and variables.
 *
 * (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de
 *          Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de
 *
 *
 * Redesigned the x86 32-bit VM architecture to deal with
 * 64-bit physical space. With current x86 CPUs this
 * means up to 64 Gigabytes physical RAM.
 *
 * Rewrote high memory support to move the page cache into
 * high memory. Implemented permanent (schedulable) kmaps
 * based on Linus' idea.
 *
 * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
 */

#include <linux/mm.h>
#include <linux/module.h>
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/pagemap.h>
#include <linux/mempool.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/highmem.h>
#include <linux/blktrace_api.h>
#include <asm/tlbflush.h>

static mempool_t *page_pool, *isa_page_pool;

static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
{
	return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
}

/*
 * Virtual_count is not a pure "count".
 *  0 means that it is not mapped, and has not been mapped
 *    since a TLB flush - it is usable.
 *  1 means that there are no users, but it has been mapped
 *    since the last TLB flush - so we can't use it.
 *  n means that there are (n-1) current users of it.
 */
#ifdef CONFIG_HIGHMEM

static int pkmap_count[LAST_PKMAP];
static unsigned int last_pkmap_nr;
static  __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);

pte_t * pkmap_page_table;

static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);

static void flush_all_zero_pkmaps(void)
{
	int i;

	flush_cache_kmaps();

	for (i = 0; i < LAST_PKMAP; i++) {
		struct page *page;

		/*
		 * zero means we don't have anything to do,
		 * >1 means that it is still in use. Only
		 * a count of 1 means that it is free but
		 * needs to be unmapped
		 */
		if (pkmap_count[i] != 1)
			continue;
		pkmap_count[i] = 0;

		/* sanity check */
		if (pte_none(pkmap_page_table[i]))
			BUG();

		/*
		 * Don't need an atomic fetch-and-clear op here;
		 * no-one has the page mapped, and cannot get at
		 * its virtual address (and hence PTE) without first
		 * getting the kmap_lock (which is held here).
		 * So no dangers, even with speculative execution.
		 */
		page = pte_page(pkmap_page_table[i]);
		pte_clear(&init_mm, (unsigned long)page_address(page),
			  &pkmap_page_table[i]);

		set_page_address(page, NULL);
	}
	flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
}

static inline unsigned long map_new_virtual(struct page *page)
{
	unsigned long vaddr;
	int count;

start:
	count = LAST_PKMAP;
	/* Find an empty entry */
	for (;;) {
		last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
		if (!last_pkmap_nr) {
			flush_all_zero_pkmaps();
			count = LAST_PKMAP;
		}
		if (!pkmap_count[last_pkmap_nr])
			break;	/* Found a usable entry */
		if (--count)
			continue;

		/*
		 * Sleep for somebody else to unmap their entries
		 */
		{
			DECLARE_WAITQUEUE(wait, current);

			__set_current_state(TASK_UNINTERRUPTIBLE);
			add_wait_queue(&pkmap_map_wait, &wait);
			spin_unlock(&kmap_lock);
			schedule();
			remove_wait_queue(&pkmap_map_wait, &wait);
			spin_lock(&kmap_lock);

			/* Somebody else might have mapped it while we slept */
			if (page_address(page))
				return (unsigned long)page_address(page);

			/* Re-start */
			goto start;
		}
	}
	vaddr = PKMAP_ADDR(last_pkmap_nr);
	set_pte_at(&init_mm, vaddr,
		   &(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));

	pkmap_count[last_pkmap_nr] = 1;
	set_page_address(page, (void *)vaddr);

	return vaddr;
}

void fastcall *kmap_high(struct page *page)
{
	unsigned long vaddr;

	/*
	 * For highmem pages, we can't trust "virtual" until
	 * after we have the lock.
	 *
	 * We cannot call this from interrupts, as it may block
	 */
	spin_lock(&kmap_lock);
	vaddr = (unsigned long)page_address(page);
	if (!vaddr)
		vaddr = map_new_virtual(page);
	pkmap_count[PKMAP_NR(vaddr)]++;
	if (pkmap_count[PKMAP_NR(vaddr)] < 2)
		BUG();
	spin_unlock(&kmap_lock);
	return (void*) vaddr;
}

EXPORT_SYMBOL(kmap_high);

void fastcall kunmap_high(struct page *page)
{
	unsigned long vaddr;
	unsigned long nr;
	int need_wakeup;

	spin_lock(&kmap_lock);
	vaddr = (unsigned long)page_address(page);
	if (!vaddr)
		BUG();
	nr = PKMAP_NR(vaddr);

	/*
	 * A count must never go down to zero
	 * without a TLB flush!
	 */
	need_wakeup = 0;
	switch (--pkmap_count[nr]) {
	case 0:
		BUG();
	case 1:
		/*
		 * Avoid an unnecessary wake_up() function call.
		 * The common case is pkmap_count[] == 1, but
		 * no waiters.
		 * The tasks queued in the wait-queue are guarded
		 * by both the lock in the wait-queue-head and by
		 * the kmap_lock.  As the kmap_lock is held here,
		 * no need for the wait-queue-head's lock.  Simply
		 * test if the queue is empty.
		 */
		need_wakeup = waitqueue_active(&pkmap_map_wait);
	}
	spin_unlock(&kmap_lock);

	/* do wake-up, if needed, race-free outside of the spin lock */
	if (need_wakeup)
		wake_up(&pkmap_map_wait);
}

EXPORT_SYMBOL(kunmap_high);

#define POOL_SIZE	64

static __init int init_emergency_pool(void)
{
	struct sysinfo i;
	si_meminfo(&i);
	si_swapinfo(&i);
        
	if (!i.totalhigh)
		return 0;

	page_pool = mempool_create_page_pool(POOL_SIZE, 0);
	if (!page_pool)
		BUG();
	printk("highmem bounce pool size: %d pages\n", POOL_SIZE);

	return 0;
}

__initcall(init_emergency_pool);

/*
 * highmem version, map in to vec
 */
static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
{
	unsigned long flags;
	unsigned char *vto;

	local_irq_save(flags);
	vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
	kunmap_atomic(vto, KM_BOUNCE_READ);
	local_irq_restore(flags);
}

#else /* CONFIG_HIGHMEM */

#define bounce_copy_vec(to, vfrom)	\
	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)

#endif

#define ISA_POOL_SIZE	16

/*
 * gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
 * as the max address, so check if the pool has already been created.
 */
int init_emergency_isa_pool(void)
{
	if (isa_page_pool)
		return 0;

	isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
				       mempool_free_pages, (void *) 0);
	if (!isa_page_pool)
		BUG();

	printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
	return 0;
}

/*
 * Simple bounce buffer support for highmem pages. Depending on the
 * queue gfp mask set, *to may or may not be a highmem page. kmap it
 * always, it will do the Right Thing
 */
static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
{
	unsigned char *vfrom;
	struct bio_vec *tovec, *fromvec;
	int i;

	__bio_for_each_segment(tovec, to, i, 0) {
		fromvec = from->bi_io_vec + i;

		/*
		 * not bounced
		 */
		if (tovec->bv_page == fromvec->bv_page)
			continue;

		/*
		 * fromvec->bv_offset and fromvec->bv_len might have been
		 * modified by the block layer, so use the original copy,
		 * bounce_copy_vec already uses tovec->bv_len
		 */
		vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;

		flush_dcache_page(tovec->bv_page);
		bounce_copy_vec(tovec, vfrom);
	}
}

static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
{
	struct bio *bio_orig = bio->bi_private;
	struct bio_vec *bvec, *org_vec;
	int i;

	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
		set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);

	/*
	 * free up bounce indirect pages used
	 */
	__bio_for_each_segment(bvec, bio, i, 0) {
		org_vec = bio_orig->bi_io_vec + i;
		if (bvec->bv_page == org_vec->bv_page)
			continue;

		mempool_free(bvec->bv_page, pool);	
		dec_page_state(nr_bounce);
	}

	bio_endio(bio_orig, bio_orig->bi_size, err);
	bio_put(bio);
}

static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
{
	if (bio->bi_size)
		return 1;

	bounce_end_io(bio, page_pool, err);
	return 0;
}

static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
{
	if (bio->bi_size)
		return 1;

	bounce_end_io(bio, isa_page_pool, err);
	return 0;
}

static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
{
	struct bio *bio_orig = bio->bi_private;

	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
		copy_to_high_bio_irq(bio_orig, bio);

	bounce_end_io(bio, pool, err);
}

static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
{
	if (bio->bi_size)
		return 1;

	__bounce_end_io_read(bio, page_pool, err);
	return 0;
}

static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
{
	if (bio->bi_size)
		return 1;

	__bounce_end_io_read(bio, isa_page_pool, err);
	return 0;
}

static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig,
			       mempool_t *pool)
{
	struct page *page;
	struct bio *bio = NULL;
	int i, rw = bio_data_dir(*bio_orig);
	struct bio_vec *to, *from;

	bio_for_each_segment(from, *bio_orig, i) {
		page = from->bv_page;

		/*
		 * is destination page below bounce pfn?
		 */
		if (page_to_pfn(page) < q->bounce_pfn)
			continue;

		/*
		 * irk, bounce it
		 */
		if (!bio)
			bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);

		to = bio->bi_io_vec + i;

		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
		to->bv_len = from->bv_len;
		to->bv_offset = from->bv_offset;
		inc_page_state(nr_bounce);

		if (rw == WRITE) {
			char *vto, *vfrom;

			flush_dcache_page(from->bv_page);
			vto = page_address(to->bv_page) + to->bv_offset;
			vfrom = kmap(from->bv_page) + from->bv_offset;
			memcpy(vto, vfrom, to->bv_len);
			kunmap(from->bv_page);
		}
	}

	/*
	 * no pages bounced
	 */
	if (!bio)
		return;

	/*
	 * at least one page was bounced, fill in possible non-highmem
	 * pages
	 */
	__bio_for_each_segment(from, *bio_orig, i, 0) {
		to = bio_iovec_idx(bio, i);
		if (!to->bv_page) {
			to->bv_page = from->bv_page;
			to->bv_len = from->bv_len;
			to->bv_offset = from->bv_offset;
		}
	}

	bio->bi_bdev = (*bio_orig)->bi_bdev;
	bio->bi_flags |= (1 << BIO_BOUNCED);
	bio->bi_sector = (*bio_orig)->bi_sector;
	bio->bi_rw = (*bio_orig)->bi_rw;

	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
	bio->bi_idx = (*bio_orig)->bi_idx;
	bio->bi_size = (*bio_orig)->bi_size;

	if (pool == page_pool) {
		bio->bi_end_io = bounce_end_io_write;
		if (rw == READ)
			bio->bi_end_io = bounce_end_io_read;
	} else {
		bio->bi_end_io = bounce_end_io_write_isa;
		if (rw == READ)
			bio->bi_end_io = bounce_end_io_read_isa;
	}

	bio->bi_private = *bio_orig;
	*bio_orig = bio;
}

void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig)
{
	mempool_t *pool;

	/*
	 * for non-isa bounce case, just check if the bounce pfn is equal
	 * to or bigger than the highest pfn in the system -- in that case,
	 * don't waste time iterating over bio segments
	 */
	if (!(q->bounce_gfp & GFP_DMA)) {
		if (q->bounce_pfn >= blk_max_pfn)
			return;
		pool = page_pool;
	} else {
		BUG_ON(!isa_page_pool);
		pool = isa_page_pool;
	}

	blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);

	/*
	 * slow path
	 */
	__blk_queue_bounce(q, bio_orig, pool);
}

EXPORT_SYMBOL(blk_queue_bounce);

#if defined(HASHED_PAGE_VIRTUAL)

#define PA_HASH_ORDER	7

/*
 * Describes one page->virtual association
 */
struct page_address_map {
	struct page *page;
	void *virtual;
	struct list_head list;
};

/*
 * page_address_map freelist, allocated from page_address_maps.
 */
static struct list_head page_address_pool;	/* freelist */
static spinlock_t pool_lock;			/* protects page_address_pool */

/*
 * Hash table bucket
 */
static struct page_address_slot {
	struct list_head lh;			/* List of page_address_maps */
	spinlock_t lock;			/* Protect this bucket's list */
} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];

static struct page_address_slot *page_slot(struct page *page)
{
	return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
}

void *page_address(struct page *page)
{
	unsigned long flags;
	void *ret;
	struct page_address_slot *pas;

	if (!PageHighMem(page))
		return lowmem_page_address(page);

	pas = page_slot(page);
	ret = NULL;
	spin_lock_irqsave(&pas->lock, flags);
	if (!list_empty(&pas->lh)) {
		struct page_address_map *pam;

		list_for_each_entry(pam, &pas->lh, list) {
			if (pam->page == page) {
				ret = pam->virtual;
				goto done;
			}
		}
	}
done:
	spin_unlock_irqrestore(&pas->lock, flags);
	return ret;
}

EXPORT_SYMBOL(page_address);

void set_page_address(struct page *page, void *virtual)
{
	unsigned long flags;
	struct page_address_slot *pas;
	struct page_address_map *pam;

	BUG_ON(!PageHighMem(page));

	pas = page_slot(page);
	if (virtual) {		/* Add */
		BUG_ON(list_empty(&page_address_pool));

		spin_lock_irqsave(&pool_lock, flags);
		pam = list_entry(page_address_pool.next,
				struct page_address_map, list);
		list_del(&pam->list);
		spin_unlock_irqrestore(&pool_lock, flags);

		pam->page = page;
		pam->virtual = virtual;

		spin_lock_irqsave(&pas->lock, flags);
		list_add_tail(&pam->list, &pas->lh);
		spin_unlock_irqrestore(&pas->lock, flags);
	} else {		/* Remove */
		spin_lock_irqsave(&pas->lock, flags);
		list_for_each_entry(pam, &pas->lh, list) {
			if (pam->page == page) {
				list_del(&pam->list);
				spin_unlock_irqrestore(&pas->lock, flags);
				spin_lock_irqsave(&pool_lock, flags);
				list_add_tail(&pam->list, &page_address_pool);
				spin_unlock_irqrestore(&pool_lock, flags);
				goto done;
			}
		}
		spin_unlock_irqrestore(&pas->lock, flags);
	}
done:
	return;
}

static struct page_address_map page_address_maps[LAST_PKMAP];

void __init page_address_init(void)
{
	int i;

	INIT_LIST_HEAD(&page_address_pool);
	for (i = 0; i < ARRAY_SIZE(page_address_maps); i++)
		list_add(&page_address_maps[i].list, &page_address_pool);
	for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
		INIT_LIST_HEAD(&page_address_htable[i].lh);
		spin_lock_init(&page_address_htable[i].lock);
	}
	spin_lock_init(&pool_lock);
}

#endif	/* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* High memory handling common code and variables.
	3	*
	4	* (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de
	5	* Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de
	6	*
	7	*
	8	* Redesigned the x86 32-bit VM architecture to deal with
	9	* 64-bit physical space. With current x86 CPUs this
	10	* means up to 64 Gigabytes physical RAM.
	11	*
	12	* Rewrote high memory support to move the page cache into
	13	* high memory. Implemented permanent (schedulable) kmaps
	14	* based on Linus' idea.
	15	*
	16	* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
	17	*/
	18
	19	#include <linux/mm.h>
	20	#include <linux/module.h>
	21	#include <linux/swap.h>
	22	#include <linux/bio.h>
	23	#include <linux/pagemap.h>
	24	#include <linux/mempool.h>
	25	#include <linux/blkdev.h>
	26	#include <linux/init.h>
	27	#include <linux/hash.h>
	28	#include <linux/highmem.h>
2056a782	29	#include <linux/blktrace_api.h>
1da177e4 LT	30	#include <asm/tlbflush.h>
	31
	32	static mempool_t page_pool, isa_page_pool;
	33
a19b27ce	34	static void mempool_alloc_pages_isa(gfp_t gfp_mask, void data)
1da177e4	35	{
a19b27ce	36	return mempool_alloc_pages(gfp_mask \| GFP_DMA, data);
1da177e4 LT	37	}
	38
	39	/*
	40	* Virtual_count is not a pure "count".
	41	* 0 means that it is not mapped, and has not been mapped
	42	* since a TLB flush - it is usable.
	43	* 1 means that there are no users, but it has been mapped
	44	* since the last TLB flush - so we can't use it.
	45	* n means that there are (n-1) current users of it.
	46	*/
	47	#ifdef CONFIG_HIGHMEM
260b2367	48
1da177e4 LT	49	static int pkmap_count[LAST_PKMAP];
	50	static unsigned int last_pkmap_nr;
	51	static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);
	52
	53	pte_t * pkmap_page_table;
	54
	55	static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
	56
	57	static void flush_all_zero_pkmaps(void)
	58	{
	59	int i;
	60
	61	flush_cache_kmaps();
	62
	63	for (i = 0; i < LAST_PKMAP; i++) {
	64	struct page *page;
	65
	66	/*
	67	* zero means we don't have anything to do,
	68	* >1 means that it is still in use. Only
	69	* a count of 1 means that it is free but
	70	* needs to be unmapped
	71	*/
	72	if (pkmap_count[i] != 1)
	73	continue;
	74	pkmap_count[i] = 0;
	75
	76	/* sanity check */
	77	if (pte_none(pkmap_page_table[i]))
	78	BUG();
	79
	80	/*
	81	* Don't need an atomic fetch-and-clear op here;
	82	* no-one has the page mapped, and cannot get at
	83	* its virtual address (and hence PTE) without first
	84	* getting the kmap_lock (which is held here).
	85	* So no dangers, even with speculative execution.
	86	*/
	87	page = pte_page(pkmap_page_table[i]);
	88	pte_clear(&init_mm, (unsigned long)page_address(page),
	89	&pkmap_page_table[i]);
	90
	91	set_page_address(page, NULL);
	92	}
	93	flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
	94	}
	95
	96	static inline unsigned long map_new_virtual(struct page *page)
	97	{
	98	unsigned long vaddr;
	99	int count;
	100
	101	start:
	102	count = LAST_PKMAP;
	103	/* Find an empty entry */
	104	for (;;) {
	105	last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
	106	if (!last_pkmap_nr) {
	107	flush_all_zero_pkmaps();
	108	count = LAST_PKMAP;
	109	}
	110	if (!pkmap_count[last_pkmap_nr])
	111	break; /* Found a usable entry */
	112	if (--count)
113	continue;
114
115	/*
116	* Sleep for somebody else to unmap their entries
117	*/
118	{
119	DECLARE_WAITQUEUE(wait, current);
120
121	__set_current_state(TASK_UNINTERRUPTIBLE);
122	add_wait_queue(&pkmap_map_wait, &wait);
123	spin_unlock(&kmap_lock);
124	schedule();
125	remove_wait_queue(&pkmap_map_wait, &wait);
126	spin_lock(&kmap_lock);
127
128	/* Somebody else might have mapped it while we slept */
129	if (page_address(page))
130	return (unsigned long)page_address(page);
131
132	/* Re-start */
133	goto start;
134	}
135	}
136	vaddr = PKMAP_ADDR(last_pkmap_nr);
137	set_pte_at(&init_mm, vaddr,
138	&(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
139
140	pkmap_count[last_pkmap_nr] = 1;
141	set_page_address(page, (void *)vaddr);
142
143	return vaddr;
144	}
145
146	void fastcall kmap_high(struct page page)
147	{
148	unsigned long vaddr;
149
150	/*
151	* For highmem pages, we can't trust "virtual" until
152	* after we have the lock.
153	*
154	* We cannot call this from interrupts, as it may block
155	*/
156	spin_lock(&kmap_lock);
157	vaddr = (unsigned long)page_address(page);
158	if (!vaddr)
159	vaddr = map_new_virtual(page);
160	pkmap_count[PKMAP_NR(vaddr)]++;
161	if (pkmap_count[PKMAP_NR(vaddr)] < 2)
162	BUG();
163	spin_unlock(&kmap_lock);
164	return (void*) vaddr;
165	}
166
167	EXPORT_SYMBOL(kmap_high);
168
169	void fastcall kunmap_high(struct page *page)
170	{
171	unsigned long vaddr;
172	unsigned long nr;
173	int need_wakeup;
174
175	spin_lock(&kmap_lock);
176	vaddr = (unsigned long)page_address(page);
177	if (!vaddr)
178	BUG();
179	nr = PKMAP_NR(vaddr);
180
181	/*
182	* A count must never go down to zero
183	* without a TLB flush!
184	*/
185	need_wakeup = 0;
186	switch (--pkmap_count[nr]) {
187	case 0:
188	BUG();
189	case 1:
190	/*
191	* Avoid an unnecessary wake_up() function call.
192	* The common case is pkmap_count[] == 1, but
193	* no waiters.
194	* The tasks queued in the wait-queue are guarded
195	* by both the lock in the wait-queue-head and by
196	* the kmap_lock. As the kmap_lock is held here,
197	* no need for the wait-queue-head's lock. Simply
198	* test if the queue is empty.
199	*/
200	need_wakeup = waitqueue_active(&pkmap_map_wait);
201	}
202	spin_unlock(&kmap_lock);
203
204	/* do wake-up, if needed, race-free outside of the spin lock */
205	if (need_wakeup)
206	wake_up(&pkmap_map_wait);
207	}
208
209	EXPORT_SYMBOL(kunmap_high);
210
211	#define POOL_SIZE 64
212
213	static __init int init_emergency_pool(void)
214	{
215	struct sysinfo i;
216	si_meminfo(&i);
217	si_swapinfo(&i);
218
219	if (!i.totalhigh)
220	return 0;
221
a19b27ce	222	page_pool = mempool_create_page_pool(POOL_SIZE, 0);
1da177e4 LT	223	if (!page_pool)
	224	BUG();
	225	printk("highmem bounce pool size: %d pages\n", POOL_SIZE);
	226
	227	return 0;
	228	}
	229
	230	__initcall(init_emergency_pool);
	231
	232	/*
	233	* highmem version, map in to vec
	234	*/
	235	static void bounce_copy_vec(struct bio_vec to, unsigned char vfrom)
	236	{
	237	unsigned long flags;
	238	unsigned char *vto;
	239
	240	local_irq_save(flags);
	241	vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
	242	memcpy(vto + to->bv_offset, vfrom, to->bv_len);
	243	kunmap_atomic(vto, KM_BOUNCE_READ);
	244	local_irq_restore(flags);
	245	}
	246
	247	#else /* CONFIG_HIGHMEM */
	248
	249	#define bounce_copy_vec(to, vfrom) \
	250	memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
	251
	252	#endif
	253
	254	#define ISA_POOL_SIZE 16
	255
	256	/*
	257	* gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
	258	* as the max address, so check if the pool has already been created.
	259	*/
	260	int init_emergency_isa_pool(void)
	261	{
	262	if (isa_page_pool)
	263	return 0;
	264
a19b27ce MD	265	isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
a19b27ce MD	266	mempool_free_pages, (void *) 0);
1da177e4 LT	267	if (!isa_page_pool)
	268	BUG();
	269
	270	printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
	271	return 0;
	272	}
	273
	274	/*
	275	* Simple bounce buffer support for highmem pages. Depending on the
	276	* queue gfp mask set, *to may or may not be a highmem page. kmap it
	277	* always, it will do the Right Thing
	278	*/
	279	static void copy_to_high_bio_irq(struct bio to, struct bio from)
	280	{
	281	unsigned char *vfrom;
	282	struct bio_vec tovec, fromvec;
	283	int i;
	284
	285	__bio_for_each_segment(tovec, to, i, 0) {
	286	fromvec = from->bi_io_vec + i;
	287
	288	/*
	289	* not bounced
	290	*/
	291	if (tovec->bv_page == fromvec->bv_page)
	292	continue;
	293
	294	/*
	295	* fromvec->bv_offset and fromvec->bv_len might have been
	296	* modified by the block layer, so use the original copy,
	297	* bounce_copy_vec already uses tovec->bv_len
	298	*/
	299	vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
	300
	301	flush_dcache_page(tovec->bv_page);
	302	bounce_copy_vec(tovec, vfrom);
	303	}
	304	}
	305
	306	static void bounce_end_io(struct bio bio, mempool_t pool, int err)
	307	{
	308	struct bio *bio_orig = bio->bi_private;
	309	struct bio_vec bvec, org_vec;
	310	int i;
	311
	312	if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
	313	set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
	314
	315	/*
	316	* free up bounce indirect pages used
	317	*/
	318	__bio_for_each_segment(bvec, bio, i, 0) {
	319	org_vec = bio_orig->bi_io_vec + i;
	320	if (bvec->bv_page == org_vec->bv_page)
	321	continue;
	322
	323	mempool_free(bvec->bv_page, pool);
edfbe2b0	324	dec_page_state(nr_bounce);
1da177e4 LT	325	}
	326
	327	bio_endio(bio_orig, bio_orig->bi_size, err);
	328	bio_put(bio);
	329	}
	330
a19b27ce	331	static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
1da177e4 LT	332	{
	333	if (bio->bi_size)
	334	return 1;
	335
	336	bounce_end_io(bio, page_pool, err);
	337	return 0;
	338	}
	339
	340	static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
	341	{
	342	if (bio->bi_size)
	343	return 1;
	344
	345	bounce_end_io(bio, isa_page_pool, err);
	346	return 0;
	347	}
	348
	349	static void __bounce_end_io_read(struct bio bio, mempool_t pool, int err)
	350	{
	351	struct bio *bio_orig = bio->bi_private;
	352
	353	if (test_bit(BIO_UPTODATE, &bio->bi_flags))
	354	copy_to_high_bio_irq(bio_orig, bio);
	355
	356	bounce_end_io(bio, pool, err);
	357	}
	358
	359	static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
	360	{
	361	if (bio->bi_size)
	362	return 1;
	363
	364	__bounce_end_io_read(bio, page_pool, err);
	365	return 0;
	366	}
	367
	368	static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
	369	{
	370	if (bio->bi_size)
	371	return 1;
	372
	373	__bounce_end_io_read(bio, isa_page_pool, err);
	374	return 0;
	375	}
	376
	377	static void __blk_queue_bounce(request_queue_t q, struct bio *bio_orig,
a19b27ce	378	mempool_t *pool)
1da177e4 LT	379	{
	380	struct page *page;
	381	struct bio *bio = NULL;
	382	int i, rw = bio_data_dir(*bio_orig);
	383	struct bio_vec to, from;
	384
	385	bio_for_each_segment(from, *bio_orig, i) {
	386	page = from->bv_page;
	387
	388	/*
	389	* is destination page below bounce pfn?
	390	*/
	391	if (page_to_pfn(page) < q->bounce_pfn)
	392	continue;
	393
	394	/*
	395	* irk, bounce it
	396	*/
	397	if (!bio)
	398	bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);
	399
	400	to = bio->bi_io_vec + i;
	401
	402	to->bv_page = mempool_alloc(pool, q->bounce_gfp);
	403	to->bv_len = from->bv_len;
	404	to->bv_offset = from->bv_offset;
edfbe2b0	405	inc_page_state(nr_bounce);
1da177e4 LT	406
	407	if (rw == WRITE) {
	408	char vto, vfrom;
	409
	410	flush_dcache_page(from->bv_page);
	411	vto = page_address(to->bv_page) + to->bv_offset;
	412	vfrom = kmap(from->bv_page) + from->bv_offset;
	413	memcpy(vto, vfrom, to->bv_len);
	414	kunmap(from->bv_page);
	415	}
	416	}
	417
	418	/*
	419	* no pages bounced
	420	*/
	421	if (!bio)
	422	return;
	423
	424	/*
	425	* at least one page was bounced, fill in possible non-highmem
	426	* pages
	427	*/
	428	__bio_for_each_segment(from, *bio_orig, i, 0) {
	429	to = bio_iovec_idx(bio, i);
	430	if (!to->bv_page) {
	431	to->bv_page = from->bv_page;
	432	to->bv_len = from->bv_len;
	433	to->bv_offset = from->bv_offset;
	434	}
	435	}
	436
	437	bio->bi_bdev = (*bio_orig)->bi_bdev;
	438	bio->bi_flags \|= (1 << BIO_BOUNCED);
	439	bio->bi_sector = (*bio_orig)->bi_sector;
	440	bio->bi_rw = (*bio_orig)->bi_rw;
	441
	442	bio->bi_vcnt = (*bio_orig)->bi_vcnt;
	443	bio->bi_idx = (*bio_orig)->bi_idx;
	444	bio->bi_size = (*bio_orig)->bi_size;
	445
	446	if (pool == page_pool) {
	447	bio->bi_end_io = bounce_end_io_write;
	448	if (rw == READ)
	449	bio->bi_end_io = bounce_end_io_read;
	450	} else {
	451	bio->bi_end_io = bounce_end_io_write_isa;
	452	if (rw == READ)
	453	bio->bi_end_io = bounce_end_io_read_isa;
	454	}
	455
	456	bio->bi_private = *bio_orig;
	457	*bio_orig = bio;
	458	}
	459
	460	void blk_queue_bounce(request_queue_t q, struct bio *bio_orig)
	461	{
	462	mempool_t *pool;
	463
	464	/*
	465	* for non-isa bounce case, just check if the bounce pfn is equal
	466	* to or bigger than the highest pfn in the system -- in that case,
	467	* don't waste time iterating over bio segments
	468	*/
	469	if (!(q->bounce_gfp & GFP_DMA)) {
470	if (q->bounce_pfn >= blk_max_pfn)
471	return;
472	pool = page_pool;
473	} else {
474	BUG_ON(!isa_page_pool);
475	pool = isa_page_pool;
476	}
477
2056a782 JA	478	blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
2056a782 JA	479
1da177e4 LT	480	/*
	481	* slow path
	482	*/
	483	__blk_queue_bounce(q, bio_orig, pool);
	484	}
	485
	486	EXPORT_SYMBOL(blk_queue_bounce);
	487
	488	#if defined(HASHED_PAGE_VIRTUAL)
	489
	490	#define PA_HASH_ORDER 7
	491
	492	/*
	493	* Describes one page->virtual association
	494	*/
	495	struct page_address_map {
	496	struct page *page;
	497	void *virtual;
	498	struct list_head list;
	499	};
	500
	501	/*
	502	* page_address_map freelist, allocated from page_address_maps.
	503	*/
	504	static struct list_head page_address_pool; /* freelist */
	505	static spinlock_t pool_lock; /* protects page_address_pool */
	506
	507	/*
	508	* Hash table bucket
	509	*/
	510	static struct page_address_slot {
	511	struct list_head lh; /* List of page_address_maps */
	512	spinlock_t lock; /* Protect this bucket's list */
	513	} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
	514
	515	static struct page_address_slot page_slot(struct page page)
	516	{
	517	return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
	518	}
	519
	520	void page_address(struct page page)
	521	{
	522	unsigned long flags;
	523	void *ret;
	524	struct page_address_slot *pas;
	525
	526	if (!PageHighMem(page))
	527	return lowmem_page_address(page);
	528
	529	pas = page_slot(page);
	530	ret = NULL;
	531	spin_lock_irqsave(&pas->lock, flags);
	532	if (!list_empty(&pas->lh)) {
	533	struct page_address_map *pam;
	534
	535	list_for_each_entry(pam, &pas->lh, list) {
	536	if (pam->page == page) {
	537	ret = pam->virtual;
	538	goto done;
	539	}
	540	}
	541	}
	542	done:
	543	spin_unlock_irqrestore(&pas->lock, flags);
544	return ret;
545	}
546
547	EXPORT_SYMBOL(page_address);
548
549	void set_page_address(struct page page, void virtual)
550	{
551	unsigned long flags;
552	struct page_address_slot *pas;
553	struct page_address_map *pam;
554
555	BUG_ON(!PageHighMem(page));
556
557	pas = page_slot(page);
558	if (virtual) { /* Add */
559	BUG_ON(list_empty(&page_address_pool));
560
561	spin_lock_irqsave(&pool_lock, flags);
562	pam = list_entry(page_address_pool.next,
563	struct page_address_map, list);
564	list_del(&pam->list);
565	spin_unlock_irqrestore(&pool_lock, flags);
566
567	pam->page = page;
568	pam->virtual = virtual;
569
570	spin_lock_irqsave(&pas->lock, flags);
571	list_add_tail(&pam->list, &pas->lh);
572	spin_unlock_irqrestore(&pas->lock, flags);
573	} else { /* Remove */
574	spin_lock_irqsave(&pas->lock, flags);
575	list_for_each_entry(pam, &pas->lh, list) {
576	if (pam->page == page) {
577	list_del(&pam->list);
578	spin_unlock_irqrestore(&pas->lock, flags);
579	spin_lock_irqsave(&pool_lock, flags);
580	list_add_tail(&pam->list, &page_address_pool);
581	spin_unlock_irqrestore(&pool_lock, flags);
582	goto done;
583	}
584	}
585	spin_unlock_irqrestore(&pas->lock, flags);
586	}
587	done:
588	return;
589	}
590
591	static struct page_address_map page_address_maps[LAST_PKMAP];
592
593	void __init page_address_init(void)
594	{
595	int i;
596
597	INIT_LIST_HEAD(&page_address_pool);
598	for (i = 0; i < ARRAY_SIZE(page_address_maps); i++)
599	list_add(&page_address_maps[i].list, &page_address_pool);
600	for (i = 0; i < ARRAY_SIZE(page_address_htable); i++) {
601	INIT_LIST_HEAD(&page_address_htable[i].lh);
602	spin_lock_init(&page_address_htable[i].lock);
603	}
604	spin_lock_init(&pool_lock);
605	}
606
607	#endif /* defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL) */