mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-25 10:19:47 +00:00
![Eric Sesterhenn](/assets/img/avatar_default.png)
this changes if() BUG(); constructs to BUG_ON() which is cleaner, contains unlikely() and can better optimized away. Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
602 lines
14 KiB
C
602 lines
14 KiB
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 */
|
|
BUG_ON(pte_none(pkmap_page_table[i]));
|
|
|
|
/*
|
|
* 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)]++;
|
|
BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
|
|
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);
|
|
BUG_ON(!vaddr);
|
|
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);
|
|
BUG_ON(!page_pool);
|
|
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);
|
|
BUG_ON(!isa_page_pool);
|
|
|
|
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) */
|