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75babcaced
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>
603 lines
14 KiB
C
603 lines
14 KiB
C
/*
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* High memory handling common code and variables.
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*
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* (C) 1999 Andrea Arcangeli, SuSE GmbH, andrea@suse.de
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* Gerhard Wichert, Siemens AG, Gerhard.Wichert@pdb.siemens.de
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*
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*
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* Redesigned the x86 32-bit VM architecture to deal with
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* 64-bit physical space. With current x86 CPUs this
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* means up to 64 Gigabytes physical RAM.
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*
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* Rewrote high memory support to move the page cache into
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* high memory. Implemented permanent (schedulable) kmaps
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* based on Linus' idea.
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*
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* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
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*/
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/swap.h>
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#include <linux/bio.h>
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#include <linux/pagemap.h>
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#include <linux/mempool.h>
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#include <linux/blkdev.h>
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#include <linux/init.h>
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#include <linux/hash.h>
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#include <linux/highmem.h>
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#include <linux/blktrace_api.h>
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#include <asm/tlbflush.h>
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static mempool_t *page_pool, *isa_page_pool;
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static void *mempool_alloc_pages_isa(gfp_t gfp_mask, void *data)
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{
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return mempool_alloc_pages(gfp_mask | GFP_DMA, data);
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}
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/*
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* Virtual_count is not a pure "count".
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* 0 means that it is not mapped, and has not been mapped
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* since a TLB flush - it is usable.
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* 1 means that there are no users, but it has been mapped
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* since the last TLB flush - so we can't use it.
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* n means that there are (n-1) current users of it.
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*/
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#ifdef CONFIG_HIGHMEM
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static int pkmap_count[LAST_PKMAP];
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static unsigned int last_pkmap_nr;
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static __cacheline_aligned_in_smp DEFINE_SPINLOCK(kmap_lock);
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pte_t * pkmap_page_table;
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static DECLARE_WAIT_QUEUE_HEAD(pkmap_map_wait);
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static void flush_all_zero_pkmaps(void)
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{
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int i;
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flush_cache_kmaps();
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for (i = 0; i < LAST_PKMAP; i++) {
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struct page *page;
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/*
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* zero means we don't have anything to do,
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* >1 means that it is still in use. Only
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* a count of 1 means that it is free but
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* needs to be unmapped
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*/
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if (pkmap_count[i] != 1)
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continue;
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pkmap_count[i] = 0;
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/* sanity check */
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BUG_ON(pte_none(pkmap_page_table[i]));
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/*
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* Don't need an atomic fetch-and-clear op here;
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* no-one has the page mapped, and cannot get at
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* its virtual address (and hence PTE) without first
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* getting the kmap_lock (which is held here).
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* So no dangers, even with speculative execution.
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*/
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page = pte_page(pkmap_page_table[i]);
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pte_clear(&init_mm, (unsigned long)page_address(page),
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&pkmap_page_table[i]);
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set_page_address(page, NULL);
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}
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flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
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}
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static inline unsigned long map_new_virtual(struct page *page)
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{
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unsigned long vaddr;
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int count;
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start:
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count = LAST_PKMAP;
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/* Find an empty entry */
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for (;;) {
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last_pkmap_nr = (last_pkmap_nr + 1) & LAST_PKMAP_MASK;
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if (!last_pkmap_nr) {
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flush_all_zero_pkmaps();
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count = LAST_PKMAP;
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}
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if (!pkmap_count[last_pkmap_nr])
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break; /* Found a usable entry */
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if (--count)
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continue;
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/*
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* Sleep for somebody else to unmap their entries
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*/
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{
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DECLARE_WAITQUEUE(wait, current);
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__set_current_state(TASK_UNINTERRUPTIBLE);
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add_wait_queue(&pkmap_map_wait, &wait);
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spin_unlock(&kmap_lock);
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schedule();
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remove_wait_queue(&pkmap_map_wait, &wait);
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spin_lock(&kmap_lock);
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/* Somebody else might have mapped it while we slept */
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if (page_address(page))
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return (unsigned long)page_address(page);
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/* Re-start */
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goto start;
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}
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}
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vaddr = PKMAP_ADDR(last_pkmap_nr);
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set_pte_at(&init_mm, vaddr,
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&(pkmap_page_table[last_pkmap_nr]), mk_pte(page, kmap_prot));
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pkmap_count[last_pkmap_nr] = 1;
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set_page_address(page, (void *)vaddr);
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return vaddr;
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}
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void fastcall *kmap_high(struct page *page)
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{
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unsigned long vaddr;
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/*
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* For highmem pages, we can't trust "virtual" until
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* after we have the lock.
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*
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* We cannot call this from interrupts, as it may block
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*/
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spin_lock(&kmap_lock);
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vaddr = (unsigned long)page_address(page);
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if (!vaddr)
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vaddr = map_new_virtual(page);
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pkmap_count[PKMAP_NR(vaddr)]++;
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BUG_ON(pkmap_count[PKMAP_NR(vaddr)] < 2);
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spin_unlock(&kmap_lock);
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return (void*) vaddr;
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}
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EXPORT_SYMBOL(kmap_high);
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void fastcall kunmap_high(struct page *page)
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{
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unsigned long vaddr;
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unsigned long nr;
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int need_wakeup;
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spin_lock(&kmap_lock);
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vaddr = (unsigned long)page_address(page);
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BUG_ON(!vaddr);
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nr = PKMAP_NR(vaddr);
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/*
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* A count must never go down to zero
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* without a TLB flush!
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*/
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need_wakeup = 0;
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switch (--pkmap_count[nr]) {
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case 0:
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BUG();
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case 1:
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/*
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* Avoid an unnecessary wake_up() function call.
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* The common case is pkmap_count[] == 1, but
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* no waiters.
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* The tasks queued in the wait-queue are guarded
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* by both the lock in the wait-queue-head and by
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* the kmap_lock. As the kmap_lock is held here,
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* no need for the wait-queue-head's lock. Simply
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* test if the queue is empty.
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*/
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need_wakeup = waitqueue_active(&pkmap_map_wait);
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}
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spin_unlock(&kmap_lock);
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/* do wake-up, if needed, race-free outside of the spin lock */
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if (need_wakeup)
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wake_up(&pkmap_map_wait);
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}
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EXPORT_SYMBOL(kunmap_high);
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#define POOL_SIZE 64
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static __init int init_emergency_pool(void)
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{
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struct sysinfo i;
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si_meminfo(&i);
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si_swapinfo(&i);
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if (!i.totalhigh)
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return 0;
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page_pool = mempool_create_page_pool(POOL_SIZE, 0);
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BUG_ON(!page_pool);
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printk("highmem bounce pool size: %d pages\n", POOL_SIZE);
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return 0;
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}
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__initcall(init_emergency_pool);
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/*
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* highmem version, map in to vec
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*/
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static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom)
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{
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unsigned long flags;
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unsigned char *vto;
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local_irq_save(flags);
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vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ);
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memcpy(vto + to->bv_offset, vfrom, to->bv_len);
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kunmap_atomic(vto, KM_BOUNCE_READ);
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local_irq_restore(flags);
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}
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#else /* CONFIG_HIGHMEM */
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#define bounce_copy_vec(to, vfrom) \
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memcpy(page_address((to)->bv_page) + (to)->bv_offset, vfrom, (to)->bv_len)
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#endif
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#define ISA_POOL_SIZE 16
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/*
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* gets called "every" time someone init's a queue with BLK_BOUNCE_ISA
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* as the max address, so check if the pool has already been created.
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*/
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int init_emergency_isa_pool(void)
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{
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if (isa_page_pool)
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return 0;
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isa_page_pool = mempool_create(ISA_POOL_SIZE, mempool_alloc_pages_isa,
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mempool_free_pages, (void *) 0);
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BUG_ON(!isa_page_pool);
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printk("isa bounce pool size: %d pages\n", ISA_POOL_SIZE);
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return 0;
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}
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/*
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* Simple bounce buffer support for highmem pages. Depending on the
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* queue gfp mask set, *to may or may not be a highmem page. kmap it
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* always, it will do the Right Thing
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*/
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static void copy_to_high_bio_irq(struct bio *to, struct bio *from)
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{
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unsigned char *vfrom;
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struct bio_vec *tovec, *fromvec;
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int i;
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__bio_for_each_segment(tovec, to, i, 0) {
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fromvec = from->bi_io_vec + i;
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/*
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* not bounced
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*/
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if (tovec->bv_page == fromvec->bv_page)
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continue;
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/*
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* fromvec->bv_offset and fromvec->bv_len might have been
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* modified by the block layer, so use the original copy,
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* bounce_copy_vec already uses tovec->bv_len
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*/
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vfrom = page_address(fromvec->bv_page) + tovec->bv_offset;
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flush_dcache_page(tovec->bv_page);
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bounce_copy_vec(tovec, vfrom);
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}
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}
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static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
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{
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struct bio *bio_orig = bio->bi_private;
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struct bio_vec *bvec, *org_vec;
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int i;
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if (test_bit(BIO_EOPNOTSUPP, &bio->bi_flags))
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set_bit(BIO_EOPNOTSUPP, &bio_orig->bi_flags);
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/*
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* free up bounce indirect pages used
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*/
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__bio_for_each_segment(bvec, bio, i, 0) {
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org_vec = bio_orig->bi_io_vec + i;
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if (bvec->bv_page == org_vec->bv_page)
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continue;
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mempool_free(bvec->bv_page, pool);
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dec_page_state(nr_bounce);
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}
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bio_endio(bio_orig, bio_orig->bi_size, err);
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bio_put(bio);
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}
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static int bounce_end_io_write(struct bio *bio, unsigned int bytes_done, int err)
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{
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if (bio->bi_size)
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return 1;
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bounce_end_io(bio, page_pool, err);
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return 0;
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}
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static int bounce_end_io_write_isa(struct bio *bio, unsigned int bytes_done, int err)
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{
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if (bio->bi_size)
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return 1;
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bounce_end_io(bio, isa_page_pool, err);
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return 0;
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}
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static void __bounce_end_io_read(struct bio *bio, mempool_t *pool, int err)
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{
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struct bio *bio_orig = bio->bi_private;
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if (test_bit(BIO_UPTODATE, &bio->bi_flags))
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copy_to_high_bio_irq(bio_orig, bio);
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bounce_end_io(bio, pool, err);
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}
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static int bounce_end_io_read(struct bio *bio, unsigned int bytes_done, int err)
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{
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if (bio->bi_size)
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return 1;
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__bounce_end_io_read(bio, page_pool, err);
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return 0;
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}
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static int bounce_end_io_read_isa(struct bio *bio, unsigned int bytes_done, int err)
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{
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if (bio->bi_size)
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return 1;
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__bounce_end_io_read(bio, isa_page_pool, err);
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return 0;
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}
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static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig,
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mempool_t *pool)
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{
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struct page *page;
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struct bio *bio = NULL;
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int i, rw = bio_data_dir(*bio_orig);
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struct bio_vec *to, *from;
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bio_for_each_segment(from, *bio_orig, i) {
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page = from->bv_page;
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/*
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* is destination page below bounce pfn?
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*/
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if (page_to_pfn(page) < q->bounce_pfn)
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continue;
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/*
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* irk, bounce it
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*/
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if (!bio)
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bio = bio_alloc(GFP_NOIO, (*bio_orig)->bi_vcnt);
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to = bio->bi_io_vec + i;
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to->bv_page = mempool_alloc(pool, q->bounce_gfp);
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to->bv_len = from->bv_len;
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to->bv_offset = from->bv_offset;
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inc_page_state(nr_bounce);
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if (rw == WRITE) {
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char *vto, *vfrom;
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flush_dcache_page(from->bv_page);
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vto = page_address(to->bv_page) + to->bv_offset;
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vfrom = kmap(from->bv_page) + from->bv_offset;
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memcpy(vto, vfrom, to->bv_len);
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kunmap(from->bv_page);
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}
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}
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/*
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* no pages bounced
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*/
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if (!bio)
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return;
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/*
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* at least one page was bounced, fill in possible non-highmem
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* pages
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*/
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__bio_for_each_segment(from, *bio_orig, i, 0) {
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to = bio_iovec_idx(bio, i);
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if (!to->bv_page) {
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to->bv_page = from->bv_page;
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to->bv_len = from->bv_len;
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to->bv_offset = from->bv_offset;
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}
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}
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bio->bi_bdev = (*bio_orig)->bi_bdev;
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bio->bi_flags |= (1 << BIO_BOUNCED);
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bio->bi_sector = (*bio_orig)->bi_sector;
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bio->bi_rw = (*bio_orig)->bi_rw;
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bio->bi_vcnt = (*bio_orig)->bi_vcnt;
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bio->bi_idx = (*bio_orig)->bi_idx;
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bio->bi_size = (*bio_orig)->bi_size;
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if (pool == page_pool) {
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bio->bi_end_io = bounce_end_io_write;
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if (rw == READ)
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bio->bi_end_io = bounce_end_io_read;
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} else {
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bio->bi_end_io = bounce_end_io_write_isa;
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if (rw == READ)
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bio->bi_end_io = bounce_end_io_read_isa;
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}
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bio->bi_private = *bio_orig;
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*bio_orig = bio;
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}
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void blk_queue_bounce(request_queue_t *q, struct bio **bio_orig)
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{
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mempool_t *pool;
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/*
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* for non-isa bounce case, just check if the bounce pfn is equal
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* to or bigger than the highest pfn in the system -- in that case,
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* don't waste time iterating over bio segments
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*/
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if (!(q->bounce_gfp & GFP_DMA)) {
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if (q->bounce_pfn >= blk_max_pfn)
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return;
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pool = page_pool;
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} else {
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BUG_ON(!isa_page_pool);
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pool = isa_page_pool;
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}
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blk_add_trace_bio(q, *bio_orig, BLK_TA_BOUNCE);
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/*
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* slow path
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*/
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__blk_queue_bounce(q, bio_orig, pool);
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}
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EXPORT_SYMBOL(blk_queue_bounce);
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#if defined(HASHED_PAGE_VIRTUAL)
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#define PA_HASH_ORDER 7
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/*
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* Describes one page->virtual association
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*/
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struct page_address_map {
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struct page *page;
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void *virtual;
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struct list_head list;
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};
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/*
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* page_address_map freelist, allocated from page_address_maps.
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*/
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static struct list_head page_address_pool; /* freelist */
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static spinlock_t pool_lock; /* protects page_address_pool */
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/*
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* Hash table bucket
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*/
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static struct page_address_slot {
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struct list_head lh; /* List of page_address_maps */
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spinlock_t lock; /* Protect this bucket's list */
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} ____cacheline_aligned_in_smp page_address_htable[1<<PA_HASH_ORDER];
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static struct page_address_slot *page_slot(struct page *page)
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{
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return &page_address_htable[hash_ptr(page, PA_HASH_ORDER)];
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}
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void *page_address(struct page *page)
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{
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unsigned long flags;
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void *ret;
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struct page_address_slot *pas;
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if (!PageHighMem(page))
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return lowmem_page_address(page);
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pas = page_slot(page);
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ret = NULL;
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spin_lock_irqsave(&pas->lock, flags);
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if (!list_empty(&pas->lh)) {
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struct page_address_map *pam;
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list_for_each_entry(pam, &pas->lh, list) {
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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) */
|