Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 1247 insertions, 0 deletions

diff --git a/arch/m68k/atari/stram.c b/arch/m68k/atari/stram.c
new file mode 100644
index 000000000000..5a3c106b40c8
--- /dev/null
+++ b/arch/m68k/atari/stram.c
@@ -0,0 +1,1247 @@
+/*
+ * arch/m68k/atari/stram.c: Functions for ST-RAM allocations
+ *
+ * Copyright 1994-97 Roman Hodek <Roman.Hodek@informatik.uni-erlangen.de>
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/kdev_t.h>
+#include <linux/major.h>
+#include <linux/init.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/pagemap.h>
+#include <linux/shm.h>
+#include <linux/bootmem.h>
+#include <linux/mount.h>
+#include <linux/blkdev.h>
+
+#include <asm/setup.h>
+#include <asm/machdep.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/atarihw.h>
+#include <asm/atari_stram.h>
+#include <asm/io.h>
+#include <asm/semaphore.h>
+
+#include <linux/swapops.h>
+
+#undef DEBUG
+
+#ifdef DEBUG
+#define DPRINTK(fmt,args...) printk( fmt, ##args )
+#else
+#define DPRINTK(fmt,args...)
+#endif
+
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_STRAM_PROC)
+/* abbrev for the && above... */
+#define DO_PROC
+#include <linux/proc_fs.h>
+#endif
+
+/* Pre-swapping comments:
+ *
+ * ++roman:
+ *
+ * New version of ST-Ram buffer allocation. Instead of using the
+ * 1 MB - 4 KB that remain when the ST-Ram chunk starts at $1000
+ * (1 MB granularity!), such buffers are reserved like this:
+ *
+ *  - If the kernel resides in ST-Ram anyway, we can take the buffer
+ *    from behind the current kernel data space the normal way
+ *    (incrementing start_mem).
+ *
+ *  - If the kernel is in TT-Ram, stram_init() initializes start and
+ *    end of the available region. Buffers are allocated from there
+ *    and mem_init() later marks the such used pages as reserved.
+ *    Since each TT-Ram chunk is at least 4 MB in size, I hope there
+ *    won't be an overrun of the ST-Ram region by normal kernel data
+ *    space.
+ *
+ * For that, ST-Ram may only be allocated while kernel initialization
+ * is going on, or exactly: before mem_init() is called. There is also
+ * no provision now for freeing ST-Ram buffers. It seems that isn't
+ * really needed.
+ *
+ */
+
+/*
+ * New Nov 1997: Use ST-RAM as swap space!
+ *
+ * In the past, there were often problems with modules that require ST-RAM
+ * buffers. Such drivers have to use __get_dma_pages(), which unfortunately
+ * often isn't very successful in allocating more than 1 page :-( [1] The net
+ * result was that most of the time you couldn't insmod such modules (ataflop,
+ * ACSI, SCSI on Falcon, Atari internal framebuffer, not to speak of acsi_slm,
+ * which needs a 1 MB buffer... :-).
+ *
+ * To overcome this limitation, ST-RAM can now be turned into a very
+ * high-speed swap space. If a request for an ST-RAM buffer comes, the kernel
+ * now tries to unswap some pages on that swap device to make some free (and
+ * contiguous) space. This works much better in comparison to
+ * __get_dma_pages(), since used swap pages can be selectively freed by either
+ * moving them to somewhere else in swap space, or by reading them back into
+ * system memory. Ok, there operation of unswapping isn't really cheap (for
+ * each page, one has to go through the page tables of all processes), but it
+ * doesn't happen that often (only when allocation ST-RAM, i.e. when loading a
+ * module that needs ST-RAM). But it at least makes it possible to load such
+ * modules!
+ *
+ * It could also be that overall system performance increases a bit due to
+ * ST-RAM swapping, since slow ST-RAM isn't used anymore for holding data or
+ * executing code in. It's then just a (very fast, compared to disk) back
+ * storage for not-so-often needed data. (But this effect must be compared
+ * with the loss of total memory...) Don't know if the effect is already
+ * visible on a TT, where the speed difference between ST- and TT-RAM isn't
+ * that dramatic, but it should on machines where TT-RAM is really much faster
+ * (e.g. Afterburner).
+ *
+ *   [1]: __get_free_pages() does a fine job if you only want one page, but if
+ * you want more (contiguous) pages, it can give you such a block only if
+ * there's already a free one. The algorithm can't try to free buffers or swap
+ * out something in order to make more free space, since all that page-freeing
+ * mechanisms work "target-less", i.e. they just free something, but not in a
+ * specific place. I.e., __get_free_pages() can't do anything to free
+ * *adjacent* pages :-( This situation becomes even worse for DMA memory,
+ * since the freeing algorithms are also blind to DMA capability of pages.
+ */
+
+/* 1998-10-20: ++andreas
+   unswap_by_move disabled because it does not handle swapped shm pages.
+*/
+
+/* 2000-05-01: ++andreas
+   Integrated with bootmem.  Remove all traces of unswap_by_move.
+*/
+
+#ifdef CONFIG_STRAM_SWAP
+#define ALIGN_IF_SWAP(x)        PAGE_ALIGN(x)
+#else
+#define ALIGN_IF_SWAP(x)        (x)
+#endif
+
+/* get index of swap page at address 'addr' */
+#define SWAP_NR(addr)           (((addr) - swap_start) >> PAGE_SHIFT)
+
+/* get address of swap page #'nr' */
+#define SWAP_ADDR(nr)           (swap_start + ((nr) << PAGE_SHIFT))
+
+/* get number of pages for 'n' bytes (already page-aligned) */
+#define N_PAGES(n)                      ((n) >> PAGE_SHIFT)
+
+/* The following two numbers define the maximum fraction of ST-RAM in total
+ * memory, below that the kernel would automatically use ST-RAM as swap
+ * space. This decision can be overridden with stram_swap= */
+#define MAX_STRAM_FRACTION_NOM          1
+#define MAX_STRAM_FRACTION_DENOM        3
+
+/* Start and end (virtual) of ST-RAM */
+static void *stram_start, *stram_end;
+
+/* set after memory_init() executed and allocations via start_mem aren't
+ * possible anymore */
+static int mem_init_done;
+
+/* set if kernel is in ST-RAM */
+static int kernel_in_stram;
+
+typedef struct stram_block {
+        struct stram_block *next;
+        void *start;
+        unsigned long size;
+        unsigned flags;
+        const char *owner;
+} BLOCK;
+
+/* values for flags field */
+#define BLOCK_FREE              0x01    /* free structure in the BLOCKs pool */
+#define BLOCK_KMALLOCED 0x02    /* structure allocated by kmalloc() */
+#define BLOCK_GFP               0x08    /* block allocated with __get_dma_pages() */
+#define BLOCK_INSWAP    0x10    /* block allocated in swap space */
+
+/* list of allocated blocks */
+static BLOCK *alloc_list;
+
+/* We can't always use kmalloc() to allocate BLOCK structures, since
+ * stram_alloc() can be called rather early. So we need some pool of
+ * statically allocated structures. 20 of them is more than enough, so in most
+ * cases we never should need to call kmalloc(). */
+#define N_STATIC_BLOCKS 20
+static BLOCK static_blocks[N_STATIC_BLOCKS];
+
+#ifdef CONFIG_STRAM_SWAP
+/* max. number of bytes to use for swapping
+ *  0 = no ST-RAM swapping
+ * -1 = do swapping (to whole ST-RAM) if it's less than MAX_STRAM_FRACTION of
+ *      total memory
+ */
+static int max_swap_size = -1;
+
+/* start and end of swapping area */
+static void *swap_start, *swap_end;
+
+/* The ST-RAM's swap info structure */
+static struct swap_info_struct *stram_swap_info;
+
+/* The ST-RAM's swap type */
+static int stram_swap_type;
+
+/* Semaphore for get_stram_region.  */
+static DECLARE_MUTEX(stram_swap_sem);
+
+/* major and minor device number of the ST-RAM device; for the major, we use
+ * the same as Amiga z2ram, which is really similar and impossible on Atari,
+ * and for the minor a relatively odd number to avoid the user creating and
+ * using that device. */
+#define STRAM_MAJOR             Z2RAM_MAJOR
+#define STRAM_MINOR             13
+
+/* Some impossible pointer value */
+#define MAGIC_FILE_P    (struct file *)0xffffdead
+
+#ifdef DO_PROC
+static unsigned stat_swap_read;
+static unsigned stat_swap_write;
+static unsigned stat_swap_force;
+#endif /* DO_PROC */
+
+#endif /* CONFIG_STRAM_SWAP */
+
+/***************************** Prototypes *****************************/
+
+#ifdef CONFIG_STRAM_SWAP
+static int swap_init(void *start_mem, void *swap_data);
+static void *get_stram_region( unsigned long n_pages );
+static void free_stram_region( unsigned long offset, unsigned long n_pages
+                               );
+static int in_some_region(void *addr);
+static unsigned long find_free_region( unsigned long n_pages, unsigned long
+                                       *total_free, unsigned long
+                                       *region_free );
+static void do_stram_request(request_queue_t *);
+static int stram_open( struct inode *inode, struct file *filp );
+static int stram_release( struct inode *inode, struct file *filp );
+static void reserve_region(void *start, void *end);
+#endif
+static BLOCK *add_region( void *addr, unsigned long size );
+static BLOCK *find_region( void *addr );
+static int remove_region( BLOCK *block );
+
+/************************* End of Prototypes **************************/
+
+
+/* ------------------------------------------------------------------------ */
+/*                                                         Public Interface                                                             */
+/* ------------------------------------------------------------------------ */
+
+/*
+ * This init function is called very early by atari/config.c
+ * It initializes some internal variables needed for stram_alloc()
+ */
+void __init atari_stram_init(void)
+{
+        int i;
+
+        /* initialize static blocks */
+        for( i = 0; i < N_STATIC_BLOCKS; ++i )
+                static_blocks[i].flags = BLOCK_FREE;
+
+        /* determine whether kernel code resides in ST-RAM (then ST-RAM is the
+         * first memory block at virtual 0x0) */
+        stram_start = phys_to_virt(0);
+        kernel_in_stram = (stram_start == 0);
+
+        for( i = 0; i < m68k_num_memory; ++i ) {
+                if (m68k_memory[i].addr == 0) {
+                        /* skip first 2kB or page (supervisor-only!) */
+                        stram_end = stram_start + m68k_memory[i].size;
+                        return;
+                }
+        }
+        /* Should never come here! (There is always ST-Ram!) */
+        panic( "atari_stram_init: no ST-RAM found!" );
+}
+
+
+/*
+ * This function is called from setup_arch() to reserve the pages needed for
+ * ST-RAM management.
+ */
+void __init atari_stram_reserve_pages(void *start_mem)
+{
+#ifdef CONFIG_STRAM_SWAP
+        /* if max_swap_size is negative (i.e. no stram_swap= option given),
+         * determine at run time whether to use ST-RAM swapping */
+        if (max_swap_size < 0)
+                /* Use swapping if ST-RAM doesn't make up more than MAX_STRAM_FRACTION
+                 * of total memory. In that case, the max. size is set to 16 MB,
+                 * because ST-RAM can never be bigger than that.
+                 * Also, never use swapping on a Hades, there's no separate ST-RAM in
+                 * that machine. */
+                max_swap_size =
+                        (!MACH_IS_HADES &&
+                         (N_PAGES(stram_end-stram_start)*MAX_STRAM_FRACTION_DENOM <=
+                          ((unsigned long)high_memory>>PAGE_SHIFT)*MAX_STRAM_FRACTION_NOM)) ? 16*1024*1024 : 0;
+        DPRINTK( "atari_stram_reserve_pages: max_swap_size = %d\n", max_swap_size );
+#endif
+
+        /* always reserve first page of ST-RAM, the first 2 kB are
+         * supervisor-only! */
+        if (!kernel_in_stram)
+                reserve_bootmem (0, PAGE_SIZE);
+
+#ifdef CONFIG_STRAM_SWAP
+        {
+                void *swap_data;
+
+                start_mem = (void *) PAGE_ALIGN ((unsigned long) start_mem);
+                /* determine first page to use as swap: if the kernel is
+                   in TT-RAM, this is the first page of (usable) ST-RAM;
+                   otherwise just use the end of kernel data (= start_mem) */
+                swap_start = !kernel_in_stram ? stram_start + PAGE_SIZE : start_mem;
+                /* decrement by one page, rest of kernel assumes that first swap page
+                 * is always reserved and maybe doesn't handle swp_entry == 0
+                 * correctly */
+                swap_start -= PAGE_SIZE;
+                swap_end = stram_end;
+                if (swap_end-swap_start > max_swap_size)
+                        swap_end =  swap_start + max_swap_size;
+                DPRINTK( "atari_stram_reserve_pages: swapping enabled; "
+                                 "swap=%p-%p\n", swap_start, swap_end);
+
+                /* reserve some amount of memory for maintainance of
+                 * swapping itself: one page for each 2048 (PAGE_SIZE/2)
+                 * swap pages. (2 bytes for each page) */
+                swap_data = start_mem;
+                start_mem += ((SWAP_NR(swap_end) + PAGE_SIZE/2 - 1)
+                              >> (PAGE_SHIFT-1)) << PAGE_SHIFT;
+                /* correct swap_start if necessary */
+                if (swap_start + PAGE_SIZE == swap_data)
+                        swap_start = start_mem - PAGE_SIZE;
+
+                if (!swap_init( start_mem, swap_data )) {
+                        printk( KERN_ERR "ST-RAM swap space initialization failed\n" );
+                        max_swap_size = 0;
+                        return;
+                }
+                /* reserve region for swapping meta-data */
+                reserve_region(swap_data, start_mem);
+                /* reserve swapping area itself */
+                reserve_region(swap_start + PAGE_SIZE, swap_end);
+
+                /*
+                 * If the whole ST-RAM is used for swapping, there are no allocatable
+                 * dma pages left. But unfortunately, some shared parts of the kernel
+                 * (particularly the SCSI mid-level) call __get_dma_pages()
+                 * unconditionally :-( These calls then fail, and scsi.c even doesn't
+                 * check for NULL return values and just crashes. The quick fix for
+                 * this (instead of doing much clean up work in the SCSI code) is to
+                 * pretend all pages are DMA-able by setting mach_max_dma_address to
+                 * ULONG_MAX. This doesn't change any functionality so far, since
+                 * get_dma_pages() shouldn't be used on Atari anyway anymore (better
+                 * use atari_stram_alloc()), and the Atari SCSI drivers don't need DMA
+                 * memory. But unfortunately there's now no kind of warning (even not
+                 * a NULL return value) if you use get_dma_pages() nevertheless :-(
+                 * You just will get non-DMA-able memory...
+                 */
+                mach_max_dma_address = 0xffffffff;
+        }
+#endif
+}
+
+void atari_stram_mem_init_hook (void)
+{
+        mem_init_done = 1;
+}
+
+
+/*
+ * This is main public interface: somehow allocate a ST-RAM block
+ * There are three strategies:
+ *
+ *  - If we're before mem_init(), we have to make a static allocation. The
+ *    region is taken in the kernel data area (if the kernel is in ST-RAM) or
+ *    from the start of ST-RAM (if the kernel is in TT-RAM) and added to the
+ *    rsvd_stram_* region. The ST-RAM is somewhere in the middle of kernel
+ *    address space in the latter case.
+ *
+ *  - If mem_init() already has been called and ST-RAM swapping is enabled,
+ *    try to get the memory from the (pseudo) swap-space, either free already
+ *    or by moving some other pages out of the swap.
+ *
+ *  - If mem_init() already has been called, and ST-RAM swapping is not
+ *    enabled, the only possibility is to try with __get_dma_pages(). This has
+ *    the disadvantage that it's very hard to get more than 1 page, and it is
+ *    likely to fail :-(
+ *
+ */
+void *atari_stram_alloc(long size, const char *owner)
+{
+        void *addr = NULL;
+        BLOCK *block;
+        int flags;
+
+        DPRINTK("atari_stram_alloc(size=%08lx,owner=%s)\n", size, owner);
+
+        size = ALIGN_IF_SWAP(size);
+        DPRINTK( "atari_stram_alloc: rounded size = %08lx\n", size );
+#ifdef CONFIG_STRAM_SWAP
+        if (max_swap_size) {
+                /* If swapping is active: make some free space in the swap
+                   "device". */
+                DPRINTK( "atari_stram_alloc: after mem_init, swapping ok, "
+                                 "calling get_region\n" );
+                addr = get_stram_region( N_PAGES(size) );
+                flags = BLOCK_INSWAP;
+        }
+        else
+#endif
+        if (!mem_init_done)
+                return alloc_bootmem_low(size);
+        else {
+                /* After mem_init() and no swapping: can only resort to
+                 * __get_dma_pages() */
+                addr = (void *)__get_dma_pages(GFP_KERNEL, get_order(size));
+                flags = BLOCK_GFP;
+                DPRINTK( "atari_stram_alloc: after mem_init, swapping off, "
+                                 "get_pages=%p\n", addr );
+        }
+
+        if (addr) {
+                if (!(block = add_region( addr, size ))) {
+                        /* out of memory for BLOCK structure :-( */
+                        DPRINTK( "atari_stram_alloc: out of mem for BLOCK -- "
+                                         "freeing again\n" );
+#ifdef CONFIG_STRAM_SWAP
+                        if (flags == BLOCK_INSWAP)
+                                free_stram_region( SWAP_NR(addr), N_PAGES(size) );
+                        else
+#endif
+                                free_pages((unsigned long)addr, get_order(size));
+                        return( NULL );
+                }
+                block->owner = owner;
+                block->flags |= flags;
+        }
+        return( addr );
+}
+
+void atari_stram_free( void *addr )
+
+{
+        BLOCK *block;
+
+        DPRINTK( "atari_stram_free(addr=%p)\n", addr );
+
+        if (!(block = find_region( addr ))) {
+                printk( KERN_ERR "Attempt to free non-allocated ST-RAM block at %p "
+                                "from %p\n", addr, __builtin_return_address(0) );
+                return;
+        }
+        DPRINTK( "atari_stram_free: found block (%p): size=%08lx, owner=%s, "
+                         "flags=%02x\n", block, block->size, block->owner, block->flags );
+
+#ifdef CONFIG_STRAM_SWAP
+        if (!max_swap_size) {
+#endif
+                if (block->flags & BLOCK_GFP) {
+                        DPRINTK("atari_stram_free: is kmalloced, order_size=%d\n",
+                                get_order(block->size));
+                        free_pages((unsigned long)addr, get_order(block->size));
+                }
+                else
+                        goto fail;
+#ifdef CONFIG_STRAM_SWAP
+        }
+        else if (block->flags & BLOCK_INSWAP) {
+                DPRINTK( "atari_stram_free: is swap-alloced\n" );
+                free_stram_region( SWAP_NR(block->start), N_PAGES(block->size) );
+        }
+        else
+                goto fail;
+#endif
+        remove_region( block );
+        return;
+
+  fail:
+        printk( KERN_ERR "atari_stram_free: cannot free block at %p "
+                        "(called from %p)\n", addr, __builtin_return_address(0) );
+}
+
+
+#ifdef CONFIG_STRAM_SWAP
+
+
+/* ------------------------------------------------------------------------ */
+/*                                                 Main Swapping Functions                                                      */
+/* ------------------------------------------------------------------------ */
+
+
+/*
+ * Initialize ST-RAM swap device
+ * (lots copied and modified from sys_swapon() in mm/swapfile.c)
+ */
+static int __init swap_init(void *start_mem, void *swap_data)
+{
+        static struct dentry fake_dentry;
+        static struct vfsmount fake_vfsmnt;
+        struct swap_info_struct *p;
+        struct inode swap_inode;
+        unsigned int type;
+        void *addr;
+        int i, j, k, prev;
+
+        DPRINTK("swap_init(start_mem=%p, swap_data=%p)\n",
+                start_mem, swap_data);
+
+        /* need at least one page for swapping to (and this also isn't very
+         * much... :-) */
+        if (swap_end - swap_start < 2*PAGE_SIZE) {
+                printk( KERN_WARNING "stram_swap_init: swap space too small\n" );
+                return( 0 );
+        }
+
+        /* find free slot in swap_info */
+        for( p = swap_info, type = 0; type < nr_swapfiles; type++, p++ )
+                if (!(p->flags & SWP_USED))
+                        break;
+        if (type >= MAX_SWAPFILES) {
+                printk( KERN_WARNING "stram_swap_init: max. number of "
+                                "swap devices exhausted\n" );
+                return( 0 );
+        }
+        if (type >= nr_swapfiles)
+                nr_swapfiles = type+1;
+
+        stram_swap_info = p;
+        stram_swap_type = type;
+
+        /* fake some dir cache entries to give us some name in /dev/swaps */
+        fake_dentry.d_parent = &fake_dentry;
+        fake_dentry.d_name.name = "stram (internal)";
+        fake_dentry.d_name.len = 16;
+        fake_vfsmnt.mnt_parent = &fake_vfsmnt;
+
+        p->flags        = SWP_USED;
+        p->swap_file    = &fake_dentry;
+        p->swap_vfsmnt  = &fake_vfsmnt;
+        p->swap_map     = swap_data;
+        p->cluster_nr   = 0;
+        p->next         = -1;
+        p->prio         = 0x7ff0;       /* a rather high priority, but not the higest
+                                                                 * to give the user a chance to override */
+
+        /* call stram_open() directly, avoids at least the overhead in
+         * constructing a dummy file structure... */
+        swap_inode.i_rdev = MKDEV( STRAM_MAJOR, STRAM_MINOR );
+        stram_open( &swap_inode, MAGIC_FILE_P );
+        p->max = SWAP_NR(swap_end);
+
+        /* initialize swap_map: set regions that are already allocated or belong
+         * to kernel data space to SWAP_MAP_BAD, otherwise to free */
+        j = 0; /* # of free pages */
+        k = 0; /* # of already allocated pages (from pre-mem_init stram_alloc()) */
+        p->lowest_bit = 0;
+        p->highest_bit = 0;
+        for( i = 1, addr = SWAP_ADDR(1); i < p->max;
+                 i++, addr += PAGE_SIZE ) {
+                if (in_some_region( addr )) {
+                        p->swap_map[i] = SWAP_MAP_BAD;
+                        ++k;
+                }
+                else if (kernel_in_stram && addr < start_mem ) {
+                        p->swap_map[i] = SWAP_MAP_BAD;
+                }
+                else {
+                        p->swap_map[i] = 0;
+                        ++j;
+                        if (!p->lowest_bit) p->lowest_bit = i;
+                        p->highest_bit = i;
+                }
+        }
+        /* first page always reserved (and doesn't really belong to swap space) */
+        p->swap_map[0] = SWAP_MAP_BAD;
+
+        /* now swapping to this device ok */
+        p->pages = j + k;
+        swap_list_lock();
+        nr_swap_pages += j;
+        p->flags = SWP_WRITEOK;
+
+        /* insert swap space into swap_list */
+        prev = -1;
+        for (i = swap_list.head; i >= 0; i = swap_info[i].next) {
+                if (p->prio >= swap_info[i].prio) {
+                        break;
+                }
+                prev = i;
+        }
+        p->next = i;
+        if (prev < 0) {
+                swap_list.head = swap_list.next = p - swap_info;
+        } else {
+                swap_info[prev].next = p - swap_info;
+        }
+        swap_list_unlock();
+
+        printk( KERN_INFO "Using %dk (%d pages) of ST-RAM as swap space.\n",
+                        p->pages << 2, p->pages );
+        return( 1 );
+}
+
+
+/*
+ * The swap entry has been read in advance, and we return 1 to indicate
+ * that the page has been used or is no longer needed.
+ *
+ * Always set the resulting pte to be nowrite (the same as COW pages
+ * after one process has exited).  We don't know just how many PTEs will
+ * share this swap entry, so be cautious and let do_wp_page work out
+ * what to do if a write is requested later.
+ */
+static inline void unswap_pte(struct vm_area_struct * vma, unsigned long
+                              address, pte_t *dir, swp_entry_t entry,
+                              struct page *page)
+{
+        pte_t pte = *dir;
+
+        if (pte_none(pte))
+                return;
+        if (pte_present(pte)) {
+                /* If this entry is swap-cached, then page must already
+                   hold the right address for any copies in physical
+                   memory */
+                if (pte_page(pte) != page)
+                        return;
+                /* We will be removing the swap cache in a moment, so... */
+                set_pte(dir, pte_mkdirty(pte));
+                return;
+        }
+        if (pte_val(pte) != entry.val)
+                return;
+
+        DPRINTK("unswap_pte: replacing entry %08lx by new page %p",
+                entry.val, page);
+        set_pte(dir, pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
+        swap_free(entry);
+        get_page(page);
+        inc_mm_counter(vma->vm_mm, rss);
+}
+
+static inline void unswap_pmd(struct vm_area_struct * vma, pmd_t *dir,
+                              unsigned long address, unsigned long size,
+                              unsigned long offset, swp_entry_t entry,
+                              struct page *page)
+{
+        pte_t * pte;
+        unsigned long end;
+
+        if (pmd_none(*dir))
+                return;
+        if (pmd_bad(*dir)) {
+                pmd_ERROR(*dir);
+                pmd_clear(dir);
+                return;
+        }
+        pte = pte_offset_kernel(dir, address);
+        offset += address & PMD_MASK;
+        address &= ~PMD_MASK;
+        end = address + size;
+        if (end > PMD_SIZE)
+                end = PMD_SIZE;
+        do {
+                unswap_pte(vma, offset+address-vma->vm_start, pte, entry, page);
+                address += PAGE_SIZE;
+                pte++;
+        } while (address < end);
+}
+
+static inline void unswap_pgd(struct vm_area_struct * vma, pgd_t *dir,
+                              unsigned long address, unsigned long size,
+                              swp_entry_t entry, struct page *page)
+{
+        pmd_t * pmd;
+        unsigned long offset, end;
+
+        if (pgd_none(*dir))
+                return;
+        if (pgd_bad(*dir)) {
+                pgd_ERROR(*dir);
+                pgd_clear(dir);
+                return;
+        }
+        pmd = pmd_offset(dir, address);
+        offset = address & PGDIR_MASK;
+        address &= ~PGDIR_MASK;
+        end = address + size;
+        if (end > PGDIR_SIZE)
+                end = PGDIR_SIZE;
+        do {
+                unswap_pmd(vma, pmd, address, end - address, offset, entry,
+                           page);
+                address = (address + PMD_SIZE) & PMD_MASK;
+                pmd++;
+        } while (address < end);
+}
+
+static void unswap_vma(struct vm_area_struct * vma, pgd_t *pgdir,
+                       swp_entry_t entry, struct page *page)
+{
+        unsigned long start = vma->vm_start, end = vma->vm_end;
+
+        do {
+                unswap_pgd(vma, pgdir, start, end - start, entry, page);
+                start = (start + PGDIR_SIZE) & PGDIR_MASK;
+                pgdir++;
+        } while (start < end);
+}
+
+static void unswap_process(struct mm_struct * mm, swp_entry_t entry,
+                           struct page *page)
+{
+        struct vm_area_struct* vma;
+
+        /*
+         * Go through process' page directory.
+         */
+        if (!mm)
+                return;
+        for (vma = mm->mmap; vma; vma = vma->vm_next) {
+                pgd_t * pgd = pgd_offset(mm, vma->vm_start);
+                unswap_vma(vma, pgd, entry, page);
+        }
+}
+
+
+static int unswap_by_read(unsigned short *map, unsigned long max,
+                          unsigned long start, unsigned long n_pages)
+{
+        struct task_struct *p;
+        struct page *page;
+        swp_entry_t entry;
+        unsigned long i;
+
+        DPRINTK( "unswapping %lu..%lu by reading in\n",
+                         start, start+n_pages-1 );
+
+        for( i = start; i < start+n_pages; ++i ) {
+                if (map[i] == SWAP_MAP_BAD) {
+                        printk( KERN_ERR "get_stram_region: page %lu already "
+                                        "reserved??\n", i );
+                        continue;
+                }
+
+                if (map[i]) {
+                        entry = swp_entry(stram_swap_type, i);
+                        DPRINTK("unswap: map[i=%lu]=%u nr_swap=%ld\n",
+                                i, map[i], nr_swap_pages);
+
+                        swap_device_lock(stram_swap_info);
+                        map[i]++;
+                        swap_device_unlock(stram_swap_info);
+                        /* Get a page for the entry, using the existing
+                           swap cache page if there is one.  Otherwise,
+                           get a clean page and read the swap into it. */
+                        page = read_swap_cache_async(entry, NULL, 0);
+                        if (!page) {
+                                swap_free(entry);
+                                return -ENOMEM;
+                        }
+                        read_lock(&tasklist_lock);
+                        for_each_process(p)
+                                unswap_process(p->mm, entry, page);
+                        read_unlock(&tasklist_lock);
+                        shmem_unuse(entry, page);
+                        /* Now get rid of the extra reference to the
+                           temporary page we've been using. */
+                        if (PageSwapCache(page))
+                                delete_from_swap_cache(page);
+                        __free_page(page);
+        #ifdef DO_PROC
+                        stat_swap_force++;
+        #endif
+                }
+
+                DPRINTK( "unswap: map[i=%lu]=%u nr_swap=%ld\n",
+                                 i, map[i], nr_swap_pages );
+                swap_list_lock();
+                swap_device_lock(stram_swap_info);
+                map[i] = SWAP_MAP_BAD;
+                if (stram_swap_info->lowest_bit == i)
+                        stram_swap_info->lowest_bit++;
+                if (stram_swap_info->highest_bit == i)
+                        stram_swap_info->highest_bit--;
+                --nr_swap_pages;
+                swap_device_unlock(stram_swap_info);
+                swap_list_unlock();
+        }
+
+        return 0;
+}
+
+/*
+ * reserve a region in ST-RAM swap space for an allocation
+ */
+static void *get_stram_region( unsigned long n_pages )
+{
+        unsigned short *map = stram_swap_info->swap_map;
+        unsigned long max = stram_swap_info->max;
+        unsigned long start, total_free, region_free;
+        int err;
+        void *ret = NULL;
+
+        DPRINTK( "get_stram_region(n_pages=%lu)\n", n_pages );
+
+        down(&stram_swap_sem);
+
+        /* disallow writing to the swap device now */
+        stram_swap_info->flags = SWP_USED;
+
+        /* find a region of n_pages pages in the swap space including as much free
+         * pages as possible (and excluding any already-reserved pages). */
+        if (!(start = find_free_region( n_pages, &total_free, &region_free )))
+                goto end;
+        DPRINTK( "get_stram_region: region starts at %lu, has %lu free pages\n",
+                         start, region_free );
+
+        err = unswap_by_read(map, max, start, n_pages);
+        if (err)
+                goto end;
+
+        ret = SWAP_ADDR(start);
+  end:
+        /* allow using swap device again */
+        stram_swap_info->flags = SWP_WRITEOK;
+        up(&stram_swap_sem);
+        DPRINTK( "get_stram_region: returning %p\n", ret );
+        return( ret );
+}
+
+
+/*
+ * free a reserved region in ST-RAM swap space
+ */
+static void free_stram_region( unsigned long offset, unsigned long n_pages )
+{
+        unsigned short *map = stram_swap_info->swap_map;
+
+        DPRINTK( "free_stram_region(offset=%lu,n_pages=%lu)\n", offset, n_pages );
+
+        if (offset < 1 || offset + n_pages > stram_swap_info->max) {
+                printk( KERN_ERR "free_stram_region: Trying to free non-ST-RAM\n" );
+                return;
+        }
+
+        swap_list_lock();
+        swap_device_lock(stram_swap_info);
+        /* un-reserve the freed pages */
+        for( ; n_pages > 0; ++offset, --n_pages ) {
+                if (map[offset] != SWAP_MAP_BAD)
+                        printk( KERN_ERR "free_stram_region: Swap page %lu was not "
+                                        "reserved\n", offset );
+                map[offset] = 0;
+        }
+
+        /* update swapping meta-data */
+        if (offset < stram_swap_info->lowest_bit)
+                stram_swap_info->lowest_bit = offset;
+        if (offset+n_pages-1 > stram_swap_info->highest_bit)
+                stram_swap_info->highest_bit = offset+n_pages-1;
+        if (stram_swap_info->prio > swap_info[swap_list.next].prio)
+                swap_list.next = swap_list.head;
+        nr_swap_pages += n_pages;
+        swap_device_unlock(stram_swap_info);
+        swap_list_unlock();
+}
+
+
+/* ------------------------------------------------------------------------ */
+/*                                              Utility Functions for Swapping                                          */
+/* ------------------------------------------------------------------------ */
+
+
+/* is addr in some of the allocated regions? */
+static int in_some_region(void *addr)
+{
+        BLOCK *p;
+
+        for( p = alloc_list; p; p = p->next ) {
+                if (p->start <= addr && addr < p->start + p->size)
+                        return( 1 );
+        }
+        return( 0 );
+}
+
+
+static unsigned long find_free_region(unsigned long n_pages,
+                                      unsigned long *total_free,
+                                      unsigned long *region_free)
+{
+        unsigned short *map = stram_swap_info->swap_map;
+        unsigned long max = stram_swap_info->max;
+        unsigned long head, tail, max_start;
+        long nfree, max_free;
+
+        /* first scan the swap space for a suitable place for the allocation */
+        head = 1;
+        max_start = 0;
+        max_free = -1;
+        *total_free = 0;
+
+  start_over:
+        /* increment tail until final window size reached, and count free pages */
+        nfree = 0;
+        for( tail = head; tail-head < n_pages && tail < max; ++tail ) {
+                if (map[tail] == SWAP_MAP_BAD) {
+                        head = tail+1;
+                        goto start_over;
+                }
+                if (!map[tail]) {
+                        ++nfree;
+                        ++*total_free;
+                }
+        }
+        if (tail-head < n_pages)
+                goto out;
+        if (nfree > max_free) {
+                max_start = head;
+                max_free  = nfree;
+                if (max_free >= n_pages)
+                        /* don't need more free pages... :-) */
+                        goto out;
+        }
+
+        /* now shift the window and look for the area where as much pages as
+         * possible are free */
+        while( tail < max ) {
+                nfree -= (map[head++] == 0);
+                if (map[tail] == SWAP_MAP_BAD) {
+                        head = tail+1;
+                        goto start_over;
+                }
+                if (!map[tail]) {
+                        ++nfree;
+                        ++*total_free;
+                }
+                ++tail;
+                if (nfree > max_free) {
+                        max_start = head;
+                        max_free  = nfree;
+                        if (max_free >= n_pages)
+                                /* don't need more free pages... :-) */
+                                goto out;
+                }
+        }
+
+  out:
+        if (max_free < 0) {
+                printk( KERN_NOTICE "get_stram_region: ST-RAM too full or fragmented "
+                                "-- can't allocate %lu pages\n", n_pages );
+                return( 0 );
+        }
+
+        *region_free = max_free;
+        return( max_start );
+}
+
+
+/* setup parameters from command line */
+void __init stram_swap_setup(char *str, int *ints)
+{
+        if (ints[0] >= 1)
+                max_swap_size = ((ints[1] < 0 ? 0 : ints[1]) * 1024) & PAGE_MASK;
+}
+
+
+/* ------------------------------------------------------------------------ */
+/*                                                              ST-RAM device                                                           */
+/* ------------------------------------------------------------------------ */
+
+static int refcnt;
+
+static void do_stram_request(request_queue_t *q)
+{
+        struct request *req;
+
+        while ((req = elv_next_request(q)) != NULL) {
+                void *start = swap_start + (req->sector << 9);
+                unsigned long len = req->current_nr_sectors << 9;
+                if ((start + len) > swap_end) {
+                        printk( KERN_ERR "stram: bad access beyond end of device: "
+                                        "block=%ld, count=%d\n",
+                                        req->sector,
+                                        req->current_nr_sectors );
+                        end_request(req, 0);
+                        continue;
+                }
+
+                if (req->cmd == READ) {
+                        memcpy(req->buffer, start, len);
+#ifdef DO_PROC
+                        stat_swap_read += N_PAGES(len);
+#endif
+                }
+                else {
+                        memcpy(start, req->buffer, len);
+#ifdef DO_PROC
+                        stat_swap_write += N_PAGES(len);
+#endif
+                }
+                end_request(req, 1);
+        }
+}
+
+
+static int stram_open( struct inode *inode, struct file *filp )
+{
+        if (filp != MAGIC_FILE_P) {
+                printk( KERN_NOTICE "Only kernel can open ST-RAM device\n" );
+                return( -EPERM );
+        }
+        if (refcnt)
+                return( -EBUSY );
+        ++refcnt;
+        return( 0 );
+}
+
+static int stram_release( struct inode *inode, struct file *filp )
+{
+        if (filp != MAGIC_FILE_P) {
+                printk( KERN_NOTICE "Only kernel can close ST-RAM device\n" );
+                return( -EPERM );
+        }
+        if (refcnt > 0)
+                --refcnt;
+        return( 0 );
+}
+
+
+static struct block_device_operations stram_fops = {
+        .open =         stram_open,
+        .release =      stram_release,
+};
+
+static struct gendisk *stram_disk;
+static struct request_queue *stram_queue;
+static DEFINE_SPINLOCK(stram_lock);
+
+int __init stram_device_init(void)
+{
+        if (!MACH_IS_ATARI)
+                /* no point in initializing this, I hope */
+                return -ENXIO;
+
+        if (!max_swap_size)
+                /* swapping not enabled */
+                return -ENXIO;
+        stram_disk = alloc_disk(1);
+        if (!stram_disk)
+                return -ENOMEM;
+
+        if (register_blkdev(STRAM_MAJOR, "stram")) {
+                put_disk(stram_disk);
+                return -ENXIO;
+        }
+
+        stram_queue = blk_init_queue(do_stram_request, &stram_lock);
+        if (!stram_queue) {
+                unregister_blkdev(STRAM_MAJOR, "stram");
+                put_disk(stram_disk);
+                return -ENOMEM;
+        }
+
+        stram_disk->major = STRAM_MAJOR;
+        stram_disk->first_minor = STRAM_MINOR;
+        stram_disk->fops = &stram_fops;
+        stram_disk->queue = stram_queue;
+        sprintf(stram_disk->disk_name, "stram");
+        set_capacity(stram_disk, (swap_end - swap_start)/512);
+        add_disk(stram_disk);
+        return 0;
+}
+
+
+
+/* ------------------------------------------------------------------------ */
+/*                                                      Misc Utility Functions                                                  */
+/* ------------------------------------------------------------------------ */
+
+/* reserve a range of pages */
+static void reserve_region(void *start, void *end)
+{
+        reserve_bootmem (virt_to_phys(start), end - start);
+}
+
+#endif /* CONFIG_STRAM_SWAP */
+
+
+/* ------------------------------------------------------------------------ */
+/*                                                        Region Management                                                             */
+/* ------------------------------------------------------------------------ */
+
+
+/* insert a region into the alloced list (sorted) */
+static BLOCK *add_region( void *addr, unsigned long size )
+{
+        BLOCK **p, *n = NULL;
+        int i;
+
+        for( i = 0; i < N_STATIC_BLOCKS; ++i ) {
+                if (static_blocks[i].flags & BLOCK_FREE) {
+                        n = &static_blocks[i];
+                        n->flags = 0;
+                        break;
+                }
+        }
+        if (!n && mem_init_done) {
+                /* if statics block pool exhausted and we can call kmalloc() already
+                 * (after mem_init()), try that */
+                n = kmalloc( sizeof(BLOCK), GFP_KERNEL );
+                if (n)
+                        n->flags = BLOCK_KMALLOCED;
+        }
+        if (!n) {
+                printk( KERN_ERR "Out of memory for ST-RAM descriptor blocks\n" );
+                return( NULL );
+        }
+        n->start = addr;
+        n->size  = size;
+
+        for( p = &alloc_list; *p; p = &((*p)->next) )
+                if ((*p)->start > addr) break;
+        n->next = *p;
+        *p = n;
+
+        return( n );
+}
+
+
+/* find a region (by start addr) in the alloced list */
+static BLOCK *find_region( void *addr )
+{
+        BLOCK *p;
+
+        for( p = alloc_list; p; p = p->next ) {
+                if (p->start == addr)
+                        return( p );
+                if (p->start > addr)
+                        break;
+        }
+        return( NULL );
+}
+
+
+/* remove a block from the alloced list */
+static int remove_region( BLOCK *block )
+{
+        BLOCK **p;
+
+        for( p = &alloc_list; *p; p = &((*p)->next) )
+                if (*p == block) break;
+        if (!*p)
+                return( 0 );
+
+        *p = block->next;
+        if (block->flags & BLOCK_KMALLOCED)
+                kfree( block );
+        else
+                block->flags |= BLOCK_FREE;
+        return( 1 );
+}
+
+
+
+/* ------------------------------------------------------------------------ */
+/*                                               /proc statistics file stuff                                            */
+/* ------------------------------------------------------------------------ */
+
+#ifdef DO_PROC
+
+#define PRINT_PROC(fmt,args...) len += sprintf( buf+len, fmt, ##args )
+
+int get_stram_list( char *buf )
+{
+        int len = 0;
+        BLOCK *p;
+#ifdef CONFIG_STRAM_SWAP
+        int i;
+        unsigned short *map = stram_swap_info->swap_map;
+        unsigned long max = stram_swap_info->max;
+        unsigned free = 0, used = 0, rsvd = 0;
+#endif
+
+#ifdef CONFIG_STRAM_SWAP
+        if (max_swap_size) {
+                for( i = 1; i < max; ++i ) {
+                        if (!map[i])
+                                ++free;
+                        else if (map[i] == SWAP_MAP_BAD)
+                                ++rsvd;
+                        else
+                                ++used;
+                }
+                PRINT_PROC(
+                        "Total ST-RAM:      %8u kB\n"
+                        "Total ST-RAM swap: %8lu kB\n"
+                        "Free swap:         %8u kB\n"
+                        "Used swap:         %8u kB\n"
+                        "Allocated swap:    %8u kB\n"
+                        "Swap Reads:        %8u\n"
+                        "Swap Writes:       %8u\n"
+                        "Swap Forced Reads: %8u\n",
+                        (stram_end - stram_start) >> 10,
+                        (max-1) << (PAGE_SHIFT-10),
+                        free << (PAGE_SHIFT-10),
+                        used << (PAGE_SHIFT-10),
+                        rsvd << (PAGE_SHIFT-10),
+                        stat_swap_read,
+                        stat_swap_write,
+                        stat_swap_force );
+        }
+        else {
+#endif
+                PRINT_PROC( "ST-RAM swapping disabled\n" );
+                PRINT_PROC("Total ST-RAM:      %8u kB\n",
+                           (stram_end - stram_start) >> 10);
+#ifdef CONFIG_STRAM_SWAP
+        }
+#endif
+
+        PRINT_PROC( "Allocated regions:\n" );
+        for( p = alloc_list; p; p = p->next ) {
+                if (len + 50 >= PAGE_SIZE)
+                        break;
+                PRINT_PROC("0x%08lx-0x%08lx: %s (",
+                           virt_to_phys(p->start),
+                           virt_to_phys(p->start+p->size-1),
+                           p->owner);
+                if (p->flags & BLOCK_GFP)
+                        PRINT_PROC( "page-alloced)\n" );
+                else if (p->flags & BLOCK_INSWAP)
+                        PRINT_PROC( "in swap)\n" );
+                else
+                        PRINT_PROC( "??)\n" );
+        }
+
+        return( len );
+}
+
+#endif
+
+
+/*
+ * Local variables:
+ *  c-indent-level: 4
+ *  tab-width: 4
+ * End:
+ */