FreeBSD/Linux Kernel Cross Reference
sys/norma/xmm_buffer.c

     /* 
      * Mach Operating System
      * Copyright (c) 1991 Carnegie Mellon University
      * All Rights Reserved.
      * 
      * Permission to use, copy, modify and distribute this software and its
      * documentation is hereby granted, provided that both the copyright
      * notice and this permission notice appear in all copies of the
      * software, derivative works or modified versions, and any portions
     * thereof, and that both notices appear in supporting documentation.
     * 
     * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS 
     * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
     * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
     * 
     * Carnegie Mellon requests users of this software to return to
     * 
     *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
     *  School of Computer Science
     *  Carnegie Mellon University
     *  Pittsburgh PA 15213-3890
     * 
     * any improvements or extensions that they make and grant Carnegie the
     * rights to redistribute these changes.
     */
    /*
     * HISTORY
     * $Log:        xmm_buffer.c,v $
     * Revision 2.2  92/03/10  16:28:53  jsb
     *      Merged in norma branch changes as of NORMA_MK7.
     *      [92/03/09  12:51:00  jsb]
     * 
     * Revision 2.1.2.5  92/02/21  11:25:30  jsb
     *      Let xmm_kobj_link handle multiple init detection.
     *      [92/02/18  08:04:06  jsb]
     * 
     *      Explicitly provide name parameter to xmm_decl macro.
     *      Changed debugging printf. Changed termination logic.
     *      [92/02/16  15:18:10  jsb]
     * 
     *      First real implementation.
     *      [92/02/09  14:17:44  jsb]
     * 
     * Revision 2.1.2.3  92/01/21  21:53:42  jsb
     *      De-linted. Supports new (dlb) memory object routines.
     *      Supports arbitrary reply ports to lock_request, etc.
     *      Converted mach_port_t (and port_t) to ipc_port_t.
     *      [92/01/20  17:18:38  jsb]
     * 
     * Revision 2.1.2.2  92/01/03  16:38:41  jsb
     *      First checkin.
     *      [91/12/31  17:26:56  jsb]
     * 
     * Revision 2.1.2.1  92/01/03  08:57:47  jsb
     *      First NORMA branch checkin.
     * 
     */
    /*
     *      File:   xmm_buffer.c
     *      Author: Joseph S. Barrera III
     *      Date:   1991
     *
     *      Xmm layer which buffers a small amount of data_written data.
     */
    
    #ifdef  KERNEL
    #include <kern/queue.h>
    #include <norma/xmm_obj.h>
    #include <mach/vm_param.h>
    #include <vm/vm_fault.h>
    #else   KERNEL
    #include <xmm_obj.h>
    #endif  KERNEL
    
    #define dprintf xmm_buffer_dprintf
    
    typedef struct buffer   *buffer_t;
    #define BUFFER_NULL     ((buffer_t) 0)
    
    struct buffer {
            queue_chain_t   lruq;
            queue_chain_t   mobjq;
            vm_map_copy_t   copy;
            xmm_obj_t       mobj;
            vm_offset_t     offset;
            buffer_t        next_free;
    };
    
    struct mobj {
            struct xmm_obj  obj;
            queue_head_t    buffers;
            boolean_t       ready;
    };
    
    #undef  KOBJ
    #define KOBJ    ((struct mobj *) kobj)
    
    #define m_buffer_copy                   m_interpose_copy
    #define m_buffer_data_unlock            m_interpose_data_unlock
   #define m_buffer_lock_completed         m_interpose_lock_completed
   #define m_buffer_supply_completed       m_interpose_supply_completed
   #define m_buffer_data_return            m_interpose_data_return
   #define m_buffer_change_completed       m_interpose_change_completed
   
   #define k_buffer_data_unavailable       k_interpose_data_unavailable
   #define k_buffer_get_attributes         k_interpose_get_attributes
   #define k_buffer_lock_request           k_interpose_lock_request
   #define k_buffer_data_error             k_interpose_data_error
   #define k_buffer_destroy                k_interpose_destroy
   #define k_buffer_data_supply            k_interpose_data_supply
   
   xmm_decl(buffer, "buffer", sizeof(struct mobj));
   
   #define XMM_BUFFER_COUNT        16
   
   struct buffer xmm_buffers[XMM_BUFFER_COUNT];
   buffer_t xmm_buffer_free_list;
   queue_head_t xmm_buffer_lru;
   
   buffer_t
   xmm_buffer_alloc()
   {
           register buffer_t buffer;
           kern_return_t kr;
           xmm_obj_t mobj;
   
           /*
            * First check the free list.
            */
           buffer = xmm_buffer_free_list;
           if (buffer != BUFFER_NULL) {
                   xmm_buffer_free_list = buffer->next_free;
                   return buffer;
           }
   
           /*
            * There's nothing on the free list, so take the oldest element
            * from the lru queue, if any.
            */
           if (queue_empty(&xmm_buffer_lru)) {
                   /*
                    * This can happen if all the buffers are being written out.
                    */
                   return BUFFER_NULL;
           }
   
           /*
            * Remove buffer off of its obj queue as well, and write out its data.
            *
            * XXX
            * Is it right for the caller to have to wait for someone else's
            * data write to be processed?
            */
           queue_remove_first(&xmm_buffer_lru, buffer, buffer_t, lruq);
           assert(buffer != BUFFER_NULL);
           mobj = buffer->mobj;
           queue_remove(&MOBJ->buffers, buffer, buffer_t, mobjq);
           kr = M_DATA_WRITE(mobj, mobj, buffer->offset,
                             (vm_offset_t) buffer->copy, PAGE_SIZE);
           if (kr != KERN_SUCCESS) {
                   /*
                    * XXX
                    * What do we do here? (eternal buffering problem)
                    */
                   printf("xmm_buffer_alloc: kr=%d/0x%x\n", kr, kr);
           }
   
           /*
            * The buffer is now free. Return it.
            */
   #if 666
           buffer->mobj = (xmm_obj_t) 0xdd66dd66;
           buffer->offset = 0xcccccccc;
   #endif
           return buffer;
   }
   
   void
   xmm_buffer_free(buffer)
           register buffer_t buffer;
   {
           buffer->next_free = xmm_buffer_free_list;
           xmm_buffer_free_list = buffer;
   }
   
   xmm_buffer_init()
   {
           int i;
           buffer_t buffer;
   
           queue_init(&xmm_buffer_lru);
           for (i = 0; i < XMM_BUFFER_COUNT; i++) {
                   buffer = &xmm_buffers[i];
                   queue_init(&buffer->mobjq);
                   queue_init(&buffer->lruq);
                   xmm_buffer_free(buffer);
           }
   }
   
   kern_return_t
   xmm_buffer_create(old_mobj, new_mobj)
           xmm_obj_t old_mobj;
           xmm_obj_t *new_mobj;
   {
           xmm_obj_t mobj;
           kern_return_t kr;
           
           kr = xmm_obj_allocate(&buffer_class, old_mobj, &mobj);
           if (kr != KERN_SUCCESS) {
                   return kr;
           }
           queue_init(&MOBJ->buffers);
           MOBJ->ready = FALSE;
           *new_mobj = mobj;
           return KERN_SUCCESS;
   }
   
   kern_return_t
   m_buffer_init(mobj, k_kobj, pagesize, internal, size)
           xmm_obj_t       mobj;
           xmm_obj_t       k_kobj;
           vm_size_t       pagesize;
           boolean_t       internal;
           vm_size_t       size;
   {
   #ifdef  lint
           M_INIT(mobj, k_kobj, pagesize, internal, size);
   #endif  lint
           assert(pagesize == PAGE_SIZE);
           xmm_kobj_link(mobj, k_kobj);
           M_INIT(mobj, mobj, pagesize, internal, size);
           return KERN_SUCCESS;
   }
   
   kern_return_t
   m_buffer_terminate(mobj, kobj)
           xmm_obj_t       mobj;
           xmm_obj_t       kobj;
   {
           buffer_t buffer;
           kern_return_t kr;
           vm_offset_t offset;
           vm_map_copy_t copy;
   
   #ifdef  lint
           M_TERMINATE(mobj, kobj);
   #endif  lint
           dprintf("xmm_buffer_terminate\n");
           while (! queue_empty(&MOBJ->buffers)) {
                   queue_remove_first(&MOBJ->buffers, buffer, buffer_t, mobjq);
                   assert(buffer != BUFFER_NULL);
                   queue_remove(&xmm_buffer_lru, buffer, buffer_t, lruq);
                   offset = buffer->offset;
                   copy = buffer->copy;
                   dprintf("dealloc 0x%x copy 0x%x\n", offset, copy);
                   xmm_buffer_free(buffer);
                   kr = M_DATA_WRITE(mobj, kobj, offset, (vm_offset_t) copy,
                                     PAGE_SIZE);
                   if (kr != KERN_SUCCESS) {
                           /*
                            * XXX
                            * What do we do here? (eternal buffering problem)
                            */
                           printf("xmm_buffer_terminate: kr=%d/0x%x\n", kr, kr);
                   }
           }
           dprintf("terminate done\n");
           return M_TERMINATE(mobj, kobj);
   }
   
   void
   m_buffer_deallocate(mobj)
           xmm_obj_t mobj;
   {
   }
   
   buffer_t
   xmm_buffer_lookup(mobj, offset)
           xmm_obj_t       mobj;
           vm_offset_t     offset;
   {
           buffer_t buffer;
   
           /*
            * Search through buffers associated with this mobj.
            * There are typically very few buffers associated
            * with any given object, so it's not worth having
            * a hash table or anything tricky.
            */
           queue_iterate(&MOBJ->buffers, buffer, buffer_t, mobjq) {
                   if (buffer->offset == offset) {
                           return buffer;
                   }
           }
           return BUFFER_NULL;
   }
   
   vm_page_t
   xmm_buffer_find_page(object, offset)
           vm_object_t object;
           vm_offset_t offset;
   {
           vm_page_t m;
           
           /*
            *      Try to find the page of data.
            */
           vm_object_lock(object);
           vm_object_paging_begin(object);
           m = vm_page_lookup(object, offset);
           if ((m != VM_PAGE_NULL) && !m->busy && !m->fictitious &&
               !m->absent && !m->error) {
           } else {
                   vm_prot_t result_prot;
                   vm_page_t top_page;
                   kern_return_t kr;
                   
                   for (;;) {
                           result_prot = VM_PROT_READ;
                           kr = vm_fault_page(object, offset,
                                              VM_PROT_READ, FALSE, FALSE,
                                              &result_prot, &m, &top_page,
                                              FALSE, (void (*)()) 0);
                           if (kr == VM_FAULT_MEMORY_SHORTAGE) {
                                   VM_PAGE_WAIT((void (*)()) 0);
                                   vm_object_lock(object);
                                   vm_object_paging_begin(object);
                                   continue;
                           }
                           if (kr != VM_FAULT_SUCCESS) {
                                   /* XXX what about data_error? */
                                   vm_object_lock(object);
                                   vm_object_paging_begin(object);
                                   continue;
                           }
                           if (top_page != VM_PAGE_NULL) {
                                   vm_object_lock(object);
                                   VM_PAGE_FREE(top_page);
                                   vm_object_paging_end(object);
                                   vm_object_unlock(object);
                           }
                           break;
                   }
           }
           assert(m);
           assert(! m->busy);
           vm_object_paging_end(object);
           vm_object_unlock(object);
           return m;
   }
   
   vm_map_copy_t
   xmm_buffer_copy(old_copy)
           vm_map_copy_t old_copy;
   {
           vm_map_copy_t new_copy;
           vm_page_t old_m, new_m;
           extern zone_t vm_map_copy_zone;
   
           dprintf("xmm_buffer_copy 0x%x type %d\n", old_copy, old_copy->type);
   
           /*
            * Allocate a new copy object.
            */
           new_copy = (vm_map_copy_t) zalloc(vm_map_copy_zone);
           if (new_copy == VM_MAP_COPY_NULL) {
                   panic("xmm_buffer_copy: zalloc");
           }
           new_copy->type = VM_MAP_COPY_PAGE_LIST;
           new_copy->cpy_npages = 1;
           new_copy->offset = 0;
           new_copy->size = PAGE_SIZE;
           new_copy->cpy_cont = ((kern_return_t (*)()) 0);
           new_copy->cpy_cont_args = (char *) VM_MAP_COPYIN_ARGS_NULL;
   
           /*
            * Allocate a new page and insert it into new copy object.
            */
           new_m = vm_page_grab();
           if (new_m == VM_PAGE_NULL) {
                   panic("xmm_buffer_copy: vm_page_grab");
           }
           new_copy->cpy_page_list[0] = new_m;
   
           /*
            * Find old page.
            */
           assert(old_copy->size == PAGE_SIZE);
           assert(old_copy->offset == 0);
           if (old_copy->type == VM_MAP_COPY_PAGE_LIST) {
                   old_m = old_copy->cpy_page_list[0];
           } else {
                   assert(old_copy->type == VM_MAP_COPY_OBJECT);
                   old_m = xmm_buffer_find_page(old_copy->cpy_object, 0);
           }
   
           /*
            * Copy old page into new, and return new copy object.
            */
           pmap_copy_page(old_m->phys_addr, new_m->phys_addr);
           return new_copy;
   }
   
   kern_return_t
   m_buffer_data_request(mobj, kobj, offset, length, desired_access)
           xmm_obj_t       mobj;
           xmm_obj_t       kobj;
           vm_offset_t     offset;
           vm_size_t       length;
           vm_prot_t       desired_access;
   {
           buffer_t buffer;
           vm_map_copy_t copy;
   
   #ifdef  lint
           M_DATA_REQUEST(mobj, kobj, offset, length, desired_access);
   #endif  lint
           /*
            * If this page was not buffered, then pass the data request through.
            */
           buffer = xmm_buffer_lookup(mobj, offset);
           if (buffer == BUFFER_NULL) {
                   return M_DATA_REQUEST(mobj, kobj, offset, length,
                                         desired_access);
           }
   
           /*
            * The page was buffered. Move it to the front of the lru queue.
            */
           queue_remove(&xmm_buffer_lru, buffer, buffer_t, lruq);
           queue_enter(&xmm_buffer_lru, buffer, buffer_t, lruq);
   
           /*
            * This copy is unfortunate and could be avoided.
            */
           copy = xmm_buffer_copy(buffer->copy);
           
           /*
            * Return data.
            */
           return K_DATA_SUPPLY(kobj, offset, (vm_offset_t) copy, length,
                                VM_PROT_NONE, FALSE, XMM_REPLY_NULL);
   }
   
   /*
    * Write data through to memory manager;
    * discard any corresponding buffered data.
    */
   kern_return_t
   m_buffer_data_write(mobj, kobj, offset, data, length)
           xmm_obj_t       mobj;
           xmm_obj_t       kobj;
           vm_offset_t     offset;
           vm_offset_t     data;
           vm_size_t       length;
   {
           buffer_t buffer;
   
   #ifdef  lint
           M_DATA_WRITE(mobj, kobj, offset, data, length);
   #endif  lint
           /*
            * Find and deallocate old data, if any.
            */
           buffer = xmm_buffer_lookup(mobj, offset);
           if (buffer != BUFFER_NULL) {
                   vm_map_copy_t copy = buffer->copy;
                   queue_remove(&MOBJ->buffers, buffer, buffer_t, mobjq);
                   queue_remove(&xmm_buffer_lru, buffer, buffer_t, lruq);
                   xmm_buffer_free(buffer);
                   dprintf("discard copy=0x%x type=%d\n", copy, copy->type);
                   vm_map_copy_discard(copy);
           }
   
           /*
            * Write new data.
            */
           return M_DATA_WRITE(mobj, kobj, offset, data, PAGE_SIZE);
   }
   
   /*
    * Buffer data to be written;
    * replace any preexisting corresponding buffered data.
    */
   m_buffer_data_write_buffered(mobj, kobj, offset, data, length)
           xmm_obj_t       mobj;
           xmm_obj_t       kobj;
           vm_offset_t     offset;
           vm_offset_t     data;
           vm_size_t       length;
   {
           buffer_t buffer;
           vm_map_copy_t copy = (vm_map_copy_t) data;
   
   #ifdef  lint
           M_DATA_WRITE(mobj, kobj, offset, data, length);
   #endif  lint
           /*
            * Be assertive.
            */
           assert(mobj == kobj);
           assert(length == PAGE_SIZE);
           assert(copy->type == VM_MAP_COPY_OBJECT ||
                  copy->type == VM_MAP_COPY_PAGE_LIST);
           assert(copy->offset == 0);
           assert(copy->size == PAGE_SIZE);
   
           /*
            * Check to see whether we have old data for this page.
            */
           buffer = xmm_buffer_lookup(mobj, offset);
           if (buffer != BUFFER_NULL) {
                   /*
                    * Replace data in buffer.
                    */
                   vm_map_copy_t old_copy = buffer->copy;
                   buffer->copy = copy;
                   dprintf("write_buffered: replace\n");
   
                   /*
                    * Move buffer to head of lru queue.
                    */
                   queue_remove(&xmm_buffer_lru, buffer, buffer_t, lruq);
                   queue_enter(&xmm_buffer_lru, buffer, buffer_t, lruq);
   
                   /*
                    * Discard data, and return.
                    */
                   dprintf("replace copy=0x%x[type=%d] with copy=0x%x[%d]\n",
                            old_copy, old_copy->type,
                            copy, copy->type);
                   vm_map_copy_discard(old_copy);
                   return KERN_SUCCESS;
           }
   
           /*
            * We don't have old data for this page, so allocate a new buffer
            * and enter it in the queues.
            */
           dprintf("write_buffered: new\n");
           buffer = xmm_buffer_alloc();
           assert(buffer != BUFFER_NULL);
           buffer->mobj = mobj;
           buffer->copy = copy;
           buffer->offset = offset;
           queue_enter(&MOBJ->buffers, buffer, buffer_t, mobjq);
           queue_enter(&xmm_buffer_lru, buffer, buffer_t, lruq);
           return KERN_SUCCESS;
   }
   
   kern_return_t
   m_buffer_unbuffer_data(mobj, offset, length, should_clean, should_flush)
           xmm_obj_t mobj;
           vm_offset_t offset;
           vm_size_t length;
           boolean_t should_clean;
           boolean_t should_flush;
   {
           buffer_t buffer;
           vm_map_copy_t copy;
   
           /*
            * If we have no data for this page, return.
            */
           buffer = xmm_buffer_lookup(mobj, offset);
           if (buffer == BUFFER_NULL) {
                   return KERN_SUCCESS;
           }
           
           /*
            * Dequeue and free buffer.
            */
           copy = buffer->copy;
           queue_remove(&MOBJ->buffers, buffer, buffer_t, mobjq);
           queue_remove(&xmm_buffer_lru, buffer, buffer_t, lruq);
           xmm_buffer_free(buffer);
   
           /*
            * Clean (write) or flush (deallocate) data.
            */
           assert(should_clean || should_flush);
           dprintf("unbuffer: clean=%d flush=%d\n", should_clean, should_flush);
           if (should_clean) {
                   return M_DATA_WRITE(mobj, mobj, offset, (vm_offset_t) copy,
                                       PAGE_SIZE);
           } else {
                   vm_map_copy_discard(copy);
                   return KERN_SUCCESS;
           }
   }
   
   k_buffer_set_ready(kobj, object_ready, may_cache, copy_strategy,
                      use_old_pageout, memory_object_name, reply)
           xmm_obj_t kobj;
           boolean_t object_ready;
           boolean_t may_cache;
           memory_object_copy_strategy_t copy_strategy;
           boolean_t use_old_pageout;
           ipc_port_t memory_object_name;
           xmm_reply_t reply;
   {
   #ifdef  lint
           K_SET_READY(kobj, object_ready, may_cache, copy_strategy,
                       use_old_pageout, memory_object_name, reply);
   #endif  lint
           if (object_ready) {
                   KOBJ->ready = TRUE;
           }
           K_SET_READY(kobj, object_ready, may_cache, copy_strategy,
                       use_old_pageout, memory_object_name, reply);
           return KERN_SUCCESS;
   }
   
   /*
    * These won't work if we are interposing. Do we care?
    */
   
   kern_return_t
   M_BUFFERED_DATA_WRITE(mobj, kobj, offset, data, length)
           xmm_obj_t mobj;
           xmm_obj_t kobj;
           vm_offset_t offset;
           vm_offset_t data;
           vm_size_t length;
   {
           if (mobj->m_mobj->class == &buffer_class) {
                   return m_buffer_data_write_buffered(mobj->m_mobj, kobj->m_kobj,
                                                       offset, data, length);
           } else {
                   return M_DATA_WRITE(mobj, kobj, offset, data, length);
           }
   }
   
   kern_return_t
   M_UNBUFFER_DATA(mobj, offset, length, should_clean, should_flush)
           xmm_obj_t mobj;
           boolean_t should_clean;
           boolean_t should_flush;
           vm_offset_t offset;
           vm_size_t length;
   {
           if (mobj->m_mobj->class == &buffer_class) {
                   return m_buffer_unbuffer_data(mobj->m_mobj, offset, length,
                                                 should_clean, should_flush);
           } else {
                   return KERN_SUCCESS;
           }
   }
   
   #include <sys/varargs.h>
   
   int xmm_buffer_debug = 0;
   
   /* VARARGS */
   xmm_buffer_dprintf(fmt, va_alist)
           char *fmt;
           va_dcl
   {
           va_list listp;
   
           if (xmm_buffer_debug) {
                   va_start(listp);
                   printf(fmt, &listp);
                   va_end(listp);
           }
   }

Cache object: 622098bec9a4918018d908e999c8c886