source: trunk/kernel/kern/blkio.c @ 27

/*
 * blkio.c - provides per-page buffers I/O
 * 
 * Copyright (c) 2008,2009,2010,2011,2012 Ghassan Almaless
 * Copyright (c) 2011,2012 UPMC Sorbonne Universites
 *
 * This file is part of ALMOS-kernel.
 *
 * ALMOS-kernel is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2.0 of the License.
 *
 * ALMOS-kernel is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with ALMOS-kernel; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <cpu.h>
#include <errno.h>
#include <scheduler.h>
#include <kmem.h>
#include <thread.h>
#include <chdev.h>
#include <driver.h>
#include <event.h>
#include <atomic.h>
#include <cluster.h>
#include <page.h>
#include <blkio.h>

static EVENT_HANDLER(blkio_async)
{
        struct blkio_s *blkio;
        struct blkio_s *info;
        struct page_s *page;
        struct thread_s *thread;
        error_t err;
        uint_t irq_state;

        blkio = event_get_argument(event);
        page  = blkio->b_page;
        info  = list_head(&page->root, struct blkio_s, b_list);
        err   = event_get_error(event);

        if(err)
        {
                printk(WARNING, "WARNING: %s: Requested I/O is failed, blk %d\n", 
                       __FUNCTION__, 
                       blkio->b_dev_rq.src);
        }

        err = (err) ? 1 : 0;

        spinlock_lock_noirq(&info->b_ctrl.lock, &irq_state);

        info->b_ctrl.cntr ++;
        info->b_ctrl.error = (info->b_ctrl.error) ? 1 : err;

        if(info->b_ctrl.cntr == info->b_ctrl.count) 
        {
                thread = wakeup_one(&info->b_ctrl.wait, WAIT_ANY);

#if CONFIG_BLKIO_DEBUG    
                if(thread != NULL)
                {
                        printk(INFO, "%s: cpu %d, wakeup tid %d on cpu %d [%u]\n",
                               __FUNCTION__,
                               cpu_get_id(),
                               thread->info.order,
                               thread_current_cpu(thread)->gid,
                               cpu_time_stamp());
                }
#endif
        }

        spinlock_unlock_noirq(&info->b_ctrl.lock, irq_state);
        return 0;
}

static void blkio_ctor(struct kcm_s *kcm, void *ptr) 
{
        struct blkio_s *blkio = (struct blkio_s *)ptr;

        spinlock_init(&blkio->b_ctrl.lock, "BlkIO");
        event_set_handler(&blkio->b_dev_rq.event, blkio_async);
        event_set_priority(&blkio->b_dev_rq.event, E_BLK);
        event_set_argument(&blkio->b_dev_rq.event, blkio);
        wait_queue_init(&blkio->b_ctrl.wait, "BLKIO Sync");
}

KMEM_OBJATTR_INIT(blkio_kmem_init)
{
        attr->type = KMEM_BLKIO;
        attr->name = "KCM BLKIO";
        attr->size = sizeof(struct blkio_s);
        attr->aligne = 0;
        attr->min = CONFIG_BLKIO_MIN;
        attr->max = CONFIG_BLKIO_MAX;
        attr->ctor = blkio_ctor;
        attr->dtor = NULL;
        return 0;
}

///////////////////////////////////
error_t blkio_init( device_t * dev,
                    page_t   * page,
                    uint32_t   count ) 
{
        kmem_req_t req;
        struct blkio_s *blkio;
        uint_t blkio_nr;

        req.type  = KMEM_BLKIO;
        req.size  = sizeof(*blkio);
        req.flags = AF_KERNEL;
  
        slist_root_init(&page->root);
        blkio_nr = count;

#if CONFIG_BLKIO_DEBUG    
        printk(INFO, "%s: cpu %d, count %d, pg @0x%x, index %d [%d]\n",
               __FUNCTION__, 
               cpu_get_id(),
               count, 
               page, 
               page->index,
               cpu_time_stamp());
#endif

        while(count)
        {
                if((blkio = kmem_alloc(&req)) == NULL) 
                {
                        blkio_destroy(page);
                        return ENOMEM;
                }
    
                blkio->b_flags = 0;
                blkio->b_page  = page;
                blkio->b_dev   = dev;

                list_push(&page->root, &blkio->b_list);
                count -= 1;
        }

        blkio = list_head(&page->root, struct blkio_s, b_list);

        blkio->b_ctrl.count = blkio_nr;
        blkio->b_ctrl.cntr  = 0;
        blkio->b_ctrl.error = 0;

        PAGE_SET(page, PG_BUFFER);
        return 0;
}  // end blkio_init()


////////////////////////////////////
error_t blkio_sync( page_t   * page,
                    uint32_t   flags ) 
{
        slist_entry_t    * iter;
        blkio_t          * blkio;
        blkio_t          * info;
        device_request_t * handler;
        error_t            err;
        uint32_t           irq_state;
        uint32_t           cntr;

        info = list_head(&page->root, struct blkio_s, b_list);
        handler = (flags & BLKIO_RD) ? info->b_dev->op.dev.read : info->b_dev->op.dev.write;
        cntr =  0;
        err =  0;

        list_foreach(&page->root, iter) 
        {
                blkio = list_element(iter, struct blkio_s, b_list);

                if(blkio->b_flags & BLKIO_INIT)
                {
                        blkio->b_flags &= ~BLKIO_INIT;
                        continue;
                }

                blkio->b_dev_rq.flags = DEV_RQ_NOBLOCK;

#if CONFIG_BLKIO_DEBUG  
                printk(INFO, "%s: cpu %d, Submitting blkio #%d, src %d, dst %x [%d]\n",
                       __FUNCTION__, 
                       cpu_get_id(),
                       cntr, 
                       blkio->b_dev_rq.src, 
                       blkio->b_dev_rq.dst, 
                       cpu_time_stamp());
#endif

                err = handler(blkio->b_dev, &blkio->b_dev_rq);
    
                if(err < 0) 
                {
                        err = EIO;
                        break;
                }

                cntr ++;
        }

        if(flags & BLKIO_SYNC) 
        {
                spinlock_lock_noirq(&info->b_ctrl.lock, &irq_state);
    
                info->b_ctrl.cntr += (info->b_ctrl.count - cntr);

                if(info->b_ctrl.cntr < info->b_ctrl.count) 
                {
                        wait_on(&info->b_ctrl.wait, WAIT_ANY);
                        spinlock_unlock_noirq(&info->b_ctrl.lock, irq_state);
                        sched_sleep(CURRENT_THREAD);

#if CONFIG_BLKIO_DEBUG
                        printk(INFO, "%s: cpu %d, tid %d, blkio ended, err %d\n",
                               __FUNCTION__, 
                               cpu_get_id(), 
                               CURRENT_THREAD->info.order, 
                               info->b_ctrl.error);
#endif

                }
                else
                        spinlock_unlock_noirq(&info->b_ctrl.lock, irq_state);

                return (info->b_ctrl.error) ? EIO : 0;
        }

        return err;
}

//////////////////////////////////////////
error_t blkio_destroy(struct page_s *page) 
{
        kmem_req_t req;
        struct slist_entry *iter;

        req.type = KMEM_BLKIO;

        list_foreach(&page->root, iter) 
        {
                req.ptr = list_element(iter, struct blkio_s, b_list);
                kmem_free(&req);
        }

        page->private = 0;
        PAGE_CLEAR(page, PG_BUFFER);
        return 0;
}