2011-04-15 05:25:47 +07:00
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/******************************************************************************
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* arch/xen/drivers/blkif/backend/main.c
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*
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* Back-end of the driver for virtual block devices. This portion of the
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* driver exports a 'unified' block-device interface that can be accessed
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* by any operating system that implements a compatible front end. A
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* reference front-end implementation can be found in:
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* arch/xen/drivers/blkif/frontend
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*
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* Copyright (c) 2003-2004, Keir Fraser & Steve Hand
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* Copyright (c) 2005, Christopher Clark
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include <linux/spinlock.h>
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#include <linux/kthread.h>
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#include <linux/list.h>
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#include <linux/delay.h>
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2009-02-10 03:05:51 +07:00
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#include <linux/freezer.h>
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2009-09-16 04:12:37 +07:00
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2011-04-15 05:25:47 +07:00
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#include <xen/balloon.h>
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2009-02-10 03:05:51 +07:00
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#include <xen/events.h>
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#include <xen/page.h>
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#include <asm/xen/hypervisor.h>
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#include <asm/xen/hypercall.h>
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2011-04-15 05:25:47 +07:00
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#include "common.h"
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/*
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* These are rather arbitrary. They are fairly large because adjacent requests
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* pulled from a communication ring are quite likely to end up being part of
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* the same scatter/gather request at the disc.
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*
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* ** TRY INCREASING 'blkif_reqs' IF WRITE SPEEDS SEEM TOO LOW **
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*
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* This will increase the chances of being able to write whole tracks.
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* 64 should be enough to keep us competitive with Linux.
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*/
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static int blkif_reqs = 64;
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module_param_named(reqs, blkif_reqs, int, 0);
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MODULE_PARM_DESC(reqs, "Number of blkback requests to allocate");
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/* Run-time switchable: /sys/module/blkback/parameters/ */
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static unsigned int log_stats = 0;
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static unsigned int debug_lvl = 0;
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module_param(log_stats, int, 0644);
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module_param(debug_lvl, int, 0644);
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/*
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* Each outstanding request that we've passed to the lower device layers has a
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* 'pending_req' allocated to it. Each buffer_head that completes decrements
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* the pendcnt towards zero. When it hits zero, the specified domain has a
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* response queued for it, with the saved 'id' passed back.
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*/
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typedef struct {
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blkif_t *blkif;
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u64 id;
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int nr_pages;
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atomic_t pendcnt;
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unsigned short operation;
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int status;
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struct list_head free_list;
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} pending_req_t;
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static pending_req_t *pending_reqs;
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static struct list_head pending_free;
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static DEFINE_SPINLOCK(pending_free_lock);
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static DECLARE_WAIT_QUEUE_HEAD(pending_free_wq);
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#define BLKBACK_INVALID_HANDLE (~0)
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static struct page **pending_pages;
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static grant_handle_t *pending_grant_handles;
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static inline int vaddr_pagenr(pending_req_t *req, int seg)
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{
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return (req - pending_reqs) * BLKIF_MAX_SEGMENTS_PER_REQUEST + seg;
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}
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static inline unsigned long vaddr(pending_req_t *req, int seg)
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{
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unsigned long pfn = page_to_pfn(pending_pages[vaddr_pagenr(req, seg)]);
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return (unsigned long)pfn_to_kaddr(pfn);
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}
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#define pending_handle(_req, _seg) \
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(pending_grant_handles[vaddr_pagenr(_req, _seg)])
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static int do_block_io_op(blkif_t *blkif);
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static void dispatch_rw_block_io(blkif_t *blkif,
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2009-02-10 03:05:51 +07:00
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struct blkif_request *req,
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2011-04-15 05:25:47 +07:00
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pending_req_t *pending_req);
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static void make_response(blkif_t *blkif, u64 id,
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unsigned short op, int st);
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/******************************************************************
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* misc small helpers
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*/
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static pending_req_t* alloc_req(void)
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{
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pending_req_t *req = NULL;
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unsigned long flags;
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spin_lock_irqsave(&pending_free_lock, flags);
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if (!list_empty(&pending_free)) {
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req = list_entry(pending_free.next, pending_req_t, free_list);
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list_del(&req->free_list);
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}
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spin_unlock_irqrestore(&pending_free_lock, flags);
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return req;
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}
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static void free_req(pending_req_t *req)
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{
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unsigned long flags;
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int was_empty;
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spin_lock_irqsave(&pending_free_lock, flags);
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was_empty = list_empty(&pending_free);
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list_add(&req->free_list, &pending_free);
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spin_unlock_irqrestore(&pending_free_lock, flags);
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if (was_empty)
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wake_up(&pending_free_wq);
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}
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static void unplug_queue(blkif_t *blkif)
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{
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if (blkif->plug == NULL)
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return;
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if (blkif->plug->unplug_fn)
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blkif->plug->unplug_fn(blkif->plug);
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blk_put_queue(blkif->plug);
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blkif->plug = NULL;
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}
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static void plug_queue(blkif_t *blkif, struct block_device *bdev)
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{
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2009-02-10 03:05:51 +07:00
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struct request_queue *q = bdev_get_queue(bdev);
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2011-04-15 05:25:47 +07:00
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if (q == blkif->plug)
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return;
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unplug_queue(blkif);
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blk_get_queue(q);
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blkif->plug = q;
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}
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static void fast_flush_area(pending_req_t *req)
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{
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struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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unsigned int i, invcount = 0;
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grant_handle_t handle;
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int ret;
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for (i = 0; i < req->nr_pages; i++) {
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handle = pending_handle(req, i);
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if (handle == BLKBACK_INVALID_HANDLE)
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continue;
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gnttab_set_unmap_op(&unmap[invcount], vaddr(req, i),
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GNTMAP_host_map, handle);
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pending_handle(req, i) = BLKBACK_INVALID_HANDLE;
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invcount++;
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}
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ret = HYPERVISOR_grant_table_op(
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GNTTABOP_unmap_grant_ref, unmap, invcount);
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BUG_ON(ret);
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}
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/******************************************************************
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* SCHEDULER FUNCTIONS
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*/
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static void print_stats(blkif_t *blkif)
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{
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printk(KERN_DEBUG "%s: oo %3d | rd %4d | wr %4d | br %4d\n",
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current->comm, blkif->st_oo_req,
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blkif->st_rd_req, blkif->st_wr_req, blkif->st_br_req);
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blkif->st_print = jiffies + msecs_to_jiffies(10 * 1000);
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blkif->st_rd_req = 0;
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blkif->st_wr_req = 0;
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blkif->st_oo_req = 0;
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}
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int blkif_schedule(void *arg)
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{
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blkif_t *blkif = arg;
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2010-03-12 04:39:50 +07:00
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struct vbd *vbd = &blkif->vbd;
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2011-04-15 05:25:47 +07:00
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blkif_get(blkif);
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if (debug_lvl)
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printk(KERN_DEBUG "%s: started\n", current->comm);
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while (!kthread_should_stop()) {
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if (try_to_freeze())
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continue;
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2010-03-12 04:39:50 +07:00
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if (unlikely(vbd->size != vbd_size(vbd)))
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vbd_resize(blkif);
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2011-04-15 05:25:47 +07:00
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wait_event_interruptible(
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blkif->wq,
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blkif->waiting_reqs || kthread_should_stop());
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wait_event_interruptible(
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pending_free_wq,
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!list_empty(&pending_free) || kthread_should_stop());
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blkif->waiting_reqs = 0;
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smp_mb(); /* clear flag *before* checking for work */
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if (do_block_io_op(blkif))
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blkif->waiting_reqs = 1;
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unplug_queue(blkif);
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if (log_stats && time_after(jiffies, blkif->st_print))
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print_stats(blkif);
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}
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if (log_stats)
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print_stats(blkif);
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if (debug_lvl)
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printk(KERN_DEBUG "%s: exiting\n", current->comm);
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blkif->xenblkd = NULL;
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blkif_put(blkif);
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return 0;
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}
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/******************************************************************
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* COMPLETION CALLBACK -- Called as bh->b_end_io()
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*/
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static void __end_block_io_op(pending_req_t *pending_req, int error)
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{
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/* An error fails the entire request. */
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if ((pending_req->operation == BLKIF_OP_WRITE_BARRIER) &&
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(error == -EOPNOTSUPP)) {
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DPRINTK("blkback: write barrier op failed, not supported\n");
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blkback_barrier(XBT_NIL, pending_req->blkif->be, 0);
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pending_req->status = BLKIF_RSP_EOPNOTSUPP;
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} else if (error) {
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DPRINTK("Buffer not up-to-date at end of operation, "
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"error=%d\n", error);
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pending_req->status = BLKIF_RSP_ERROR;
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}
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if (atomic_dec_and_test(&pending_req->pendcnt)) {
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fast_flush_area(pending_req);
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make_response(pending_req->blkif, pending_req->id,
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pending_req->operation, pending_req->status);
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blkif_put(pending_req->blkif);
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free_req(pending_req);
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}
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}
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2009-02-10 03:05:51 +07:00
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static void end_block_io_op(struct bio *bio, int error)
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2011-04-15 05:25:47 +07:00
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{
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__end_block_io_op(bio->bi_private, error);
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bio_put(bio);
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}
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/******************************************************************************
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* NOTIFICATION FROM GUEST OS.
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*/
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static void blkif_notify_work(blkif_t *blkif)
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{
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blkif->waiting_reqs = 1;
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wake_up(&blkif->wq);
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}
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2009-02-10 03:05:51 +07:00
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irqreturn_t blkif_be_int(int irq, void *dev_id)
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2011-04-15 05:25:47 +07:00
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{
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blkif_notify_work(dev_id);
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return IRQ_HANDLED;
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}
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/******************************************************************
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* DOWNWARD CALLS -- These interface with the block-device layer proper.
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*/
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static int do_block_io_op(blkif_t *blkif)
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{
|
2009-02-10 03:05:51 +07:00
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union blkif_back_rings *blk_rings = &blkif->blk_rings;
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struct blkif_request req;
|
2011-04-15 05:25:47 +07:00
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pending_req_t *pending_req;
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RING_IDX rc, rp;
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int more_to_do = 0;
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rc = blk_rings->common.req_cons;
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rp = blk_rings->common.sring->req_prod;
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rmb(); /* Ensure we see queued requests up to 'rp'. */
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while (rc != rp) {
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if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
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break;
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|
2009-03-06 15:29:15 +07:00
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if (kthread_should_stop()) {
|
2011-04-15 05:25:47 +07:00
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more_to_do = 1;
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break;
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}
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2009-03-06 15:29:15 +07:00
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pending_req = alloc_req();
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if (NULL == pending_req) {
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blkif->st_oo_req++;
|
2011-04-15 05:25:47 +07:00
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more_to_do = 1;
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break;
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}
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switch (blkif->blk_protocol) {
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|
case BLKIF_PROTOCOL_NATIVE:
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memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req));
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break;
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case BLKIF_PROTOCOL_X86_32:
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blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc));
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break;
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|
case BLKIF_PROTOCOL_X86_64:
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blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc));
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|
break;
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|
default:
|
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|
|
BUG();
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|
}
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|
|
blk_rings->common.req_cons = ++rc; /* before make_response() */
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|
|
|
|
|
|
|
/* Apply all sanity checks to /private copy/ of request. */
|
|
|
|
barrier();
|
|
|
|
|
|
|
|
switch (req.operation) {
|
|
|
|
case BLKIF_OP_READ:
|
|
|
|
blkif->st_rd_req++;
|
|
|
|
dispatch_rw_block_io(blkif, &req, pending_req);
|
|
|
|
break;
|
|
|
|
case BLKIF_OP_WRITE_BARRIER:
|
|
|
|
blkif->st_br_req++;
|
|
|
|
/* fall through */
|
|
|
|
case BLKIF_OP_WRITE:
|
|
|
|
blkif->st_wr_req++;
|
|
|
|
dispatch_rw_block_io(blkif, &req, pending_req);
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
/* A good sign something is wrong: sleep for a while to
|
|
|
|
* avoid excessive CPU consumption by a bad guest. */
|
|
|
|
msleep(1);
|
|
|
|
DPRINTK("error: unknown block io operation [%d]\n",
|
|
|
|
req.operation);
|
|
|
|
make_response(blkif, req.id, req.operation,
|
|
|
|
BLKIF_RSP_ERROR);
|
|
|
|
free_req(pending_req);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Yield point for this unbounded loop. */
|
|
|
|
cond_resched();
|
|
|
|
}
|
|
|
|
|
|
|
|
return more_to_do;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void dispatch_rw_block_io(blkif_t *blkif,
|
2009-02-10 03:05:51 +07:00
|
|
|
struct blkif_request *req,
|
2011-04-15 05:25:47 +07:00
|
|
|
pending_req_t *pending_req)
|
|
|
|
{
|
|
|
|
struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
|
|
struct phys_req preq;
|
|
|
|
struct {
|
|
|
|
unsigned long buf; unsigned int nsec;
|
|
|
|
} seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
|
|
|
|
unsigned int nseg;
|
|
|
|
struct bio *bio = NULL;
|
|
|
|
int ret, i;
|
|
|
|
int operation;
|
|
|
|
|
|
|
|
switch (req->operation) {
|
|
|
|
case BLKIF_OP_READ:
|
|
|
|
operation = READ;
|
|
|
|
break;
|
|
|
|
case BLKIF_OP_WRITE:
|
|
|
|
operation = WRITE;
|
|
|
|
break;
|
|
|
|
case BLKIF_OP_WRITE_BARRIER:
|
2011-02-25 05:22:41 +07:00
|
|
|
operation = REQ_FLUSH | REQ_FUA;
|
2011-04-15 05:25:47 +07:00
|
|
|
break;
|
|
|
|
default:
|
|
|
|
operation = 0; /* make gcc happy */
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Check that number of segments is sane. */
|
|
|
|
nseg = req->nr_segments;
|
2011-02-25 05:22:41 +07:00
|
|
|
if (unlikely(nseg == 0 && operation != (REQ_FLUSH | REQ_FUA)) ||
|
2011-04-15 05:25:47 +07:00
|
|
|
unlikely(nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) {
|
|
|
|
DPRINTK("Bad number of segments in request (%d)\n", nseg);
|
|
|
|
goto fail_response;
|
|
|
|
}
|
|
|
|
|
|
|
|
preq.dev = req->handle;
|
|
|
|
preq.sector_number = req->sector_number;
|
|
|
|
preq.nr_sects = 0;
|
|
|
|
|
|
|
|
pending_req->blkif = blkif;
|
|
|
|
pending_req->id = req->id;
|
|
|
|
pending_req->operation = req->operation;
|
|
|
|
pending_req->status = BLKIF_RSP_OKAY;
|
|
|
|
pending_req->nr_pages = nseg;
|
|
|
|
|
|
|
|
for (i = 0; i < nseg; i++) {
|
|
|
|
uint32_t flags;
|
|
|
|
|
|
|
|
seg[i].nsec = req->seg[i].last_sect -
|
|
|
|
req->seg[i].first_sect + 1;
|
|
|
|
|
|
|
|
if ((req->seg[i].last_sect >= (PAGE_SIZE >> 9)) ||
|
|
|
|
(req->seg[i].last_sect < req->seg[i].first_sect))
|
|
|
|
goto fail_response;
|
|
|
|
preq.nr_sects += seg[i].nsec;
|
|
|
|
|
|
|
|
flags = GNTMAP_host_map;
|
|
|
|
if (operation != READ)
|
|
|
|
flags |= GNTMAP_readonly;
|
|
|
|
gnttab_set_map_op(&map[i], vaddr(pending_req, i), flags,
|
|
|
|
req->seg[i].gref, blkif->domid);
|
|
|
|
}
|
|
|
|
|
|
|
|
ret = HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, map, nseg);
|
|
|
|
BUG_ON(ret);
|
|
|
|
|
|
|
|
for (i = 0; i < nseg; i++) {
|
|
|
|
if (unlikely(map[i].status != 0)) {
|
|
|
|
DPRINTK("invalid buffer -- could not remap it\n");
|
|
|
|
map[i].handle = BLKBACK_INVALID_HANDLE;
|
|
|
|
ret |= 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
pending_handle(pending_req, i) = map[i].handle;
|
|
|
|
|
|
|
|
if (ret)
|
|
|
|
continue;
|
|
|
|
|
|
|
|
set_phys_to_machine(__pa(vaddr(
|
|
|
|
pending_req, i)) >> PAGE_SHIFT,
|
|
|
|
FOREIGN_FRAME(map[i].dev_bus_addr >> PAGE_SHIFT));
|
|
|
|
seg[i].buf = map[i].dev_bus_addr |
|
|
|
|
(req->seg[i].first_sect << 9);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (ret)
|
|
|
|
goto fail_flush;
|
|
|
|
|
|
|
|
if (vbd_translate(&preq, blkif, operation) != 0) {
|
|
|
|
DPRINTK("access denied: %s of [%llu,%llu] on dev=%04x\n",
|
|
|
|
operation == READ ? "read" : "write",
|
|
|
|
preq.sector_number,
|
|
|
|
preq.sector_number + preq.nr_sects, preq.dev);
|
|
|
|
goto fail_flush;
|
|
|
|
}
|
|
|
|
|
|
|
|
plug_queue(blkif, preq.bdev);
|
|
|
|
atomic_set(&pending_req->pendcnt, 1);
|
|
|
|
blkif_get(blkif);
|
|
|
|
|
|
|
|
for (i = 0; i < nseg; i++) {
|
|
|
|
if (((int)preq.sector_number|(int)seg[i].nsec) &
|
2009-06-30 04:58:45 +07:00
|
|
|
((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
|
2011-04-15 05:25:47 +07:00
|
|
|
DPRINTK("Misaligned I/O request from domain %d",
|
|
|
|
blkif->domid);
|
|
|
|
goto fail_put_bio;
|
|
|
|
}
|
|
|
|
|
|
|
|
while ((bio == NULL) ||
|
|
|
|
(bio_add_page(bio,
|
|
|
|
virt_to_page(vaddr(pending_req, i)),
|
|
|
|
seg[i].nsec << 9,
|
|
|
|
seg[i].buf & ~PAGE_MASK) == 0)) {
|
|
|
|
if (bio) {
|
|
|
|
atomic_inc(&pending_req->pendcnt);
|
|
|
|
submit_bio(operation, bio);
|
|
|
|
}
|
|
|
|
|
|
|
|
bio = bio_alloc(GFP_KERNEL, nseg-i);
|
|
|
|
if (unlikely(bio == NULL))
|
|
|
|
goto fail_put_bio;
|
|
|
|
|
|
|
|
bio->bi_bdev = preq.bdev;
|
|
|
|
bio->bi_private = pending_req;
|
|
|
|
bio->bi_end_io = end_block_io_op;
|
|
|
|
bio->bi_sector = preq.sector_number;
|
|
|
|
}
|
|
|
|
|
|
|
|
preq.sector_number += seg[i].nsec;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!bio) {
|
2011-02-25 05:22:41 +07:00
|
|
|
BUG_ON(operation != (REQ_FLUSH | REQ_FUA));
|
2011-04-15 05:25:47 +07:00
|
|
|
bio = bio_alloc(GFP_KERNEL, 0);
|
|
|
|
if (unlikely(bio == NULL))
|
|
|
|
goto fail_put_bio;
|
|
|
|
|
|
|
|
bio->bi_bdev = preq.bdev;
|
|
|
|
bio->bi_private = pending_req;
|
|
|
|
bio->bi_end_io = end_block_io_op;
|
|
|
|
bio->bi_sector = -1;
|
|
|
|
}
|
|
|
|
|
|
|
|
submit_bio(operation, bio);
|
|
|
|
|
|
|
|
if (operation == READ)
|
|
|
|
blkif->st_rd_sect += preq.nr_sects;
|
2011-02-25 05:22:41 +07:00
|
|
|
else if (operation == WRITE || operation == (REQ_FLUSH | REQ_FUA))
|
2011-04-15 05:25:47 +07:00
|
|
|
blkif->st_wr_sect += preq.nr_sects;
|
|
|
|
|
|
|
|
return;
|
|
|
|
|
|
|
|
fail_flush:
|
|
|
|
fast_flush_area(pending_req);
|
|
|
|
fail_response:
|
|
|
|
make_response(blkif, req->id, req->operation, BLKIF_RSP_ERROR);
|
|
|
|
free_req(pending_req);
|
|
|
|
msleep(1); /* back off a bit */
|
|
|
|
return;
|
|
|
|
|
|
|
|
fail_put_bio:
|
|
|
|
__end_block_io_op(pending_req, -EINVAL);
|
|
|
|
if (bio)
|
|
|
|
bio_put(bio);
|
|
|
|
unplug_queue(blkif);
|
|
|
|
msleep(1); /* back off a bit */
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/******************************************************************
|
|
|
|
* MISCELLANEOUS SETUP / TEARDOWN / DEBUGGING
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
|
|
static void make_response(blkif_t *blkif, u64 id,
|
|
|
|
unsigned short op, int st)
|
|
|
|
{
|
2009-02-10 03:05:51 +07:00
|
|
|
struct blkif_response resp;
|
2011-04-15 05:25:47 +07:00
|
|
|
unsigned long flags;
|
2009-02-10 03:05:51 +07:00
|
|
|
union blkif_back_rings *blk_rings = &blkif->blk_rings;
|
2011-04-15 05:25:47 +07:00
|
|
|
int more_to_do = 0;
|
|
|
|
int notify;
|
|
|
|
|
|
|
|
resp.id = id;
|
|
|
|
resp.operation = op;
|
|
|
|
resp.status = st;
|
|
|
|
|
|
|
|
spin_lock_irqsave(&blkif->blk_ring_lock, flags);
|
|
|
|
/* Place on the response ring for the relevant domain. */
|
|
|
|
switch (blkif->blk_protocol) {
|
|
|
|
case BLKIF_PROTOCOL_NATIVE:
|
|
|
|
memcpy(RING_GET_RESPONSE(&blk_rings->native, blk_rings->native.rsp_prod_pvt),
|
|
|
|
&resp, sizeof(resp));
|
|
|
|
break;
|
|
|
|
case BLKIF_PROTOCOL_X86_32:
|
|
|
|
memcpy(RING_GET_RESPONSE(&blk_rings->x86_32, blk_rings->x86_32.rsp_prod_pvt),
|
|
|
|
&resp, sizeof(resp));
|
|
|
|
break;
|
|
|
|
case BLKIF_PROTOCOL_X86_64:
|
|
|
|
memcpy(RING_GET_RESPONSE(&blk_rings->x86_64, blk_rings->x86_64.rsp_prod_pvt),
|
|
|
|
&resp, sizeof(resp));
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
BUG();
|
|
|
|
}
|
|
|
|
blk_rings->common.rsp_prod_pvt++;
|
|
|
|
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
|
|
|
|
if (blk_rings->common.rsp_prod_pvt == blk_rings->common.req_cons) {
|
|
|
|
/*
|
|
|
|
* Tail check for pending requests. Allows frontend to avoid
|
|
|
|
* notifications if requests are already in flight (lower
|
|
|
|
* overheads and promotes batching).
|
|
|
|
*/
|
|
|
|
RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
|
|
|
|
|
|
|
|
} else if (RING_HAS_UNCONSUMED_REQUESTS(&blk_rings->common)) {
|
|
|
|
more_to_do = 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
spin_unlock_irqrestore(&blkif->blk_ring_lock, flags);
|
|
|
|
|
|
|
|
if (more_to_do)
|
|
|
|
blkif_notify_work(blkif);
|
|
|
|
if (notify)
|
|
|
|
notify_remote_via_irq(blkif->irq);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int __init blkif_init(void)
|
|
|
|
{
|
|
|
|
int i, mmap_pages;
|
2009-10-09 00:23:09 +07:00
|
|
|
int rc = 0;
|
2011-04-15 05:25:47 +07:00
|
|
|
|
2009-02-10 03:05:51 +07:00
|
|
|
if (!xen_pv_domain())
|
2011-04-15 05:25:47 +07:00
|
|
|
return -ENODEV;
|
|
|
|
|
|
|
|
mmap_pages = blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST;
|
|
|
|
|
|
|
|
pending_reqs = kmalloc(sizeof(pending_reqs[0]) *
|
|
|
|
blkif_reqs, GFP_KERNEL);
|
|
|
|
pending_grant_handles = kmalloc(sizeof(pending_grant_handles[0]) *
|
|
|
|
mmap_pages, GFP_KERNEL);
|
|
|
|
pending_pages = alloc_empty_pages_and_pagevec(mmap_pages);
|
|
|
|
|
2009-10-09 00:23:09 +07:00
|
|
|
if (!pending_reqs || !pending_grant_handles || !pending_pages) {
|
|
|
|
rc = -ENOMEM;
|
2011-04-15 05:25:47 +07:00
|
|
|
goto out_of_memory;
|
2009-10-09 00:23:09 +07:00
|
|
|
}
|
2011-04-15 05:25:47 +07:00
|
|
|
|
|
|
|
for (i = 0; i < mmap_pages; i++)
|
|
|
|
pending_grant_handles[i] = BLKBACK_INVALID_HANDLE;
|
|
|
|
|
2009-10-09 00:23:09 +07:00
|
|
|
rc = blkif_interface_init();
|
|
|
|
if (rc)
|
|
|
|
goto failed_init;
|
2011-04-15 05:25:47 +07:00
|
|
|
|
|
|
|
memset(pending_reqs, 0, sizeof(pending_reqs));
|
|
|
|
INIT_LIST_HEAD(&pending_free);
|
|
|
|
|
|
|
|
for (i = 0; i < blkif_reqs; i++)
|
|
|
|
list_add_tail(&pending_reqs[i].free_list, &pending_free);
|
|
|
|
|
2009-10-09 00:23:09 +07:00
|
|
|
rc = blkif_xenbus_init();
|
|
|
|
if (rc)
|
|
|
|
goto failed_init;
|
2011-04-15 05:25:47 +07:00
|
|
|
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
out_of_memory:
|
2009-10-09 00:23:09 +07:00
|
|
|
printk(KERN_ERR "%s: out of memory\n", __func__);
|
|
|
|
failed_init:
|
2011-04-15 05:25:47 +07:00
|
|
|
kfree(pending_reqs);
|
|
|
|
kfree(pending_grant_handles);
|
|
|
|
free_empty_pages_and_pagevec(pending_pages, mmap_pages);
|
2009-10-09 00:23:09 +07:00
|
|
|
return rc;
|
2011-04-15 05:25:47 +07:00
|
|
|
}
|
|
|
|
|
|
|
|
module_init(blkif_init);
|
|
|
|
|
|
|
|
MODULE_LICENSE("Dual BSD/GPL");
|