drivers/block/xen-blkback/common.h

   1 /*
   2  * This program is free software; you can redistribute it and/or
   3  * modify it under the terms of the GNU General Public License version 2
   4  * as published by the Free Software Foundation; or, when distributed
   5  * separately from the Linux kernel or incorporated into other
   6  * software packages, subject to the following license:
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this source file (the "Software"), to deal in the Software without
  10  * restriction, including without limitation the rights to use, copy, modify,
  11  * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  12  * and to permit persons to whom the Software is furnished to do so, subject to
  13  * the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  21  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  23  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  24  * IN THE SOFTWARE.
  25  */
  26
  27 #ifndef __BLKIF__BACKEND__COMMON_H__
  28 #define __BLKIF__BACKEND__COMMON_H__
  29
  30 #include <linux/version.h>
  31 #include <linux/module.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/slab.h>
  34 #include <linux/blkdev.h>
  35 #include <linux/vmalloc.h>
  36 #include <linux/wait.h>
  37 #include <linux/io.h>
  38 #include <asm/setup.h>
  39 #include <asm/pgalloc.h>
  40 #include <asm/hypervisor.h>
  41 #include <xen/blkif.h>
  42 #include <xen/grant_table.h>
  43 #include <xen/xenbus.h>
  44
  45 #define DRV_PFX "xen-blkback:"
  46 #define DPRINTK(fmt, args...)                           \
  47         pr_debug(DRV_PFX "(%s:%d) " fmt ".\n",  \
  48                  __func__, __LINE__, ##args)
  49
  50 struct vbd {
  51         /* What the domain refers to this vbd as. */
  52         blkif_vdev_t            handle;
  53         /* Non-zero -> read-only */
  54         unsigned char           readonly;
  55         /* VDISK_xxx */
  56         unsigned char           type;
  57         /* phys device that this vbd maps to. */
  58         u32                     pdevice;
  59         struct block_device     *bdev;
  60         /* Cached size parameter. */
  61         sector_t                size;
  62         bool                    flush_support;
  63 };
  64
  65 struct backend_info;
  66
  67 struct blkif_st {
  68         /* Unique identifier for this interface. */
  69         domid_t                 domid;
  70         unsigned int            handle;
  71         /* Physical parameters of the comms window. */
  72         unsigned int            irq;
  73         /* Comms information. */
  74         enum blkif_protocol     blk_protocol;
  75         union blkif_back_rings  blk_rings;
  76         struct vm_struct        *blk_ring_area;
  77         /* The VBD attached to this interface. */
  78         struct vbd              vbd;
  79         /* Back pointer to the backend_info. */
  80         struct backend_info     *be;
  81         /* Private fields. */
  82         spinlock_t              blk_ring_lock;
  83         atomic_t                refcnt;
  84
  85         wait_queue_head_t       wq;
  86         /* One thread per one blkif. */
  87         struct task_struct      *xenblkd;
  88         unsigned int            waiting_reqs;
  89
  90         /* statistics */
  91         unsigned long           st_print;
  92         int                     st_rd_req;
  93         int                     st_wr_req;
  94         int                     st_oo_req;
  95         int                     st_f_req;
  96         int                     st_rd_sect;
  97         int                     st_wr_sect;
  98
  99         wait_queue_head_t       waiting_to_free;
 100
 101         grant_handle_t          shmem_handle;
 102         grant_ref_t             shmem_ref;
 103 };
 104
 105
 106 #define vbd_sz(_v)      ((_v)->bdev->bd_part ? \
 107                          (_v)->bdev->bd_part->nr_sects : \
 108                           get_capacity((_v)->bdev->bd_disk))
 109
 110 #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
 111 #define xen_blkif_put(_b)                               \
 112         do {                                            \
 113                 if (atomic_dec_and_test(&(_b)->refcnt)) \
 114                         wake_up(&(_b)->waiting_to_free);\
 115         } while (0)
 116
 117 struct phys_req {
 118         unsigned short          dev;
 119         unsigned short          nr_sects;
 120         struct block_device     *bdev;
 121         blkif_sector_t          sector_number;
 122 };
 123 int xen_blkif_interface_init(void);
 124
 125 int xen_blkif_xenbus_init(void);
 126
 127 irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
 128 int xen_blkif_schedule(void *arg);
 129
 130 int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
 131                               struct backend_info *be, int state);
 132
 133 struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
 134
 135 static inline void blkif_get_x86_32_req(struct blkif_request *dst,
 136                                         struct blkif_x86_32_request *src)
 137 {
 138         int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
 139         dst->operation = src->operation;
 140         dst->nr_segments = src->nr_segments;
 141         dst->handle = src->handle;
 142         dst->id = src->id;
 143         dst->u.rw.sector_number = src->sector_number;
 144         barrier();
 145         if (n > dst->nr_segments)
 146                 n = dst->nr_segments;
 147         for (i = 0; i < n; i++)
 148                 dst->u.rw.seg[i] = src->seg[i];
 149 }
 150
 151 static inline void blkif_get_x86_64_req(struct blkif_request *dst,
 152                                         struct blkif_x86_64_request *src)
 153 {
 154         int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST;
 155         dst->operation = src->operation;
 156         dst->nr_segments = src->nr_segments;
 157         dst->handle = src->handle;
 158         dst->id = src->id;
 159         dst->u.rw.sector_number = src->sector_number;
 160         barrier();
 161         if (n > dst->nr_segments)
 162                 n = dst->nr_segments;
 163         for (i = 0; i < n; i++)
 164                 dst->u.rw.seg[i] = src->seg[i];
 165 }
 166
 167 #endif /* __BLKIF__BACKEND__COMMON_H__ */