drivers/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 DPRINTK(_f, _a...)                      \
  46         pr_debug("(file=%s, line=%d) " _f,      \
  47                  __FILE__ , __LINE__ , ## _a)
  48
  49 struct vbd {
  50         blkif_vdev_t   handle;      /* what the domain refers to this vbd as */
  51         unsigned char  readonly;    /* Non-zero -> read-only */
  52         unsigned char  type;        /* VDISK_xxx */
  53         u32            pdevice;     /* phys device that this vbd maps to */
  54         struct block_device *bdev;
  55         sector_t       size;        /* Cached size parameter */
  56 };
  57
  58 struct backend_info;
  59
  60 struct blkif_st {
  61         /* Unique identifier for this interface. */
  62         domid_t           domid;
  63         unsigned int      handle;
  64         /* Physical parameters of the comms window. */
  65         unsigned int      irq;
  66         /* Comms information. */
  67         enum blkif_protocol blk_protocol;
  68         union blkif_back_rings blk_rings;
  69         struct vm_struct *blk_ring_area;
  70         /* The VBD attached to this interface. */
  71         struct vbd        vbd;
  72         /* Back pointer to the backend_info. */
  73         struct backend_info *be;
  74         /* Private fields. */
  75         spinlock_t       blk_ring_lock;
  76         atomic_t         refcnt;
  77
  78         wait_queue_head_t   wq;
  79         /* One thread per one blkif. */
  80         struct task_struct  *xenblkd;
  81         unsigned int        waiting_reqs;
  82         struct request_queue     *plug;
  83
  84         /* statistics */
  85         unsigned long       st_print;
  86         int                 st_rd_req;
  87         int                 st_wr_req;
  88         int                 st_oo_req;
  89         int                 st_br_req;
  90         int                 st_rd_sect;
  91         int                 st_wr_sect;
  92
  93         wait_queue_head_t waiting_to_free;
  94
  95         grant_handle_t shmem_handle;
  96         grant_ref_t    shmem_ref;
  97 };
  98
  99 struct blkif_st *blkif_alloc(domid_t domid);
 100 void blkif_disconnect(struct blkif_st *blkif);
 101 void blkif_free(struct blkif_st *blkif);
 102 int blkif_map(struct blkif_st *blkif, unsigned long shared_page,
 103               unsigned int evtchn);
 104 void vbd_resize(struct blkif_st *blkif);
 105
 106 #define blkif_get(_b) (atomic_inc(&(_b)->refcnt))
 107 #define blkif_put(_b)                                   \
 108         do {                                            \
 109                 if (atomic_dec_and_test(&(_b)->refcnt)) \
 110                         wake_up(&(_b)->waiting_to_free);\
 111         } while (0)
 112
 113 /* Create a vbd. */
 114 int vbd_create(struct blkif_st *blkif, blkif_vdev_t vdevice, unsigned major,
 115                unsigned minor, int readonly, int cdrom);
 116 void vbd_free(struct vbd *vbd);
 117
 118 unsigned long long vbd_size(struct vbd *vbd);
 119 unsigned int vbd_info(struct vbd *vbd);
 120 unsigned long vbd_secsize(struct vbd *vbd);
 121
 122 struct phys_req {
 123         unsigned short       dev;
 124         unsigned short       nr_sects;
 125         struct block_device *bdev;
 126         blkif_sector_t       sector_number;
 127 };
 128
 129 int vbd_translate(struct phys_req *req, struct blkif_st *blkif, int operation);
 130
 131 int blkif_interface_init(void);
 132
 133 int blkif_xenbus_init(void);
 134
 135 irqreturn_t blkif_be_int(int irq, void *dev_id);
 136 int blkif_schedule(void *arg);
 137
 138 int blkback_barrier(struct xenbus_transaction xbt,
 139                     struct backend_info *be, int state);
 140
 141 struct xenbus_device *blkback_xenbus(struct backend_info *be);
 142
 143 #endif /* __BLKIF__BACKEND__COMMON_H__ */