/* * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #ifndef __XEN_BLKIF__BACKEND__COMMON_H__ #define __XEN_BLKIF__BACKEND__COMMON_H__ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRV_PFX "xen-blkback:" #define DPRINTK(fmt, args...) \ pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ __func__, __LINE__, ##args) /* Not a real protocol. Used to generate ring structs which contain * the elements common to all protocols only. This way we get a * compiler-checkable way to use common struct elements, so we can * avoid using switch(protocol) in a number of places. */ struct blkif_common_request { char dummy; }; struct blkif_common_response { char dummy; }; /* i386 protocol version */ #pragma pack(push, 4) struct blkif_x86_32_request_rw { blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; }; struct blkif_x86_32_request_discard { blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; }; struct blkif_x86_32_request { uint8_t operation; /* BLKIF_OP_??? */ uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint64_t id; /* private guest value, echoed in resp */ union { struct blkif_x86_32_request_rw rw; struct blkif_x86_32_request_discard discard; } u; }; struct blkif_x86_32_response { uint64_t id; /* copied from request */ uint8_t operation; /* copied from request */ int16_t status; /* BLKIF_RSP_??? */ }; #pragma pack(pop) /* x86_64 protocol version */ struct blkif_x86_64_request_rw { blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; }; struct blkif_x86_64_request_discard { blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ uint64_t nr_sectors; }; struct blkif_x86_64_request { uint8_t operation; /* BLKIF_OP_??? */ uint8_t nr_segments; /* number of segments */ blkif_vdev_t handle; /* only for read/write requests */ uint64_t __attribute__((__aligned__(8))) id; union { struct blkif_x86_64_request_rw rw; struct blkif_x86_64_request_discard discard; } u; }; struct blkif_x86_64_response { uint64_t __attribute__((__aligned__(8))) id; uint8_t operation; /* copied from request */ int16_t status; /* BLKIF_RSP_??? */ }; DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, struct blkif_common_response); DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, struct blkif_x86_32_response); DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, struct blkif_x86_64_response); union blkif_back_rings { struct blkif_back_ring native; struct blkif_common_back_ring common; struct blkif_x86_32_back_ring x86_32; struct blkif_x86_64_back_ring x86_64; }; enum blkif_protocol { BLKIF_PROTOCOL_NATIVE = 1, BLKIF_PROTOCOL_X86_32 = 2, BLKIF_PROTOCOL_X86_64 = 3, }; enum blkif_backend_type { BLKIF_BACKEND_PHY = 1, BLKIF_BACKEND_FILE = 2, }; struct xen_vbd { /* What the domain refers to this vbd as. */ blkif_vdev_t handle; /* Non-zero -> read-only */ unsigned char readonly; /* VDISK_xxx */ unsigned char type; /* phys device that this vbd maps to. */ u32 pdevice; struct block_device *bdev; /* Cached size parameter. */ sector_t size; bool flush_support; }; struct backend_info; struct xen_blkif { /* Unique identifier for this interface. */ domid_t domid; unsigned int handle; /* Physical parameters of the comms window. */ unsigned int irq; /* Comms information. */ enum blkif_protocol blk_protocol; enum blkif_backend_type blk_backend_type; union blkif_back_rings blk_rings; void *blk_ring; /* The VBD attached to this interface. */ struct xen_vbd vbd; /* Back pointer to the backend_info. */ struct backend_info *be; /* Private fields. */ spinlock_t blk_ring_lock; atomic_t refcnt; wait_queue_head_t wq; /* for barrier (drain) requests */ struct completion drain_complete; atomic_t drain; /* One thread per one blkif. */ struct task_struct *xenblkd; unsigned int waiting_reqs; /* statistics */ unsigned long st_print; int st_rd_req; int st_wr_req; int st_oo_req; int st_f_req; int st_ds_req; int st_rd_sect; int st_wr_sect; wait_queue_head_t waiting_to_free; }; #define vbd_sz(_v) ((_v)->bdev->bd_part ? \ (_v)->bdev->bd_part->nr_sects : \ get_capacity((_v)->bdev->bd_disk)) #define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) #define xen_blkif_put(_b) \ do { \ if (atomic_dec_and_test(&(_b)->refcnt)) \ wake_up(&(_b)->waiting_to_free);\ } while (0) struct phys_req { unsigned short dev; blkif_sector_t nr_sects; struct block_device *bdev; blkif_sector_t sector_number; }; int xen_blkif_interface_init(void); int xen_blkif_xenbus_init(void); irqreturn_t xen_blkif_be_int(int irq, void *dev_id); int xen_blkif_schedule(void *arg); int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, struct backend_info *be, int state); int xen_blkbk_barrier(struct xenbus_transaction xbt, struct backend_info *be, int state); struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be); static inline void blkif_get_x86_32_req(struct blkif_request *dst, struct blkif_x86_32_request *src) { int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST; dst->operation = src->operation; dst->nr_segments = src->nr_segments; dst->handle = src->handle; dst->id = src->id; switch (src->operation) { case BLKIF_OP_READ: case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: case BLKIF_OP_FLUSH_DISKCACHE: dst->u.rw.sector_number = src->u.rw.sector_number; barrier(); if (n > dst->nr_segments) n = dst->nr_segments; for (i = 0; i < n; i++) dst->u.rw.seg[i] = src->u.rw.seg[i]; break; case BLKIF_OP_DISCARD: dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break; default: break; } } static inline void blkif_get_x86_64_req(struct blkif_request *dst, struct blkif_x86_64_request *src) { int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST; dst->operation = src->operation; dst->nr_segments = src->nr_segments; dst->handle = src->handle; dst->id = src->id; switch (src->operation) { case BLKIF_OP_READ: case BLKIF_OP_WRITE: case BLKIF_OP_WRITE_BARRIER: case BLKIF_OP_FLUSH_DISKCACHE: dst->u.rw.sector_number = src->u.rw.sector_number; barrier(); if (n > dst->nr_segments) n = dst->nr_segments; for (i = 0; i < n; i++) dst->u.rw.seg[i] = src->u.rw.seg[i]; break; case BLKIF_OP_DISCARD: dst->u.discard.sector_number = src->u.discard.sector_number; dst->u.discard.nr_sectors = src->u.discard.nr_sectors; break; default: break; } } #endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */