[Zrouter-src-freebsd] ZRouter.org: push to FreeBSD HEAD tree
zrouter-src-freebsd at zrouter.org
zrouter-src-freebsd at zrouter.org
Fri Mar 2 15:39:41 UTC 2012
details: http://zrouter.org/hg/FreeBSD/head//rev/002c51375413
changeset: 393:002c51375413
user: ray at terran.dlink.ua
date: Fri Mar 02 17:15:10 2012 +0200
description:
Update to FreeBSD-HEAD @232391
diffstat:
head/sys/xen/interface/io/blkif.h | 500 +++++++++++++++++++++++++++++++++++--
head/sys/xen/interface/io/netif.h | 4 +
head/sys/xen/xenbus/xenbusvar.h | 16 +-
3 files changed, 486 insertions(+), 34 deletions(-)
diffs (628 lines):
diff -r 9b5d5e90f457 -r 002c51375413 head/sys/xen/interface/io/blkif.h
--- a/head/sys/xen/interface/io/blkif.h Fri Mar 02 17:14:40 2012 +0200
+++ b/head/sys/xen/interface/io/blkif.h Fri Mar 02 17:15:10 2012 +0200
@@ -1,8 +1,8 @@
/******************************************************************************
* blkif.h
- *
+ *
* Unified block-device I/O interface for Xen guest OSes.
- *
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
@@ -22,6 +22,7 @@
* DEALINGS IN THE SOFTWARE.
*
* Copyright (c) 2003-2004, Keir Fraser
+ * Copyright (c) 2012, Spectra Logic Corporation
*/
#ifndef __XEN_PUBLIC_IO_BLKIF_H__
@@ -35,7 +36,7 @@
* notification can be made conditional on req_event (i.e., the generic
* hold-off mechanism provided by the ring macros). Backends must set
* req_event appropriately (e.g., using RING_FINAL_CHECK_FOR_REQUESTS()).
- *
+ *
* Back->front notifications: When enqueuing a new response, sending a
* notification can be made conditional on rsp_event (i.e., the generic
* hold-off mechanism provided by the ring macros). Frontends must set
@@ -48,37 +49,417 @@
#define blkif_sector_t uint64_t
/*
+ * Feature and Parameter Negotiation
+ * =================================
+ * The two halves of a Xen block driver utilize nodes within the XenStore to
+ * communicate capabilities and to negotiate operating parameters. This
+ * section enumerates these nodes which reside in the respective front and
+ * backend portions of the XenStore, following the XenBus convention.
+ *
+ * All data in the XenStore is stored as strings. Nodes specifying numeric
+ * values are encoded in decimal. Integer value ranges listed below are
+ * expressed as fixed sized integer types capable of storing the conversion
+ * of a properly formatted node string, without loss of information.
+ *
+ * Any specified default value is in effect if the corresponding XenBus node
+ * is not present in the XenStore.
+ *
+ * XenStore nodes in sections marked "PRIVATE" are solely for use by the
+ * driver side whose XenBus tree contains them.
+ *
+ * XenStore nodes marked "DEPRECATED" in their notes section should only be
+ * used to provide interoperability with legacy implementations.
+ *
+ * See the XenBus state transition diagram below for details on when XenBus
+ * nodes must be published and when they can be queried.
+ *
+ *****************************************************************************
+ * Backend XenBus Nodes
+ *****************************************************************************
+ *
+ *------------------ Backend Device Identification (PRIVATE) ------------------
+ *
+ * mode
+ * Values: "r" (read only), "w" (writable)
+ *
+ * The read or write access permissions to the backing store to be
+ * granted to the frontend.
+ *
+ * params
+ * Values: string
+ *
+ * Data used by the backend driver to locate and configure the backing
+ * device. The format and semantics of this data vary according to the
+ * backing device in use and are outside the scope of this specification.
+ *
+ * type
+ * Values: "file", "phy", "tap"
+ *
+ * The type of the backing device/object.
+ *
+ *--------------------------------- Features ---------------------------------
+ *
+ * feature-barrier
+ * Values: 0/1 (boolean)
+ * Default Value: 0
+ *
+ * A value of "1" indicates that the backend can process requests
+ * containing the BLKIF_OP_WRITE_BARRIER request opcode. Requests
+ * of this type may still be returned at any time with the
+ * BLKIF_RSP_EOPNOTSUPP result code.
+ *
+ * feature-flush-cache
+ * Values: 0/1 (boolean)
+ * Default Value: 0
+ *
+ * A value of "1" indicates that the backend can process requests
+ * containing the BLKIF_OP_FLUSH_DISKCACHE request opcode. Requests
+ * of this type may still be returned at any time with the
+ * BLKIF_RSP_EOPNOTSUPP result code.
+ *
+ * feature-discard
+ * Values: 0/1 (boolean)
+ * Default Value: 0
+ *
+ * A value of "1" indicates that the backend can process requests
+ * containing the BLKIF_OP_DISCARD request opcode. Requests
+ * of this type may still be returned at any time with the
+ * BLKIF_RSP_EOPNOTSUPP result code.
+ *
+ *----------------------- Request Transport Parameters ------------------------
+ *
+ * max-ring-page-order
+ * Values: <uint32_t>
+ * Default Value: 0
+ * Notes: 1, 3
+ *
+ * The maximum supported size of the request ring buffer in units of
+ * lb(machine pages). (e.g. 0 == 1 page, 1 = 2 pages, 2 == 4 pages,
+ * etc.).
+ *
+ * max-ring-pages
+ * Values: <uint32_t>
+ * Default Value: 1
+ * Notes: DEPRECATED, 2, 3
+ *
+ * The maximum supported size of the request ring buffer in units of
+ * machine pages. The value must be a power of 2.
+ *
+ * max-requests <uint32_t>
+ * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
+ * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages)
+ *
+ * The maximum number of concurrent, logical requests supported by
+ * the backend.
+ *
+ * Note: A logical request may span multiple ring entries.
+ *
+ * max-request-segments
+ * Values: <uint8_t>
+ * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
+ * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST
+ *
+ * The maximum value of blkif_request.nr_segments supported by
+ * the backend.
+ *
+ * max-request-size
+ * Values: <uint32_t>
+ * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
+ * Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST * PAGE_SIZE
+ *
+ * The maximum amount of data, in bytes, that can be referenced by a
+ * request type that accesses frontend memory (currently BLKIF_OP_READ,
+ * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
+ *
+ *------------------------- Backend Device Properties -------------------------
+ *
+ * discard-alignment
+ * Values: <uint32_t>
+ * Default Value: 0
+ * Notes: 4, 5
+ *
+ * The offset, in bytes from the beginning of the virtual block device,
+ * to the first, addressable, discard extent on the underlying device.
+ *
+ * discard-granularity
+ * Values: <uint32_t>
+ * Default Value: <"sector-size">
+ * Notes: 4
+ *
+ * The size, in bytes, of the individually addressable discard extents
+ * of the underlying device.
+ *
+ * discard-secure
+ * Values: 0/1 (boolean)
+ * Default Value: 0
+ *
+ * A value of "1" indicates that the backend can process BLKIF_OP_DISCARD
+ * requests with the BLKIF_DISCARD_SECURE flag set.
+ *
+ * info
+ * Values: <uint32_t> (bitmap)
+ *
+ * A collection of bit flags describing attributes of the backing
+ * device. The VDISK_* macros define the meaning of each bit
+ * location.
+ *
+ * sector-size
+ * Values: <uint32_t>
+ *
+ * The size, in bytes, of the individually addressible data blocks
+ * on the backend device.
+ *
+ * sectors
+ * Values: <uint64_t>
+ *
+ * The size of the backend device, expressed in units of its native
+ * sector size ("sector-size").
+ *
+ *****************************************************************************
+ * Frontend XenBus Nodes
+ *****************************************************************************
+ *
+ *----------------------- Request Transport Parameters -----------------------
+ *
+ * event-channel
+ * Values: <uint32_t>
+ *
+ * The identifier of the Xen event channel used to signal activity
+ * in the ring buffer.
+ *
+ * ring-ref
+ * Values: <uint32_t>
+ * Notes: 6
+ *
+ * The Xen grant reference granting permission for the backend to map
+ * the sole page in a single page sized ring buffer.
+ *
+ * ring-ref%u
+ * Values: <uint32_t>
+ * Notes: 6
+ *
+ * For a frontend providing a multi-page ring, a "number of ring pages"
+ * sized list of nodes, each containing a Xen grant reference granting
+ * permission for the backend to map the page of the ring located
+ * at page index "%u". Page indexes are zero based.
+ *
+ * protocol
+ * Values: string (XEN_IO_PROTO_ABI_*)
+ * Default Value: XEN_IO_PROTO_ABI_NATIVE
+ *
+ * The machine ABI rules governing the format of all ring request and
+ * response structures.
+ *
+ * ring-page-order
+ * Values: <uint32_t>
+ * Default Value: 0
+ * Maximum Value: MAX(ffs(max-ring-pages) - 1, max-ring-page-order)
+ * Notes: 1, 3
+ *
+ * The size of the frontend allocated request ring buffer in units
+ * of lb(machine pages). (e.g. 0 == 1 page, 1 = 2 pages, 2 == 4 pages,
+ * etc.).
+ *
+ * num-ring-pages
+ * Values: <uint32_t>
+ * Default Value: 1
+ * Maximum Value: MAX(max-ring-pages,(0x1 << max-ring-page-order))
+ * Notes: DEPRECATED, 2, 3
+ *
+ * The size of the frontend allocated request ring buffer in units of
+ * machine pages. The value must be a power of 2.
+ *
+ * max-requests
+ * Values: <uint32_t>
+ * Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
+ * Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages)
+ *
+ * The maximum number of concurrent, logical requests that will be
+ * issued by the frontend.
+ *
+ * Note: A logical request may span multiple ring entries.
+ *
+ * max-request-segments
+ * Values: <uint8_t>
+ * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
+ * Maximum Value: MIN(255, backend/max-request-segments)
+ *
+ * The maximum value the frontend will set in the
+ * blkif_request.nr_segments field.
+ *
+ * max-request-size
+ * Values: <uint32_t>
+ * Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
+ * Maximum Value: max-request-segments * PAGE_SIZE
+ *
+ * The maximum amount of data, in bytes, that can be referenced by
+ * a request type that accesses frontend memory (currently BLKIF_OP_READ,
+ * BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
+ *
+ *------------------------- Virtual Device Properties -------------------------
+ *
+ * device-type
+ * Values: "disk", "cdrom", "floppy", etc.
+ *
+ * virtual-device
+ * Values: <uint32_t>
+ *
+ * A value indicating the physical device to virtualize within the
+ * frontend's domain. (e.g. "The first ATA disk", "The third SCSI
+ * disk", etc.)
+ *
+ * See docs/misc/vbd-interface.txt for details on the format of this
+ * value.
+ *
+ * Notes
+ * -----
+ * (1) Multi-page ring buffer scheme first developed in the Citrix XenServer
+ * PV drivers.
+ * (2) Multi-page ring buffer scheme first used in some Red Hat distributions
+ * including a distribution deployed on certain nodes of the Amazon
+ * EC2 cluster.
+ * (3) Support for multi-page ring buffers was implemented independently,
+ * in slightly different forms, by both Citrix and Red Hat/Amazon.
+ * For full interoperability, block front and backends should publish
+ * identical ring parameters, adjusted for unit differences, to the
+ * XenStore nodes used in both schemes.
+ * (4) Devices that support discard functionality may internally allocate
+ * space (discardable extents) in units that are larger than the
+ * exported logical block size.
+ * (5) The discard-alignment parameter allows a physical device to be
+ * partitioned into virtual devices that do not necessarily begin or
+ * end on a discardable extent boundary.
+ * (6) When there is only a single page allocated to the request ring,
+ * 'ring-ref' is used to communicate the grant reference for this
+ * page to the backend. When using a multi-page ring, the 'ring-ref'
+ * node is not created. Instead 'ring-ref0' - 'ring-refN' are used.
+ */
+
+/*
+ * STATE DIAGRAMS
+ *
+ *****************************************************************************
+ * Startup *
+ *****************************************************************************
+ *
+ * Tool stack creates front and back nodes with state XenbusStateInitialising.
+ *
+ * Front Back
+ * ================================= =====================================
+ * XenbusStateInitialising XenbusStateInitialising
+ * o Query virtual device o Query backend device identification
+ * properties. data.
+ * o Setup OS device instance. o Open and validate backend device.
+ * o Publish backend features and
+ * transport parameters.
+ * |
+ * |
+ * V
+ * XenbusStateInitWait
+ *
+ * o Query backend features and
+ * transport parameters.
+ * o Allocate and initialize the
+ * request ring.
+ * o Publish transport parameters
+ * that will be in effect during
+ * this connection.
+ * |
+ * |
+ * V
+ * XenbusStateInitialised
+ *
+ * o Query frontend transport parameters.
+ * o Connect to the request ring and
+ * event channel.
+ * o Publish backend device properties.
+ * |
+ * |
+ * V
+ * XenbusStateConnected
+ *
+ * o Query backend device properties.
+ * o Finalize OS virtual device
+ * instance.
+ * |
+ * |
+ * V
+ * XenbusStateConnected
+ *
+ * Note: Drivers that do not support any optional features, or the negotiation
+ * of transport parameters, can skip certain states in the state machine:
+ *
+ * o A frontend may transition to XenbusStateInitialised without
+ * waiting for the backend to enter XenbusStateInitWait. In this
+ * case, default transport parameters are in effect and any
+ * transport parameters published by the frontend must contain
+ * their default values.
+ *
+ * o A backend may transition to XenbusStateInitialised, bypassing
+ * XenbusStateInitWait, without waiting for the frontend to first
+ * enter the XenbusStateInitialised state. In this case, default
+ * transport parameters are in effect and any transport parameters
+ * published by the backend must contain their default values.
+ *
+ * Drivers that support optional features and/or transport parameter
+ * negotiation must tolerate these additional state transition paths.
+ * In general this means performing the work of any skipped state
+ * transition, if it has not already been performed, in addition to the
+ * work associated with entry into the current state.
+ */
+
+/*
* REQUEST CODES.
*/
#define BLKIF_OP_READ 0
#define BLKIF_OP_WRITE 1
/*
- * Recognised only if "feature-barrier" is present in backend xenbus info.
- * The "feature-barrier" node contains a boolean indicating whether barrier
- * requests are likely to succeed or fail. Either way, a barrier request
- * may fail at any time with BLKIF_RSP_EOPNOTSUPP if it is unsupported by
- * the underlying block-device hardware. The boolean simply indicates whether
- * or not it is worthwhile for the frontend to attempt barrier requests.
- * If a backend does not recognise BLKIF_OP_WRITE_BARRIER, it should *not*
- * create the "feature-barrier" node!
+ * All writes issued prior to a request with the BLKIF_OP_WRITE_BARRIER
+ * operation code ("barrier request") must be completed prior to the
+ * execution of the barrier request. All writes issued after the barrier
+ * request must not execute until after the completion of the barrier request.
+ *
+ * Optional. See "feature-barrier" XenBus node documentation above.
*/
#define BLKIF_OP_WRITE_BARRIER 2
/*
- * Recognised if "feature-flush-cache" is present in backend xenbus
- * info. A flush will ask the underlying storage hardware to flush its
- * non-volatile caches as appropriate. The "feature-flush-cache" node
- * contains a boolean indicating whether flush requests are likely to
- * succeed or fail. Either way, a flush request may fail at any time
- * with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying
- * block-device hardware. The boolean simply indicates whether or not it
- * is worthwhile for the frontend to attempt flushes. If a backend does
- * not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the
- * "feature-flush-cache" node!
+ * Commit any uncommitted contents of the backing device's volatile cache
+ * to stable storage.
+ *
+ * Optional. See "feature-flush-cache" XenBus node documentation above.
*/
#define BLKIF_OP_FLUSH_DISKCACHE 3
+/*
+ * Used in SLES sources for device specific command packet
+ * contained within the request. Reserved for that purpose.
+ */
+#define BLKIF_OP_RESERVED_1 4
+/*
+ * Indicate to the backend device that a region of storage is no longer in
+ * use, and may be discarded at any time without impact to the client. If
+ * the BLKIF_DISCARD_SECURE flag is set on the request, all copies of the
+ * discarded region on the device must be rendered unrecoverable before the
+ * command returns.
+ *
+ * This operation is analogous to performing a trim (ATA) or unmap (SCSI),
+ * command on a native device.
+ *
+ * More information about trim/unmap operations can be found at:
+ * http://t13.org/Documents/UploadedDocuments/docs2008/
+ * e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
+ * http://www.seagate.com/staticfiles/support/disc/manuals/
+ * Interface%20manuals/100293068c.pdf
+ *
+ * Optional. See "feature-discard", "discard-alignment",
+ * "discard-granularity", and "discard-secure" in the XenBus node
+ * documentation above.
+ */
+#define BLKIF_OP_DISCARD 5
/*
* Maximum scatter/gather segments associated with a request header block.
+ * This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE.
+ * NB. This could be 12 if the ring indexes weren't stored in the same page.
*/
#define BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK 11
@@ -92,6 +473,13 @@
*/
#define BLKIF_MAX_SEGMENTS_PER_REQUEST 255
+/*
+ * NB. first_sect and last_sect in blkif_request_segment, as well as
+ * sector_number in blkif_request, are always expressed in 512-byte units.
+ * However they must be properly aligned to the real sector size of the
+ * physical disk, which is reported in the "sector-size" node in the backend
+ * xenbus info. Also the xenbus "sectors" node is expressed in 512-byte units.
+ */
struct blkif_request_segment {
grant_ref_t gref; /* reference to I/O buffer frame */
/* @first_sect: first sector in frame to transfer (inclusive). */
@@ -100,16 +488,60 @@
};
typedef struct blkif_request_segment blkif_request_segment_t;
+/*
+ * Starting ring element for any I/O request.
+ *
+ * One or more segment blocks can be inserted into the request ring
+ * just after a blkif_request_t, allowing requests to operate on
+ * up to BLKIF_MAX_SEGMENTS_PER_REQUEST.
+ *
+ * BLKIF_SEGS_TO_BLOCKS() can be used on blkif_requst.nr_segments
+ * to determine the number of contiguous ring entries associated
+ * with this request.
+ *
+ * Note: Due to the way Xen request rings operate, the producer and
+ * consumer indices of the ring must be incremented by the
+ * BLKIF_SEGS_TO_BLOCKS() value of the associated request.
+ * (e.g. a response to a 3 ring entry request must also consume
+ * 3 entries in the ring, even though only the first ring entry
+ * in the response has any data.)
+ */
struct blkif_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 */
blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
- struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
+ blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
};
typedef struct blkif_request blkif_request_t;
+/*
+ * A segment block is a ring request structure that contains only
+ * segment data.
+ *
+ * sizeof(struct blkif_segment_block) <= sizeof(struct blkif_request)
+ */
+struct blkif_segment_block {
+ blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK];
+};
+typedef struct blkif_segment_block blkif_segment_block_t;
+
+/*
+ * Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD
+ * sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request)
+ */
+struct blkif_request_discard {
+ uint8_t operation; /* BLKIF_OP_DISCARD */
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
+#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
+ blkif_vdev_t handle; /* same as for read/write requests */
+ uint64_t id; /* private guest value, echoed in resp */
+ blkif_sector_t sector_number;/* start sector idx on disk */
+ uint64_t nr_sectors; /* number of contiguous sectors to discard*/
+};
+typedef struct blkif_request_discard blkif_request_discard_t;
+
struct blkif_response {
uint64_t id; /* copied from request */
uint8_t operation; /* copied from request */
@@ -130,24 +562,26 @@
/*
* Generate blkif ring structures and types.
*/
-
DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
-#define BLKRING_GET_SG_REQUEST(_r, _idx) \
- ((struct blkif_request_segment *)RING_GET_REQUEST(_r, _idx))
-
-#define VDISK_CDROM 0x1
-#define VDISK_REMOVABLE 0x2
-#define VDISK_READONLY 0x4
+/*
+ * Index to, and treat as a segment block, an entry in the ring.
+ */
+#define BLKRING_GET_SEG_BLOCK(_r, _idx) \
+ (((blkif_segment_block_t *)RING_GET_REQUEST(_r, _idx))->seg)
/*
* The number of ring request blocks required to handle an I/O
* request containing _segs segments.
*/
-#define BLKIF_SEGS_TO_BLOCKS(_segs) \
- ((((_segs - BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK) \
- + (BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK - 1)) \
- / BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK) + /*header_block*/1)
+#define BLKIF_SEGS_TO_BLOCKS(_segs) \
+ ((((_segs - BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK) \
+ + (BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK - 1)) \
+ / BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK) + /*header_block*/1)
+
+#define VDISK_CDROM 0x1
+#define VDISK_REMOVABLE 0x2
+#define VDISK_READONLY 0x4
#endif /* __XEN_PUBLIC_IO_BLKIF_H__ */
diff -r 9b5d5e90f457 -r 002c51375413 head/sys/xen/interface/io/netif.h
--- a/head/sys/xen/interface/io/netif.h Fri Mar 02 17:14:40 2012 +0200
+++ b/head/sys/xen/interface/io/netif.h Fri Mar 02 17:15:10 2012 +0200
@@ -173,6 +173,10 @@
#define _NETRXF_extra_info (3)
#define NETRXF_extra_info (1U<<_NETRXF_extra_info)
+/* GSO Prefix descriptor. */
+#define _NETRXF_gso_prefix (4)
+#define NETRXF_gso_prefix (1U<<_NETRXF_gso_prefix)
+
struct netif_rx_response {
uint16_t id;
uint16_t offset; /* Offset in page of start of received packet */
diff -r 9b5d5e90f457 -r 002c51375413 head/sys/xen/xenbus/xenbusvar.h
--- a/head/sys/xen/xenbus/xenbusvar.h Fri Mar 02 17:14:40 2012 +0200
+++ b/head/sys/xen/xenbus/xenbusvar.h Fri Mar 02 17:15:10 2012 +0200
@@ -23,7 +23,7 @@
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*
- * $FreeBSD: head/sys/xen/xenbus/xenbusvar.h 222975 2011-06-11 04:59:01Z gibbs $
+ * $FreeBSD: head/sys/xen/xenbus/xenbusvar.h 231743 2012-02-15 06:45:49Z gibbs $
*/
/**
@@ -104,6 +104,20 @@
XenbusState xenbus_read_driver_state(const char *path);
/**
+ * Return the state of the "other end" (peer) of a XenBus device.
+ *
+ * \param dev The XenBus device whose peer to query.
+ *
+ * \return The current state of the peer device or XenbusStateClosed if no
+ * state can be read.
+ */
+static inline XenbusState
+xenbus_get_otherend_state(device_t dev)
+{
+ return (xenbus_read_driver_state(xenbus_get_otherend_path(dev)));
+}
+
+/**
* Initialize and register a watch on the given path (client suplied storage).
*
* \param dev The XenBus device requesting the watch service.
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