*
* 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
+ * 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.
+ *
* Copyright (c) 2003-2004, Keir Fraser
*/
* rsp_event appropriately (e.g., using RING_FINAL_CHECK_FOR_RESPONSES()).
*/
-typedef uint16_t blkif_vdev_t;
-typedef uint64_t blkif_sector_t;
+#ifndef blkif_vdev_t
+#define blkif_vdev_t uint16_t
+#endif
+#define blkif_sector_t uint64_t
/*
* REQUEST CODES.
#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
+ * 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
* create the "feature-barrier" node!
*/
#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
* "feature-flush-cache" node!
*/
#define BLKIF_OP_FLUSH_DISKCACHE 3
-
+/*
+ * Device specific command packet contained within the request
+ */
+#define BLKIF_OP_PACKET 4
/*
* Recognised only if "feature-discard" is present in backend xenbus info.
* The "feature-discard" node contains a boolean indicating whether trim
* e07154r6-Data_Set_Management_Proposal_for_ATA-ACS2.doc
* http://www.seagate.com/staticfiles/support/disc/manuals/
* Interface%20manuals/100293068c.pdf
- * The backend can optionally provide three extra XenBus attributes to
+ * The backend can optionally provide these extra XenBus attributes to
* further optimize the discard functionality:
* 'discard-aligment' - Devices that support discard functionality may
* internally allocate space in units that are bigger than the exported
* logical block size. The discard-alignment parameter indicates how many bytes
* the beginning of the partition is offset from the internal allocation unit's
- * natural alignment.
+ * natural alignment. Do not confuse this with natural disk alignment offset.
* 'discard-granularity' - Devices that support discard functionality may
* internally allocate space using units that are bigger than the logical block
* size. The discard-granularity parameter indicates the size of the internal
* allocation unit in bytes if reported by the device. Otherwise the
* discard-granularity will be set to match the device's physical block size.
+ * It is the minimum size you can discard.
* 'discard-secure' - All copies of the discarded sectors (potentially created
* by garbage collection) must also be erased. To use this feature, the flag
- * BLKIF_DISCARD_SECURE must be set in the blkif_request_trim.
+ * BLKIF_DISCARD_SECURE must be set in the blkif_request_discard.
*/
#define BLKIF_OP_DISCARD 5
*/
#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
-struct blkif_request_rw {
- uint8_t nr_segments; /* number of segments */
- blkif_vdev_t handle; /* only for read/write requests */
+/*
+ * 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). */
+ /* @last_sect: last sector in frame to transfer (inclusive). */
+ uint8_t first_sect, last_sect;
+};
+
+struct blkif_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+#if !defined(CONFIG_PARAVIRT_XEN) || defined(HAVE_XEN_PLATFORM_COMPAT_H)
+ 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_REQUEST];
+};
+#else
+ union {
+ struct __attribute__((__packed__)) blkif_request_rw {
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
#ifdef CONFIG_X86_64
- uint32_t _pad1; /* offsetof(blkif_request,u.rw.id) == 8 */
+ uint32_t _pad1; /* offsetof(blkif_request,u.rw.id) == 8 */
#endif
- 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 {
- grant_ref_t gref; /* reference to I/O buffer frame */
- /* @first_sect: first sector in frame to transfer (inclusive). */
- /* @last_sect: last sector in frame to transfer (inclusive). */
- uint8_t first_sect, last_sect;
- } seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
-} __attribute__((__packed__));
-
-struct blkif_request_discard {
- uint8_t flag; /* BLKIF_DISCARD_SECURE or zero. */
-#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
- blkif_vdev_t _pad1; /* 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_REQUEST];
+ } rw;
+ struct __attribute__((__packed__)) blkif_request_discard {
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero. */
+#define BLKIF_DISCARD_SECURE (1<<0) /* ignored if discard-secure=0 */
+ blkif_vdev_t _pad1; /* only for read/write requests */
#ifdef CONFIG_X86_64
- uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/
+ uint32_t _pad2; /* offsetof(blkif_req..,u.discard.id)==8*/
#endif
- uint64_t id; /* private guest value, echoed in resp */
- blkif_sector_t sector_number;
- uint64_t nr_sectors;
- uint8_t _pad3;
+ uint64_t id; /* private guest value, echoed in resp */
+ blkif_sector_t sector_number;
+ uint64_t nr_sectors;
+ uint8_t _pad3;
+ } discard;
+ } u;
} __attribute__((__packed__));
+#endif
+typedef struct blkif_request blkif_request_t;
-struct blkif_request {
- uint8_t operation; /* BLKIF_OP_??? */
- union {
- struct blkif_request_rw rw;
- struct blkif_request_discard discard;
- } u;
-} __attribute__((__packed__));
+#if !defined(CONFIG_PARAVIRT_XEN) || defined(HAVE_XEN_PLATFORM_COMPAT_H)
+/*
+ * Cast to this structure when blkif_request.operation == BLKIF_OP_TRIM
+ * 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;
+#endif
struct blkif_response {
- uint64_t id; /* copied from request */
- uint8_t operation; /* copied from request */
- int16_t status; /* BLKIF_RSP_??? */
+ uint64_t id; /* copied from request */
+ uint8_t operation; /* copied from request */
+ int16_t status; /* BLKIF_RSP_??? */
};
+typedef struct blkif_response blkif_response_t;
/*
* STATUS RETURN CODES.
projects / linux-flexiantxendom0-3.2.10.git / blobdiff