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Revert 24875:a59c1dcfe968 "blkif.h: Define and document the request number/size/segments extension"
Breaks the build. Signed-off-by: Keir Fraser <keir@xen.org>
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@@ -145,32 +145,6 @@
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* The maximum supported size of the request ring buffer in units of
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* machine pages. The value must be a power of 2.
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*
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* max-requests <uint32_t>
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* Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
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* Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages)
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*
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* The maximum number of concurrent, logical requests that will be
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* issued by the backend.
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*
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* Note: A logical request may span multiple ring entries.
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*
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* max-request-segments
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* Values: <uint8_t>
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* Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
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* Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST
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*
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* The maximum value of blkif_request.nr_segments supported by
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* the backend.
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*
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* max-request-size
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* Values: <uint32_t>
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* Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
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* Maximum Value: BLKIF_MAX_SEGMENTS_PER_REQUEST * PAGE_SIZE
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*
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* The maximum amount of data, in bytes, that can be referenced by a
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* request type that accesses frontend memory (currently BLKIF_OP_READ,
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* BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
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*
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*------------------------- Backend Device Properties -------------------------
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*
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* discard-aligment
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@@ -268,33 +242,6 @@
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* The size of the frontend allocated request ring buffer in units of
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* machine pages. The value must be a power of 2.
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*
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* max-requests
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* Values: <uint32_t>
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* Default Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE)
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* Maximum Value: BLKIF_MAX_RING_REQUESTS(PAGE_SIZE * max-ring-pages)
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*
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* The maximum number of concurrent, logical requests that will be
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* issued by the frontend.
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*
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* Note: A logical request may span multiple ring entries.
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*
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* max-request-segments
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* Values: <uint8_t>
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* Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
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* Maximum Value: MIN(255, backend/max-request-segments)
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*
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* The maximum value the frontend will set in the
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* blkif_request.nr_segments field.
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*
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* max-request-size
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* Values: <uint32_t>
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* Default Value: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK * PAGE_SIZE
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* Maximum Value: max-request-segments * PAGE_SIZE
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*
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* The maximum amount of data, in bytes, that can be referenced by
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* a request type that accesses frontend memory (currently BLKIF_OP_READ,
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* BLKIF_OP_WRITE, or BLKIF_OP_WRITE_BARRIER).
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*
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*------------------------- Virtual Device Properties -------------------------
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*
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* device-type
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@@ -456,28 +403,11 @@
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#define BLKIF_OP_DISCARD 5
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/*
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* Maximum scatter/gather segments associated with a request header block.
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* Maximum scatter/gather segments per request.
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* This is carefully chosen so that sizeof(blkif_ring_t) <= PAGE_SIZE.
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* NB. This could be 12 if the ring indexes weren't stored in the same page.
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*/
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#define BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK 11
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/*
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* Maximum scatter/gather segments associated with a segment block.
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*/
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#define BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK 14
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#if __XEN_INTERFACE_VERSION__ >= 0x00040201
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/*
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* Maximum scatter/gather segments per request (header + segment blocks).
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*/
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#define BLKIF_MAX_SEGMENTS_PER_REQUEST 255
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#else
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/*
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* Maximum scatter/gather segments per request (header block only).
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*/
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#define BLKIF_MAX_SEGMENTS_PER_REQUEST BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
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#endif
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#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
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/*
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* NB. first_sect and last_sect in blkif_request_segment, as well as
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@@ -492,25 +422,9 @@ struct blkif_request_segment {
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/* @last_sect: last sector in frame to transfer (inclusive). */
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uint8_t first_sect, last_sect;
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};
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typedef struct blkif_request_segment blkif_request_segment_t;
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/*
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* Starting ring element for any I/O request.
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*
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* One or more segment blocks can be inserted into the request ring
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* just after a blkif_request_t, allowing requests to operate on
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* up to BLKIF_MAX_SEGMENTS_PER_REQUEST.
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*
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* BLKIF_SEGS_TO_BLOCKS() can be used on blkif_requst.nr_segments
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* to determine the number of contiguous ring entries associated
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* with this request.
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*
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* Note: Due to the way Xen request rings operate, the producer and
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* consumer indices of the ring must be incremented by the
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* BLKIF_SEGS_TO_BLOCKS() value of the associated request.
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* (e.g. a response to a 3 ring entry request must also consume
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* 3 entries in the ring, even though only the first ring entry
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* in the response has any data.)
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*/
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struct blkif_request {
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uint8_t operation; /* BLKIF_OP_??? */
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@@ -518,21 +432,10 @@ struct blkif_request {
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blkif_vdev_t handle; /* only for read/write requests */
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uint64_t id; /* private guest value, echoed in resp */
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blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
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blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
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struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
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};
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typedef struct blkif_request blkif_request_t;
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/*
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* A segment block is a ring request structure that contains only
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* segment data.
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*
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* sizeof(struct blkif_segment_block) <= sizeof(struct blkif_request)
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*/
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struct blkif_segment_block {
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blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK];
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};
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typedef struct blkif_segment_block blkif_segment_block_t;
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/*
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* Cast to this structure when blkif_request.operation == BLKIF_OP_DISCARD
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* sizeof(struct blkif_request_discard) <= sizeof(struct blkif_request)
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@@ -570,21 +473,6 @@ typedef struct blkif_response blkif_response_t;
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*/
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DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
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/*
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* Index to, and treat as a segment block, an entry in the ring.
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*/
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#define BLKRING_GET_SEG_BLOCK(_r, _idx) \
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(((blkif_segment_block_t *)RING_GET_REQUEST(_r, _idx))->seg)
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/*
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* The number of ring request blocks required to handle an I/O
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* request containing _segs segments.
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*/
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#define BLKIF_SEGS_TO_BLOCKS(_segs) \
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((((_segs - BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK) \
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+ (BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK - 1)) \
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/ BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK) + /*header_block*/1)
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#define VDISK_CDROM 0x1
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#define VDISK_REMOVABLE 0x2
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#define VDISK_READONLY 0x4
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@@ -27,7 +27,7 @@
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#ifndef __XEN_PUBLIC_XEN_COMPAT_H__
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#define __XEN_PUBLIC_XEN_COMPAT_H__
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#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040201
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#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040200
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#if defined(__XEN__) || defined(__XEN_TOOLS__)
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/* Xen is built with matching headers and implements the latest interface. */
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