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>

2 files changed, 4 insertions, 116 deletions

diff --git a/xen/include/public/io/blkif.h b/xen/include/public/io/blkif.h
index 4f1fc86699..d71c7f1699 100644
--- a/xen/include/public/io/blkif.h
+++ b/xen/include/public/io/blkif.h
@@ -145,32 +145,6 @@
  *      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 that will be
- *      issued 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-aligment
@@ -268,33 +242,6 @@
  *      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
@@ -456,28 +403,11 @@
 #define BLKIF_OP_DISCARD           5
 
 /*
- * Maximum scatter/gather segments associated with a request header block.
+ * Maximum scatter/gather segments per request.
  * 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
-
-/*
- * Maximum scatter/gather segments associated with a segment block.
- */
-#define BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK 14
-
-#if __XEN_INTERFACE_VERSION__ >= 0x00040201
-/*
- * Maximum scatter/gather segments per request (header + segment blocks).
- */
-#define BLKIF_MAX_SEGMENTS_PER_REQUEST 255
-#else
-/*
- * Maximum scatter/gather segments per request (header block only).
- */
-#define BLKIF_MAX_SEGMENTS_PER_REQUEST BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK
-#endif
+#define BLKIF_MAX_SEGMENTS_PER_REQUEST 11
 
 /*
  * NB. first_sect and last_sect in blkif_request_segment, as well as
@@ -492,25 +422,9 @@ struct blkif_request_segment {
     /* @last_sect: last sector in frame to transfer (inclusive).     */
     uint8_t     first_sect, last_sect;
 };
-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_???                         */
@@ -518,22 +432,11 @@ struct blkif_request {
     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)  */
-    blkif_request_segment_t seg[BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK];
+    struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
 };
 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)
  */
@@ -570,21 +473,6 @@ typedef struct blkif_response blkif_response_t;
  */
 DEFINE_RING_TYPES(blkif, struct blkif_request, struct blkif_response);
 
-/*
- * 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 VDISK_CDROM        0x1
 #define VDISK_REMOVABLE    0x2
 #define VDISK_READONLY     0x4
diff --git a/xen/include/public/xen-compat.h b/xen/include/public/xen-compat.h
index d982e5ebd8..d8c55bfc8f 100644
--- a/xen/include/public/xen-compat.h
+++ b/xen/include/public/xen-compat.h
@@ -27,7 +27,7 @@
 #ifndef __XEN_PUBLIC_XEN_COMPAT_H__
 #define __XEN_PUBLIC_XEN_COMPAT_H__
 
-#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040201
+#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040200
 
 #if defined(__XEN__) || defined(__XEN_TOOLS__)
 /* Xen is built with matching headers and implements the latest interface. */