Garbage collect comments which related to the pre-r284296 support for a

"segment block" extension in FreeBSD's Xen blkfront/blkback drivers.

Since this commit only affects comments, it should have no functional
effect.
This commit is contained in:
Colin Percival 2015-06-21 06:05:33 +00:00
parent 91fb36cfa8
commit c077dc26e7
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=284664

View File

@ -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 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
@ -269,33 +243,6 @@
* 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
@ -457,7 +404,9 @@
#define BLKIF_OP_DISCARD 5
/*
* Maximum scatter/gather segments per request (header + segment blocks).
* 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_REQUEST 11
@ -478,21 +427,6 @@ 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_??? */