Re: [win-pv-devel] [PATCH 1/3] Prepare SCSIOP_UNMAP correctly

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Owen Smith [mailto:owen.smith@xxxxxxxxxx]
> Sent: 28 October 2014 11:27
> To: win-pv-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: Paul Durrant; Owen Smith
> Subject: [PATCH 1/3] Prepare SCSIOP_UNMAP correctly
> 
> SCSIOP_UNMAP requests contain a list of extents to discard
> and each BLKIF_OP_DISCARD only handles a single extent.
> Break a SRB doen into multiple ring requests as neccessary.
> 
> Signed-off-by: Owen Smith <owen.smith@xxxxxxxxxx>

Acked-by: Paul Durrant <paul.durrant@xxxxxxxxxx>

> ---
>  src/xenvbd/pdo.c | 69
> ++++++++++++++++++++++++++++++++++++++++++++------------
>  1 file changed, 54 insertions(+), 15 deletions(-)
> 
> diff --git a/src/xenvbd/pdo.c b/src/xenvbd/pdo.c
> index 9762944..3f18621 100644
> --- a/src/xenvbd/pdo.c
> +++ b/src/xenvbd/pdo.c
> @@ -1452,26 +1452,65 @@ PrepareUnmap(
>      __in PSCSI_REQUEST_BLOCK     Srb
>      )
>  {
> -    PXENVBD_SRBEXT  SrbExt = GetSrbExt(Srb);
> -    PXENVBD_REQUEST Request = __LookasideAlloc(&Pdo->RequestList);
> -    if (Request == NULL)
> -        return STATUS_UNSUCCESSFUL;
> +    PXENVBD_SRBEXT      SrbExt = GetSrbExt(Srb);
> +    PUNMAP_LIST_HEADER  Unmap = Srb->DataBuffer;
> +    ULONG               Count = _byteswap_ushort(*(PUSHORT)Unmap-
> >DataLength) /
> +                                _byteswap_ushort(*(PUSHORT)Unmap-
> >BlockDescrDataLength);
> +    ULONG               Index;
> +    LIST_ENTRY          List;
> 
> -    SrbExt->Count = 1;
> -    // mark the SRB as pending, completion will check for pending to detect
> failures
> +    InitializeListHead(&List);
> +    SrbExt->Count = 0;
>      Srb->SrbStatus = SRB_STATUS_PENDING;
> 
> -    Request->Srb        = Srb;
> -    Request->Id         = PdoGetTag(Pdo);
> -    Request->Operation  = BLKIF_OP_DISCARD;
> -    Request->FirstSector = Cdb_LogicalBlock(Srb);
> -    Request->NrSectors   = Cdb_TransferBlock(Srb);
> -    Request->Flags       = 0;
> -    InitializeListHead(&Request->Segments);
> +    for (Index = 0; Index < Count; ++Index) {
> +        PUNMAP_BLOCK_DESCRIPTOR Descr = &Unmap->Descriptors[Index];
> +        PXENVBD_REQUEST         Request = __LookasideAlloc(&Pdo-
> >RequestList);
> +        if (Request == NULL)
> +            goto fail1;
> +
> +        ++SrbExt->Count;
> +        InsertTailList(&List, &Request->Entry);
> +
> +        Request->Srb            = Srb;
> +        Request->Id             = PdoGetTag(Pdo);
> +        Request->Operation      = BLKIF_OP_DISCARD;
> +        Request->FirstSector    = _byteswap_uint64(*(PULONG64)Descr-
> >StartingLba);
> +        Request->NrSectors      = _byteswap_ulong(*(PULONG)Descr-
> >LbaCount);
> +        Request->Flags          = 0;
> +        InitializeListHead(&Request->Segments);
> +    }
> +
> +    for (;;) {
> +        PXENVBD_REQUEST Request;
> +        PLIST_ENTRY     Entry;
> +
> +        Entry = RemoveHeadList(&List);
> +        if (Entry == &List)
> +            break;
> +
> +        Request = CONTAINING_RECORD(Entry, XENVBD_REQUEST, Entry);
> +        __PdoIncBlkifOpCount(Pdo, Request);
> +        QueueAppend(&Pdo->PreparedReqs, &Request->Entry);
> +    }
> 
> -    __PdoIncBlkifOpCount(Pdo, Request);
> -    QueueAppend(&Pdo->PreparedReqs, &Request->Entry);
>      return STATUS_SUCCESS;
> +
> +
> +fail1:
> +    for (;;) {
> +        PXENVBD_REQUEST Request;
> +        PLIST_ENTRY     Entry;
> +
> +        Entry = RemoveHeadList(&List);
> +        if (Entry == &List)
> +            break;
> +
> +        Request = CONTAINING_RECORD(Entry, XENVBD_REQUEST, Entry);
> +        __LookasideFree(&Pdo->RequestList, Request);
> +        --SrbExt->Count;
> +    }
> +    return STATUS_NO_MEMORY;
>  }
> 
> 
> //=========================================================
> ====================
> --
> 1.9.4.msysgit.1


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