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    Subject[RFC 11/11] scsi: storvsc: Support PAGE_SIZE larger than 4K
    Date
    Hyper-V always use 4k page size (HV_HYP_PAGE_SIZE), so when
    communicating with Hyper-V, a guest should always use HV_HYP_PAGE_SIZE
    as the unit for page related data. For storvsc, the data is
    vmbus_packet_mpb_array. And since in scsi_cmnd, sglist of pages (in unit
    of PAGE_SIZE) is used, we need convert pages in the sglist of scsi_cmnd
    into Hyper-V pages in vmbus_packet_mpb_array.

    This patch does the conversion by dividing pages in sglist into Hyper-V
    pages, offset and indexes in vmbus_packet_mpb_array are recalculated
    accordingly.

    Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
    ---
    drivers/scsi/storvsc_drv.c | 27 +++++++++++++++++++++------
    1 file changed, 21 insertions(+), 6 deletions(-)

    diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
    index fb41636519ee..c54d25f279bc 100644
    --- a/drivers/scsi/storvsc_drv.c
    +++ b/drivers/scsi/storvsc_drv.c
    @@ -1561,7 +1561,7 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
    struct hv_host_device *host_dev = shost_priv(host);
    struct hv_device *dev = host_dev->dev;
    struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
    - int i;
    + int i, j, k;
    struct scatterlist *sgl;
    unsigned int sg_count = 0;
    struct vmscsi_request *vm_srb;
    @@ -1569,6 +1569,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
    struct vmbus_packet_mpb_array *payload;
    u32 payload_sz;
    u32 length;
    + int subpage_idx = 0;
    + unsigned int hvpg_count = 0;

    if (vmstor_proto_version <= VMSTOR_PROTO_VERSION_WIN8) {
    /*
    @@ -1643,23 +1645,36 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
    payload_sz = sizeof(cmd_request->mpb);

    if (sg_count) {
    - if (sg_count > MAX_PAGE_BUFFER_COUNT) {
    + hvpg_count = sg_count * (PAGE_SIZE / HV_HYP_PAGE_SIZE);
    + if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {

    - payload_sz = (sg_count * sizeof(u64) +
    + payload_sz = (hvpg_count * sizeof(u64) +
    sizeof(struct vmbus_packet_mpb_array));
    payload = kzalloc(payload_sz, GFP_ATOMIC);
    if (!payload)
    return SCSI_MLQUEUE_DEVICE_BUSY;
    }

    + /*
    + * sgl is a list of PAGEs, and payload->range.pfn_array
    + * expects the page number in the unit of HV_HYP_PAGE_SIZE (the
    + * page size that Hyper-V uses, so here we need to divide PAGEs
    + * into HV_HYP_PAGE in case that PAGE_SIZE > HV_HYP_PAGE_SIZE.
    + */
    payload->range.len = length;
    - payload->range.offset = sgl[0].offset;
    + payload->range.offset = sgl[0].offset & ~HV_HYP_PAGE_MASK;
    + subpage_idx = sgl[0].offset >> HV_HYP_PAGE_SHIFT;

    cur_sgl = sgl;
    + k = 0;
    for (i = 0; i < sg_count; i++) {
    - payload->range.pfn_array[i] =
    - page_to_pfn(sg_page((cur_sgl)));
    + for (j = subpage_idx; j < (PAGE_SIZE / HV_HYP_PAGE_SIZE); j++) {
    + payload->range.pfn_array[k] =
    + page_to_hvpfn(sg_page((cur_sgl))) + j;
    + k++;
    + }
    cur_sgl = sg_next(cur_sgl);
    + subpage_idx = 0;
    }
    }

    --
    2.27.0
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