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scsi: storvsc: Support PAGE_SIZE larger than 4K

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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>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20200916034817.30282-12-boqun.feng@gmail.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Boqun Feng 2020-09-16 11:48:17 +08:00 committed by Wei Liu
parent 061dc93ef6
commit 8f43710543
1 changed files with 49 additions and 7 deletions
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56
drivers/scsi/storvsc_drv.c
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@ -1739,23 +1739,65 @@ 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) {
unsigned int hvpgoff = 0;
unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK;
unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
u64 hvpfn;
payload_sz = (sg_count * sizeof(u64) +
if (hvpg_count > MAX_PAGE_BUFFER_COUNT) {
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.
* Besides, payload->range.offset should be the offset in one
* HV_HYP_PAGE.
*/
payload->range.len = length;
payload->range.offset = sgl[0].offset;
payload->range.offset = offset_in_hvpg;
hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT;
cur_sgl = sgl;
for (i = 0; i < sg_count; i++) {
payload->range.pfn_array[i] =
page_to_pfn(sg_page((cur_sgl)));
cur_sgl = sg_next(cur_sgl);
for (i = 0; i < hvpg_count; i++) {
/*
* 'i' is the index of hv pages in the payload and
* 'hvpgoff' is the offset (in hv pages) of the first
* hv page in the the first page. The relationship
* between the sum of 'i' and 'hvpgoff' and the offset
* (in hv pages) in a payload page ('hvpgoff_in_page')
* is as follow:
*
* |------------------ PAGE -------------------|
* | NR_HV_HYP_PAGES_IN_PAGE hvpgs in total |
* |hvpg|hvpg| ... |hvpg|... |hvpg|
* ^ ^ ^ ^
* +-hvpgoff-+ +-hvpgoff_in_page-+
* ^ |
* +--------------------- i ---------------------------+
*/
unsigned int hvpgoff_in_page =
(i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE;
/*
* Two cases that we need to fetch a page:
* 1) i == 0, the first step or
* 2) hvpgoff_in_page == 0, when we reach the boundary
* of a page.
*/
if (hvpgoff_in_page == 0 || i == 0) {
hvpfn = page_to_hvpfn(sg_page(cur_sgl));
cur_sgl = sg_next(cur_sgl);
}
payload->range.pfn_array[i] = hvpfn + hvpgoff_in_page;
}
}