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authorMichael Kelley <mikelley@microsoft.com>2021-02-24 01:44:54 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2021-03-17 07:04:40 +0300
commit3d9c3dcc58e968403f29767726407bc680e087b5 (patch)
tree5fb4eeaecd3eeb00281c0037eb07bfbbcef805ec /drivers/scsi/storvsc_drv.c
parent471ee95ccca9c417344453f73a39681cfde39af1 (diff)
downloadlinux-3d9c3dcc58e968403f29767726407bc680e087b5.tar.xz
scsi: storvsc: Enable scatterlist entry lengths > 4Kbytes
storvsc currently sets .dma_boundary to limit scatterlist entries to 4 Kbytes, which is less efficient with huge pages that offer large chunks of contiguous physical memory. Improve the algorithm for creating the Hyper-V guest physical address PFN array so that scatterlist entries with lengths > 4Kbytes are handled. As a result, remove the .dma_boundary setting. The improved algorithm also adds support for scatterlist entries with offsets >= 4Kbytes, which is supported by many other SCSI low-level drivers. And it retains support for architectures where possibly PAGE_SIZE != HV_HYP_PAGE_SIZE (such as ARM64). Link: https://lore.kernel.org/r/1614120294-1930-1-git-send-email-mikelley@microsoft.com Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/storvsc_drv.c')
-rw-r--r--drivers/scsi/storvsc_drv.c66
1 files changed, 23 insertions, 43 deletions
diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index dfe005c03734..e6718a74e5da 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -1692,9 +1692,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
struct storvsc_cmd_request *cmd_request = scsi_cmd_priv(scmnd);
int i;
struct scatterlist *sgl;
- unsigned int sg_count = 0;
+ unsigned int sg_count;
struct vmscsi_request *vm_srb;
- struct scatterlist *cur_sgl;
struct vmbus_packet_mpb_array *payload;
u32 payload_sz;
u32 length;
@@ -1773,8 +1772,8 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
payload_sz = sizeof(cmd_request->mpb);
if (sg_count) {
- unsigned int hvpgoff = 0;
- unsigned long offset_in_hvpg = sgl->offset & ~HV_HYP_PAGE_MASK;
+ unsigned int hvpgoff, hvpfns_to_add;
+ unsigned long offset_in_hvpg = offset_in_hvpage(sgl->offset);
unsigned int hvpg_count = HVPFN_UP(offset_in_hvpg + length);
u64 hvpfn;
@@ -1787,51 +1786,34 @@ static int storvsc_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scmnd)
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 = offset_in_hvpg;
- hvpgoff = sgl->offset >> HV_HYP_PAGE_SHIFT;
- cur_sgl = sgl;
- for (i = 0; i < hvpg_count; i++) {
+
+ for (i = 0; sgl != NULL; sgl = sg_next(sgl)) {
/*
- * '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 ---------------------------+
+ * Init values for the current sgl entry. hvpgoff
+ * and hvpfns_to_add are in units of Hyper-V size
+ * pages. Handling the PAGE_SIZE != HV_HYP_PAGE_SIZE
+ * case also handles values of sgl->offset that are
+ * larger than PAGE_SIZE. Such offsets are handled
+ * even on other than the first sgl entry, provided
+ * they are a multiple of PAGE_SIZE.
*/
- unsigned int hvpgoff_in_page =
- (i + hvpgoff) % NR_HV_HYP_PAGES_IN_PAGE;
+ hvpgoff = HVPFN_DOWN(sgl->offset);
+ hvpfn = page_to_hvpfn(sg_page(sgl)) + hvpgoff;
+ hvpfns_to_add = HVPFN_UP(sgl->offset + sgl->length) -
+ hvpgoff;
/*
- * 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.
+ * Fill the next portion of the PFN array with
+ * sequential Hyper-V PFNs for the continguous physical
+ * memory described by the sgl entry. The end of the
+ * last sgl should be reached at the same time that
+ * the PFN array is filled.
*/
- 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;
+ while (hvpfns_to_add--)
+ payload->range.pfn_array[i++] = hvpfn++;
}
}
@@ -1865,8 +1847,6 @@ static struct scsi_host_template scsi_driver = {
.slave_configure = storvsc_device_configure,
.cmd_per_lun = 2048,
.this_id = -1,
- /* Make sure we dont get a sg segment crosses a page boundary */
- .dma_boundary = PAGE_SIZE-1,
/* Ensure there are no gaps in presented sgls */
.virt_boundary_mask = PAGE_SIZE-1,
.no_write_same = 1,