96 lines
3.8 KiB
Diff
96 lines
3.8 KiB
Diff
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From: Mike Christie <michaelc@cs.wisc.edu>
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Date: Tue, 21 Apr 2015 03:42:24 -0400
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Subject: [PATCH] SCSI: add 1024 max sectors black list flag
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This works around a issue with qnap iscsi targets not handling large IOs
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very well.
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The target returns:
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VPD INQUIRY: Block limits page (SBC)
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Maximum compare and write length: 1 blocks
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Optimal transfer length granularity: 1 blocks
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Maximum transfer length: 4294967295 blocks
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Optimal transfer length: 4294967295 blocks
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Maximum prefetch, xdread, xdwrite transfer length: 0 blocks
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Maximum unmap LBA count: 8388607
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Maximum unmap block descriptor count: 1
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Optimal unmap granularity: 16383
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Unmap granularity alignment valid: 0
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Unmap granularity alignment: 0
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Maximum write same length: 0xffffffff blocks
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Maximum atomic transfer length: 0
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Atomic alignment: 0
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Atomic transfer length granularity: 0
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and it is *sometimes* able to handle at least one IO of size up to 8 MB. We
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have seen in traces where it will sometimes work, but other times it
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looks like it fails and it looks like it returns failures if we send
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multiple large IOs sometimes. Also it looks like it can return 2 different
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errors. It will sometimes send iscsi reject errors indicating out of
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resources or it will send invalid cdb illegal requests check conditions.
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And then when it sends iscsi rejects it does not seem to handle retries
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when there are command sequence holes, so I could not just add code to
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try and gracefully handle that error code.
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The problem is that we do not have a good contact for the company,
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so we are not able to determine under what conditions it returns
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which error and why it sometimes works.
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So, this patch just adds a new black list flag to set targets like this to
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the old max safe sectors of 1024. The max_hw_sectors changes added in 3.19
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caused this regression, so I also ccing stable.
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Reported-by: Christian Hesse <list@eworm.de>
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Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
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Cc: stable@vger.kernel.org
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---
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drivers/scsi/scsi_devinfo.c | 1 +
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drivers/scsi/scsi_scan.c | 6 ++++++
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include/scsi/scsi_devinfo.h | 1 +
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3 files changed, 8 insertions(+)
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diff --git a/drivers/scsi/scsi_devinfo.c b/drivers/scsi/scsi_devinfo.c
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index 262ab837a704..9f77d23239a2 100644
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--- a/drivers/scsi/scsi_devinfo.c
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+++ b/drivers/scsi/scsi_devinfo.c
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@@ -226,6 +226,7 @@ static struct {
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{"PIONEER", "CD-ROM DRM-624X", NULL, BLIST_FORCELUN | BLIST_SINGLELUN},
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{"Promise", "VTrak E610f", NULL, BLIST_SPARSELUN | BLIST_NO_RSOC},
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{"Promise", "", NULL, BLIST_SPARSELUN},
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+ {"QNAP", "iSCSI Storage", NULL, BLIST_MAX_1024},
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{"QUANTUM", "XP34301", "1071", BLIST_NOTQ},
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{"REGAL", "CDC-4X", NULL, BLIST_MAX5LUN | BLIST_SINGLELUN},
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{"SanDisk", "ImageMate CF-SD1", NULL, BLIST_FORCELUN},
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diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
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index 60aae01caa89..6efab1c455e1 100644
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--- a/drivers/scsi/scsi_scan.c
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+++ b/drivers/scsi/scsi_scan.c
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@@ -897,6 +897,12 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
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*/
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if (*bflags & BLIST_MAX_512)
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blk_queue_max_hw_sectors(sdev->request_queue, 512);
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+ /*
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+ * Max 1024 sector transfer length for targets that report incorrect
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+ * max/optimal lengths and relied on the old block layer safe default
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+ */
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+ else if (*bflags & BLIST_MAX_1024)
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+ blk_queue_max_hw_sectors(sdev->request_queue, 1024);
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/*
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* Some devices may not want to have a start command automatically
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diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
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index 183eaab7c380..96e3f56519e7 100644
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--- a/include/scsi/scsi_devinfo.h
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+++ b/include/scsi/scsi_devinfo.h
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@@ -36,5 +36,6 @@
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for sequential scan */
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#define BLIST_TRY_VPD_PAGES 0x10000000 /* Attempt to read VPD pages */
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#define BLIST_NO_RSOC 0x20000000 /* don't try to issue RSOC */
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+#define BLIST_MAX_1024 0x40000000 /* maximum 1024 sector cdb length */
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#endif
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--
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2.1.0
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