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authorMike Christie <michaelc@cs.wisc.edu>2015-04-20 22:42:24 -0500
committerJames Bottomley <JBottomley@Odin.com>2015-04-27 09:38:06 -0700
commit35e9a9f93994d7f7d12afa41169c7ba05513721b (patch)
treeb84ccdeda9a56a49e017b802a9c72758078bcac2 /include/scsi
parentb787f68c36d49bb1d9236f403813641efa74a031 (diff)
SCSI: add 1024 max sectors black list flag
This works around a issue with qnap iscsi targets not handling large IOs very well. The target returns: VPD INQUIRY: Block limits page (SBC) Maximum compare and write length: 1 blocks Optimal transfer length granularity: 1 blocks Maximum transfer length: 4294967295 blocks Optimal transfer length: 4294967295 blocks Maximum prefetch, xdread, xdwrite transfer length: 0 blocks Maximum unmap LBA count: 8388607 Maximum unmap block descriptor count: 1 Optimal unmap granularity: 16383 Unmap granularity alignment valid: 0 Unmap granularity alignment: 0 Maximum write same length: 0xffffffff blocks Maximum atomic transfer length: 0 Atomic alignment: 0 Atomic transfer length granularity: 0 and it is *sometimes* able to handle at least one IO of size up to 8 MB. We have seen in traces where it will sometimes work, but other times it looks like it fails and it looks like it returns failures if we send multiple large IOs sometimes. Also it looks like it can return 2 different errors. It will sometimes send iscsi reject errors indicating out of resources or it will send invalid cdb illegal requests check conditions. And then when it sends iscsi rejects it does not seem to handle retries when there are command sequence holes, so I could not just add code to try and gracefully handle that error code. The problem is that we do not have a good contact for the company, so we are not able to determine under what conditions it returns which error and why it sometimes works. So, this patch just adds a new black list flag to set targets like this to the old max safe sectors of 1024. The max_hw_sectors changes added in 3.19 caused this regression, so I also ccing stable. Reported-by: Christian Hesse <list@eworm.de> Signed-off-by: Mike Christie <michaelc@cs.wisc.edu> Cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
Diffstat (limited to 'include/scsi')
-rw-r--r--include/scsi/scsi_devinfo.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/scsi/scsi_devinfo.h b/include/scsi/scsi_devinfo.h
index 183eaab7c380..96e3f56519e7 100644
--- a/include/scsi/scsi_devinfo.h
+++ b/include/scsi/scsi_devinfo.h
@@ -36,5 +36,6 @@
for sequential scan */
#define BLIST_TRY_VPD_PAGES 0x10000000 /* Attempt to read VPD pages */
#define BLIST_NO_RSOC 0x20000000 /* don't try to issue RSOC */
+#define BLIST_MAX_1024 0x40000000 /* maximum 1024 sector cdb length */
#endif

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