1. 30 Nov, 2016 1 commit
    • Uma Krishnan's avatar
      scsi: cxlflash: Set sg_tablesize to 1 instead of SG_NONE · 68ab2d76
      Uma Krishnan authored
      The following Oops is encountered when blk_mq is enabled with the
      cxlflash driver:
      
      [ 2960.817172] Oops: Kernel access of bad area, sig: 11 [#5]
      [ 2960.817309] NIP  __blk_mq_run_hw_queue+0x278/0x4c0
      [ 2960.817313] LR __blk_mq_run_hw_queue+0x2bc/0x4c0
      [ 2960.817314] Call Trace:
      [ 2960.817320] __blk_mq_run_hw_queue+0x2bc/0x4c0 (unreliable)
      [ 2960.817324] blk_mq_run_hw_queue+0xd8/0x100
      [ 2960.817329] blk_mq_insert_requests+0x14c/0x1f0
      [ 2960.817333] blk_mq_flush_plug_list+0x150/0x190
      [ 2960.817338] blk_flush_plug_list+0x11c/0x2b0
      [ 2960.817344] blk_finish_plug+0x58/0x80
      [ 2960.817348] __do_page_cache_readahead+0x1c0/0x2e0
      [ 2960.817352] force_page_cache_readahead+0x68/0xd0
      [ 2960.817356] generic_file_read_iter+0x43c/0x6a0
      [ 2960.817359] blkdev_read_iter+0x68/0xa0
      [ 2960.817361] __vfs_read+0x11c/0x180
      [ 2960.817364] vfs_read+0xa4/0x1c0
      [ 2960.817366] SyS_read+0x6c/0x110
      [ 2960.817369] system_call+0x38/0xb4
      
      The SCSI blk_mq stack assumes that sg_tablesize is always a non-zero
      value with scsi_mq_setup_tags() allocating tags using sg_tablesize.
      The cxlflash driver currently uses SG_NONE (0) for the sg_tablesize
      as the devices it supports are not capable of scatter gather. This
      mismatch of values results in the Oops above.
      
      To resolve this issue, sg_tablesize for cxlflash can simply be set
      to 1, a value which satisfies the constraints in cxlflash and the
      lack of support of SG_NONE in SCSI blk_mq.
      Signed-off-by: default avatarUma Krishnan <ukrishn@linux.vnet.ibm.com>
      Acked-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
      Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
      68ab2d76
  2. 29 Nov, 2016 19 commits
  3. 25 Nov, 2016 13 commits
  4. 22 Nov, 2016 4 commits
  5. 18 Nov, 2016 3 commits