kernel/drivers/scsi/scsi_sysfs.c, branch linux-4.8.y

scsi: avoid a permanent stop of the scsi device's request queue

2017-01-09T07:21:54Z

commit d2a145252c52792bc59e4767b486b26c430af4bb upstream. A race between scanning and fc_remote_port_delete() may result in a permanent stop if the device gets blocked before scsi_sysfs_add_sdev() and unblocked after. The reason is that blocking a device sets both the SDEV_BLOCKED state and the QUEUE_FLAG_STOPPED. However, scsi_sysfs_add_sdev() unconditionally sets SDEV_RUNNING which causes the device to be ignored by scsi_target_unblock() and thus never have its QUEUE_FLAG_STOPPED cleared leading to a device which is apparently running but has a stopped queue. We actually have two places where SDEV_RUNNING is set: once in scsi_add_lun() which respects the blocked flag and once in scsi_sysfs_add_sdev() which doesn't. Since the second set is entirely spurious, simply remove it to fix the problem. Reported-by: Zengxi Chen Signed-off-by: Wei Fang Reviewed-by: Ewan D. Milne Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman

Revert "scsi: fix soft lockup in scsi_remove_target() on module removal"

2016-04-15T20:53:07Z

Now that we've done a more comprehensive fix with the intermediate target state we can remove the previous hack introduced with commit 90a88d6ef88e ("scsi: fix soft lockup in scsi_remove_target() on module removal"). Signed-off-by: Johannes Thumshirn Cc: stable@vger.kernel.org Reviewed-by: Ewan D. Milne Reviewed-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: Add intermediate STARGET_REMOVE state to scsi_target_state

2016-04-15T20:51:53Z

Add intermediate STARGET_REMOVE state to scsi_target_state to avoid running into the BUG_ON() in scsi_target_reap(). The STARGET_REMOVE state is only valid in the path from scsi_remove_target() to scsi_target_destroy() indicating this target is going to be removed. This re-fixes the problem introduced in commits bc3f02a795d3 ("[SCSI] scsi_remove_target: fix softlockup regression on hot remove") and 40998193560d ("scsi: restart list search after unlock in scsi_remove_target") in a more comprehensive way. [mkp: Included James' fix for scsi_target_destroy()] Signed-off-by: Johannes Thumshirn Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38 Cc: stable@vger.kernel.org Reported-by: Sergey Senozhatsky Tested-by: Sergey Senozhatsky Reviewed-by: Ewan D. Milne Reviewed-by: Hannes Reinecke Reviewed-by: James Bottomley Signed-off-by: Martin K. Petersen

scsi: disable automatic target scan

2016-04-11T20:57:09Z

On larger installations it is useful to disable automatic LUN scanning, and only add the required LUNs via udev rules. This can speed up bootup dramatically. This patch introduces a new scan module parameter value 'manual', which works like 'none', but can be overridden by setting the 'rescan' value from scsi_scan_target to 'SCSI_SCAN_MANUAL'. And it updates all relevant callers to set the 'rescan' value to 'SCSI_SCAN_MANUAL' if invoked via the 'scan' option in sysfs. Signed-off-by: Hannes Reinecke Reviewed-by: Ewan D. Milne Tested-by: Laurence Oberman Signed-off-by: Martin K. Petersen

scsi: Declare local symbols static

2016-03-30T00:29:55Z

Avoid that building with W=1 causes gcc to report warnings about symbols that have not been declared. Cc: Hannes Reinecke Signed-off-by: Bart Van Assche Reviewed-by: Hannes Reinicke Reviewed-by: Christoph Hellwig Reviewed-by: Ewan Milne Signed-off-by: Martin K. Petersen

scsi_sysfs: Fix typo in is_bin_visible()

2016-03-11T01:29:54Z

The test for the existence vpd_pg83 is inverted. Fixes: 7e47976bcff ("scsi_sysfs: add 'is_bin_visible' callback") Signed-off-by: Hannes Reinecke Reviewed-by: Johannes Thumshirn Reported-by: Ewan Milne Reviewed-by: Laurence Oberman loberman@redhat.com> Signed-off-by: Martin K. Petersen

scsi_sysfs: call 'device_add' after attaching device handler

2016-03-05T22:21:41Z

'device_add' will be evaluating the 'is_visible' callback when creating the sysfs attributes. As by this time the device handler has not been attached the 'access_state' attribute will never be visible. This patch moves the code around so that the device handler is present by the time 'is_visible' is evaluated to correctly display the 'access_state' attribute. Signed-off-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Bart van Assche Signed-off-by: Martin K. Petersen

scsi: Add 'access_state' and 'preferred_path' attribute

2016-03-05T22:14:37Z

Add an 'access_state' field to struct scsi_device and display them in sysfs as 'access_state' and 'preferred_path' attribute. Signed-off-by: Hannes Reinecke Reviewed-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Bart van Assche Signed-off-by: Martin K. Petersen

scsi_sysfs: add 'is_bin_visible' callback

2016-03-05T22:10:03Z

Add 'is_bin_visible' callback to blank out unsupported vpd pages. Reviewed-by: Shane Seymour Reviewed-by: Johannes Thumshirn Reviewed-by: Christoph Hellwig Signed-off-by: Hannes Reinecke Signed-off-by: Martin K. Petersen

scsi: fix soft lockup in scsi_remove_target() on module removal

2016-02-12T05:47:32Z

This softlockup is currently happening: [ 444.088002] NMI watchdog: BUG: soft lockup - CPU#1 stuck for 22s! [kworker/1:1:29] [ 444.088002] Modules linked in: lpfc(-) qla2x00tgt(O) qla2xxx_scst(O) scst_vdisk(O) scsi_transport_fc libcrc32c scst(O) dlm configfs nfsd lockd grace nfs_acl auth_rpcgss sunrpc ed d snd_pcm_oss snd_mixer_oss snd_seq snd_seq_device dm_mod iTCO_wdt snd_hda_codec_realtek snd_hda_codec_generic gpio_ich iTCO_vendor_support ppdev snd_hda_intel snd_hda_codec snd_hda _core snd_hwdep tg3 snd_pcm snd_timer libphy lpc_ich parport_pc ptp acpi_cpufreq snd pps_core fjes parport i2c_i801 ehci_pci tpm_tis tpm sr_mod cdrom soundcore floppy hwmon sg 8250_ fintek pcspkr i915 drm_kms_helper uhci_hcd ehci_hcd drm fb_sys_fops sysimgblt sysfillrect syscopyarea i2c_algo_bit usbcore button video usb_common fan ata_generic ata_piix libata th ermal [ 444.088002] CPU: 1 PID: 29 Comm: kworker/1:1 Tainted: G O 4.4.0-rc5-2.g1e923a3-default #1 [ 444.088002] Hardware name: FUJITSU SIEMENS ESPRIMO E /D2164-A1, BIOS 5.00 R1.10.2164.A1 05/08/2006 [ 444.088002] Workqueue: fc_wq_4 fc_rport_final_delete [scsi_transport_fc] [ 444.088002] task: f6266ec0 ti: f6268000 task.ti: f6268000 [ 444.088002] EIP: 0060:[] EFLAGS: 00000286 CPU: 1 [ 444.088002] EIP is at _raw_spin_unlock_irqrestore+0x14/0x20 [ 444.088002] EAX: 00000286 EBX: f20d3800 ECX: 00000002 EDX: 00000286 [ 444.088002] ESI: f50ba800 EDI: f2146848 EBP: f6269ec8 ESP: f6269ec8 [ 444.088002] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 [ 444.088002] CR0: 8005003b CR2: 08f96600 CR3: 363ae000 CR4: 000006d0 [ 444.088002] Stack: [ 444.088002] f6269eec c066b0f7 00000286 f2146848 f50ba808 f50ba800 f50ba800 f2146a90 [ 444.088002] f2146848 f6269f08 f8f0a4ed f3141000 f2146800 f2146a90 f619fa00 00000040 [ 444.088002] f6269f40 c026cb25 00000001 166c6392 00000061 f6757140 f6136340 00000004 [ 444.088002] Call Trace: [ 444.088002] [] scsi_remove_target+0x167/0x1c0 [ 444.088002] [] fc_rport_final_delete+0x9d/0x1e0 [scsi_transport_fc] [ 444.088002] [] process_one_work+0x155/0x3e0 [ 444.088002] [] worker_thread+0x37/0x490 [ 444.088002] [] kthread+0x9b/0xb0 [ 444.088002] [] ret_from_kernel_thread+0x21/0x40 What appears to be happening is that something has pinned the target so it can't go into STARGET_DEL via final release and the loop in scsi_remove_target spins endlessly until that happens. The fix for this soft lockup is to not keep looping over a device that we've called remove on but which hasn't gone into DEL state. This patch will retain a simplistic memory of the last target and not keep looping over it. Reported-by: Sebastian Herbszt Tested-by: Sebastian Herbszt Fixes: 40998193560dab6c3ce8d25f4fa58a23e252ef38 Cc: stable@vger.kernel.org Signed-off-by: James Bottomley