Large queues of I/O to offline devices that are eventually submitted when
devices are unblocked result in a many repeated "rejecting I/O to offline
device" messages. These messages can fill up the dmesg buffer in crash
dumps so no useful prior messages remain. In addition, if a serial console
is used, the flood of messages can cause a hard lockup in the console code.
Introduce a flag indicating the message has already been logged for the
device, and reset the flag when scsi_device_set_state() changes the device
state.
Link: https://lore.kernel.org/r/20200311143930.20674-1-emilne@redhat.com
Reviewed-by: Bart van Assche <bvanassche@acm.org>
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This file had its own peculiar style, not following any other
files inside the Kernel (as far as I saw).
Had to do a number of changes here, starting by removing the two
leading asterisks from each line, adding table and literal
block markups and changing whitespace and blank lines.
The end result is that (IMHO), it is now a lot easier to read
it as a text file, while producing a good html output.
Link: https://lore.kernel.org/r/6f8e4da4ea643adbe048f55504a59427c5e50c97.1583136624.git.mchehab+huawei@kernel.org
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
iSCSI session destruction can be arbitrarily slow, since it might require
network operations and serialization inside the SCSI layer. This patch
adds a new user event to trigger the destruction work asynchronously,
releasing the rx_queue_mutex as soon as the operation is queued and before
it is performed. This change allows other operations to run in other
sessions in the meantime, removing one of the major iSCSI bottlenecks for
us.
To prevent the session from being used after the destruction request, we
remove it immediately from the sesslist. This simplifies the locking
required during the asynchronous removal.
Link: https://lore.kernel.org/r/20200227195945.761719-1-krisman@collabora.com
Co-developed-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Co-developed-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Frank Mayhar <fmayhar@google.com>
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When an SVC node goes down as part of a node reboot, its WWPNs are moved to
the remaining node. When the node is back online, its WWPNs are moved
back. The result is that the WWPN moves from one NPort_ID to another, then
back again. The ibmvfc driver was forcing the old port to be removed, but
not sending an implicit logout. When the WWPN showed up at the new
location, the PLOGI failed as there was already a login established for the
old scsi id. The patch below fixes this by ensuring we always send an
implicit logout for any scsi id associated with an rport prior to calling
fc_remote_port_delete.
Link: https://lore.kernel.org/r/1582767943-16611-1-git-send-email-brking@linux.vnet.ibm.com
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The current codebase makes use of the zero-length array language extension
to the C90 standard, but the preferred mechanism to declare variable-length
types such as these ones is a flexible array member[1][2], introduced in
C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning in
case the flexible array does not occur last in the structure, which will
help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by this
change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Link: https://lore.kernel.org/r/20200224161406.GA21454@embeddedor
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Satish Kharat <satishkh@cisco.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
When trying to rescan disks in petitboot shell, we hit the following
softlockup stacktrace:
Kernel panic - not syncing: System is deadlocked on memory
[ 241.223394] CPU: 32 PID: 693 Comm: sh Not tainted 5.4.16-openpower1 #1
[ 241.223406] Call Trace:
[ 241.223415] [c0000003f07c3180] [c000000000493fc4] dump_stack+0xa4/0xd8 (unreliable)
[ 241.223432] [c0000003f07c31c0] [c00000000007d4ac] panic+0x148/0x3cc
[ 241.223446] [c0000003f07c3260] [c000000000114b10] out_of_memory+0x468/0x4c4
[ 241.223461] [c0000003f07c3300] [c0000000001472b0] __alloc_pages_slowpath+0x594/0x6d8
[ 241.223476] [c0000003f07c3420] [c00000000014757c] __alloc_pages_nodemask+0x188/0x1a4
[ 241.223492] [c0000003f07c34a0] [c000000000153e10] alloc_pages_current+0xcc/0xd8
[ 241.223508] [c0000003f07c34e0] [c0000000001577ac] alloc_slab_page+0x30/0x98
[ 241.223524] [c0000003f07c3520] [c0000000001597fc] new_slab+0x138/0x40c
[ 241.223538] [c0000003f07c35f0] [c00000000015b204] ___slab_alloc+0x1e4/0x404
[ 241.223552] [c0000003f07c36c0] [c00000000015b450] __slab_alloc+0x2c/0x48
[ 241.223566] [c0000003f07c36f0] [c00000000015b754] kmem_cache_alloc_node+0x9c/0x1b4
[ 241.223582] [c0000003f07c3760] [c000000000218c48] blk_alloc_queue_node+0x34/0x270
[ 241.223599] [c0000003f07c37b0] [c000000000226574] blk_mq_init_queue+0x2c/0x78
[ 241.223615] [c0000003f07c37e0] [c0000000002ff710] scsi_mq_alloc_queue+0x28/0x70
[ 241.223631] [c0000003f07c3810] [c0000000003005b8] scsi_alloc_sdev+0x184/0x264
[ 241.223647] [c0000003f07c38a0] [c000000000300ba0] scsi_probe_and_add_lun+0x288/0xa3c
[ 241.223663] [c0000003f07c3a00] [c000000000301768] __scsi_scan_target+0xcc/0x478
[ 241.223679] [c0000003f07c3b20] [c000000000301c64] scsi_scan_channel.part.9+0x74/0x7c
[ 241.223696] [c0000003f07c3b70] [c000000000301df4] scsi_scan_host_selected+0xe0/0x158
[ 241.223712] [c0000003f07c3bd0] [c000000000303f04] store_scan+0x104/0x114
[ 241.223727] [c0000003f07c3cb0] [c0000000002d5ac4] dev_attr_store+0x30/0x4c
[ 241.223741] [c0000003f07c3cd0] [c0000000001dbc34] sysfs_kf_write+0x64/0x78
[ 241.223756] [c0000003f07c3cf0] [c0000000001da858] kernfs_fop_write+0x170/0x1b8
[ 241.223773] [c0000003f07c3d40] [c0000000001621fc] __vfs_write+0x34/0x60
[ 241.223787] [c0000003f07c3d60] [c000000000163c2c] vfs_write+0xa8/0xcc
[ 241.223802] [c0000003f07c3db0] [c000000000163df4] ksys_write+0x70/0xbc
[ 241.223816] [c0000003f07c3e20] [c00000000000b40c] system_call+0x5c/0x68
As a part of the scan process Linux will allocate and configure a
scsi_device for each target to be scanned. If the device is not present,
then the scsi_device is torn down. As a part of scsi_device teardown a
workqueue item will be scheduled and the lockups we see are because there
are 250k workqueue items to be processed. Accoding to the specification of
SIS-64 sas controller, max_channel should be decreased on SIS-64 adapters
to 4.
The patch fixes softlockup issue.
Thanks for Oliver Halloran's help with debugging and explanation!
Link: https://lore.kernel.org/r/1583510248-23672-1-git-send-email-wenxiong@linux.vnet.ibm.com
Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Replace the open-coded implementation for reading the PCIe DSN with
pci_get_dsn().
The original code used a for-loop that looped over each of the 8 bytes
and copied them into a temporary buffer. pci_get_dsn() uses two calls to
pci_read_config_dword, and correctly bitwise ORs them into a u64. Thus,
we can simplify the snprintf significantly using %016llX on a u64 value.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use scsi_host_block() and scsi_host_unblock() instead of
scsi_block_requests()/scsi_unblock_requests() to block and unblock I/O.
This has the advantage that the block layer will stop sending I/O to the
adapter instead of having the SCSI midlayer requeueing I/O internally.
Link: https://lore.kernel.org/r/20200228075318.91255-10-hare@suse.de
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Balsundar P < Balsundar.P@microchip.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
