Asutosh Das [Wed, 25 Mar 2020 18:29:00 +0000 (11:29 -0700)]
scsi: ufshcd: Update the set frequency to devfreq
Currently, the frequency that devfreq provides the driver always leads the
clocks to be scaled up. Hence, round the clock-rate to the nearest
frequency before deciding to scale.
Also update the devfreq statistics of current frequency.
Nitin Rawat [Tue, 24 Mar 2020 21:48:21 +0000 (14:48 -0700)]
scsi: ufs: Resume ufs host before accessing ufs device
As a part of sysfs reading of descriptors/attributes/flags, query commands
should only be executed when hba's power runtime status is active. To
guarantee this, add pm_runtime_get/put_sync() to those paths where query
commands are sent.
Stanley Chu [Wed, 18 Mar 2020 10:40:15 +0000 (18:40 +0800)]
scsi: ufs: make HCE polling more compact to improve initialization latency
Reduce the waiting period between each HCE (Host Controller Enable) polling
from 5 ms to 1 ms. Also increase the maximum polling times to make "total
polling time" roughly the same.
This change could make HCE initialization faster to improve latency of
ufshcd initialization, error recovery, and resume behaviors.
Stanley Chu [Wed, 18 Mar 2020 10:40:14 +0000 (18:40 +0800)]
scsi: ufs: allow custom delay prior to host enabling
Currently a 1 ms delay is applied before polling CONTROLLER_ENABLE
bit. This delay may not be required or can be changed in different
controllers. Make the delay as a changeable value in struct ufs_hba to
allow it customized by vendors.
Stanley Chu [Wed, 18 Mar 2020 10:40:12 +0000 (18:40 +0800)]
scsi: ufs: introduce common and flexible delay function
Introduce a common delay function to provide flexible way for users to take
choices of udelay and usleep_range into consideration according to the
required delay time.
Stanley Chu [Wed, 18 Mar 2020 10:40:11 +0000 (18:40 +0800)]
scsi: ufs: use an enum for host capabilities
Use an enum to specify the host capabilities instead of #defines inside the
structure definition.
Link: https://lore.kernel.org/r/20200318104016.28049-3-stanley.chu@mediatek.com Reviewed-by: Avri Altman <avri.altman@wdc.com> Reviewed-by: Can Guo <cang@codeaurora.org> Reviewed-by: Bean Huo <beanhuo@micron.com> Reviewed-by: Asutosh Das <asutoshd@codeaurora.org> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stanley Chu [Wed, 18 Mar 2020 10:40:10 +0000 (18:40 +0800)]
scsi: ufs: fix uninitialized tx_lanes in ufshcd_disable_tx_lcc()
In ufshcd_disable_tx_lcc(), if ufshcd_dme_get() or ufshcd_dme_peer_get()
get fail, uninitialized variable "tx_lanes" may be used as unexpected lane
ID for DME configuration.
Fix this issue by initializing "tx_lanes".
Link: https://lore.kernel.org/r/20200318104016.28049-2-stanley.chu@mediatek.com Reviewed-by: Avri Altman <avri.altman@wdc.com> Reviewed-by: Can Guo <cang@codeaurora.org> Reviewed-by: Asutosh Das <asutoshd@codeaurora.org> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
If an iSCSI connection happens to fail while the daemon isn't running (due
to a crash or for another reason), the kernel failure report is not
received. When the daemon restarts, there is insufficient kernel state in
sysfs for it to know that this happened. open-iscsi tries to reopen every
connection, but on different initiators, we'd like to know which
connections have failed.
There is session->state, but that has a different lifetime than an iSCSI
connection, so it doesn't directly reflect the connection state.
[mkp: typos]
Link: https://lore.kernel.org/r/20200317233422.532961-1-krisman@collabora.com Cc: Khazhismel Kumykov <khazhy@google.com> Suggested-by: Junho Ryu <jayr@google.com> Reviewed-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Trace events target_sequencer_start and target_cmd_complete
(include/trace/events/target.h) are ready to show NAA identifier, LUN ID,
and many other important command details in the system log:
However, it's still hard to identify command on the initiator and command
on the target in the real life output of system log. For that purpose SCSI
provides a command identifier or task tag (term used in previous
standards). This patch adds tag ID in the system log's output:
kworker/1:1-35 [001] .... 1392.989456: target_cmd_complete:
naa.5001405ec1ba6364 <- LUN 001 tag 0x1 status GOOD (sense len 0)
SERVICE_ACTION_IN_16 data_length 32
CDB 9e 10 00 00 00 00 00 00 00 00 00 00 00 20 00 00 (TA:SIMPLE C:00)
Link: https://lore.kernel.org/r/226e01deaa9baf46d6ff3b8698bc9fe881f7dfc1.camel@dubeyko.com Reviewed-by: Roman Bolshakov <r.bolshakov@yadro.com> Reviewed-by: Konstantin Shelekhin <k.shelekhin@yadro.com> Reviewed-by: Bart van Assche <bvanassche@acm.org> Signed-off-by: Viacheslav Dubeyko <v.dubeiko@yadro.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi: target: iscsi: calling iscsit_stop_session() inside iscsit_close_session() has no effect
iscsit_close_session() can only be called when nconn is zero (otherwise a
kernel panic is triggered). If nconn is zero then iscsit_stop_session()
does nothing and exits, so calling it makes no sense.
We still need to call iscsit_check_session_usage_count() because this
function will sleep if the session's refcount is not zero and we don't want
to destroy the session structure if it's still being referenced.
scsi: target: fix hang when multiple threads try to destroy the same iscsi session
A number of hangs have been reported against the target driver; they are
due to the fact that multiple threads may try to destroy the iscsi session
at the same time. This may be reproduced for example when a "targetcli
iscsi/iqn.../tpg1 disable" command is executed while a logout operation is
underway.
When this happens, two or more threads may end up sleeping and waiting for
iscsit_close_connection() to execute "complete(session_wait_comp)". Only
one of the threads will wake up and proceed to destroy the session
structure, the remaining threads will hang forever.
Note that if the blocked threads are somehow forced to wake up with
complete_all(), they will try to free the same iscsi session structure
destroyed by the first thread, causing double frees, memory corruptions
etc...
With this patch, the threads that want to destroy the iscsi session will
increase the session refcount and will set the "session_close" flag to 1;
then they wait for the driver to close the remaining active connections.
When the last connection is closed, iscsit_close_connection() will wake up
all the threads and will wait for the session's refcount to reach zero;
when this happens, iscsit_close_connection() will destroy the session
structure because no one is referencing it anymore.
INFO: task targetcli:5971 blocked for more than 120 seconds.
Tainted: P OE 4.15.0-72-generic #81~16.04.1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
targetcli D 0 5971 1 0x00000080
Call Trace:
__schedule+0x3d6/0x8b0
? vprintk_func+0x44/0xe0
schedule+0x36/0x80
schedule_timeout+0x1db/0x370
? __dynamic_pr_debug+0x8a/0xb0
wait_for_completion+0xb4/0x140
? wake_up_q+0x70/0x70
iscsit_free_session+0x13d/0x1a0 [iscsi_target_mod]
iscsit_release_sessions_for_tpg+0x16b/0x1e0 [iscsi_target_mod]
iscsit_tpg_disable_portal_group+0xca/0x1c0 [iscsi_target_mod]
lio_target_tpg_enable_store+0x66/0xe0 [iscsi_target_mod]
configfs_write_file+0xb9/0x120
__vfs_write+0x1b/0x40
vfs_write+0xb8/0x1b0
SyS_write+0x5c/0xe0
do_syscall_64+0x73/0x130
entry_SYSCALL_64_after_hwframe+0x3d/0xa2
Link: https://lore.kernel.org/r/20200313170656.9716-3-mlombard@redhat.com Reported-by: Matt Coleman <mcoleman@datto.com> Tested-by: Matt Coleman <mcoleman@datto.com> Tested-by: Rahul Kundu <rahul.kundu@chelsio.com> Signed-off-by: Maurizio Lombardi <mlombard@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
scsi: aha1740: Fix an errro handling path in aha1740_probe()
If 'dma_map_single()' fails, the ref counted 'shpnt' will be decremented
twice because 'scsi_host_put()' is called in the if block, and in the error
handling path.
Daniel Wagner [Thu, 6 Feb 2020 13:54:43 +0000 (14:54 +0100)]
scsi: qla2xxx: Remove non functional code
Remove code which has no functional use anymore since commit 3c75ad1d87c7
("scsi: qla2xxx: Remove defer flag to indicate immeadiate port loss").
While at it remove also the stale function documentation.
Link: https://lore.kernel.org/r/20200206135443.110701-1-dwagner@suse.de Reviewed-by: Arun Easi <aeasi@marvell.com> Reviewed-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Daniel Wagner <dwagner@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Viswas G [Mon, 16 Mar 2020 07:49:06 +0000 (13:19 +0530)]
scsi: pm80xx: Introduce read and write length for IOCTL payload structure
Removed the common length and introduce read and write length for IOCTL
payload structure.
[mkp: fixed SoB ordering]
Link: https://lore.kernel.org/r/20200316074906.9119-7-deepak.ukey@microchip.com Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Viswas G <viswas.g@microchip.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Deepak Ukey [Mon, 16 Mar 2020 07:49:05 +0000 (13:19 +0530)]
scsi: pm80xx: sysfs attribute for non fatal dump
Added the sysfs attribute for non fatal log so that management utility can
get the non fatal dump from driver. The non-fatal error is an error
condition or abnormal behavior detected by the host, or detected and
reported by the controller to the host.The non-fatal error does not stop
the controller firmware and enables it to still respond to host requests.
A typical example of a non-fatal error is an I/O timeout or an unusual
error notification from the controller. Since the firmware is operational,
the error dump information is pushed to host memory (by firmware) upon
request from the host.
Link: https://lore.kernel.org/r/20200316074906.9119-6-deepak.ukey@microchip.com Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Viswas G <Viswas.G@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
1) Move the instance tracking down after we think the instance is good to
go. Avoids having a use-after free.
2) There are goto targets for trying to cleanup if the hw fails to
initialize, but there's some overlap depending on who thinks they own
the sub-structures.
Link: https://lore.kernel.org/r/20200316074906.9119-5-deepak.ukey@microchip.com Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Peter Chang <dpf@google.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Viswas G <Viswas.G@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
yuuzheng [Mon, 16 Mar 2020 07:49:03 +0000 (13:19 +0530)]
scsi: pm80xx: Free the tag when mpi_set_phy_profile_resp is received
In pm80xx driver, the command mpi_set_phy_profile_req is sent by host
during boot to configure the phy profile such as analog setting page, rate
control page. However, the tag is not freed when its response is
received. As a result, 16 tags are missing for each HBA after boot. When
NCQ is enabled with queue depth 16, it needs at least, 15 * 16 = 240 tags
for each HBA to achieve the best performance. In current pm80xx driver with
setting CCB_MAX = 256, the total number of tags in each HBA is 255 for data
IO. Hence, without returning those tags to the pool after boot, some device
will finally be forced to non-ncq mode by ATA layer due to excessive errors
(i.e. LLDD cannot allocate tag for queued task).
Link: https://lore.kernel.org/r/20200316074906.9119-4-deepak.ukey@microchip.com Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: yuuzheng <yuuzheng@google.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Viswas G <Viswas.G@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Vikram Auradkar [Mon, 16 Mar 2020 07:49:02 +0000 (13:19 +0530)]
scsi: pm80xx: Deal with kexec reboots
A kexec reboot causes the controller fw to assert. This assertion shows up
in two ways, the controller doesn't show up as ready and an interrupt is
waiting as soon as the handler is registered. To resolve this added below
fix:
- Split the interrupt handling setup into two parts, setup and request.
- If the controller ready register indicates not-ready, but that the not
readiness is only on the IOC units we can still try a reset to bring the
system back to the pre-reboot state.
Link: https://lore.kernel.org/r/20200316074906.9119-3-deepak.ukey@microchip.com Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Vikram Auradkar <auradkar@google.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Viswas G <Viswas.G@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Peter Chang [Mon, 16 Mar 2020 07:49:01 +0000 (13:19 +0530)]
scsi: pm80xx: Increase request sg length
Increasing the per-request size maximum (max_sectors_kb) runs into the
per-device DMA scatter gather list limit (max_segments) for users of the io
vector system calls (eg, readv and writev). This is because the kernel
combines io vectors into DMA segments when possible, but it doesn't work
for our user because the vectors in the buffer cache get scrambled. This
change bumps the advertised max scatter gather length to 528 to cover 2M w/
x86's 4k pages and some extra for the user checksum. It trims the size of
some of the tables we don't care about and exposes all of the command slots
upstream to the SCSI layer. Also reduced the PM8001_MAX_CCB to 256 as
pm8001 driver has memory limit depend on machine capability. If we increase
the sg length, we need to trade-off it by decreasing PM8001_MAX_CCB.
PM8001_MAX_CCB = 256 does not have any influence on normal use
Link: https://lore.kernel.org/r/20200316074906.9119-2-deepak.ukey@microchip.com Reported-by: kbuild test robot <lkp@intel.com> Acked-by: Jack Wang <jinpu.wang@cloud.ionos.com> Signed-off-by: Peter Chang <dpf@google.com> Signed-off-by: Deepak Ukey <deepak.ukey@microchip.com> Signed-off-by: Viswas G <Viswas.G@microchip.com> Signed-off-by: Radha Ramachandran <radha@google.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:41 +0000 (10:42 +0100)]
scsi: smartpqi: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-9-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Don Brace <don.brace@microsemi.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:40 +0000 (10:42 +0100)]
scsi: core: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-8-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: linux-scsi@vger.kernel.org Reviewed-by: Bart van Assche <bvanassche@acm.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:39 +0000 (10:42 +0100)]
scsi: megaraid_sas: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Also corrected the wrongly passed limit size. The remaining buffer size
must be decremented.
Link: https://lore.kernel.org/r/20200315094241.9086-7-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Sumit Saxena <sumit.saxena@broadcom.com> Cc: Shivasharan S <shivasharan.srikanteshwara@broadcom.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:38 +0000 (10:42 +0100)]
scsi: ipr: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-6-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Brian King <brking@us.ibm.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:37 +0000 (10:42 +0100)]
scsi: gdth: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
[mkp: checkpatch fix]
Link: https://lore.kernel.org/r/20200315094241.9086-5-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Achim Leubner <achim_leubner@adaptec.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:36 +0000 (10:42 +0100)]
scsi: fnic: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-4-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Satish Kharat <satishkh@cisco.com> Cc: Sesidhar Baddela <sebaddel@cisco.com> Cc: Karan Tilak Kumar <kartilak@cisco.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:35 +0000 (10:42 +0100)]
scsi: be2iscsi: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-3-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Subbu Seetharaman <subbu.seetharaman@broadcom.com> Cc: Ketan Mukadam <ketan.mukadam@broadcom.com> Cc: Jitendra Bhivare <jitendra.bhivare@broadcom.com> Cc: linux-scsi@vger.kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Takashi Iwai [Sun, 15 Mar 2020 09:42:34 +0000 (10:42 +0100)]
scsi: aacraid: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the actual
output size, the succeeding calls may go beyond the given buffer limit.
Fix it by replacing with scnprintf().
Link: https://lore.kernel.org/r/20200315094241.9086-2-tiwai@suse.de Cc: "James E . J . Bottomley" <jejb@linux.ibm.com> Cc: "Martin K . Petersen" <martin.petersen@oracle.com> Cc: Adaptec OEM Raid Solutions <aacraid@microsemi.com> Cc: linux-scsi@vger.kernel.org Acked-by: Balsundar P <Balsundar.P@microchip.com> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Jens Remus [Thu, 12 Mar 2020 17:45:04 +0000 (18:45 +0100)]
scsi: zfcp: enhance handling of FC Endpoint Security errors
Enable for explicit FCP channel FC Endpoint Security error reporting and
handle any FSF security errors according to specification. Take the
following recovery actions when a FSF_SECURITY_ERROR is reported for the
specified FSF commands:
- Open Port: Retry the command if possible
- Send FCP : Physically close the remote port and reopen
For Open Port the command status is set to error, which triggers a retry.
For Send FCP the command status is set to error and recovery is triggered
to physically reopen the remote port.
Link: https://lore.kernel.org/r/20200312174505.51294-10-maier@linux.ibm.com Reviewed-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Jens Remus [Thu, 12 Mar 2020 17:45:03 +0000 (18:45 +0100)]
scsi: zfcp: trace FC Endpoint Security of FCP devices and connections
Trace changes in Fibre Channel Endpoint Security capabilities of FCP
devices as well as changes in Fibre Channel Endpoint Security state of
their connections to FC remote ports as FC Endpoint Security changes with
trace level 3 in HBA DBF.
A change in FC Endpoint Security capabilities of FCP devices is traced as
response to FSF command FSF_QTCB_EXCHANGE_PORT_DATA with a trace tag of
"fsfcesa" and a WWPN of ZFCP_DBF_INVALID_WWPN = 0x0000000000000000 (see
FC-FS-4 §18 "Name_Identifier Formats", NAA field).
A change in FC Endpoint Security state of connections between FCP devices
and FC remote ports is traced as response to FSF command
FSF_QTCB_OPEN_PORT_WITH_DID with a trace tag of "fsfcesp".
Example trace record of FC Endpoint Security capability change of FCP
device formatted with zfcpdbf from s390-tools:
Timestamp : ...
Area : HBA
Subarea : 00
Level : 3
Exception : -
CPU ID : ...
Caller : 0x...
Record ID : 5 ZFCP_DBF_HBA_FCES
Tag : fsfcesa FSF FC Endpoint Security adapter
Request ID : 0x...
Request status : 0x00000010
FSF cmnd : 0x0000000e FSF_QTCB_EXCHANGE_PORT_DATA
FSF sequence no: 0x...
FSF issued : ...
FSF stat : 0x00000000 FSF_GOOD
FSF stat qual : n/a
Prot stat : n/a
Prot stat qual : n/a
Port handle : 0x00000000 none (invalid)
LUN handle : n/a
WWPN : 0x0000000000000000 ZFCP_DBF_INVALID_WWPN
FCES old : 0x00000000 old FC Endpoint Security
FCES new : 0x00000007 new FC Endpoint Security
Example trace record of FC Endpoint Security change of connection to
FC remote port formatted with zfcpdbf from s390-tools:
Timestamp : ...
Area : HBA
Subarea : 00
Level : 3
Exception : -
CPU ID : ...
Caller : 0x...
Record ID : 5 ZFCP_DBF_HBA_FCES
Tag : fsfcesp FSF FC Endpoint Security port
Request ID : 0x...
Request status : 0x00000010
FSF cmnd : 0x00000005 FSF_QTCB_OPEN_PORT_WITH_DID
FSF sequence no: 0x...
FSF issued : ...
FSF stat : 0x00000000 FSF_GOOD
FSF stat qual : n/a
Prot stat : n/a
Prot stat qual : n/a
Port handle : 0x...
WWPN : 0x500507630401120c WWPN
FCES old : 0x00000000 old FC Endpoint Security
FCES new : 0x00000004 new FC Endpoint Security
Link: https://lore.kernel.org/r/20200312174505.51294-9-maier@linux.ibm.com Reviewed-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Jens Remus [Thu, 12 Mar 2020 17:45:02 +0000 (18:45 +0100)]
scsi: zfcp: log FC Endpoint Security of connections
Log the usage of and subsequent changes in FC Endpoint Security of
connections between FCP devices and FC remote ports to the kernel ring
buffer. Activation of FC Endpoint Security is logged as informational.
Change and deactivation are logged as warning.
No logging takes place, if FC Endpoint Security is not used (i.e. never
activated) on a connection or if it does not change during reopen of a port
(e.g. due to adapter or port recovery).
Jens Remus [Thu, 12 Mar 2020 17:45:01 +0000 (18:45 +0100)]
scsi: zfcp: report FC Endpoint Security in sysfs
Add an interface to read Fibre Channel Endpoint Security information of FCP
channels and their connections to FC remote ports. It comes in the form of
new sysfs attributes that are attached to the CCW device representing the
FCP device and its zfcp port objects.
The read-only sysfs attribute "fc_security" of a CCW device representing a
FCP device shows the FC Endpoint Security capabilities of the device.
Possible values are: "unknown", "unsupported", "none", or a comma-
separated list of one or more mnemonics and/or one hexadecimal value
representing the supported FC Endpoint Security:
The read-only sysfs attribute "fc_security" of a zfcp port object shows the
FC Endpoint Security used on the connection between its parent FCP device
and the FC remote port. Possible values are: "unknown", "unsupported",
"none", or a mnemonic or hexadecimal value representing the FC Endpoint
Security used:
Authentication: Connection has been authenticated
Encryption : Connection is encrypted
Both sysfs attributes may return hexadecimal values instead of mnemonics,
if the mnemonic lookup table does not contain an entry for the FC Endpoint
Security reported by the FCP device.
Link: https://lore.kernel.org/r/20200312174505.51294-7-maier@linux.ibm.com Reviewed-by: Fedor Loshakov <loshakov@linux.ibm.com> Reviewed-by: Steffen Maier <maier@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Jens Remus [Thu, 12 Mar 2020 17:45:00 +0000 (18:45 +0100)]
scsi: zfcp: auto variables for dereferenced structs in open port handler
Introduce automatic variables for adapter and QTCB bottom in
zfcp_fsf_open_port_handler(). This facilitates subsequent changes to meet
the 80 character per line limit.
Link: https://lore.kernel.org/r/20200312174505.51294-6-maier@linux.ibm.com Reviewed-by: Fedor Loshakov <loshakov@linux.ibm.com> Reviewed-by: Steffen Maier <maier@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Steffen Maier [Thu, 12 Mar 2020 17:44:59 +0000 (18:44 +0100)]
scsi: zfcp: fix fc_host attributes that should be unknown on local link down
When we get an unsolicited notification on local link went down,
zfcp_fsf_status_read_link_down() calls zfcp_fsf_link_down_info_eval().
This only blocks rports, and sets ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED and
ZFCP_STATUS_COMMON_ERP_FAILED. Only the fc_host port_state changes to
"Linkdown", because zfcp_scsi_get_host_port_state() is an active callback
and uses the adapter status.
Other fc_host attributes model, port_id, port_type, speed, fabric_name (and
zfcp device attributes card_version, peer_wwpn, peer_wwnn, peer_d_id) which
depend on a local link, continued to show their last known "good" value.
Only if something triggered an exchange config data, some values were
updated to their unknown equivalent via case
FSF_EXCHANGE_CONFIG_DATA_INCOMPLETE due to local link down. Triggers for
exchange config data are adapter recovery, or reading any of the following
zfcp-specific scsi host sysfs attributes "requests", "megabytes", or
"seconds_active" in /sys/devices/css*/*.*.*/*.*.*/host*/scsi_host/host*/.
The other fc_host attributes active_fc4s and permanent_port_name continued
to show their last known "good" value. Only if something triggered an
exchange port data, some values changed. Active_fc4s became all zeros as
unknown equivalent during link down. Permanent_port_name does not depend
on a local link. But for non-NPIV FCP devices, permanent_port_name
erroneously became whatever value fc_host port_name had at that point in
time (see previous paragraph). Triggers for exchange port data are the
zfcp-specific scsi host sysfs attribute "utilization", or
[{reset,get}_fc_host_stats] write anything into "reset_statistics" or read
any of the other attributes under
/sys/devices/css*/*.*.*/*.*.*/host*/fc_host/host*/statistics/.
(cf. v4.9 commit bd77befa5bcf ("zfcp: fix fc_host port_type with NPIV"))
This is particularly confusing when using "lszfcp -b <fcpdevbusid> -Ha" or
dbginfo.sh which read fc_host attributes and also scsi_host attributes.
After link down, the first invocation produces (abbreviated):
Factor out the resetting of local link dependent fc_host attributes from
zfcp_fsf_exchange_config_data_handler() case
FSF_EXCHANGE_CONFIG_DATA_INCOMPLETE into a new helper function
zfcp_fsf_fc_host_link_down(). All code places that detect local link down
(SRB, FSF_PROT_LINK_DOWN, xconf data/port incomplete) call
zfcp_fsf_link_down_info_eval(). Call the new helper from there. This works
because zfcp_fsf_link_down_info_eval() and thus the helper is called before
zfcp_fsf_exchange_{config,port}_evaluate().
Port_name and node_name are always valid, so never reset them.
Get the permanent_port_name from exchange port data unconditionally as it
always has a valid known good value, even during link down.
Note: Rather than hardcode in zfcp_fsf_exchange_config_evaluate(), fc_host
supported_classes could theoretically get its value from
fsf_qtcb_bottom_port.class_of_service in zfcp_fsf_exchange_port_evaluate().
When the link comes back, we get a different notification, perform adapter
recovery, and this triggers an implicit exchange config data followed by
exchange port data filling in the link dependent fc_host attributes with
known good values again.
Link: https://lore.kernel.org/r/20200312174505.51294-5-maier@linux.ibm.com Reviewed-by: Jens Remus <jremus@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Steffen Maier [Thu, 12 Mar 2020 17:44:58 +0000 (18:44 +0100)]
scsi: zfcp: wire previously driver-specific sysfs attributes also to fc_host
Manufacturer, HBA model, firmware version, and hardware version. Use the
same value format as for the driver-specific attributes. Keep the
driver-specific attributes for stable user space sysfs API.
Link: https://lore.kernel.org/r/20200312174505.51294-4-maier@linux.ibm.com Reviewed-by: Jens Remus <jremus@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Each FCP channel of these card features might need one SAN fabric re-login
after concurrent microcode update in order to show the proper fabric name.
Possible ways to trigger a SAN fabric re-login are one of: Pull fibres
between FCP channel port and SAN switch port on either side and re-plug,
disable SAN switch port adjacent to FCP channel port and re-enable switch
port, or at Service Element toggle off all CHPIDs of FCP channel over all
LPARs and toggle CHPIDs on again. Zfcp operating subchannels (FCP devices)
on such FCP channel recovers a fabric re-login.
Initialize fabric name for any topology and have it an invalid WWPN 0x0 for
anything but fabric topology. Otherwise for e.g. point-to-point topology
one could see the initial -1 from fc_host_setup() and after a link unplug
our fabric name would turn to 0x0 (with subsequent commit ("zfcp: fix
fc_host attributes that should be unknown on local link down") and stay 0x0
on link replug. I did not initialize to 0x0 somewhere even earlier in the
code path such that it would not flap from real to 0x0 to real on e.g. an
exchange config data with fabric topology.
Link: https://lore.kernel.org/r/20200312174505.51294-3-maier@linux.ibm.com Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Jens Remus <jremus@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Before that, the user had to use the sysfs attribute "port_add" of an FCP
device (adapter) to add and open remote (target) ports, even for the remote
peer port in point-to-point topology. That code path did a proper port open
recovery trigger taking the erp_lock.
Since above commit, a new helper function zfcp_erp_open_ptp_port()
performed an UNlocked port open recovery trigger. This can race with other
parallel recovery triggers. In zfcp_erp_action_enqueue() this could corrupt
e.g. adapter->erp_total_count or adapter->erp_ready_head.
As already found for fabric topology in v4.17 commit fa89adba1941 ("scsi:
zfcp: fix infinite iteration on ERP ready list"), there was an endless loop
during tracing of rport (un)block. A subsequent v4.18 commit 9e156c54ace3
("scsi: zfcp: assert that the ERP lock is held when tracing a recovery
trigger") introduced a lockdep assertion for that case.
As a side effect, that lockdep assertion now uncovered the unlocked code
path for PtP. It is from within an adapter ERP action:
zfcp_erp_strategy[1479] intentionally DROPs erp lock around
zfcp_erp_strategy_do_action()
zfcp_erp_strategy_do_action[1441] NO erp lock
zfcp_erp_adapter_strategy[876] NO erp lock
zfcp_erp_adapter_strategy_open[855] NO erp lock
zfcp_erp_adapter_strategy_open_fsf[806]NO erp lock
zfcp_erp_adapter_strat_fsf_xconf[772] erp lock only around
zfcp_erp_action_to_running(),
BUT *_not_* around
zfcp_erp_enqueue_ptp_port()
zfcp_erp_enqueue_ptp_port[728] BUG: *_not_* taking erp lock
_zfcp_erp_port_reopen[432] assumes to be called with erp lock
zfcp_erp_action_enqueue[314] assumes to be called with erp lock
zfcp_dbf_rec_trig[288] _checks_ to be called with erp lock:
lockdep_assert_held(&adapter->erp_lock);
It causes the following lockdep warning:
WARNING: CPU: 2 PID: 775 at drivers/s390/scsi/zfcp_dbf.c:288
zfcp_dbf_rec_trig+0x16a/0x188
no locks held by zfcperp0.0.17c0/775.
Fix this by using the proper locked recovery trigger helper function.
Link: https://lore.kernel.org/r/20200312174505.51294-2-maier@linux.ibm.com Fixes: cc8c282963bd ("[SCSI] zfcp: Automatically attach remote ports") Cc: <stable@vger.kernel.org> #v2.6.27+ Reviewed-by: Jens Remus <jremus@linux.ibm.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Signed-off-by: Steffen Maier <maier@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bart Van Assche [Fri, 13 Mar 2020 20:31:02 +0000 (13:31 -0700)]
scsi: scsi_trace: Use get_unaligned_be24()
This makes the SCSI tracing code slightly easier to read.
Link: https://lore.kernel.org/r/20200313203102.16613-6-bvanassche@acm.org Fixes: bf8162354233 ("[SCSI] add scsi trace core functions and put trace points") Cc: Christoph Hellwig <hch@lst.de> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Reported-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bart Van Assche [Fri, 13 Mar 2020 20:31:01 +0000 (13:31 -0700)]
scsi: st: Use get_unaligned_be24() and sign_extend32()
Use these functions instead of open-coding them.
Link: https://lore.kernel.org/r/20200313203102.16613-5-bvanassche@acm.org Cc: Kai Makisara <Kai.Makisara@kolumbus.fi> Cc: James E.J. Bottomley <jejb@linux.ibm.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Move the get_unaligned_be24(), get_unaligned_le24() and
put_unaligned_le24() definitions from various drivers into
include/linux/unaligned/generic.h. Add a put_unaligned_be24()
implementation.
Link: https://lore.kernel.org/r/20200313203102.16613-4-bvanassche@acm.org Cc: Keith Busch <kbusch@kernel.org> Cc: Sagi Grimberg <sagi@grimberg.me> Cc: Jens Axboe <axboe@fb.com> Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> # For drivers/usb Reviewed-by: Felipe Balbi <balbi@kernel.org> # For drivers/usb/gadget Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Bart Van Assche [Fri, 13 Mar 2020 20:30:59 +0000 (13:30 -0700)]
scsi: c6x: Include <linux/unaligned/generic.h> instead of duplicating it
Use the generic __{get,put}_unaligned_[bl]e() definitions instead of
duplicating these. Since a later patch will add more definitions into
<linux/unaligned/generic.h>, this patch ensures that these definitions have
to be added only once. See also commit a7f626c1948a ("C6X: headers"). See
also commit 6510d41954dc ("kernel: Move arches to use common unaligned
access").
Link: https://lore.kernel.org/r/20200313203102.16613-3-bvanassche@acm.org Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Mark Salter <msalter@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
The C language supports implicitly casting a void pointer into a non-void
pointer. Remove explicit void pointer to non-void pointer casts because
these are superfluous.
Link: https://lore.kernel.org/r/20200313203102.16613-2-bvanassche@acm.org Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Ryan Attard [Wed, 26 Feb 2020 17:05:19 +0000 (11:05 -0600)]
scsi: core: Allow non-root users to perform ZBC commands
Allow users with read permissions to issue REPORT ZONE commands and users
with write permissions to manage zones on block devices supporting the ZBC
specification.
Ewan D. Milne [Wed, 11 Mar 2020 14:39:30 +0000 (10:39 -0400)]
scsi: core: avoid repetitive logging of device offline messages
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.
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.
scsi: qla2xxx: add ring buffer for tracing debug logs
Having this log in a ring buffer helps to diagnose qla2xxx driver and
firmware issues instead of having to reproduce the problem with
extended_logging enabled. This saves cycles and helps when it is hard
to reproduce problem.
drivers/scsi/aacraid/aachba.c:813:23:
warning: cast between incompatible function types from
'int (*)(struct scsi_cmnd *)' to 'void (*)(struct scsi_cmnd *)'
[-Wcast-function-type]
Link: https://lore.kernel.org/r/20200309155319.12658-1-tranmanphong@gmail.com Reviewed-by: Bart van Assche <bvanassche@acm.org> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Phong Tran <tranmanphong@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Stanley Chu [Mon, 2 Mar 2020 13:53:46 +0000 (21:53 +0800)]
scsi: ufs-mediatek: fix HOST_PA_TACTIVATE quirk for Samsung UFS Devices
Device quirk "UFS_DEVICE_QUIRK_HOST_PA_TACTIVATE" is enabled for all
Samsung devices by default currently.
However MediaTek UFS host requires different host PA_TACTIVATE
configuration. Hence clear this quirk first and then apply vendor-specific
value in vops callback.
Randy Dunlap [Sun, 8 Mar 2020 05:01:15 +0000 (21:01 -0800)]
scsi: fusion: fix if-statement empty body warning
When driver debugging is not enabled, change the debug print macros
to use the no_printk() macro.
This fixes a gcc warning when -Wextra is set:
../drivers/message/fusion/mptlan.c:266:39: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
I have verified that there is very little object code change (with
gcc 7.5.0). There are a few changes like:
cmp %a,%b
jl $1
to
cmp %b,%a
jg $1
Link: https://lore.kernel.org/r/ff9df31b-c4c1-c942-1cbf-18039e084c8e@infradead.org Cc: Bart Van Assche <bvanassche@acm.org> Cc: "James E.J. Bottomley" <jejb@linux.ibm.com> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: linux-scsi@vger.kernel.org Cc: MPT-FusionLinux.pdl@broadcom.com Cc: Suganath Prabu Subramani <suganath-prabu.subramani@broadcom.com> Cc: Chaitra P B <chaitra.basappa@broadcom.com> Cc: Sathya Prakash <sathya.prakash@broadcom.com> Reviewed-by: Bart van Assche <bvanassche@acm.org> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Frank Mayhar [Thu, 27 Feb 2020 19:59:45 +0000 (14:59 -0500)]
scsi: iscsi: Add support for asynchronous iSCSI session destruction
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>
Sagar Biradar [Thu, 13 Feb 2020 00:29:31 +0000 (16:29 -0800)]
scsi: aacraid: Disabling TM path and only processing IOP reset
Fixes the occasional adapter panic when sg_reset is issued with -d, -t, -b
and -H flags. Removal of command type HBA_IU_TYPE_SCSI_TM_REQ in
aac_hba_send since iu_type, request_id and fib_flags are not populated.
Device and target reset handlers are made to send TMF commands only when
reset_state is 0.
Brian King [Thu, 27 Feb 2020 01:45:43 +0000 (19:45 -0600)]
scsi: ibmvfc: Avoid loss of all paths during SVC node reboot
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.
scsi: Replace zero-length array with flexible-array member
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]
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>
projects / thirdparty / linux.git / log
