linux-stable.git/drivers/scsi/scsi_debug.c, branch v5.8

scsi: scsi_debug: Parser tables and code interaction

2020-05-20T02:25:52+00:00

This patch is in response to a static analyser report from Dan Carpenter
titled: "[bug report] scsi: scsi_debug: Add per_host_store option".  This
code may not clear the static analyzer reports, but may shed light on why
they occur. Amongst other things this driver has a table driven SCSI
command parser which also involves some C code. There are some invariants
between the table entries and the corresponding C code (i.e. the resp_*()
functions) that, if broken, may lead to a NULL dereference.  And the report
is valid, at least in the case of the PRE-FETCH command.  Alas, that is not
one of the cases that the static analyzer reported.

In this particular corner case: when the fake_rw flag is set and the table
entry for a "store"-accessing command does not have the required F_FAKE_RW
flag set, do the following. Call BUG_ON() in the devip2sip() very close to
a comment block explaining why it was called and how to fix it.
checkpatch.pl complains about the BUG_ON() but there is no reasonable
remedial action that can be taken at run time.

This change allows the code reported by the static analyzer to be
simplified. Comments were also added to the table flags (e.g.  F_FAKE_RW)
so developers who add commands might be more inclined to use them
(properly).

Link: https://lore.kernel.org/r/20200513013943.25285-1-dgilbert@interlog.com
Reported-by: Dan Carpenter 
Signed-off-by: Douglas Gilbert 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Fix an error handling bug in sdeb_zbc_model_str()

2020-05-12T03:21:27+00:00

This test is checking the wrong variable.  It should be testing "res".
The "sdeb_zbc_model" variable is an enum (unsigned in this situation)
and we never assign negative values to it.

[mkp: fixed commit desc issue reported by Doug]

Link: https://lore.kernel.org/r/20200509100408.GA5555@mwanda
Fixes: 9267e0eb41fe ("scsi: scsi_debug: Add ZBC module parameter")
Acked-by: Douglas Gilbert 
Signed-off-by: Dan Carpenter 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Disallow zone sizes that are not powers of 2

2020-05-08T00:45:02+00:00

Allowing a non-power-of-2 zone size forces the use of direct division
operations of 64-bit sector values to obtain a zone number or number of
zones. Doing so without using do_div() leads to compilation errors on
32-bit architectures.

Devices with a zone size that is not a power of 2 do not exist today so
allowing their emulation is of limited interest as the sd driver will not
support them anyway. To fix this compilation error, instead of using
do_div() for sector values divisions, simply disallow zone size values that
are not a power of 2.

[mkp: commit desc]

Link: https://lore.kernel.org/r/20200507023526.221574-1-damien.lemoal@wdc.com
Fixes: 98e0a689868c ("scsi: scsi_debug: Add zone_size_mb module parameter")
Fixes: f0d1cf9378bd ("scsi: scsi_debug: Add ZBC zone commands")
Reviewed-by: Johannes Thumshirn 
Acked-by: Geert Uytterhoeven 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Implement ZBC host-aware emulation

2020-05-05T04:37:34+00:00

Implement ZBC host-aware device model emulation. The main changes from the
host-managed emulation are the device type (TYPE_DISK is used), relaxation
of access checks for read and write operations and different handling of a
sequential write preferred zone write pointer as mandated by the ZBC r05
specifications.

To facilitate the implementation and avoid a lot of "if" statement, the
zmodel field is added to the device information and the z_type field to the
zone state data structure.

Link: https://lore.kernel.org/r/20200422104221.378203-8-damien.lemoal@wdc.com
Tested-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add zone_size_mb module parameter

2020-05-05T04:37:33+00:00

Add the zone_size_mb module parameters to control the zone size of a ZBC
device. If the zone size specified is not a divisor of the device capacity,
the last zone of the device will be created as a smaller "runt" zone. This
parameter is ignored for device types other than 0x14 (zbc=2 case).

Note: for testing purposes, zone sizes that are not a power of 2 are
accepted but will result in the drive being rejected by the sd driver.

Link: https://lore.kernel.org/r/20200422104221.378203-7-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add zone_nr_conv module parameter

2020-05-05T04:37:32+00:00

Allow controlling the number of conventional zones of a ZBC device with the
new zone_nr_conv module parameter. The default value is 1 and the specified
value must be less than the total number of zones of the device. This
parameter is ignored for device types other than 0x14 (zbc=2 case).

Link: https://lore.kernel.org/r/20200422104221.378203-6-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add zone_max_open module parameter

2020-05-05T04:37:32+00:00

Add the zone_max_open module parameters to control the maximum number of
open zones of a ZBC device. This parameter is ignored for device types
other than 0x14 (zbc=2 case).

Link: https://lore.kernel.org/r/20200422104221.378203-5-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add ZBC module parameter

2020-05-05T04:37:31+00:00

Add the zbc module parameter to take either:
    0: none         (probably a conventional disk)
    1: host-aware
    2: host-managed

These values are chosen to match 'enum blk_zoned_model' found in
include/linux/blkdev.h . Instead of "none", "no" or "0" can be given.
Instead of "host-aware", "aware or "1" can be given. Instead of
"host-managed", "managed" or "2" can be given.

Note: the zbc parameter can only be given at driver/module load time; it
cannot be changed via sysfs thereafter.

At this time there is no ZBC "host-aware" implementation so that string (or
the value '1') results in a modprobe error.

Link: https://lore.kernel.org/r/20200422104221.378203-4-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add ZBC zone commands

2020-05-05T04:37:30+00:00

Add support for the 5 ZBC commands and enough functionality to emulate a
host-managed device with one conventional zone and a set of sequential
write-required zones up to the disk capacity.

Link: https://lore.kernel.org/r/20200422104221.378203-3-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen

scsi: scsi_debug: Add ZBC mode and VPD pages

2020-05-05T04:37:29+00:00

The ZBC standard "piggy-backs" on many, but not all, of the facilities in
SBC. Add those ZBC mode pages (plus mode parameter block descriptors
(e.g. "WP")) and VPD pages in common with SBC. Add ZBC specific VPD page
for the host-managed ZBC device type (ptype=0x14).

Link: https://lore.kernel.org/r/20200422104221.378203-2-damien.lemoal@wdc.com
Signed-off-by: Douglas Gilbert 
Signed-off-by: Damien Le Moal 
Signed-off-by: Martin K. Petersen