• Damien Le Moal's avatar
    scsi: core: Disable CDL by default · 52912ca8
    Damien Le Moal authored
    For SCSI devices supporting the Command Duration Limits feature set, the
    user can enable/disable this feature use through the sysfs device attribute
    "cdl_enable". This attribute modification triggers a call to
    scsi_cdl_enable() to enable and disable the feature for ATA devices and set
    the scsi device cdl_enable field to the user provided bool value.  For SCSI
    devices supporting CDL, the feature set is always enabled and
    scsi_cdl_enable() is reduced to setting the cdl_enable field.
    
    However, for ATA devices, a drive may spin-up with the CDL feature enabled
    by default. But the SCSI device cdl_enable field is always initialized to
    false (CDL disabled), regardless of the actual device CDL feature
    state. For ATA devices managed by libata (or libsas), libata-core always
    disables the CDL feature set when the device is attached, thus syncing the
    state of the CDL feature on the device and of the SCSI device cdl_enable
    field. However, for ATA devices connected to a SAS HBA, the CDL feature is
    not disabled on scan for ATA devices that have this feature enabled by
    default, leading to an inconsistent state of the feature on the device with
    the SCSI device cdl_enable field.
    
    Avoid this inconsistency by adding a call to scsi_cdl_enable() in
    scsi_cdl_check() to make sure that the device-side state of the CDL feature
    set always matches the scsi device cdl_enable field state.  This implies
    that CDL will always be disabled for ATA devices connected to SAS HBAs,
    which is consistent with libata/libsas initialization of the device.
    Reported-by: default avatarScott McCoy <scott.mccoy@wdc.com>
    Fixes: 1b22cfb1 ("scsi: core: Allow enabling and disabling command duration limits")
    Cc: stable@vger.kernel.org
    Signed-off-by: default avatarDamien Le Moal <dlemoal@kernel.org>
    Link: https://lore.kernel.org/r/20240607012507.111488-1-dlemoal@kernel.orgReviewed-by: default avatarNiklas Cassel <cassel@kernel.org>
    Reviewed-by: default avatarIgor Pylypiv <ipylypiv@google.com>
    Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
    Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
    Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
    52912ca8
scsi.c 28.4 KB