From 1b22cfb14142aba7742d307c4f8d7006f919308c Mon Sep 17 00:00:00 2001 From: Damien Le Moal Date: Thu, 11 May 2023 03:13:42 +0200 Subject: scsi: core: Allow enabling and disabling command duration limits Add the sysfs scsi_device attribute cdl_enable to allow a user to enable or disable a device command duration limits feature. CDL is disabled by default. This feature must be explicitly enabled by a user by setting the cdl_enable attribute to 1. The new function scsi_cdl_enable() does not do anything beside setting the cdl_enable field of struct scsi_device in the case of a (real) SCSI device (e.g. a SAS HDD). For ATA devices, the command duration limits feature needs to be enabled/disabled using the ATA feature sub-page of the control mode page. To do so, the scsi_cdl_enable() function checks if this mode page is supported using scsi_mode_sense(). If it is, scsi_mode_select() is used to enable and disable CDL. Signed-off-by: Damien Le Moal Reviewed-by: Hannes Reinecke Co-developed-by: Niklas Cassel Signed-off-by: Niklas Cassel Link: https://lore.kernel.org/r/20230511011356.227789-10-nks@flawful.org Signed-off-by: Martin K. Petersen --- drivers/scsi/scsi.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) (limited to 'drivers/scsi/scsi.c') diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index c03814ce23ca..c4bf99a842f3 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -651,6 +651,68 @@ void scsi_cdl_check(struct scsi_device *sdev) kfree(buf); } +/** + * scsi_cdl_enable - Enable or disable a SCSI device supports for Command + * Duration Limits + * @sdev: The target device + * @enable: the target state + */ +int scsi_cdl_enable(struct scsi_device *sdev, bool enable) +{ + struct scsi_mode_data data; + struct scsi_sense_hdr sshdr; + struct scsi_vpd *vpd; + bool is_ata = false; + char buf[64]; + int ret; + + if (!sdev->cdl_supported) + return -EOPNOTSUPP; + + rcu_read_lock(); + vpd = rcu_dereference(sdev->vpd_pg89); + if (vpd) + is_ata = true; + rcu_read_unlock(); + + /* + * For ATA devices, CDL needs to be enabled with a SET FEATURES command. + */ + if (is_ata) { + char *buf_data; + int len; + + ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf), + 5 * HZ, 3, &data, NULL); + if (ret) + return -EINVAL; + + /* Enable CDL using the ATA feature page */ + len = min_t(size_t, sizeof(buf), + data.length - data.header_length - + data.block_descriptor_length); + buf_data = buf + data.header_length + + data.block_descriptor_length; + if (enable) + buf_data[4] = 0x02; + else + buf_data[4] = 0; + + ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3, + &data, &sshdr); + if (ret) { + if (scsi_sense_valid(&sshdr)) + scsi_print_sense_hdr(sdev, + dev_name(&sdev->sdev_gendev), &sshdr); + return ret; + } + } + + sdev->cdl_enable = enable; + + return 0; +} + /** * scsi_device_get - get an additional reference to a scsi_device * @sdev: device to get a reference to -- cgit v1.2.3