diff options
| author | Hannes Reinecke <hare@suse.de> | 2025-10-31 13:39:12 -0700 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2025-11-12 17:02:31 -0500 |
| commit | d630fbf6fc8ce2fc95de7784de5499387b682dc1 (patch) | |
| tree | a774fbc162d725be584dc20d8b1a2f9307d4aad8 /include | |
| parent | a47c7bef57858d29b83cd7f101112f52821439f9 (diff) | |
scsi: core: Support allocating a pseudo SCSI device
Allocate a pseudo SCSI device if 'nr_reserved_cmds' has been set. Pseudo
SCSI devices have the SCSI ID <max_id>:U64_MAX so they won't clash with
any devices the LLD might create. Pseudo SCSI devices are excluded from
scanning and will not show up in sysfs. Additionally, pseudo SCSI
devices are skipped by shost_for_each_device(). This prevents that the
SCSI error handler tries to submit a reset to a non-existent logical
unit.
Do not allocate a budget map for pseudo SCSI devices since the
cmd_per_lun limit does not apply to pseudo SCSI devices.
Do not perform queue depth ramp up / ramp down for pseudo SCSI devices.
Pseudo SCSI devices will be used to send internal commands to a storage
device.
[ bvanassche: edited patch description / renamed host_sdev into
pseudo_sdev / unexported scsi_get_host_dev() / modified error path in
scsi_get_pseudo_dev() / skip pseudo devices in __scsi_iterate_devices()
and also when calling sdev_init(), sdev_configure() and sdev_destroy().
See also
https://lore.kernel.org/linux-scsi/20211125151048.103910-2-hare@suse.de/ ]
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://patch.msgid.link/20251031204029.2883185-5-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/scsi/scsi_device.h | 16 | ||||
| -rw-r--r-- | include/scsi/scsi_host.h | 6 |
2 files changed, 22 insertions, 0 deletions
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 4c106342c4ae..918631088711 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -589,6 +589,22 @@ static inline unsigned int sdev_id(struct scsi_device *sdev) #define scmd_id(scmd) sdev_id((scmd)->device) #define scmd_channel(scmd) sdev_channel((scmd)->device) +/** + * scsi_device_is_pseudo_dev() - Whether a device is a pseudo SCSI device. + * @sdev: SCSI device to examine + * + * A pseudo SCSI device can be used to allocate SCSI commands but does not show + * up in sysfs. Additionally, the logical unit information in *@sdev is made up. + * + * This function tests the LUN number instead of comparing @sdev with + * @sdev->host->pseudo_sdev because this function may be called before + * @sdev->host->pseudo_sdev has been initialized. + */ +static inline bool scsi_device_is_pseudo_dev(struct scsi_device *sdev) +{ + return sdev->lun == U64_MAX; +} + /* * checks for positions of the SCSI state machine */ diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 7b8f144ccf7d..4f945a20d198 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -722,6 +722,12 @@ struct Scsi_Host { struct device shost_gendev, shost_dev; /* + * A SCSI device structure used for sending internal commands to the + * HBA. There is no corresponding logical unit inside the SCSI device. + */ + struct scsi_device *pseudo_sdev; + + /* * Points to the transport data (if any) which is allocated * separately */ |