Subject: scsi_dh: add skeleton for SCSI Device Handlers From: Chandra Seetharaman <sekharan@xxxxxxxxxx> Add base support to the SCSI subsystem for SCSI device handlers. Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx> Signed-off-by: Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx> --- drivers/scsi/Kconfig | 2 2 + 0 - 0 ! drivers/scsi/Makefile | 1 1 + 0 - 0 ! drivers/scsi/device_handler/Kconfig | 12 12 + 0 - 0 ! drivers/scsi/device_handler/Makefile | 4 4 + 0 - 0 ! drivers/scsi/device_handler/scsi_dh.c | 146 146 + 0 - 0 ! drivers/scsi/scsi_error.c | 10 10 + 0 - 0 ! drivers/scsi/scsi_lib.c | 5 5 + 0 - 0 ! include/scsi/scsi_device.h | 18 18 + 0 - 0 ! include/scsi/scsi_dh.h | 58 58 + 0 - 0 ! 9 files changed, 256 insertions(+) Index: linux-2.6.25-rc2-mm1/drivers/scsi/Kconfig =================================================================== --- linux-2.6.25-rc2-mm1.orig/drivers/scsi/Kconfig +++ linux-2.6.25-rc2-mm1/drivers/scsi/Kconfig @@ -1749,4 +1749,6 @@ endif # SCSI_LOWLEVEL source "drivers/scsi/pcmcia/Kconfig" +source "drivers/scsi/device_handler/Kconfig" + endmenu Index: linux-2.6.25-rc2-mm1/drivers/scsi/Makefile =================================================================== --- linux-2.6.25-rc2-mm1.orig/drivers/scsi/Makefile +++ linux-2.6.25-rc2-mm1/drivers/scsi/Makefile @@ -34,6 +34,7 @@ obj-$(CONFIG_SCSI_ISCSI_ATTRS) += scsi_t obj-$(CONFIG_SCSI_SAS_ATTRS) += scsi_transport_sas.o obj-$(CONFIG_SCSI_SAS_LIBSAS) += libsas/ obj-$(CONFIG_SCSI_SRP_ATTRS) += scsi_transport_srp.o +obj-$(CONFIG_SCSI_DH) += device_handler/ obj-$(CONFIG_ISCSI_TCP) += libiscsi.o iscsi_tcp.o obj-$(CONFIG_INFINIBAND_ISER) += libiscsi.o Index: linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/Kconfig =================================================================== --- /dev/null +++ linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/Kconfig @@ -0,0 +1,12 @@ +# +# SCSI Device Handler configuration +# + +menuconfig SCSI_DH + bool "SCSI Device Handlers" + depends on SCSI!=n + default n + help + SCSI Device Handlers provide device specific support for + devices utilized in multipath configurations. Say Y here to + select support for specific hardware. Index: linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/Makefile =================================================================== --- /dev/null +++ linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/Makefile @@ -0,0 +1,4 @@ +# +# SCSI Device Handler +# +obj-$(CONFIG_SCSI_DH) += scsi_dh.o Index: linux-2.6.25-rc2-mm1/drivers/scsi/scsi_error.c =================================================================== --- linux-2.6.25-rc2-mm1.orig/drivers/scsi/scsi_error.c +++ linux-2.6.25-rc2-mm1/drivers/scsi/scsi_error.c @@ -298,6 +298,7 @@ static inline void scsi_eh_prt_fail_stat */ static int scsi_check_sense(struct scsi_cmnd *scmd) { + struct scsi_device *sdev = scmd->device; struct scsi_sense_hdr sshdr; if (! scsi_command_normalize_sense(scmd, &sshdr)) @@ -306,6 +307,15 @@ static int scsi_check_sense(struct scsi_ if (scsi_sense_is_deferred(&sshdr)) return NEEDS_RETRY; + if (sdev->sdev_dh && sdev->sdev_dh->check_sense) { + int rc; + + rc = sdev->sdev_dh->check_sense(sdev, &sshdr); + if (rc != SUCCESS) + return rc; + /* handler does not care. Drop down to default handling */ + } + /* * Previous logic looked for FILEMARK, EOM or ILI which are * mainly associated with tapes and returned SUCCESS. Index: linux-2.6.25-rc2-mm1/include/scsi/scsi_device.h =================================================================== --- linux-2.6.25-rc2-mm1.orig/include/scsi/scsi_device.h +++ linux-2.6.25-rc2-mm1/include/scsi/scsi_device.h @@ -161,9 +161,25 @@ struct scsi_device { struct execute_work ew; /* used to get process context on put */ + struct scsi_device_handler *sdev_dh; + void *sdev_dh_data; enum scsi_device_state sdev_state; unsigned long sdev_data[0]; } __attribute__((aligned(sizeof(unsigned long)))); + +struct scsi_device_handler { + /* Used by the infrastructure */ + struct list_head list; /* list of scsi_device_handlers */ + struct notifier_block nb; + + /* Filled by the hardware handler */ + struct module *module; + const char *name; + int (*check_sense)(struct scsi_device *, struct scsi_sense_hdr *); + int (*activate)(struct scsi_device *); + int (*prep_fn)(struct scsi_device *); +}; + #define to_scsi_device(d) \ container_of(d, struct scsi_device, sdev_gendev) #define class_to_sdev(d) \ @@ -229,7 +245,9 @@ extern struct scsi_device *__scsi_add_de uint, uint, uint, void *hostdata); extern int scsi_add_device(struct Scsi_Host *host, uint channel, uint target, uint lun); +extern int scsi_register_device_handler(struct scsi_device_handler *sdev_dh); extern void scsi_remove_device(struct scsi_device *); +extern int scsi_unregister_device_handler(struct scsi_device_handler *sdev_dh); extern int scsi_device_get(struct scsi_device *); extern void scsi_device_put(struct scsi_device *); Index: linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/scsi_dh.c =================================================================== --- /dev/null +++ linux-2.6.25-rc2-mm1/drivers/scsi/device_handler/scsi_dh.c @@ -0,0 +1,146 @@ +/* + * SCSI device handler infrastruture. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2007 + * Authors: + * Chandra Seetharaman <sekharan@xxxxxxxxxx> + * Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> + */ + +#include <scsi/scsi_dh.h> +#include "../scsi_priv.h" + +static DEFINE_SPINLOCK(list_lock); +static LIST_HEAD(scsi_dh_list); + +static struct scsi_device_handler *get_device_handler(const char *name) +{ + struct scsi_device_handler *tmp, *found = NULL; + + spin_lock(&list_lock); + list_for_each_entry(tmp, &scsi_dh_list, list) { + if (!strcmp(tmp->name, name)) { + found = tmp; + break; + } + } + spin_unlock(&list_lock); + return found; +} + +static int scsi_dh_notifier_add(struct device *dev, void *data) +{ + struct scsi_device_handler *sdev_dh = data; + + sdev_dh->nb.notifier_call(&sdev_dh->nb, BUS_NOTIFY_ADD_DEVICE, dev); + return 0; +} + +/* + * scsi_register_device_handler - register a device handler personality + * module. + * @sdev_dh - device handler to be registered. + * + * Returns 0 on success, -EBUSY if handler already registered. + */ +int scsi_register_device_handler(struct scsi_device_handler *sdev_dh) +{ + int ret = -EBUSY; + struct scsi_device_handler *tmp; + + tmp = get_device_handler(sdev_dh->name); + if (tmp) + goto done; + + ret = bus_register_notifier(&scsi_bus_type, &sdev_dh->nb); + + bus_for_each_dev(&scsi_bus_type, NULL, sdev_dh, scsi_dh_notifier_add); + spin_lock(&list_lock); + list_add(&sdev_dh->list, &scsi_dh_list); + spin_unlock(&list_lock); + +done: + return ret; +} +EXPORT_SYMBOL_GPL(scsi_register_device_handler); + +static int scsi_dh_notifier_remove(struct device *dev, void *data) +{ + struct scsi_device_handler *sdev_dh = data; + + sdev_dh->nb.notifier_call(&sdev_dh->nb, BUS_NOTIFY_DEL_DEVICE, dev); + return 0; +} + +/* + * scsi_unregister_device_handler - register a device handler personality + * module. + * @sdev_dh - device handler to be unregistered. + * + * Returns 0 on success, -ENODEV if handler not registered. + */ +int scsi_unregister_device_handler(struct scsi_device_handler *sdev_dh) +{ + int ret = -ENODEV; + struct scsi_device_handler *tmp; + + tmp = get_device_handler(sdev_dh->name); + if (!tmp) + goto done; + + ret = bus_unregister_notifier(&scsi_bus_type, &sdev_dh->nb); + + bus_for_each_dev(&scsi_bus_type, NULL, sdev_dh, + scsi_dh_notifier_remove); + spin_lock(&list_lock); + list_del(&sdev_dh->list); + spin_unlock(&list_lock); + +done: + return ret; +} +EXPORT_SYMBOL_GPL(scsi_unregister_device_handler); + +/* + * scsi_dh_activate - activate the path associated with the scsi_device + * corresponding to the given request queue. + * @q - Request queue that is associated with the scsi_device to be + * activated. + */ +int scsi_dh_activate(struct request_queue *q) +{ + int err = SCSI_DH_NOSYS; + struct scsi_device *sdev; + struct scsi_device_handler *sdev_dh; + unsigned long flags; + + spin_lock_irqsave(q->queue_lock, flags); + sdev = q->queuedata; + sdev_dh = sdev->sdev_dh; + if (!sdev || !sdev_dh || !get_device(&sdev->sdev_gendev)) { + spin_unlock_irqrestore(q->queue_lock, flags); + goto done; + } + spin_unlock_irqrestore(q->queue_lock, flags); + + if (sdev_dh->activate) + err = sdev_dh->activate(sdev); + put_device(&sdev->sdev_gendev); +done: + return err; +} +EXPORT_SYMBOL_GPL(scsi_dh_activate); Index: linux-2.6.25-rc2-mm1/include/scsi/scsi_dh.h =================================================================== --- /dev/null +++ linux-2.6.25-rc2-mm1/include/scsi/scsi_dh.h @@ -0,0 +1,58 @@ +/* + * Header file for SCSI device handler infrastruture. + * + * Modified version of patches posted by Mike Christie <michaelc@xxxxxxxxxxx> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright IBM Corporation, 2007 + * Authors: + * Chandra Seetharaman <sekharan@xxxxxxxxxx> + * Mike Anderson <andmike@xxxxxxxxxxxxxxxxxx> + */ + +#include <scsi/scsi_device.h> + +enum { + SCSI_DH_OK = 0, + /* + * device errors + */ + SCSI_DH_DEV_FAILED, /* generic device error */ + SCSI_DH_DEV_TEMP_BUSY, + SCSI_DH_DEVICE_MAX, /* max device blkerr definition */ + + /* + * transport errors + */ + SCSI_DH_NOTCONN = SCSI_DH_DEVICE_MAX + 1, + SCSI_DH_CONN_FAILURE, + SCSI_DH_TRANSPORT_MAX, /* max transport blkerr definition */ + + /* + * driver and generic errors + */ + SCSI_DH_IO = SCSI_DH_TRANSPORT_MAX + 1, /* generic error */ + SCSI_DH_INVALID_IO, + SCSI_DH_RETRY, /* retry the req, but not immediately */ + SCSI_DH_IMM_RETRY, /* immediately retry the req */ + SCSI_DH_TIMED_OUT, + SCSI_DH_RES_TEMP_UNAVAIL, + SCSI_DH_DEV_OFFLINED, + SCSI_DH_NOSYS, + SCSI_DH_DRIVER_MAX, +}; + +extern int scsi_dh_activate(struct request_queue *); Index: linux-2.6.25-rc2-mm1/drivers/scsi/scsi_lib.c =================================================================== --- linux-2.6.25-rc2-mm1.orig/drivers/scsi/scsi_lib.c +++ linux-2.6.25-rc2-mm1/drivers/scsi/scsi_lib.c @@ -1156,6 +1156,11 @@ int scsi_setup_fs_cmnd(struct scsi_devic struct scsi_cmnd *cmd; int ret = scsi_prep_state_check(sdev, req); + if ((ret == BLKPREP_OK) && (req->cmd_type == REQ_TYPE_FS)) { + if (sdev->sdev_dh && sdev->sdev_dh->prep_fn) + ret = sdev->sdev_dh->prep_fn(sdev); + } + if (ret != BLKPREP_OK) return ret; /* -- ---------------------------------------------------------------------- Chandra Seetharaman | Be careful what you choose.... - sekharan@xxxxxxxxxx | .......you may get it. ---------------------------------------------------------------------- -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel