diff options
| -rw-r--r-- | Documentation/ABI/stable/sysfs-transport-srp | 31 | ||||
| -rw-r--r-- | drivers/scsi/scsi_transport_srp.c | 430 | ||||
| -rw-r--r-- | include/scsi/scsi_transport_srp.h | 74 |
3 files changed, 532 insertions, 3 deletions
diff --git a/Documentation/ABI/stable/sysfs-transport-srp b/Documentation/ABI/stable/sysfs-transport-srp index b36fb0dc13c8..8b6acc775b71 100644 --- a/Documentation/ABI/stable/sysfs-transport-srp +++ b/Documentation/ABI/stable/sysfs-transport-srp @@ -5,6 +5,24 @@ Contact: linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org Description: Instructs an SRP initiator to disconnect from a target and to remove all LUNs imported from that target. +What: /sys/class/srp_remote_ports/port-<h>:<n>/dev_loss_tmo +Date: February 1, 2014 +KernelVersion: 3.13 +Contact: linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org +Description: Number of seconds the SCSI layer will wait after a transport + layer error has been observed before removing a target port. + Zero means immediate removal. Setting this attribute to "off" + will disable the dev_loss timer. + +What: /sys/class/srp_remote_ports/port-<h>:<n>/fast_io_fail_tmo +Date: February 1, 2014 +KernelVersion: 3.13 +Contact: linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org +Description: Number of seconds the SCSI layer will wait after a transport + layer error has been observed before failing I/O. Zero means + failing I/O immediately. Setting this attribute to "off" will + disable the fast_io_fail timer. + What: /sys/class/srp_remote_ports/port-<h>:<n>/port_id Date: June 27, 2007 KernelVersion: 2.6.24 @@ -17,3 +35,16 @@ Date: June 27, 2007 KernelVersion: 2.6.24 Contact: linux-scsi@vger.kernel.org Description: Role of the remote port. Either "SRP Initiator" or "SRP Target". + +What: /sys/class/srp_remote_ports/port-<h>:<n>/state +Date: February 1, 2014 +KernelVersion: 3.13 +Contact: linux-scsi@vger.kernel.org, linux-rdma@vger.kernel.org +Description: State of the transport layer used for communication with the + remote port. "running" if the transport layer is operational; + "blocked" if a transport layer error has been encountered but + the fast_io_fail_tmo timer has not yet fired; "fail-fast" + after the fast_io_fail_tmo timer has fired and before the + "dev_loss_tmo" timer has fired; "lost" after the + "dev_loss_tmo" timer has fired and before the port is finally + removed. diff --git a/drivers/scsi/scsi_transport_srp.c b/drivers/scsi/scsi_transport_srp.c index f7ba94aa52cb..2696e26b3423 100644 --- a/drivers/scsi/scsi_transport_srp.c +++ b/drivers/scsi/scsi_transport_srp.c @@ -24,12 +24,15 @@ #include <linux/err.h> #include <linux/slab.h> #include <linux/string.h> +#include <linux/delay.h> #include <scsi/scsi.h> +#include <scsi/scsi_cmnd.h> #include <scsi/scsi_device.h> #include <scsi/scsi_host.h> #include <scsi/scsi_transport.h> #include <scsi/scsi_transport_srp.h> +#include "scsi_priv.h" #include "scsi_transport_srp_internal.h" struct srp_host_attrs { @@ -38,7 +41,7 @@ struct srp_host_attrs { #define to_srp_host_attrs(host) ((struct srp_host_attrs *)(host)->shost_data) #define SRP_HOST_ATTRS 0 -#define SRP_RPORT_ATTRS 3 +#define SRP_RPORT_ATTRS 6 struct srp_internal { struct scsi_transport_template t; @@ -54,6 +57,34 @@ struct srp_internal { #define dev_to_rport(d) container_of(d, struct srp_rport, dev) #define transport_class_to_srp_rport(dev) dev_to_rport((dev)->parent) +static inline struct Scsi_Host *rport_to_shost(struct srp_rport *r) +{ + return dev_to_shost(r->dev.parent); +} + +/** + * srp_tmo_valid() - check timeout combination validity + * + * The combination of the timeout parameters must be such that SCSI commands + * are finished in a reasonable time. Hence do not allow the fast I/O fail + * timeout to exceed SCSI_DEVICE_BLOCK_MAX_TIMEOUT. Furthermore, these + * parameters must be such that multipath can detect failed paths timely. + * Hence do not allow both parameters to be disabled simultaneously. + */ +int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo) +{ + if (fast_io_fail_tmo < 0 && dev_loss_tmo < 0) + return -EINVAL; + if (fast_io_fail_tmo > SCSI_DEVICE_BLOCK_MAX_TIMEOUT) + return -EINVAL; + if (dev_loss_tmo >= LONG_MAX / HZ) + return -EINVAL; + if (fast_io_fail_tmo >= 0 && dev_loss_tmo >= 0 && + fast_io_fail_tmo >= dev_loss_tmo) + return -EINVAL; + return 0; +} +EXPORT_SYMBOL_GPL(srp_tmo_valid); static int srp_host_setup(struct transport_container *tc, struct device *dev, struct device *cdev) @@ -134,10 +165,383 @@ static ssize_t store_srp_rport_delete(struct device *dev, static DEVICE_ATTR(delete, S_IWUSR, NULL, store_srp_rport_delete); +static ssize_t show_srp_rport_state(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + static const char *const state_name[] = { + [SRP_RPORT_RUNNING] = "running", + [SRP_RPORT_BLOCKED] = "blocked", + [SRP_RPORT_FAIL_FAST] = "fail-fast", + [SRP_RPORT_LOST] = "lost", + }; + struct srp_rport *rport = transport_class_to_srp_rport(dev); + enum srp_rport_state state = rport->state; + + return sprintf(buf, "%s\n", + (unsigned)state < ARRAY_SIZE(state_name) ? + state_name[state] : "???"); +} + +static DEVICE_ATTR(state, S_IRUGO, show_srp_rport_state, NULL); + +static ssize_t srp_show_tmo(char *buf, int tmo) +{ + return tmo >= 0 ? sprintf(buf, "%d\n", tmo) : sprintf(buf, "off\n"); +} + +static int srp_parse_tmo(int *tmo, const char *buf) +{ + int res = 0; + + if (strncmp(buf, "off", 3) != 0) + res = kstrtoint(buf, 0, tmo); + else + *tmo = -1; + + return res; +} + +static ssize_t show_srp_rport_fast_io_fail_tmo(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct srp_rport *rport = transport_class_to_srp_rport(dev); + + return srp_show_tmo(buf, rport->fast_io_fail_tmo); +} + +static ssize_t store_srp_rport_fast_io_fail_tmo(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct srp_rport *rport = transport_class_to_srp_rport(dev); + int res; + int fast_io_fail_tmo; + + res = srp_parse_tmo(&fast_io_fail_tmo, buf); + if (res) + goto out; + res = srp_tmo_valid(fast_io_fail_tmo, rport->dev_loss_tmo); + if (res) + goto out; + rport->fast_io_fail_tmo = fast_io_fail_tmo; + res = count; + +out: + return res; +} + +static DEVICE_ATTR(fast_io_fail_tmo, S_IRUGO | S_IWUSR, + show_srp_rport_fast_io_fail_tmo, + store_srp_rport_fast_io_fail_tmo); + +static ssize_t show_srp_rport_dev_loss_tmo(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct srp_rport *rport = transport_class_to_srp_rport(dev); + + return srp_show_tmo(buf, rport->dev_loss_tmo); +} + +static ssize_t store_srp_rport_dev_loss_tmo(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct srp_rport *rport = transport_class_to_srp_rport(dev); + int res; + int dev_loss_tmo; + + res = srp_parse_tmo(&dev_loss_tmo, buf); + if (res) + goto out; + res = srp_tmo_valid(rport->fast_io_fail_tmo, dev_loss_tmo); + if (res) + goto out; + rport->dev_loss_tmo = dev_loss_tmo; + res = count; + +out: + return res; +} + +static DEVICE_ATTR(dev_loss_tmo, S_IRUGO | S_IWUSR, + show_srp_rport_dev_loss_tmo, + store_srp_rport_dev_loss_tmo); + +static int srp_rport_set_state(struct srp_rport *rport, + enum srp_rport_state new_state) +{ + enum srp_rport_state old_state = rport->state; + + lockdep_assert_held(&rport->mutex); + + switch (new_state) { + case SRP_RPORT_RUNNING: + switch (old_state) { + case SRP_RPORT_LOST: + goto invalid; + default: + break; + } + break; + case SRP_RPORT_BLOCKED: + switch (old_state) { + case SRP_RPORT_RUNNING: + break; + default: + goto invalid; + } + break; + case SRP_RPORT_FAIL_FAST: + switch (old_state) { + case SRP_RPORT_LOST: + goto invalid; + default: + break; + } + break; + case SRP_RPORT_LOST: + break; + } + rport->state = new_state; + return 0; + +invalid: + return -EINVAL; +} + +static void __rport_fail_io_fast(struct srp_rport *rport) +{ + struct Scsi_Host *shost = rport_to_shost(rport); + struct srp_internal *i; + + lockdep_assert_held(&rport->mutex); + + if (srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST)) + return; + scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE); + + /* Involve the LLD if possible to terminate all I/O on the rport. */ + i = to_srp_internal(shost->transportt); + if (i->f->terminate_rport_io) + i->f->terminate_rport_io(rport); +} + +/** + * rport_fast_io_fail_timedout() - fast I/O failure timeout handler + */ +static void rport_fast_io_fail_timedout(struct work_struct *work) +{ + struct srp_rport *rport = container_of(to_delayed_work(work), + struct srp_rport, fast_io_fail_work); + struct Scsi_Host *shost = rport_to_shost(rport); + + pr_info("fast_io_fail_tmo expired for SRP %s / %s.\n", + dev_name(&rport->dev), dev_name(&shost->shost_gendev)); + + mutex_lock(&rport->mutex); + if (rport->state == SRP_RPORT_BLOCKED) + __rport_fail_io_fast(rport); + mutex_unlock(&rport->mutex); +} + +/** + * rport_dev_loss_timedout() - device loss timeout handler + */ +static void rport_dev_loss_timedout(struct work_struct *work) +{ + struct srp_rport *rport = container_of(to_delayed_work(work), + struct srp_rport, dev_loss_work); + struct Scsi_Host *shost = rport_to_shost(rport); + struct srp_internal *i = to_srp_internal(shost->transportt); + + pr_info("dev_loss_tmo expired for SRP %s / %s.\n", + dev_name(&rport->dev), dev_name(&shost->shost_gendev)); + + mutex_lock(&rport->mutex); + WARN_ON(srp_rport_set_state(rport, SRP_RPORT_LOST) != 0); + scsi_target_unblock(rport->dev.parent, SDEV_TRANSPORT_OFFLINE); + mutex_unlock(&rport->mutex); + + i->f->rport_delete(rport); +} + +static void __srp_start_tl_fail_timers(struct srp_rport *rport) +{ + struct Scsi_Host *shost = rport_to_shost(rport); + int fast_io_fail_tmo, dev_loss_tmo; + + lockdep_assert_held(&rport->mutex); + + if (!rport->deleted) { + fast_io_fail_tmo = rport->fast_io_fail_tmo; + dev_loss_tmo = rport->dev_loss_tmo; + pr_debug("%s current state: %d\n", + dev_name(&shost->shost_gendev), rport->state); + + if (fast_io_fail_tmo >= 0 && + srp_rport_set_state(rport, SRP_RPORT_BLOCKED) == 0) { + pr_debug("%s new state: %d\n", + dev_name(&shost->shost_gendev), + rport->state); + scsi_target_block(&shost->shost_gendev); + queue_delayed_work(system_long_wq, + &rport->fast_io_fail_work, + 1UL * fast_io_fail_tmo * HZ); + } + if (dev_loss_tmo >= 0) + queue_delayed_work(system_long_wq, + &rport->dev_loss_work, + 1UL * dev_loss_tmo * HZ); + } else { + pr_debug("%s has already been deleted\n", + dev_name(&shost->shost_gendev)); + srp_rport_set_state(rport, SRP_RPORT_FAIL_FAST); + scsi_target_unblock(&shost->shost_gendev, + SDEV_TRANSPORT_OFFLINE); + } +} + +/** + * srp_start_tl_fail_timers() - start the transport layer failure timers + * + * Start the transport layer fast I/O failure and device loss timers. Do not + * modify a timer that was already started. + */ +void srp_start_tl_fail_timers(struct srp_rport *rport) +{ + mutex_lock(&rport->mutex); + __srp_start_tl_fail_timers(rport); + mutex_unlock(&rport->mutex); +} +EXPORT_SYMBOL(srp_start_tl_fail_timers); + +/** + * scsi_request_fn_active() - number of kernel threads inside scsi_request_fn() + */ +static int scsi_request_fn_active(struct Scsi_Host *shost) +{ + struct scsi_device *sdev; + struct request_queue *q; + int request_fn_active = 0; + + shost_for_each_device(sdev, shost) { + q = sdev->request_queue; + + spin_lock_irq(q->queue_lock); + request_fn_active += q->request_fn_active; + spin_unlock_irq(q->queue_lock); + } + + return request_fn_active; +} + +/** + * srp_reconnect_rport() - reconnect to an SRP target port + * + * Blocks SCSI command queueing before invoking reconnect() such that + * queuecommand() won't be invoked concurrently with reconnect() from outside + * the SCSI EH. This is important since a reconnect() implementation may + * reallocate resources needed by queuecommand(). + * + * Notes: + * - This function neither waits until outstanding requests have finished nor + * tries to abort these. It is the responsibility of the reconnect() + * function to finish outstanding commands before reconnecting to the target + * port. + * - It is the responsibility of the caller to ensure that the resources + * reallocated by the reconnect() function won't be used while this function + * is in progress. One possible strategy is to invoke this function from + * the context of the SCSI EH thread only. Another possible strategy is to + * lock the rport mutex inside each SCSI LLD callback that can be invoked by + * the SCSI EH (the scsi_host_template.eh_*() functions and also the + * scsi_host_template.queuecommand() function). + */ +int srp_reconnect_rport(struct srp_rport *rport) +{ + struct Scsi_Host *shost = rport_to_shost(rport); + struct srp_internal *i = to_srp_internal(shost->transportt); + struct scsi_device *sdev; + int res; + + pr_debug("SCSI host %s\n", dev_name(&shost->shost_gendev)); + + res = mutex_lock_interruptible(&rport->mutex); + if (res) + goto out; + scsi_target_block(&shost->shost_gendev); + while (scsi_request_fn_active(shost)) + msleep(20); + res = i->f->reconnect(rport); + pr_debug("%s (state %d): transport.reconnect() returned %d\n", + dev_name(&shost->shost_gendev), rport->state, res); + if (res == 0) { + cancel_delayed_work(&rport->fast_io_fail_work); + cancel_delayed_work(&rport->dev_loss_work); + + srp_rport_set_state(rport, SRP_RPORT_RUNNING); + scsi_target_unblock(&shost->shost_gendev, SDEV_RUNNING); + /* + * If the SCSI error handler has offlined one or more devices, + * invoking scsi_target_unblock() won't change the state of + * these devices into running so do that explicitly. + */ + spin_lock_irq(shost->host_lock); + __shost_for_each_device(sdev, shost) + if (sdev->sdev_state == SDEV_OFFLINE) + sdev->sdev_state = SDEV_RUNNING; + spin_unlock_irq(shost->host_lock); + } else if (rport->state == SRP_RPORT_RUNNING) { + /* + * srp_reconnect_rport() was invoked with fast_io_fail + * off. Mark the port as failed and start the TL failure + * timers if these had not yet been started. + */ + __rport_fail_io_fast(rport); + scsi_target_unblock(&shost->shost_gendev, + SDEV_TRANSPORT_OFFLINE); + __srp_start_tl_fail_timers(rport); + } else if (rport->state != SRP_RPORT_BLOCKED) { + scsi_target_unblock(&shost->shost_gendev, + SDEV_TRANSPORT_OFFLINE); + } + mutex_unlock(&rport->mutex); + +out: + return res; +} +EXPORT_SYMBOL(srp_reconnect_rport); + +/** + * srp_timed_out() - SRP transport intercept of the SCSI timeout EH + * + * If a timeout occurs while an rport is in the blocked state, ask the SCSI + * EH to continue waiting (BLK_EH_RESET_TIMER). Otherwise let the SCSI core + * handle the timeout (BLK_EH_NOT_HANDLED). + * + * Note: This function is called from soft-IRQ context and with the request + * queue lock held. + */ +static enum blk_eh_timer_return srp_timed_out(struct scsi_cmnd *scmd) +{ + struct scsi_device *sdev = scmd->device; + struct Scsi_Host *shost = sdev->host; + struct srp_internal *i = to_srp_internal(shost->transportt); + + pr_debug("timeout for sdev %s\n", dev_name(&sdev->sdev_gendev)); + return i->f->reset_timer_if_blocked && scsi_device_blocked(sdev) ? + BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED; +} + static void srp_rport_release(struct device *dev) { struct srp_rport *rport = dev_to_rport(dev); + cancel_delayed_work_sync(&rport->fast_io_fail_work); + cancel_delayed_work_sync(&rport->dev_loss_work); + put_device(dev->parent); kfree(rport); } @@ -214,12 +618,15 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost, { struct srp_rport *rport; struct device *parent = &shost->shost_gendev; + struct srp_internal *i = to_srp_internal(shost->transportt); int id, ret; rport = kzalloc(sizeof(*rport), GFP_KERNEL); if (!rport) return ERR_PTR(-ENOMEM); + mutex_init(&rport->mutex); + device_initialize(&rport->dev); rport->dev.parent = get_device(parent); @@ -228,6 +635,13 @@ struct srp_rport *srp_rport_add(struct Scsi_Host *shost, memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id)); rport->roles = ids->roles; + rport->fast_io_fail_tmo = i->f->fast_io_fail_tmo ? + *i->f->fast_io_fail_tmo : 15; + rport->dev_loss_tmo = i->f->dev_loss_tmo ? *i->f->dev_loss_tmo : 60; + INIT_DELAYED_WORK(&rport->fast_io_fail_work, + rport_fast_io_fail_timedout); + INIT_DELAYED_WORK(&rport->dev_loss_work, rport_dev_loss_timedout); + id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id); dev_set_name(&rport->dev, "port-%d:%d", shost->host_no, id); @@ -277,6 +691,13 @@ void srp_rport_del(struct srp_rport *rport) transport_remove_device(dev); device_del(dev); transport_destroy_device(dev); + + mutex_lock(&rport->mutex); + if (rport->state == SRP_RPORT_BLOCKED) + __rport_fail_io_fast(rport); + rport->deleted = true; + mutex_unlock(&rport->mutex); + put_device(dev); } EXPORT_SYMBOL_GPL(srp_rport_del); @@ -328,6 +749,8 @@ srp_attach_transport(struct srp_function_template *ft) if (!i) return NULL; + i->t.eh_timed_out = srp_timed_out; + i->t.tsk_mgmt_response = srp_tsk_mgmt_response; i->t.it_nexus_response = srp_it_nexus_response; @@ -345,6 +768,11 @@ srp_attach_transport(struct srp_function_template *ft) count = 0; i->rport_attrs[count++] = &dev_attr_port_id; i->rport_attrs[count++] = &dev_attr_roles; + if (ft->has_rport_state) { + i->rport_attrs[count++] = &dev_attr_state; + i->rport_attrs[count++] = &dev_attr_fast_io_fail_tmo; + i->rport_attrs[count++] = &dev_attr_dev_loss_tmo; + } if (ft->rport_delete) i->rport_attrs[count++] = &dev_attr_delete; i->rport_attrs[count++] = NULL; diff --git a/include/scsi/scsi_transport_srp.h b/include/scsi/scsi_transport_srp.h index 5a2d2d1081c1..ee7001677f64 100644 --- a/include/scsi/scsi_transport_srp.h +++ b/include/scsi/scsi_transport_srp.h @@ -13,6 +13,26 @@ struct srp_rport_identifiers { u8 roles; }; +/** + * enum srp_rport_state - SRP transport layer state + * @SRP_RPORT_RUNNING: Transport layer operational. + * @SRP_RPORT_BLOCKED: Transport layer not operational; fast I/O fail timer + * is running and I/O has been blocked. + * @SRP_RPORT_FAIL_FAST: Fast I/O fail timer has expired; fail I/O fast. + * @SRP_RPORT_LOST: Device loss timer has expired; port is being removed. + */ +enum srp_rport_state { + SRP_RPORT_RUNNING, + SRP_RPORT_BLOCKED, + SRP_RPORT_FAIL_FAST, + SRP_RPORT_LOST, +}; + +/** + * struct srp_rport + * @lld_data: LLD private data. + * @mutex: Protects against concurrent rport fast_io_fail / dev_loss_tmo. + */ struct srp_rport { /* for initiator and target drivers */ @@ -23,11 +43,38 @@ struct srp_rport { /* for initiator drivers */ - void *lld_data; /* LLD private data */ + void *lld_data; + + struct mutex mutex; + enum srp_rport_state state; + bool deleted; + int fast_io_fail_tmo; + int dev_loss_tmo; + struct delayed_work fast_io_fail_work; + struct delayed_work dev_loss_work; }; +/** + * struct srp_function_template + * @has_rport_state: Whether or not to create the state, fast_io_fail_tmo and + * dev_loss_tmo sysfs attribute for an rport. + * @reset_timer_if_blocked: Whether or srp_timed_out() should reset the command + * timer if the device on which it has been queued is blocked. + * @fast_io_fail_tmo: If not NULL, points to the default fast_io_fail_tmo value. + * @dev_loss_tmo: If not NULL, points to the default dev_loss_tmo value. + * @reconnect: Callback function for reconnecting to the target. See also + * srp_reconnect_rport(). + * @terminate_rport_io: Callback function for terminating all outstanding I/O + * requests for an rport. + */ struct srp_function_template { /* for initiator drivers */ + bool has_rport_state; + bool reset_timer_if_blocked; + int *fast_io_fail_tmo; + int *dev_loss_tmo; + int (*reconnect)(struct srp_rport *rport); + void (*terminate_rport_io)(struct srp_rport *rport); void (*rport_delete)(struct srp_rport *rport); /* for target drivers */ int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int); @@ -43,7 +90,30 @@ extern void srp_rport_put(struct srp_rport *rport); extern struct srp_rport *srp_rport_add(struct Scsi_Host *, struct srp_rport_identifiers *); extern void srp_rport_del(struct srp_rport *); - +extern int srp_tmo_valid(int fast_io_fail_tmo, int dev_loss_tmo); +extern int srp_reconnect_rport(struct srp_rport *rport); +extern void srp_start_tl_fail_timers(struct srp_rport *rport); extern void srp_remove_host(struct Scsi_Host *); +/** + * srp_chkready() - evaluate the transport layer state before I/O + * + * Returns a SCSI result code that can be returned by the LLD queuecommand() + * implementation. The role of this function is similar to that of + * fc_remote_port_chkready(). + */ +static inline int srp_chkready(struct srp_rport *rport) +{ + switch (rport->state) { + case SRP_RPORT_RUNNING: + case SRP_RPORT_BLOCKED: + default: + return 0; + case SRP_RPORT_FAIL_FAST: + return DID_TRANSPORT_FAILFAST << 16; + case SRP_RPORT_LOST: + return DID_NO_CONNECT << 16; + } +} + #endif |