diff options
Diffstat (limited to '')
-rw-r--r-- | drivers/s390/scsi/zfcp_diag.c | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/drivers/s390/scsi/zfcp_diag.c b/drivers/s390/scsi/zfcp_diag.c new file mode 100644 index 000000000..67a8f4e57 --- /dev/null +++ b/drivers/s390/scsi/zfcp_diag.c @@ -0,0 +1,305 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * zfcp device driver + * + * Functions to handle diagnostics. + * + * Copyright IBM Corp. 2018 + */ + +#include <linux/spinlock.h> +#include <linux/jiffies.h> +#include <linux/string.h> +#include <linux/kernfs.h> +#include <linux/sysfs.h> +#include <linux/errno.h> +#include <linux/slab.h> + +#include "zfcp_diag.h" +#include "zfcp_ext.h" +#include "zfcp_def.h" + +static DECLARE_WAIT_QUEUE_HEAD(__zfcp_diag_publish_wait); + +/** + * zfcp_diag_adapter_setup() - Setup storage for adapter diagnostics. + * @adapter: the adapter to setup diagnostics for. + * + * Creates the data-structures to store the diagnostics for an adapter. This + * overwrites whatever was stored before at &zfcp_adapter->diagnostics! + * + * Return: + * * 0 - Everyting is OK + * * -ENOMEM - Could not allocate all/parts of the data-structures; + * &zfcp_adapter->diagnostics remains unchanged + */ +int zfcp_diag_adapter_setup(struct zfcp_adapter *const adapter) +{ + struct zfcp_diag_adapter *diag; + struct zfcp_diag_header *hdr; + + diag = kzalloc(sizeof(*diag), GFP_KERNEL); + if (diag == NULL) + return -ENOMEM; + + diag->max_age = (5 * 1000); /* default value: 5 s */ + + /* setup header for port_data */ + hdr = &diag->port_data.header; + + spin_lock_init(&hdr->access_lock); + hdr->buffer = &diag->port_data.data; + hdr->buffer_size = sizeof(diag->port_data.data); + /* set the timestamp so that the first test on age will always fail */ + hdr->timestamp = jiffies - msecs_to_jiffies(diag->max_age); + + /* setup header for config_data */ + hdr = &diag->config_data.header; + + spin_lock_init(&hdr->access_lock); + hdr->buffer = &diag->config_data.data; + hdr->buffer_size = sizeof(diag->config_data.data); + /* set the timestamp so that the first test on age will always fail */ + hdr->timestamp = jiffies - msecs_to_jiffies(diag->max_age); + + adapter->diagnostics = diag; + return 0; +} + +/** + * zfcp_diag_adapter_free() - Frees all adapter diagnostics allocations. + * @adapter: the adapter whose diagnostic structures should be freed. + * + * Frees all data-structures in the given adapter that store diagnostics + * information. Can savely be called with partially setup diagnostics. + */ +void zfcp_diag_adapter_free(struct zfcp_adapter *const adapter) +{ + kfree(adapter->diagnostics); + adapter->diagnostics = NULL; +} + +/** + * zfcp_diag_sysfs_setup() - Setup the sysfs-group for adapter-diagnostics. + * @adapter: target adapter to which the group should be added. + * + * Return: 0 on success; Something else otherwise (see sysfs_create_group()). + */ +int zfcp_diag_sysfs_setup(struct zfcp_adapter *const adapter) +{ + int rc = sysfs_create_group(&adapter->ccw_device->dev.kobj, + &zfcp_sysfs_diag_attr_group); + if (rc == 0) + adapter->diagnostics->sysfs_established = 1; + + return rc; +} + +/** + * zfcp_diag_sysfs_destroy() - Remove the sysfs-group for adapter-diagnostics. + * @adapter: target adapter from which the group should be removed. + */ +void zfcp_diag_sysfs_destroy(struct zfcp_adapter *const adapter) +{ + if (adapter->diagnostics == NULL || + !adapter->diagnostics->sysfs_established) + return; + + /* + * We need this state-handling so we can prevent warnings being printed + * on the kernel-console in case we have to abort a halfway done + * zfcp_adapter_enqueue(), in which the sysfs-group was not yet + * established. sysfs_remove_group() does this checking as well, but + * still prints a warning in case we try to remove a group that has not + * been established before + */ + adapter->diagnostics->sysfs_established = 0; + sysfs_remove_group(&adapter->ccw_device->dev.kobj, + &zfcp_sysfs_diag_attr_group); +} + + +/** + * zfcp_diag_update_xdata() - Update a diagnostics buffer. + * @hdr: the meta data to update. + * @data: data to use for the update. + * @incomplete: flag stating whether the data in @data is incomplete. + */ +void zfcp_diag_update_xdata(struct zfcp_diag_header *const hdr, + const void *const data, const bool incomplete) +{ + const unsigned long capture_timestamp = jiffies; + unsigned long flags; + + spin_lock_irqsave(&hdr->access_lock, flags); + + /* make sure we never go into the past with an update */ + if (!time_after_eq(capture_timestamp, hdr->timestamp)) + goto out; + + hdr->timestamp = capture_timestamp; + hdr->incomplete = incomplete; + memcpy(hdr->buffer, data, hdr->buffer_size); +out: + spin_unlock_irqrestore(&hdr->access_lock, flags); +} + +/** + * zfcp_diag_update_port_data_buffer() - Implementation of + * &typedef zfcp_diag_update_buffer_func + * to collect and update Port Data. + * @adapter: Adapter to collect Port Data from. + * + * This call is SYNCHRONOUS ! It blocks till the respective command has + * finished completely, or has failed in some way. + * + * Return: + * * 0 - Successfully retrieved new Diagnostics and Updated the buffer; + * this also includes cases where data was retrieved, but + * incomplete; you'll have to check the flag ``incomplete`` + * of &struct zfcp_diag_header. + * * see zfcp_fsf_exchange_port_data_sync() for possible error-codes ( + * excluding -EAGAIN) + */ +int zfcp_diag_update_port_data_buffer(struct zfcp_adapter *const adapter) +{ + int rc; + + rc = zfcp_fsf_exchange_port_data_sync(adapter->qdio, NULL); + if (rc == -EAGAIN) + rc = 0; /* signaling incomplete via struct zfcp_diag_header */ + + /* buffer-data was updated in zfcp_fsf_exchange_port_data_handler() */ + + return rc; +} + +/** + * zfcp_diag_update_config_data_buffer() - Implementation of + * &typedef zfcp_diag_update_buffer_func + * to collect and update Config Data. + * @adapter: Adapter to collect Config Data from. + * + * This call is SYNCHRONOUS ! It blocks till the respective command has + * finished completely, or has failed in some way. + * + * Return: + * * 0 - Successfully retrieved new Diagnostics and Updated the buffer; + * this also includes cases where data was retrieved, but + * incomplete; you'll have to check the flag ``incomplete`` + * of &struct zfcp_diag_header. + * * see zfcp_fsf_exchange_config_data_sync() for possible error-codes ( + * excluding -EAGAIN) + */ +int zfcp_diag_update_config_data_buffer(struct zfcp_adapter *const adapter) +{ + int rc; + + rc = zfcp_fsf_exchange_config_data_sync(adapter->qdio, NULL); + if (rc == -EAGAIN) + rc = 0; /* signaling incomplete via struct zfcp_diag_header */ + + /* buffer-data was updated in zfcp_fsf_exchange_config_data_handler() */ + + return rc; +} + +static int __zfcp_diag_update_buffer(struct zfcp_adapter *const adapter, + struct zfcp_diag_header *const hdr, + zfcp_diag_update_buffer_func buffer_update, + unsigned long *const flags) + __must_hold(hdr->access_lock) +{ + int rc; + + if (hdr->updating == 1) { + rc = wait_event_interruptible_lock_irq(__zfcp_diag_publish_wait, + hdr->updating == 0, + hdr->access_lock); + rc = (rc == 0 ? -EAGAIN : -EINTR); + } else { + hdr->updating = 1; + spin_unlock_irqrestore(&hdr->access_lock, *flags); + + /* unlocked, because update function sleeps */ + rc = buffer_update(adapter); + + spin_lock_irqsave(&hdr->access_lock, *flags); + hdr->updating = 0; + + /* + * every thread waiting here went via an interruptible wait, + * so its fine to only wake those + */ + wake_up_interruptible_all(&__zfcp_diag_publish_wait); + } + + return rc; +} + +static bool +__zfcp_diag_test_buffer_age_isfresh(const struct zfcp_diag_adapter *const diag, + const struct zfcp_diag_header *const hdr) + __must_hold(hdr->access_lock) +{ + const unsigned long now = jiffies; + + /* + * Should not happen (data is from the future).. if it does, still + * signal that it needs refresh + */ + if (!time_after_eq(now, hdr->timestamp)) + return false; + + if (jiffies_to_msecs(now - hdr->timestamp) >= diag->max_age) + return false; + + return true; +} + +/** + * zfcp_diag_update_buffer_limited() - Collect diagnostics and update a + * diagnostics buffer rate limited. + * @adapter: Adapter to collect the diagnostics from. + * @hdr: buffer-header for which to update with the collected diagnostics. + * @buffer_update: Specific implementation for collecting and updating. + * + * This function will cause an update of the given @hdr by calling the also + * given @buffer_update function. If called by multiple sources at the same + * time, it will synchornize the update by only allowing one source to call + * @buffer_update and the others to wait for that source to complete instead + * (the wait is interruptible). + * + * Additionally this version is rate-limited and will only exit if either the + * buffer is fresh enough (within the limit) - it will do nothing if the buffer + * is fresh enough to begin with -, or if the source/thread that started this + * update is the one that made the update (to prevent endless loops). + * + * Return: + * * 0 - If the update was successfully published and/or the buffer is + * fresh enough + * * -EINTR - If the thread went into the wait-state and was interrupted + * * whatever @buffer_update returns + */ +int zfcp_diag_update_buffer_limited(struct zfcp_adapter *const adapter, + struct zfcp_diag_header *const hdr, + zfcp_diag_update_buffer_func buffer_update) +{ + unsigned long flags; + int rc; + + spin_lock_irqsave(&hdr->access_lock, flags); + + for (rc = 0; + !__zfcp_diag_test_buffer_age_isfresh(adapter->diagnostics, hdr); + rc = 0) { + rc = __zfcp_diag_update_buffer(adapter, hdr, buffer_update, + &flags); + if (rc != -EAGAIN) + break; + } + + spin_unlock_irqrestore(&hdr->access_lock, flags); + + return rc; +} |