diff options
Diffstat (limited to 'drivers/s390/block/dasd_eer.c')
| -rw-r--r-- | drivers/s390/block/dasd_eer.c | 1090 |
1 files changed, 1090 insertions, 0 deletions
diff --git a/drivers/s390/block/dasd_eer.c b/drivers/s390/block/dasd_eer.c new file mode 100644 index 0000000..f70cd77 --- /dev/null +++ b/drivers/s390/block/dasd_eer.c @@ -0,0 +1,1090 @@ +/* + * character device driver for extended error reporting + * + * + * Copyright (C) 2005 IBM Corporation + * extended error reporting for DASD ECKD devices + * Author(s): Stefan Weinhuber <wein@de.ibm.com> + * + */ + +#include <linux/init.h> +#include <linux/fs.h> +#include <linux/kernel.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/device.h> +#include <linux/workqueue.h> +#include <linux/poll.h> +#include <linux/notifier.h> + +#include <asm/uaccess.h> +#include <asm/semaphore.h> +#include <asm/atomic.h> +#include <asm/ebcdic.h> + +#include "dasd_int.h" +#include "dasd_eckd.h" + + +MODULE_LICENSE("GPL"); + +MODULE_AUTHOR("Stefan Weinhuber <wein@de.ibm.com>"); +MODULE_DESCRIPTION("DASD extended error reporting module"); + + +#ifdef PRINTK_HEADER +#undef PRINTK_HEADER +#endif /* PRINTK_HEADER */ +#define PRINTK_HEADER "dasd(eer):" + + + + + +/*****************************************************************************/ +/* the internal buffer */ +/*****************************************************************************/ + +/* + * The internal buffer is meant to store obaque blobs of data, so it doesn't + * know of higher level concepts like triggers. + * It consists of a number of pages that are used as a ringbuffer. Each data + * blob is stored in a simple record that consists of an integer, which + * contains the size of the following data, and the data bytes themselfes. + * + * To allow for multiple independent readers we create one internal buffer + * each time the device is opened and destroy the buffer when the file is + * closed again. + * + * One record can be written to a buffer by using the functions + * - dasd_eer_start_record (one time per record to write the size to the buffer + * and reserve the space for the data) + * - dasd_eer_write_buffer (one or more times per record to write the data) + * The data can be written in several steps but you will have to compute + * the total size up front for the invocation of dasd_eer_start_record. + * If the ringbuffer is full, dasd_eer_start_record will remove the required + * number of old records. + * + * A record is typically read in two steps, first read the integer that + * specifies the size of the following data, then read the data. + * Both can be done by + * - dasd_eer_read_buffer + * + * For all mentioned functions you need to get the bufferlock first and keep it + * until a complete record is written or read. + */ + + +/* + * Alle information necessary to keep track of an internal buffer is kept in + * a struct eerbuffer. The buffer specific to a file pointer is strored in + * the private_data field of that file. To be able to write data to all + * existing buffers, each buffer is also added to the bufferlist. + * If the user doesn't want to read a complete record in one go, we have to + * keep track of the rest of the record. residual stores the number of bytes + * that are still to deliver. If the rest of the record is invalidated between + * two reads then residual will be set to -1 so that the next read will fail. + * All entries in the eerbuffer structure are protected with the bufferlock. + * To avoid races between writing to a buffer on the one side and creating + * and destroying buffers on the other side, the bufferlock must also be used + * to protect the bufferlist. + */ + +struct eerbuffer { + struct list_head list; + char **buffer; + int buffersize; + int buffer_page_count; + int head; + int tail; + int residual; +}; + +LIST_HEAD(bufferlist); + +static spinlock_t bufferlock = SPIN_LOCK_UNLOCKED; + +DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue); + +/* + * How many free bytes are available on the buffer. + * needs to be called with bufferlock held + */ +static int +dasd_eer_get_free_bytes(struct eerbuffer *eerb) +{ + if (eerb->head < eerb->tail) { + return eerb->tail - eerb->head - 1; + } else + return eerb->buffersize - eerb->head + eerb->tail -1; +} + +/* + * How many bytes of buffer space are used. + * needs to be called with bufferlock held + */ +static int +dasd_eer_get_filled_bytes(struct eerbuffer *eerb) +{ + + if (eerb->head >= eerb->tail) { + return eerb->head - eerb->tail; + } else + return eerb->buffersize - eerb->tail + eerb->head; +} + +/* + * The dasd_eer_write_buffer function just copies count bytes of data + * to the buffer. Make sure to call dasd_eer_start_record first, to + * make sure that enough free space is available. + * needs to be called with bufferlock held + */ +static void +dasd_eer_write_buffer(struct eerbuffer *eerb, int count, char *data) +{ + + unsigned long headindex,localhead; + unsigned long rest, len; + char *nextdata; + + nextdata = data; + rest = count; + while (rest > 0) { + headindex = eerb->head / PAGE_SIZE; + localhead = eerb->head % PAGE_SIZE; + len = min(rest, (PAGE_SIZE - localhead)); + memcpy(eerb->buffer[headindex]+localhead, nextdata, len); + nextdata += len; + rest -= len; + eerb->head += len; + if ( eerb->head == eerb->buffersize ) + eerb->head = 0; /* wrap around */ + if (eerb->head > eerb->buffersize) { + MESSAGE(KERN_ERR, "%s", "runaway buffer head."); + BUG(); + } + } +} + +/* + * needs to be called with bufferlock held + */ +static int +dasd_eer_read_buffer(struct eerbuffer *eerb, int count, char *data) +{ + + unsigned long tailindex,localtail; + unsigned long rest, len, finalcount; + char *nextdata; + + finalcount = min(count, dasd_eer_get_filled_bytes(eerb)); + nextdata = data; + rest = finalcount; + while (rest > 0) { + tailindex = eerb->tail / PAGE_SIZE; + localtail = eerb->tail % PAGE_SIZE; + len = min(rest, (PAGE_SIZE - localtail)); + memcpy(nextdata, eerb->buffer[tailindex]+localtail, len); + nextdata += len; + rest -= len; + eerb->tail += len; + if ( eerb->tail == eerb->buffersize ) + eerb->tail = 0; /* wrap around */ + if (eerb->tail > eerb->buffersize) { + MESSAGE(KERN_ERR, "%s", "runaway buffer tail."); + BUG(); + } + } + return finalcount; +} + +/* + * Whenever you want to write a blob of data to the internal buffer you + * have to start by using this function first. It will write the number + * of bytes that will be written to the buffer. If necessary it will remove + * old records to make room for the new one. + * needs to be called with bufferlock held + */ +static int +dasd_eer_start_record(struct eerbuffer *eerb, int count) +{ + int tailcount; + if (count + sizeof(count) > eerb->buffersize) + return -ENOMEM; + while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) { + if (eerb->residual > 0) { + eerb->tail += eerb->residual; + if (eerb->tail >= eerb->buffersize) + eerb->tail -= eerb->buffersize; + eerb->residual = -1; + } + dasd_eer_read_buffer(eerb, sizeof(tailcount), + (char*)(&tailcount)); + eerb->tail += tailcount; + if (eerb->tail >= eerb->buffersize) + eerb->tail -= eerb->buffersize; + } + dasd_eer_write_buffer(eerb, sizeof(count), (char*)(&count)); + + return 0; +}; + +/* + * release pages that are not used anymore + */ +static void +dasd_eer_free_buffer_pages(char **buf, int no_pages) +{ + int i; + + for (i = 0; i < no_pages; ++i) { + free_page((unsigned long)buf[i]); + } +} + +/* + * allocate a new set of memory pages + */ +static int +dasd_eer_allocate_buffer_pages(char **buf, int no_pages) +{ + int i; + + for (i = 0; i < no_pages; ++i) { + buf[i] = (char *) get_zeroed_page(GFP_KERNEL); + if (!buf[i]) { + dasd_eer_free_buffer_pages(buf, i); + return -ENOMEM; + } + } + return 0; +} + +/* + * empty the buffer by resetting head and tail + * In case there is a half read data blob in the buffer, we set residual + * to -1 to indicate that the remainder of the blob is lost. + */ +static void +dasd_eer_purge_buffer(struct eerbuffer *eerb) +{ + unsigned long flags; + + spin_lock_irqsave(&bufferlock, flags); + if (eerb->residual > 0) + eerb->residual = -1; + eerb->tail=0; + eerb->head=0; + spin_unlock_irqrestore(&bufferlock, flags); +} + +/* + * set the size of the buffer, newsize is the new number of pages to be used + * we don't try to copy any data back an forth, so any resize will also purge + * the buffer + */ +static int +dasd_eer_resize_buffer(struct eerbuffer *eerb, int newsize) +{ + int i, oldcount, reuse; + char **new; + char **old; + unsigned long flags; + + if (newsize < 1) + return -EINVAL; + if (eerb->buffer_page_count == newsize) { + /* documented behaviour is that any successfull invocation + * will purge all records */ + dasd_eer_purge_buffer(eerb); + return 0; + } + new = kmalloc(newsize*sizeof(char*), GFP_KERNEL); + if (!new) + return -ENOMEM; + + reuse=min(eerb->buffer_page_count, newsize); + for (i = 0; i < reuse; ++i) { + new[i] = eerb->buffer[i]; + } + if (eerb->buffer_page_count < newsize) { + if (dasd_eer_allocate_buffer_pages( + &new[eerb->buffer_page_count], + newsize - eerb->buffer_page_count)) { + kfree(new); + return -ENOMEM; + } + } + + spin_lock_irqsave(&bufferlock, flags); + old = eerb->buffer; + eerb->buffer = new; + if (eerb->residual > 0) + eerb->residual = -1; + eerb->tail = 0; + eerb->head = 0; + oldcount = eerb->buffer_page_count; + eerb->buffer_page_count = newsize; + spin_unlock_irqrestore(&bufferlock, flags); + + if (oldcount > newsize) { + for (i = newsize; i < oldcount; ++i) { + free_page((unsigned long)old[i]); + } + } + kfree(old); + + return 0; +} + + +/*****************************************************************************/ +/* The extended error reporting functionality */ +/*****************************************************************************/ + +/* + * When a DASD device driver wants to report an error, it calls the + * function dasd_eer_write_trigger (via a notifier mechanism) and gives the + * respective trigger ID as parameter. + * Currently there are four kinds of triggers: + * + * DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems + * DASD_EER_PPRCSUSPEND: PPRC was suspended + * DASD_EER_NOPATH: There is no path to the device left. + * DASD_EER_STATECHANGE: The state of the device has changed. + * + * For the first three triggers all required information can be supplied by + * the caller. For these triggers a record is written by the function + * dasd_eer_write_standard_trigger. + * + * When dasd_eer_write_trigger is called to write a DASD_EER_STATECHANGE + * trigger, we have to gather the necessary sense data first. We cannot queue + * the necessary SNSS (sense subsystem status) request immediatly, since we + * are likely to run in a deadlock situation. Instead, we schedule a + * work_struct that calls the function dasd_eer_sense_subsystem_status to + * create and start an SNSS request asynchronously. + * + * To avoid memory allocations at runtime, the necessary memory is allocated + * when the extended error reporting is enabled for a device (by + * dasd_eer_probe). There is one private eer data structure for each eer + * enabled DASD device. It contains memory for the work_struct, one SNSS cqr + * and a flags field that is used to coordinate the use of the cqr. The call + * to write a state change trigger can come in at any time, so we have one flag + * CQR_IN_USE that protects the cqr itself. When this flag indicates that the + * cqr is currently in use, dasd_eer_sense_subsystem_status cannot start a + * second request but sets the SNSS_REQUESTED flag instead. + * + * When the request is finished, the callback function dasd_eer_SNSS_cb + * is called. This function will invoke the function + * dasd_eer_write_SNSS_trigger to finally write the trigger. It will also + * check the SNSS_REQUESTED flag and if it is set it will call + * dasd_eer_sense_subsystem_status again. + * + * To avoid race conditions during the handling of the lock, the flags must + * be protected by the snsslock. + */ + +struct dasd_eer_private { + struct dasd_ccw_req *cqr; + unsigned long flags; + struct work_struct worker; +}; + +static void dasd_eer_destroy(struct dasd_device *device, + struct dasd_eer_private *eer); +static int +dasd_eer_write_trigger(struct dasd_eer_trigger *trigger); +static void dasd_eer_sense_subsystem_status(void *data); +static int dasd_eer_notify(struct notifier_block *self, + unsigned long action, void *data); + +struct workqueue_struct *dasd_eer_workqueue; + +#define SNSS_DATA_SIZE 44 +static spinlock_t snsslock = SPIN_LOCK_UNLOCKED; + +#define DASD_EER_BUSID_SIZE 10 +struct dasd_eer_header { + __u32 total_size; + __u32 trigger; + __u64 tv_sec; + __u64 tv_usec; + char busid[DASD_EER_BUSID_SIZE]; +} __attribute__ ((packed)); + +static struct notifier_block dasd_eer_nb = { + .notifier_call = dasd_eer_notify, +}; + +/* + * flags for use with dasd_eer_private + */ +#define CQR_IN_USE 0 +#define SNSS_REQUESTED 1 + +/* + * This function checks if extended error reporting is available for a given + * dasd_device. If yes, then it creates and returns a struct dasd_eer, + * otherwise it returns an -EPERM error pointer. + */ +struct dasd_eer_private * +dasd_eer_probe(struct dasd_device *device) +{ + struct dasd_eer_private *private; + + if (!(device && device->discipline + && !strcmp(device->discipline->name, "ECKD"))) { + return ERR_PTR(-EPERM); + } + /* allocate the private data structure */ + private = (struct dasd_eer_private *)kmalloc( + sizeof(struct dasd_eer_private), GFP_KERNEL); + if (!private) { + return ERR_PTR(-ENOMEM); + } + INIT_WORK(&private->worker, dasd_eer_sense_subsystem_status, + (void *)device); + private->cqr = dasd_kmalloc_request("ECKD", + 1 /* SNSS */ , + SNSS_DATA_SIZE , + device); + if (!private->cqr) { + kfree(private); + return ERR_PTR(-ENOMEM); + } + private->flags = 0; + return private; +}; + +/* + * If our private SNSS request is queued, remove it from the + * dasd ccw queue so we can free the requests memory. + */ +static void +dasd_eer_dequeue_SNSS_request(struct dasd_device *device, + struct dasd_eer_private *eer) +{ + struct list_head *lst, *nxt; + struct dasd_ccw_req *cqr, *erpcqr; + dasd_erp_fn_t erp_fn; + + spin_lock_irq(get_ccwdev_lock(device->cdev)); + list_for_each_safe(lst, nxt, &device->ccw_queue) { + cqr = list_entry(lst, struct dasd_ccw_req, list); + /* we are looking for two kinds or requests */ + /* first kind: our SNSS request: */ + if (cqr == eer->cqr) { + if (cqr->status == DASD_CQR_IN_IO) + device->discipline->term_IO(cqr); + list_del(&cqr->list); + break; + } + /* second kind: ERP requests for our SNSS request */ + if (cqr->refers) { + /* If this erp request chain ends in our cqr, then */ + /* cal the erp_postaction to clean it up */ + erpcqr = cqr; + while (erpcqr->refers) { + erpcqr = erpcqr->refers; + } + if (erpcqr == eer->cqr) { + erp_fn = device->discipline->erp_postaction( + cqr); + erp_fn(cqr); + } + continue; + } + } + spin_unlock_irq(get_ccwdev_lock(device->cdev)); +} + +/* + * This function dismantles a struct dasd_eer that was created by + * dasd_eer_probe. Since we want to free our private data structure, + * we must make sure that the memory is not in use anymore. + * We have to flush the work queue and remove a possible SNSS request + * from the dasd queue. + */ +static void +dasd_eer_destroy(struct dasd_device *device, struct dasd_eer_private *eer) +{ + flush_workqueue(dasd_eer_workqueue); + dasd_eer_dequeue_SNSS_request(device, eer); + dasd_kfree_request(eer->cqr, device); + kfree(eer); +}; + +/* + * enable the extended error reporting for a particular device + */ +static int +dasd_eer_enable_on_device(struct dasd_device *device) +{ + void *eer; + if (!device) + return -ENODEV; + if (device->eer) + return 0; + if (!try_module_get(THIS_MODULE)) { + return -EINVAL; + } + eer = (void *)dasd_eer_probe(device); + if (IS_ERR(eer)) { + module_put(THIS_MODULE); + return PTR_ERR(eer); + } + device->eer = eer; + return 0; +} + +/* + * enable the extended error reporting for a particular device + */ +static int +dasd_eer_disable_on_device(struct dasd_device *device) +{ + struct dasd_eer_private *eer = device->eer; + + if (!device) + return -ENODEV; + if (!device->eer) + return 0; + device->eer = NULL; + dasd_eer_destroy(device,eer); + module_put(THIS_MODULE); + + return 0; +} + +/* + * Set extended error reporting (eer) + * Note: This will be registered as a DASD ioctl, to be called on DASD devices. + */ +static int +dasd_ioctl_set_eer(struct block_device *bdev, int no, long args) +{ + struct dasd_device *device; + int intval; + + if (!capable(CAP_SYS_ADMIN)) + return -EACCES; + if (bdev != bdev->bd_contains) + /* Error-reporting is not allowed for partitions */ + return -EINVAL; + if (get_user(intval, (int __user *) args)) + return -EFAULT; + device = bdev->bd_disk->private_data; + if (device == NULL) + return -ENODEV; + + intval = (intval != 0); + DEV_MESSAGE (KERN_DEBUG, device, + "set eer on device to %d", intval); + if (intval) + return dasd_eer_enable_on_device(device); + else + return dasd_eer_disable_on_device(device); +} + +/* + * Get value of extended error reporting. + * Note: This will be registered as a DASD ioctl, to be called on DASD devices. + */ +static int +dasd_ioctl_get_eer(struct block_device *bdev, int no, long args) +{ + struct dasd_device *device; + + device = bdev->bd_disk->private_data; + if (device == NULL) + return -ENODEV; + return put_user((device->eer != NULL), (int __user *) args); +} + +/* + * The following function can be used for those triggers that have + * all necessary data available when the function is called. + * If the parameter cqr is not NULL, the chain of requests will be searched + * for valid sense data, and all valid sense data sets will be added to + * the triggers data. + */ +static int +dasd_eer_write_standard_trigger(int trigger, struct dasd_device *device, + struct dasd_ccw_req *cqr) +{ + struct dasd_ccw_req *temp_cqr; + int data_size; + struct timeval tv; + struct dasd_eer_header header; + unsigned long flags; + struct eerbuffer *eerb; + + /* go through cqr chain and count the valid sense data sets */ + temp_cqr = cqr; + data_size = 0; + while (temp_cqr) { + if (temp_cqr->irb.esw.esw0.erw.cons) + data_size += 32; + temp_cqr = temp_cqr->refers; + } + + header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ + header.trigger = trigger; + do_gettimeofday(&tv); + header.tv_sec = tv.tv_sec; + header.tv_usec = tv.tv_usec; + strncpy(header.busid, device->cdev->dev.bus_id, DASD_EER_BUSID_SIZE); + + spin_lock_irqsave(&bufferlock, flags); + list_for_each_entry(eerb, &bufferlist, list) { + dasd_eer_start_record(eerb, header.total_size); + dasd_eer_write_buffer(eerb, sizeof(header), (char*)(&header)); + temp_cqr = cqr; + while (temp_cqr) { + if (temp_cqr->irb.esw.esw0.erw.cons) + dasd_eer_write_buffer(eerb, 32, cqr->irb.ecw); + temp_cqr = temp_cqr->refers; + } + dasd_eer_write_buffer(eerb, 4,"EOR"); + } + spin_unlock_irqrestore(&bufferlock, flags); + + wake_up_interruptible(&dasd_eer_read_wait_queue); + + return 0; +} + +/* + * This function writes a DASD_EER_STATECHANGE trigger. + */ +static void +dasd_eer_write_SNSS_trigger(struct dasd_device *device, + struct dasd_ccw_req *cqr) +{ + int data_size; + int snss_rc; + struct timeval tv; + struct dasd_eer_header header; + unsigned long flags; + struct eerbuffer *eerb; + + snss_rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0; + if (snss_rc) + data_size = 0; + else + data_size = SNSS_DATA_SIZE; + + header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ + header.trigger = DASD_EER_STATECHANGE; + do_gettimeofday(&tv); + header.tv_sec = tv.tv_sec; + header.tv_usec = tv.tv_usec; + strncpy(header.busid, device->cdev->dev.bus_id, DASD_EER_BUSID_SIZE); + + spin_lock_irqsave(&bufferlock, flags); + list_for_each_entry(eerb, &bufferlist, list) { + dasd_eer_start_record(eerb, header.total_size); + dasd_eer_write_buffer(eerb, sizeof(header),(char*)(&header)); + if (!snss_rc) + dasd_eer_write_buffer(eerb, SNSS_DATA_SIZE, cqr->data); + dasd_eer_write_buffer(eerb, 4,"EOR"); + } + spin_unlock_irqrestore(&bufferlock, flags); + + wake_up_interruptible(&dasd_eer_read_wait_queue); +} + +/* + * callback function for use with SNSS request + */ +static void +dasd_eer_SNSS_cb(struct dasd_ccw_req *cqr, void *data) +{ + struct dasd_device *device; + struct dasd_eer_private *private; + unsigned long irqflags; + + device = (struct dasd_device *)data; + private = (struct dasd_eer_private *)device->eer; + dasd_eer_write_SNSS_trigger(device, cqr); + spin_lock_irqsave(&snsslock, irqflags); + if(!test_and_clear_bit(SNSS_REQUESTED, &private->flags)) { + clear_bit(CQR_IN_USE, &private->flags); + spin_unlock_irqrestore(&snsslock, irqflags); + return; + }; + clear_bit(CQR_IN_USE, &private->flags); + spin_unlock_irqrestore(&snsslock, irqflags); + dasd_eer_sense_subsystem_status(device); + return; +} + +/* + * clean a used cqr before using it again + */ +static void +dasd_eer_clean_SNSS_request(struct dasd_ccw_req *cqr) +{ + struct ccw1 *cpaddr = cqr->cpaddr; + void *data = cqr->data; + + memset(cqr, 0, sizeof(struct dasd_ccw_req)); + memset(cpaddr, 0, sizeof(struct ccw1)); + memset(data, 0, SNSS_DATA_SIZE); + cqr->cpaddr = cpaddr; + cqr->data = data; + strncpy((char *) &cqr->magic, "ECKD", 4); + ASCEBC((char *) &cqr->magic, 4); + set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags); +} + +/* + * build and start an SNSS request + * This function is called from a work queue so we have to + * pass the dasd_device pointer as a void pointer. + */ +static void +dasd_eer_sense_subsystem_status(void *data) +{ + struct dasd_device *device; + struct dasd_eer_private *private; + struct dasd_ccw_req *cqr; + struct ccw1 *ccw; + unsigned long irqflags; + + device = (struct dasd_device *)data; + private = (struct dasd_eer_private *)device->eer; + if (!private) /* device not eer enabled any more */ + return; + cqr = private->cqr; + spin_lock_irqsave(&snsslock, irqflags); + if(test_and_set_bit(CQR_IN_USE, &private->flags)) { + set_bit(SNSS_REQUESTED, &private->flags); + spin_unlock_irqrestore(&snsslock, irqflags); + return; + }; + spin_unlock_irqrestore(&snsslock, irqflags); + dasd_eer_clean_SNSS_request(cqr); + cqr->device = device; + cqr->retries = 255; + cqr->expires = 10 * HZ; + + ccw = cqr->cpaddr; + ccw->cmd_code = DASD_ECKD_CCW_SNSS; + ccw->count = SNSS_DATA_SIZE; + ccw->flags = 0; + ccw->cda = (__u32)(addr_t)cqr->data; + + cqr->buildclk = get_clock(); + cqr->status = DASD_CQR_FILLED; + cqr->callback = dasd_eer_SNSS_cb; + cqr->callback_data = (void *)device; + dasd_add_request_head(cqr); + + return; +} + +/* + * This function is called for all triggers. It calls the appropriate + * function that writes the actual trigger records. + */ +static int +dasd_eer_write_trigger(struct dasd_eer_trigger *trigger) +{ + int rc; + struct dasd_eer_private *private = trigger->device->eer; + + switch (trigger->id) { + case DASD_EER_FATALERROR: + case DASD_EER_PPRCSUSPEND: + rc = dasd_eer_write_standard_trigger( + trigger->id, trigger->device, trigger->cqr); + break; + case DASD_EER_NOPATH: + rc = dasd_eer_write_standard_trigger( + trigger->id, trigger->device, NULL); + break; + case DASD_EER_STATECHANGE: + if (queue_work(dasd_eer_workqueue, &private->worker)) { + rc=0; + } else { + /* If the work_struct was already queued, it can't + * be queued again. But this is OK since we don't + * need to have it queued twice. + */ + rc = -EBUSY; + } + break; + default: /* unknown trigger, so we write it without any sense data */ + rc = dasd_eer_write_standard_trigger( + trigger->id, trigger->device, NULL); + break; + } + return rc; +} + +/* + * This function is registered with the dasd device driver and gets called + * for all dasd eer notifications. + */ +static int dasd_eer_notify(struct notifier_block *self, + unsigned long action, void *data) +{ + switch (action) { + case DASD_EER_DISABLE: + dasd_eer_disable_on_device((struct dasd_device *)data); + break; + case DASD_EER_TRIGGER: + dasd_eer_write_trigger((struct dasd_eer_trigger *)data); + break; + } + return NOTIFY_OK; +} + + +/*****************************************************************************/ +/* the device operations */ +/*****************************************************************************/ + +/* + * On the one side we need a lock to access our internal buffer, on the + * other side a copy_to_user can sleep. So we need to copy the data we have + * to transfer in a readbuffer, which is protected by the readbuffer_mutex. + */ +static char readbuffer[PAGE_SIZE]; +DECLARE_MUTEX(readbuffer_mutex); + + +static int +dasd_eer_open(struct inode *inp, struct file *filp) +{ + struct eerbuffer *eerb; + unsigned long flags; + + eerb = kmalloc(sizeof(struct eerbuffer), GFP_KERNEL); + eerb->head = 0; + eerb->tail = 0; + eerb->residual = 0; + eerb->buffer_page_count = 1; + eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE; + eerb->buffer = kmalloc(eerb->buffer_page_count*sizeof(char*), + GFP_KERNEL); + if (!eerb->buffer) + return -ENOMEM; + if (dasd_eer_allocate_buffer_pages(eerb->buffer, + eerb->buffer_page_count)) { + kfree(eerb->buffer); + return -ENOMEM; + } + filp->private_data = eerb; + spin_lock_irqsave(&bufferlock, flags); + list_add(&eerb->list, &bufferlist); + spin_unlock_irqrestore(&bufferlock, flags); + + return nonseekable_open(inp,filp); +} + +static int +dasd_eer_close(struct inode *inp, struct file *filp) +{ + struct eerbuffer *eerb; + unsigned long flags; + + eerb = (struct eerbuffer *)filp->private_data; + spin_lock_irqsave(&bufferlock, flags); + list_del(&eerb->list); + spin_unlock_irqrestore(&bufferlock, flags); + dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count); + kfree(eerb->buffer); + kfree(eerb); + + return 0; +} + +static long +dasd_eer_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) +{ + int intval; + struct eerbuffer *eerb; + + eerb = (struct eerbuffer *)filp->private_data; + switch (cmd) { + case DASD_EER_PURGE: + dasd_eer_purge_buffer(eerb); + return 0; + case DASD_EER_SETBUFSIZE: + if (get_user(intval, (int __user *)arg)) + return -EFAULT; + return dasd_eer_resize_buffer(eerb, intval); + default: + return -ENOIOCTLCMD; + } +} + +static ssize_t +dasd_eer_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) +{ + int tc,rc; + int tailcount,effective_count; + unsigned long flags; + struct eerbuffer *eerb; + + eerb = (struct eerbuffer *)filp->private_data; + if(down_interruptible(&readbuffer_mutex)) + return -ERESTARTSYS; + + spin_lock_irqsave(&bufferlock, flags); + + if (eerb->residual < 0) { /* the remainder of this record */ + /* has been deleted */ + eerb->residual = 0; + spin_unlock_irqrestore(&bufferlock, flags); + up(&readbuffer_mutex); + return -EIO; + } else if (eerb->residual > 0) { + /* OK we still have a second half of a record to deliver */ + effective_count = min(eerb->residual, (int)count); + eerb->residual -= effective_count; + } else { + tc = 0; + while (!tc) { + tc = dasd_eer_read_buffer(eerb, + sizeof(tailcount), (char*)(&tailcount)); + if (!tc) { + /* no data available */ + spin_unlock_irqrestore(&bufferlock, flags); + up(&readbuffer_mutex); + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + rc = wait_event_interruptible( + dasd_eer_read_wait_queue, + eerb->head != eerb->tail); + if (rc) { + return rc; + } + if(down_interruptible(&readbuffer_mutex)) + return -ERESTARTSYS; + spin_lock_irqsave(&bufferlock, flags); + } + } + WARN_ON(tc != sizeof(tailcount)); + effective_count = min(tailcount,(int)count); + eerb->residual = tailcount - effective_count; + } + + tc = dasd_eer_read_buffer(eerb, effective_count, readbuffer); + WARN_ON(tc != effective_count); + + spin_unlock_irqrestore(&bufferlock, flags); + + if (copy_to_user(buf, readbuffer, effective_count)) { + up(&readbuffer_mutex); + return -EFAULT; + } + + up(&readbuffer_mutex); + return effective_count; +} + +static unsigned int +dasd_eer_poll (struct file *filp, poll_table *ptable) +{ + unsigned int mask; + unsigned long flags; + struct eerbuffer *eerb; + + eerb = (struct eerbuffer *)filp->private_data; + poll_wait(filp, &dasd_eer_read_wait_queue, ptable); + spin_lock_irqsave(&bufferlock, flags); + if (eerb->head != eerb->tail) + mask = POLLIN | POLLRDNORM ; + else + mask = 0; + spin_unlock_irqrestore(&bufferlock, flags); + return mask; +} + +static struct file_operations dasd_eer_fops = { + .open = &dasd_eer_open, + .release = &dasd_eer_close, + .unlocked_ioctl = &dasd_eer_ioctl, + .compat_ioctl = &dasd_eer_ioctl, + .read = &dasd_eer_read, + .poll = &dasd_eer_poll, + .owner = THIS_MODULE, +}; + +static struct miscdevice dasd_eer_dev = { + .minor = MISC_DYNAMIC_MINOR, + .name = "dasd_eer", + .fops = &dasd_eer_fops, +}; + + +/*****************************************************************************/ +/* Init and exit */ +/*****************************************************************************/ + +static int +__init dasd_eer_init(void) +{ + int rc; + + dasd_eer_workqueue = create_singlethread_workqueue("dasd_eer"); + if (!dasd_eer_workqueue) { + MESSAGE(KERN_ERR , "%s", "dasd_eer_init could not " + "create workqueue \n"); + rc = -ENOMEM; + goto out; + } + + rc = dasd_register_eer_notifier(&dasd_eer_nb); + if (rc) { + MESSAGE(KERN_ERR, "%s", "dasd_eer_init could not " + "register error reporting"); + goto queue; + } + + dasd_ioctl_no_register(THIS_MODULE, BIODASDEERSET, dasd_ioctl_set_eer); + dasd_ioctl_no_register(THIS_MODULE, BIODASDEERGET, dasd_ioctl_get_eer); + + /* we don't need our own character device, + * so we just register as misc device */ + rc = misc_register(&dasd_eer_dev); + if (rc) { + MESSAGE(KERN_ERR, "%s", "dasd_eer_init could not " + "register misc device"); + goto unregister; + } + + return 0; + +unregister: + dasd_unregister_eer_notifier(&dasd_eer_nb); + dasd_ioctl_no_unregister(THIS_MODULE, BIODASDEERSET, + dasd_ioctl_set_eer); + dasd_ioctl_no_unregister(THIS_MODULE, BIODASDEERGET, + dasd_ioctl_get_eer); +queue: + destroy_workqueue(dasd_eer_workqueue); +out: + return rc; + +} +module_init(dasd_eer_init); + +static void +__exit dasd_eer_exit(void) +{ + dasd_unregister_eer_notifier(&dasd_eer_nb); + dasd_ioctl_no_unregister(THIS_MODULE, BIODASDEERSET, + dasd_ioctl_set_eer); + dasd_ioctl_no_unregister(THIS_MODULE, BIODASDEERGET, + dasd_ioctl_get_eer); + destroy_workqueue(dasd_eer_workqueue); + + WARN_ON(misc_deregister(&dasd_eer_dev) != 0); +} +module_exit(dasd_eer_exit); |
