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724 lines
20 KiB
724 lines
20 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Character device driver for extended error reporting. |
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* |
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* Copyright IBM Corp. 2005 |
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* extended error reporting for DASD ECKD devices |
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* Author(s): Stefan Weinhuber <[email protected]> |
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*/ |
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|
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#define KMSG_COMPONENT "dasd-eckd" |
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|
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#include <linux/init.h> |
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#include <linux/fs.h> |
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#include <linux/kernel.h> |
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#include <linux/miscdevice.h> |
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#include <linux/module.h> |
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#include <linux/moduleparam.h> |
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#include <linux/device.h> |
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#include <linux/poll.h> |
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#include <linux/mutex.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/uaccess.h> |
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#include <linux/atomic.h> |
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#include <asm/ebcdic.h> |
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#include "dasd_int.h" |
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#include "dasd_eckd.h" |
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#ifdef PRINTK_HEADER |
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#undef PRINTK_HEADER |
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#endif /* PRINTK_HEADER */ |
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#define PRINTK_HEADER "dasd(eer):" |
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|
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/* |
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* SECTION: the internal buffer |
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*/ |
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|
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/* |
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* The internal buffer is meant to store obaque blobs of data, so it does |
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* not know of higher level concepts like triggers. |
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* It consists of a number of pages that are used as a ringbuffer. Each data |
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* blob is stored in a simple record that consists of an integer, which |
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* contains the size of the following data, and the data bytes themselfes. |
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* |
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* To allow for multiple independent readers we create one internal buffer |
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* each time the device is opened and destroy the buffer when the file is |
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* closed again. The number of pages used for this buffer is determined by |
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* the module parmeter eer_pages. |
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* |
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* One record can be written to a buffer by using the functions |
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* - dasd_eer_start_record (one time per record to write the size to the |
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* buffer and reserve the space for the data) |
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* - dasd_eer_write_buffer (one or more times per record to write the data) |
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* The data can be written in several steps but you will have to compute |
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* the total size up front for the invocation of dasd_eer_start_record. |
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* If the ringbuffer is full, dasd_eer_start_record will remove the required |
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* number of old records. |
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* |
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* A record is typically read in two steps, first read the integer that |
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* specifies the size of the following data, then read the data. |
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* Both can be done by |
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* - dasd_eer_read_buffer |
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* |
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* For all mentioned functions you need to get the bufferlock first and keep |
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* it until a complete record is written or read. |
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* |
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* All information necessary to keep track of an internal buffer is kept in |
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* a struct eerbuffer. The buffer specific to a file pointer is strored in |
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* the private_data field of that file. To be able to write data to all |
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* existing buffers, each buffer is also added to the bufferlist. |
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* If the user does not want to read a complete record in one go, we have to |
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* keep track of the rest of the record. residual stores the number of bytes |
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* that are still to deliver. If the rest of the record is invalidated between |
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* two reads then residual will be set to -1 so that the next read will fail. |
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* All entries in the eerbuffer structure are protected with the bufferlock. |
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* To avoid races between writing to a buffer on the one side and creating |
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* and destroying buffers on the other side, the bufferlock must also be used |
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* to protect the bufferlist. |
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*/ |
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|
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static int eer_pages = 5; |
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module_param(eer_pages, int, S_IRUGO|S_IWUSR); |
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struct eerbuffer { |
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struct list_head list; |
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char **buffer; |
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int buffersize; |
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int buffer_page_count; |
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int head; |
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int tail; |
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int residual; |
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}; |
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|
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static LIST_HEAD(bufferlist); |
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static DEFINE_SPINLOCK(bufferlock); |
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static DECLARE_WAIT_QUEUE_HEAD(dasd_eer_read_wait_queue); |
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|
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/* |
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* How many free bytes are available on the buffer. |
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* Needs to be called with bufferlock held. |
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*/ |
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static int dasd_eer_get_free_bytes(struct eerbuffer *eerb) |
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{ |
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if (eerb->head < eerb->tail) |
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return eerb->tail - eerb->head - 1; |
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return eerb->buffersize - eerb->head + eerb->tail -1; |
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} |
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|
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/* |
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* How many bytes of buffer space are used. |
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* Needs to be called with bufferlock held. |
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*/ |
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static int dasd_eer_get_filled_bytes(struct eerbuffer *eerb) |
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{ |
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|
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if (eerb->head >= eerb->tail) |
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return eerb->head - eerb->tail; |
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return eerb->buffersize - eerb->tail + eerb->head; |
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} |
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|
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/* |
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* The dasd_eer_write_buffer function just copies count bytes of data |
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* to the buffer. Make sure to call dasd_eer_start_record first, to |
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* make sure that enough free space is available. |
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* Needs to be called with bufferlock held. |
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*/ |
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static void dasd_eer_write_buffer(struct eerbuffer *eerb, |
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char *data, int count) |
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{ |
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|
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unsigned long headindex,localhead; |
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unsigned long rest, len; |
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char *nextdata; |
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nextdata = data; |
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rest = count; |
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while (rest > 0) { |
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headindex = eerb->head / PAGE_SIZE; |
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localhead = eerb->head % PAGE_SIZE; |
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len = min(rest, PAGE_SIZE - localhead); |
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memcpy(eerb->buffer[headindex]+localhead, nextdata, len); |
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nextdata += len; |
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rest -= len; |
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eerb->head += len; |
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if (eerb->head == eerb->buffersize) |
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eerb->head = 0; /* wrap around */ |
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BUG_ON(eerb->head > eerb->buffersize); |
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} |
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} |
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|
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/* |
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* Needs to be called with bufferlock held. |
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*/ |
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static int dasd_eer_read_buffer(struct eerbuffer *eerb, char *data, int count) |
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{ |
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|
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unsigned long tailindex,localtail; |
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unsigned long rest, len, finalcount; |
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char *nextdata; |
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finalcount = min(count, dasd_eer_get_filled_bytes(eerb)); |
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nextdata = data; |
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rest = finalcount; |
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while (rest > 0) { |
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tailindex = eerb->tail / PAGE_SIZE; |
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localtail = eerb->tail % PAGE_SIZE; |
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len = min(rest, PAGE_SIZE - localtail); |
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memcpy(nextdata, eerb->buffer[tailindex] + localtail, len); |
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nextdata += len; |
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rest -= len; |
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eerb->tail += len; |
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if (eerb->tail == eerb->buffersize) |
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eerb->tail = 0; /* wrap around */ |
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BUG_ON(eerb->tail > eerb->buffersize); |
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} |
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return finalcount; |
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} |
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|
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/* |
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* Whenever you want to write a blob of data to the internal buffer you |
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* have to start by using this function first. It will write the number |
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* of bytes that will be written to the buffer. If necessary it will remove |
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* old records to make room for the new one. |
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* Needs to be called with bufferlock held. |
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*/ |
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static int dasd_eer_start_record(struct eerbuffer *eerb, int count) |
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{ |
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int tailcount; |
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if (count + sizeof(count) > eerb->buffersize) |
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return -ENOMEM; |
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while (dasd_eer_get_free_bytes(eerb) < count + sizeof(count)) { |
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if (eerb->residual > 0) { |
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eerb->tail += eerb->residual; |
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if (eerb->tail >= eerb->buffersize) |
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eerb->tail -= eerb->buffersize; |
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eerb->residual = -1; |
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} |
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dasd_eer_read_buffer(eerb, (char *) &tailcount, |
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sizeof(tailcount)); |
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eerb->tail += tailcount; |
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if (eerb->tail >= eerb->buffersize) |
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eerb->tail -= eerb->buffersize; |
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} |
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dasd_eer_write_buffer(eerb, (char*) &count, sizeof(count)); |
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|
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return 0; |
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}; |
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|
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/* |
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* Release pages that are not used anymore. |
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*/ |
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static void dasd_eer_free_buffer_pages(char **buf, int no_pages) |
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{ |
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int i; |
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|
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for (i = 0; i < no_pages; i++) |
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free_page((unsigned long) buf[i]); |
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} |
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/* |
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* Allocate a new set of memory pages. |
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*/ |
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static int dasd_eer_allocate_buffer_pages(char **buf, int no_pages) |
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{ |
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int i; |
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for (i = 0; i < no_pages; i++) { |
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buf[i] = (char *) get_zeroed_page(GFP_KERNEL); |
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if (!buf[i]) { |
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dasd_eer_free_buffer_pages(buf, i); |
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return -ENOMEM; |
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} |
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} |
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return 0; |
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} |
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|
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/* |
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* SECTION: The extended error reporting functionality |
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*/ |
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|
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/* |
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* When a DASD device driver wants to report an error, it calls the |
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* function dasd_eer_write and gives the respective trigger ID as |
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* parameter. Currently there are four kinds of triggers: |
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* |
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* DASD_EER_FATALERROR: all kinds of unrecoverable I/O problems |
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* DASD_EER_PPRCSUSPEND: PPRC was suspended |
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* DASD_EER_NOPATH: There is no path to the device left. |
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* DASD_EER_STATECHANGE: The state of the device has changed. |
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* |
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* For the first three triggers all required information can be supplied by |
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* the caller. For these triggers a record is written by the function |
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* dasd_eer_write_standard_trigger. |
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* |
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* The DASD_EER_STATECHANGE trigger is special since a sense subsystem |
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* status ccw need to be executed to gather the necessary sense data first. |
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* The dasd_eer_snss function will queue the SNSS request and the request |
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* callback will then call dasd_eer_write with the DASD_EER_STATCHANGE |
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* trigger. |
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* |
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* To avoid memory allocations at runtime, the necessary memory is allocated |
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* when the extended error reporting is enabled for a device (by |
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* dasd_eer_probe). There is one sense subsystem status request for each |
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* eer enabled DASD device. The presence of the cqr in device->eer_cqr |
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* indicates that eer is enable for the device. The use of the snss request |
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* is protected by the DASD_FLAG_EER_IN_USE bit. When this flag indicates |
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* that the cqr is currently in use, dasd_eer_snss cannot start a second |
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* request but sets the DASD_FLAG_EER_SNSS flag instead. The callback of |
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* the SNSS request will check the bit and call dasd_eer_snss again. |
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*/ |
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#define SNSS_DATA_SIZE 44 |
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#define DASD_EER_BUSID_SIZE 10 |
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struct dasd_eer_header { |
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__u32 total_size; |
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__u32 trigger; |
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__u64 tv_sec; |
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__u64 tv_usec; |
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char busid[DASD_EER_BUSID_SIZE]; |
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} __attribute__ ((packed)); |
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|
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/* |
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* The following function can be used for those triggers that have |
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* all necessary data available when the function is called. |
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* If the parameter cqr is not NULL, the chain of requests will be searched |
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* for valid sense data, and all valid sense data sets will be added to |
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* the triggers data. |
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*/ |
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static void dasd_eer_write_standard_trigger(struct dasd_device *device, |
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struct dasd_ccw_req *cqr, |
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int trigger) |
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{ |
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struct dasd_ccw_req *temp_cqr; |
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int data_size; |
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struct timespec64 ts; |
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struct dasd_eer_header header; |
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unsigned long flags; |
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struct eerbuffer *eerb; |
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char *sense; |
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|
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/* go through cqr chain and count the valid sense data sets */ |
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data_size = 0; |
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for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) |
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if (dasd_get_sense(&temp_cqr->irb)) |
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data_size += 32; |
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header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ |
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header.trigger = trigger; |
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ktime_get_real_ts64(&ts); |
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header.tv_sec = ts.tv_sec; |
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header.tv_usec = ts.tv_nsec / NSEC_PER_USEC; |
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strlcpy(header.busid, dev_name(&device->cdev->dev), |
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DASD_EER_BUSID_SIZE); |
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spin_lock_irqsave(&bufferlock, flags); |
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list_for_each_entry(eerb, &bufferlist, list) { |
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dasd_eer_start_record(eerb, header.total_size); |
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dasd_eer_write_buffer(eerb, (char *) &header, sizeof(header)); |
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for (temp_cqr = cqr; temp_cqr; temp_cqr = temp_cqr->refers) { |
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sense = dasd_get_sense(&temp_cqr->irb); |
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if (sense) |
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dasd_eer_write_buffer(eerb, sense, 32); |
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} |
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dasd_eer_write_buffer(eerb, "EOR", 4); |
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} |
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spin_unlock_irqrestore(&bufferlock, flags); |
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wake_up_interruptible(&dasd_eer_read_wait_queue); |
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} |
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|
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/* |
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* This function writes a DASD_EER_STATECHANGE trigger. |
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*/ |
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static void dasd_eer_write_snss_trigger(struct dasd_device *device, |
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struct dasd_ccw_req *cqr, |
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int trigger) |
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{ |
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int data_size; |
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int snss_rc; |
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struct timespec64 ts; |
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struct dasd_eer_header header; |
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unsigned long flags; |
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struct eerbuffer *eerb; |
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snss_rc = (cqr->status == DASD_CQR_DONE) ? 0 : -EIO; |
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if (snss_rc) |
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data_size = 0; |
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else |
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data_size = SNSS_DATA_SIZE; |
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|
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header.total_size = sizeof(header) + data_size + 4; /* "EOR" */ |
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header.trigger = DASD_EER_STATECHANGE; |
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ktime_get_real_ts64(&ts); |
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header.tv_sec = ts.tv_sec; |
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header.tv_usec = ts.tv_nsec / NSEC_PER_USEC; |
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strlcpy(header.busid, dev_name(&device->cdev->dev), |
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DASD_EER_BUSID_SIZE); |
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|
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spin_lock_irqsave(&bufferlock, flags); |
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list_for_each_entry(eerb, &bufferlist, list) { |
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dasd_eer_start_record(eerb, header.total_size); |
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dasd_eer_write_buffer(eerb, (char *) &header , sizeof(header)); |
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if (!snss_rc) |
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dasd_eer_write_buffer(eerb, cqr->data, SNSS_DATA_SIZE); |
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dasd_eer_write_buffer(eerb, "EOR", 4); |
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} |
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spin_unlock_irqrestore(&bufferlock, flags); |
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wake_up_interruptible(&dasd_eer_read_wait_queue); |
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} |
|
|
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/* |
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* This function is called for all triggers. It calls the appropriate |
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* function that writes the actual trigger records. |
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*/ |
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void dasd_eer_write(struct dasd_device *device, struct dasd_ccw_req *cqr, |
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unsigned int id) |
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{ |
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if (!device->eer_cqr) |
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return; |
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switch (id) { |
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case DASD_EER_FATALERROR: |
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case DASD_EER_PPRCSUSPEND: |
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dasd_eer_write_standard_trigger(device, cqr, id); |
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break; |
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case DASD_EER_NOPATH: |
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case DASD_EER_NOSPC: |
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dasd_eer_write_standard_trigger(device, NULL, id); |
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break; |
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case DASD_EER_STATECHANGE: |
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dasd_eer_write_snss_trigger(device, cqr, id); |
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break; |
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default: /* unknown trigger, so we write it without any sense data */ |
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dasd_eer_write_standard_trigger(device, NULL, id); |
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break; |
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} |
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} |
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EXPORT_SYMBOL(dasd_eer_write); |
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|
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/* |
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* Start a sense subsystem status request. |
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* Needs to be called with the device held. |
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*/ |
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void dasd_eer_snss(struct dasd_device *device) |
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{ |
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struct dasd_ccw_req *cqr; |
|
|
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cqr = device->eer_cqr; |
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if (!cqr) /* Device not eer enabled. */ |
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return; |
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if (test_and_set_bit(DASD_FLAG_EER_IN_USE, &device->flags)) { |
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/* Sense subsystem status request in use. */ |
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set_bit(DASD_FLAG_EER_SNSS, &device->flags); |
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return; |
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} |
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/* cdev is already locked, can't use dasd_add_request_head */ |
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clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
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cqr->status = DASD_CQR_QUEUED; |
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list_add(&cqr->devlist, &device->ccw_queue); |
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dasd_schedule_device_bh(device); |
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} |
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|
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/* |
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* Callback function for use with sense subsystem status request. |
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*/ |
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static void dasd_eer_snss_cb(struct dasd_ccw_req *cqr, void *data) |
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{ |
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struct dasd_device *device = cqr->startdev; |
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unsigned long flags; |
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|
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dasd_eer_write(device, cqr, DASD_EER_STATECHANGE); |
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spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
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if (device->eer_cqr == cqr) { |
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clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); |
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if (test_bit(DASD_FLAG_EER_SNSS, &device->flags)) |
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/* Another SNSS has been requested in the meantime. */ |
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dasd_eer_snss(device); |
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cqr = NULL; |
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} |
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spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); |
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if (cqr) |
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/* |
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* Extended error recovery has been switched off while |
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* the SNSS request was running. It could even have |
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* been switched off and on again in which case there |
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* is a new ccw in device->eer_cqr. Free the "old" |
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* snss request now. |
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*/ |
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dasd_sfree_request(cqr, device); |
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} |
|
|
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/* |
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* Enable error reporting on a given device. |
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*/ |
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int dasd_eer_enable(struct dasd_device *device) |
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{ |
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struct dasd_ccw_req *cqr = NULL; |
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unsigned long flags; |
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struct ccw1 *ccw; |
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int rc = 0; |
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|
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spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
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if (device->eer_cqr) |
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goto out; |
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else if (!device->discipline || |
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strcmp(device->discipline->name, "ECKD")) |
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rc = -EMEDIUMTYPE; |
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else if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) |
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rc = -EBUSY; |
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|
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if (rc) |
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goto out; |
|
|
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cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */, |
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SNSS_DATA_SIZE, device, NULL); |
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if (IS_ERR(cqr)) { |
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rc = -ENOMEM; |
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cqr = NULL; |
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goto out; |
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} |
|
|
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cqr->startdev = device; |
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cqr->retries = 255; |
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cqr->expires = 10 * HZ; |
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clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags); |
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set_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags); |
|
|
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ccw = cqr->cpaddr; |
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ccw->cmd_code = DASD_ECKD_CCW_SNSS; |
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ccw->count = SNSS_DATA_SIZE; |
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ccw->flags = 0; |
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ccw->cda = (__u32)(addr_t) cqr->data; |
|
|
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cqr->buildclk = get_tod_clock(); |
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cqr->status = DASD_CQR_FILLED; |
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cqr->callback = dasd_eer_snss_cb; |
|
|
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if (!device->eer_cqr) { |
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device->eer_cqr = cqr; |
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cqr = NULL; |
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} |
|
|
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out: |
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spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); |
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|
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if (cqr) |
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dasd_sfree_request(cqr, device); |
|
|
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return rc; |
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} |
|
|
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/* |
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* Disable error reporting on a given device. |
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*/ |
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void dasd_eer_disable(struct dasd_device *device) |
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{ |
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struct dasd_ccw_req *cqr; |
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unsigned long flags; |
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int in_use; |
|
|
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if (!device->eer_cqr) |
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return; |
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spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags); |
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cqr = device->eer_cqr; |
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device->eer_cqr = NULL; |
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clear_bit(DASD_FLAG_EER_SNSS, &device->flags); |
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in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags); |
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spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags); |
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if (cqr && !in_use) |
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dasd_sfree_request(cqr, device); |
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} |
|
|
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/* |
|
* SECTION: the device operations |
|
*/ |
|
|
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/* |
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* On the one side we need a lock to access our internal buffer, on the |
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* other side a copy_to_user can sleep. So we need to copy the data we have |
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* to transfer in a readbuffer, which is protected by the readbuffer_mutex. |
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*/ |
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static char readbuffer[PAGE_SIZE]; |
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static DEFINE_MUTEX(readbuffer_mutex); |
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|
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static int dasd_eer_open(struct inode *inp, struct file *filp) |
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{ |
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struct eerbuffer *eerb; |
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unsigned long flags; |
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|
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eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL); |
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if (!eerb) |
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return -ENOMEM; |
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eerb->buffer_page_count = eer_pages; |
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if (eerb->buffer_page_count < 1 || |
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eerb->buffer_page_count > INT_MAX / PAGE_SIZE) { |
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kfree(eerb); |
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DBF_EVENT(DBF_WARNING, "can't open device since module " |
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"parameter eer_pages is smaller than 1 or" |
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" bigger than %d", (int)(INT_MAX / PAGE_SIZE)); |
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return -EINVAL; |
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} |
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eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE; |
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eerb->buffer = kmalloc_array(eerb->buffer_page_count, sizeof(char *), |
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GFP_KERNEL); |
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if (!eerb->buffer) { |
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kfree(eerb); |
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return -ENOMEM; |
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} |
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if (dasd_eer_allocate_buffer_pages(eerb->buffer, |
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eerb->buffer_page_count)) { |
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kfree(eerb->buffer); |
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kfree(eerb); |
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return -ENOMEM; |
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} |
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filp->private_data = eerb; |
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spin_lock_irqsave(&bufferlock, flags); |
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list_add(&eerb->list, &bufferlist); |
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spin_unlock_irqrestore(&bufferlock, flags); |
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|
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return nonseekable_open(inp,filp); |
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} |
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|
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static int dasd_eer_close(struct inode *inp, struct file *filp) |
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{ |
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struct eerbuffer *eerb; |
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unsigned long flags; |
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|
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eerb = (struct eerbuffer *) filp->private_data; |
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spin_lock_irqsave(&bufferlock, flags); |
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list_del(&eerb->list); |
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spin_unlock_irqrestore(&bufferlock, flags); |
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dasd_eer_free_buffer_pages(eerb->buffer, eerb->buffer_page_count); |
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kfree(eerb->buffer); |
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kfree(eerb); |
|
|
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return 0; |
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} |
|
|
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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; |
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if (mutex_lock_interruptible(&readbuffer_mutex)) |
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return -ERESTARTSYS; |
|
|
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spin_lock_irqsave(&bufferlock, flags); |
|
|
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if (eerb->residual < 0) { /* the remainder of this record */ |
|
/* has been deleted */ |
|
eerb->residual = 0; |
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spin_unlock_irqrestore(&bufferlock, flags); |
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mutex_unlock(&readbuffer_mutex); |
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return -EIO; |
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} 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) { |
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tc = dasd_eer_read_buffer(eerb, (char *) &tailcount, |
|
sizeof(tailcount)); |
|
if (!tc) { |
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/* no data available */ |
|
spin_unlock_irqrestore(&bufferlock, flags); |
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mutex_unlock(&readbuffer_mutex); |
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if (filp->f_flags & O_NONBLOCK) |
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return -EAGAIN; |
|
rc = wait_event_interruptible( |
|
dasd_eer_read_wait_queue, |
|
eerb->head != eerb->tail); |
|
if (rc) |
|
return rc; |
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if (mutex_lock_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, readbuffer, effective_count); |
|
WARN_ON(tc != effective_count); |
|
|
|
spin_unlock_irqrestore(&bufferlock, flags); |
|
|
|
if (copy_to_user(buf, readbuffer, effective_count)) { |
|
mutex_unlock(&readbuffer_mutex); |
|
return -EFAULT; |
|
} |
|
|
|
mutex_unlock(&readbuffer_mutex); |
|
return effective_count; |
|
} |
|
|
|
static __poll_t dasd_eer_poll(struct file *filp, poll_table *ptable) |
|
{ |
|
__poll_t 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 = EPOLLIN | EPOLLRDNORM ; |
|
else |
|
mask = 0; |
|
spin_unlock_irqrestore(&bufferlock, flags); |
|
return mask; |
|
} |
|
|
|
static const struct file_operations dasd_eer_fops = { |
|
.open = &dasd_eer_open, |
|
.release = &dasd_eer_close, |
|
.read = &dasd_eer_read, |
|
.poll = &dasd_eer_poll, |
|
.owner = THIS_MODULE, |
|
.llseek = noop_llseek, |
|
}; |
|
|
|
static struct miscdevice *dasd_eer_dev = NULL; |
|
|
|
int __init dasd_eer_init(void) |
|
{ |
|
int rc; |
|
|
|
dasd_eer_dev = kzalloc(sizeof(*dasd_eer_dev), GFP_KERNEL); |
|
if (!dasd_eer_dev) |
|
return -ENOMEM; |
|
|
|
dasd_eer_dev->minor = MISC_DYNAMIC_MINOR; |
|
dasd_eer_dev->name = "dasd_eer"; |
|
dasd_eer_dev->fops = &dasd_eer_fops; |
|
|
|
rc = misc_register(dasd_eer_dev); |
|
if (rc) { |
|
kfree(dasd_eer_dev); |
|
dasd_eer_dev = NULL; |
|
DBF_EVENT(DBF_ERR, "%s", "dasd_eer_init could not " |
|
"register misc device"); |
|
return rc; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
void dasd_eer_exit(void) |
|
{ |
|
if (dasd_eer_dev) { |
|
misc_deregister(dasd_eer_dev); |
|
kfree(dasd_eer_dev); |
|
dasd_eer_dev = NULL; |
|
} |
|
}
|
|
|