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![Vasily Gorbik](/assets/img/avatar_default.png)
ccw "busid" should always be NUL-terminated, as evident from e.g. get_ccwdev_by_busid doing "return (strcmp(bus_id, dev_name(dev)) == 0)". Replace all strncpy initializing busid with strlcpy. This fixes the following gcc 8 warnings: drivers/s390/scsi/zfcp_aux.c:104:2: warning: 'strncpy' specified bound 20 equals destination size [-Wstringop-truncation] strncpy(busid, token, ZFCP_BUS_ID_SIZE); drivers/s390/block/dasd_eer.c:316:2: warning: 'strncpy' specified bound 10 equals destination size [-Wstringop-truncation] strncpy(header.busid, dev_name(&device->cdev->dev), DASD_EER_BUSID_SIZE); drivers/s390/block/dasd_eer.c:359:2: warning: 'strncpy' specified bound 10 equals destination size [-Wstringop-truncation] strncpy(header.busid, dev_name(&device->cdev->dev), DASD_EER_BUSID_SIZE); drivers/s390/block/dasd_devmap.c:429:3: warning: 'strncpy' specified bound 20 equals destination size [-Wstringop-truncation] strncpy(new->bus_id, bus_id, DASD_BUS_ID_SIZE); Acked-by: Stefan Haberland <sth@linux.ibm.com> Acked-by: Steffen Maier <maier@linux.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
723 lines
20 KiB
C
723 lines
20 KiB
C
// 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 <wein@de.ibm.com>
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*/
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#define KMSG_COMPONENT "dasd-eckd"
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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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* SECTION: the internal buffer
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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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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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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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* 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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* 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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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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* 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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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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* 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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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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* 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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return 0;
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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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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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* SECTION: The extended error reporting functionality
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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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* 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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/* 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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* 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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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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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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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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* 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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* 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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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
|
|
* is a new ccw in device->eer_cqr. Free the "old"
|
|
* snss request now.
|
|
*/
|
|
dasd_sfree_request(cqr, device);
|
|
}
|
|
|
|
/*
|
|
* Enable error reporting on a given device.
|
|
*/
|
|
int dasd_eer_enable(struct dasd_device *device)
|
|
{
|
|
struct dasd_ccw_req *cqr = NULL;
|
|
unsigned long flags;
|
|
struct ccw1 *ccw;
|
|
int rc = 0;
|
|
|
|
spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
|
|
if (device->eer_cqr)
|
|
goto out;
|
|
else if (!device->discipline ||
|
|
strcmp(device->discipline->name, "ECKD"))
|
|
rc = -EMEDIUMTYPE;
|
|
else if (test_bit(DASD_FLAG_OFFLINE, &device->flags))
|
|
rc = -EBUSY;
|
|
|
|
if (rc)
|
|
goto out;
|
|
|
|
cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1 /* SNSS */,
|
|
SNSS_DATA_SIZE, device, NULL);
|
|
if (IS_ERR(cqr)) {
|
|
rc = -ENOMEM;
|
|
cqr = NULL;
|
|
goto out;
|
|
}
|
|
|
|
cqr->startdev = device;
|
|
cqr->retries = 255;
|
|
cqr->expires = 10 * HZ;
|
|
clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
|
|
set_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags);
|
|
|
|
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_tod_clock();
|
|
cqr->status = DASD_CQR_FILLED;
|
|
cqr->callback = dasd_eer_snss_cb;
|
|
|
|
if (!device->eer_cqr) {
|
|
device->eer_cqr = cqr;
|
|
cqr = NULL;
|
|
}
|
|
|
|
out:
|
|
spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
|
|
|
|
if (cqr)
|
|
dasd_sfree_request(cqr, device);
|
|
|
|
return rc;
|
|
}
|
|
|
|
/*
|
|
* Disable error reporting on a given device.
|
|
*/
|
|
void dasd_eer_disable(struct dasd_device *device)
|
|
{
|
|
struct dasd_ccw_req *cqr;
|
|
unsigned long flags;
|
|
int in_use;
|
|
|
|
if (!device->eer_cqr)
|
|
return;
|
|
spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
|
|
cqr = device->eer_cqr;
|
|
device->eer_cqr = NULL;
|
|
clear_bit(DASD_FLAG_EER_SNSS, &device->flags);
|
|
in_use = test_and_clear_bit(DASD_FLAG_EER_IN_USE, &device->flags);
|
|
spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
|
|
if (cqr && !in_use)
|
|
dasd_sfree_request(cqr, device);
|
|
}
|
|
|
|
/*
|
|
* SECTION: 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];
|
|
static DEFINE_MUTEX(readbuffer_mutex);
|
|
|
|
static int dasd_eer_open(struct inode *inp, struct file *filp)
|
|
{
|
|
struct eerbuffer *eerb;
|
|
unsigned long flags;
|
|
|
|
eerb = kzalloc(sizeof(struct eerbuffer), GFP_KERNEL);
|
|
if (!eerb)
|
|
return -ENOMEM;
|
|
eerb->buffer_page_count = eer_pages;
|
|
if (eerb->buffer_page_count < 1 ||
|
|
eerb->buffer_page_count > INT_MAX / PAGE_SIZE) {
|
|
kfree(eerb);
|
|
DBF_EVENT(DBF_WARNING, "can't open device since module "
|
|
"parameter eer_pages is smaller than 1 or"
|
|
" bigger than %d", (int)(INT_MAX / PAGE_SIZE));
|
|
return -EINVAL;
|
|
}
|
|
eerb->buffersize = eerb->buffer_page_count * PAGE_SIZE;
|
|
eerb->buffer = kmalloc_array(eerb->buffer_page_count, sizeof(char *),
|
|
GFP_KERNEL);
|
|
if (!eerb->buffer) {
|
|
kfree(eerb);
|
|
return -ENOMEM;
|
|
}
|
|
if (dasd_eer_allocate_buffer_pages(eerb->buffer,
|
|
eerb->buffer_page_count)) {
|
|
kfree(eerb->buffer);
|
|
kfree(eerb);
|
|
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 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 (mutex_lock_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);
|
|
mutex_unlock(&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, (char *) &tailcount,
|
|
sizeof(tailcount));
|
|
if (!tc) {
|
|
/* no data available */
|
|
spin_unlock_irqrestore(&bufferlock, flags);
|
|
mutex_unlock(&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 (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;
|
|
}
|
|
}
|