[mirror_ubuntu-artful-kernel.git] / drivers / scsi / scsi_logging.c

/*
 * scsi_logging.c
 *
 * Copyright (C) 2014 SUSE Linux Products GmbH
 * Copyright (C) 2014 Hannes Reinecke <hare@suse.de>
 *
 * This file is released under the GPLv2
 */

#include <linux/kernel.h>
#include <linux/atomic.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_dbg.h>

#define SCSI_LOG_SPOOLSIZE 4096
#define SCSI_LOG_BUFSIZE 128

#if (SCSI_LOG_SPOOLSIZE / SCSI_LOG_BUFSIZE) > BITS_PER_LONG
#warning SCSI logging bitmask too large
#endif

struct scsi_log_buf {
	char buffer[SCSI_LOG_SPOOLSIZE];
	unsigned long map;
};

static DEFINE_PER_CPU(struct scsi_log_buf, scsi_format_log);

static char *scsi_log_reserve_buffer(size_t *len)
{
	struct scsi_log_buf *buf;
	unsigned long map_bits = sizeof(buf->buffer) / SCSI_LOG_BUFSIZE;
	unsigned long idx = 0;

	preempt_disable();
	buf = this_cpu_ptr(&scsi_format_log);
	idx = find_first_zero_bit(&buf->map, map_bits);
	if (likely(idx < map_bits)) {
		while (test_and_set_bit(idx, &buf->map)) {
			idx = find_next_zero_bit(&buf->map, map_bits, idx);
			if (idx >= map_bits)
				break;
		}
	}
	if (WARN_ON(idx >= map_bits)) {
		preempt_enable();
		return NULL;
	}
	*len = SCSI_LOG_BUFSIZE;
	return buf->buffer + idx * SCSI_LOG_BUFSIZE;
}

static void scsi_log_release_buffer(char *bufptr)
{
	struct scsi_log_buf *buf;
	unsigned long idx;
	int ret;

	buf = this_cpu_ptr(&scsi_format_log);
	if (bufptr >= buf->buffer &&
	    bufptr < buf->buffer + SCSI_LOG_SPOOLSIZE) {
		idx = (bufptr - buf->buffer) / SCSI_LOG_BUFSIZE;
		ret = test_and_clear_bit(idx, &buf->map);
		WARN_ON(!ret);
	}
	preempt_enable();
}

int sdev_prefix_printk(const char *level, const struct scsi_device *sdev,
		       const char *name, const char *fmt, ...)
{
	va_list args;
	char *logbuf;
	size_t off = 0, logbuf_len;
	int ret;

	if (!sdev)
		return 0;

	logbuf = scsi_log_reserve_buffer(&logbuf_len);
	if (!logbuf)
		return 0;

	if (name)
		off += scnprintf(logbuf + off, logbuf_len - off,
				 "[%s] ", name);
	va_start(args, fmt);
	off += vscnprintf(logbuf + off, logbuf_len - off, fmt, args);
	va_end(args);
	ret = dev_printk(level, &sdev->sdev_gendev, "%s", logbuf);
	scsi_log_release_buffer(logbuf);
	return ret;
}
EXPORT_SYMBOL(sdev_prefix_printk);

int scmd_printk(const char *level, const struct scsi_cmnd *scmd,
		const char *fmt, ...)
{
	struct gendisk *disk = scmd->request->rq_disk;
	va_list args;
	char *logbuf;
	size_t off = 0, logbuf_len;
	int ret;

	if (!scmd || !scmd->cmnd)
		return 0;

	logbuf = scsi_log_reserve_buffer(&logbuf_len);
	if (!logbuf)
		return 0;
	if (disk)
		off += scnprintf(logbuf + off, logbuf_len - off,
				 "[%s] ", disk->disk_name);
	va_start(args, fmt);
	off += vscnprintf(logbuf + off, logbuf_len - off, fmt, args);
	va_end(args);
	ret = dev_printk(level, &scmd->device->sdev_gendev, "%s", logbuf);
	scsi_log_release_buffer(logbuf);
	return ret;
}
EXPORT_SYMBOL(scmd_printk);
Commit	Line	Data
ded85c19 HR	1	/*
	2	* scsi_logging.c
	3	*
	4	* Copyright (C) 2014 SUSE Linux Products GmbH
	5	* Copyright (C) 2014 Hannes Reinecke <hare@suse.de>
	6	*
	7	* This file is released under the GPLv2
	8	*/
	9
	10	#include <linux/kernel.h>
	11	#include <linux/atomic.h>
	12
	13	#include <scsi/scsi.h>
	14	#include <scsi/scsi_cmnd.h>
	15	#include <scsi/scsi_device.h>
	16	#include <scsi/scsi_dbg.h>
	17
	18	#define SCSI_LOG_SPOOLSIZE 4096
	19	#define SCSI_LOG_BUFSIZE 128
	20
	21	#if (SCSI_LOG_SPOOLSIZE / SCSI_LOG_BUFSIZE) > BITS_PER_LONG
	22	#warning SCSI logging bitmask too large
	23	#endif
	24
	25	struct scsi_log_buf {
	26	char buffer[SCSI_LOG_SPOOLSIZE];
	27	unsigned long map;
	28	};
	29
	30	static DEFINE_PER_CPU(struct scsi_log_buf, scsi_format_log);
	31
	32	static char scsi_log_reserve_buffer(size_t len)
	33	{
	34	struct scsi_log_buf *buf;
	35	unsigned long map_bits = sizeof(buf->buffer) / SCSI_LOG_BUFSIZE;
	36	unsigned long idx = 0;
	37
	38	preempt_disable();
	39	buf = this_cpu_ptr(&scsi_format_log);
	40	idx = find_first_zero_bit(&buf->map, map_bits);
	41	if (likely(idx < map_bits)) {
	42	while (test_and_set_bit(idx, &buf->map)) {
	43	idx = find_next_zero_bit(&buf->map, map_bits, idx);
	44	if (idx >= map_bits)
	45	break;
	46	}
	47	}
	48	if (WARN_ON(idx >= map_bits)) {
	49	preempt_enable();
	50	return NULL;
	51	}
	52	*len = SCSI_LOG_BUFSIZE;
	53	return buf->buffer + idx * SCSI_LOG_BUFSIZE;
	54	}
	55
	56	static void scsi_log_release_buffer(char *bufptr)
	57	{
	58	struct scsi_log_buf *buf;
	59	unsigned long idx;
	60	int ret;
	61
	62	buf = this_cpu_ptr(&scsi_format_log);
	63	if (bufptr >= buf->buffer &&
	64	bufptr < buf->buffer + SCSI_LOG_SPOOLSIZE) {
65	idx = (bufptr - buf->buffer) / SCSI_LOG_BUFSIZE;
66	ret = test_and_clear_bit(idx, &buf->map);
67	WARN_ON(!ret);
68	}
69	preempt_enable();
70	}
71
72	int sdev_prefix_printk(const char level, const struct scsi_device sdev,
73	const char name, const char fmt, ...)
74	{
75	va_list args;
76	char *logbuf;
77	size_t off = 0, logbuf_len;
78	int ret;
79
80	if (!sdev)
81	return 0;
82
83	logbuf = scsi_log_reserve_buffer(&logbuf_len);
84	if (!logbuf)
85	return 0;
86
87	if (name)
88	off += scnprintf(logbuf + off, logbuf_len - off,
89	"[%s] ", name);
90	va_start(args, fmt);
91	off += vscnprintf(logbuf + off, logbuf_len - off, fmt, args);
92	va_end(args);
93	ret = dev_printk(level, &sdev->sdev_gendev, "%s", logbuf);
94	scsi_log_release_buffer(logbuf);
95	return ret;
96	}
97	EXPORT_SYMBOL(sdev_prefix_printk);
98
99	int scmd_printk(const char level, const struct scsi_cmnd scmd,
100	const char *fmt, ...)
101	{
102	struct gendisk *disk = scmd->request->rq_disk;
103	va_list args;
104	char *logbuf;
105	size_t off = 0, logbuf_len;
106	int ret;
107
108	if (!scmd \|\| !scmd->cmnd)
109	return 0;
110
111	logbuf = scsi_log_reserve_buffer(&logbuf_len);
112	if (!logbuf)
113	return 0;
114	if (disk)
115	off += scnprintf(logbuf + off, logbuf_len - off,
116	"[%s] ", disk->disk_name);
117	va_start(args, fmt);
118	off += vscnprintf(logbuf + off, logbuf_len - off, fmt, args);
119	va_end(args);
120	ret = dev_printk(level, &scmd->device->sdev_gendev, "%s", logbuf);
121	scsi_log_release_buffer(logbuf);
122	return ret;
123	}
124	EXPORT_SYMBOL(scmd_printk);