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1 /*
2  *  linux/drivers/scsi/esas2r/esas2r_log.c
3  *      For use with ATTO ExpressSAS R6xx SAS/SATA RAID controllers
4  *
5  *  Copyright (c) 2001-2013 ATTO Technology, Inc.
6  *  (mailto:linuxdrivers@attotech.com)
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; either version 2
11  * of the License, or (at your option) any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16  * GNU General Public License for more details.
17  *
18  * NO WARRANTY
19  * THE PROGRAM IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OR
20  * CONDITIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED INCLUDING, WITHOUT
21  * LIMITATION, ANY WARRANTIES OR CONDITIONS OF TITLE, NON-INFRINGEMENT,
22  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Each Recipient is
23  * solely responsible for determining the appropriateness of using and
24  * distributing the Program and assumes all risks associated with its
25  * exercise of rights under this Agreement, including but not limited to
26  * the risks and costs of program errors, damage to or loss of data,
27  * programs or equipment, and unavailability or interruption of operations.
28  *
29  * DISCLAIMER OF LIABILITY
30  * NEITHER RECIPIENT NOR ANY CONTRIBUTORS SHALL HAVE ANY LIABILITY FOR ANY
31  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING WITHOUT LIMITATION LOST PROFITS), HOWEVER CAUSED AND
33  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
34  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
35  * USE OR DISTRIBUTION OF THE PROGRAM OR THE EXERCISE OF ANY RIGHTS GRANTED
36  * HEREUNDER, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES
37  *
38  * You should have received a copy of the GNU General Public License
39  * along with this program; if not, write to the Free Software
40  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
41  * USA.
42  */
43 
44 #include "esas2r.h"
45 
46 /*
47  * this module within the driver is tasked with providing logging functionality.
48  * the event_log_level module parameter controls the level of messages that are
49  * written to the system log.  the default level of messages that are written
50  * are critical and warning messages.  if other types of messages are desired,
51  * one simply needs to load the module with the correct value for the
52  * event_log_level module parameter.  for example:
53  *
54  * insmod <module> event_log_level=1
55  *
56  * will load the module and only critical events will be written by this module
57  * to the system log.  if critical, warning, and information-level messages are
58  * desired, the correct value for the event_log_level module parameter
59  * would be as follows:
60  *
61  * insmod <module> event_log_level=3
62  */
63 
64 #define EVENT_LOG_BUFF_SIZE 1024
65 
66 static long event_log_level = ESAS2R_LOG_DFLT;
67 
68 module_param(event_log_level, long, S_IRUGO | S_IRUSR);
69 MODULE_PARM_DESC(event_log_level,
70 		 "Specifies the level of events to report to the system log.  Critical and warning level events are logged by default.");
71 
72 /* A shared buffer to use for formatting messages. */
73 static char event_buffer[EVENT_LOG_BUFF_SIZE];
74 
75 /* A lock to protect the shared buffer used for formatting messages. */
76 static DEFINE_SPINLOCK(event_buffer_lock);
77 
78 /**
79  * translates an esas2r-defined logging event level to a kernel logging level.
80  *
81  * @param [in] level the esas2r-defined logging event level to translate
82  *
83  * @return the corresponding kernel logging level.
84  */
translate_esas2r_event_level_to_kernel(const long level)85 static const char *translate_esas2r_event_level_to_kernel(const long level)
86 {
87 	switch (level) {
88 	case ESAS2R_LOG_CRIT:
89 		return KERN_CRIT;
90 
91 	case ESAS2R_LOG_WARN:
92 		return KERN_WARNING;
93 
94 	case ESAS2R_LOG_INFO:
95 		return KERN_INFO;
96 
97 	case ESAS2R_LOG_DEBG:
98 	case ESAS2R_LOG_TRCE:
99 	default:
100 		return KERN_DEBUG;
101 	}
102 }
103 
104 /**
105  * the master logging function.  this function will format the message as
106  * outlined by the formatting string, the input device information and the
107  * substitution arguments and output the resulting string to the system log.
108  *
109  * @param [in] level  the event log level of the message
110  * @param [in] dev    the device information
111  * @param [in] format the formatting string for the message
112  * @param [in] args   the substition arguments to the formatting string
113  *
114  * @return 0 on success, or -1 if an error occurred.
115  */
esas2r_log_master(const long level,const struct device * dev,const char * format,va_list args)116 static int esas2r_log_master(const long level,
117 			     const struct device *dev,
118 			     const char *format,
119 			     va_list args)
120 {
121 	if (level <= event_log_level) {
122 		unsigned long flags = 0;
123 		int retval = 0;
124 		char *buffer = event_buffer;
125 		size_t buflen = EVENT_LOG_BUFF_SIZE;
126 		const char *fmt_nodev = "%s%s: ";
127 		const char *fmt_dev = "%s%s [%s, %s, %s]";
128 		const char *slevel =
129 			translate_esas2r_event_level_to_kernel(level);
130 
131 		spin_lock_irqsave(&event_buffer_lock, flags);
132 
133 		if (buffer == NULL) {
134 			spin_unlock_irqrestore(&event_buffer_lock, flags);
135 			return -1;
136 		}
137 
138 		memset(buffer, 0, buflen);
139 
140 		/*
141 		 * format the level onto the beginning of the string and do
142 		 * some pointer arithmetic to move the pointer to the point
143 		 * where the actual message can be inserted.
144 		 */
145 
146 		if (dev == NULL) {
147 			snprintf(buffer, buflen, fmt_nodev, slevel,
148 				 ESAS2R_DRVR_NAME);
149 		} else {
150 			snprintf(buffer, buflen, fmt_dev, slevel,
151 				 ESAS2R_DRVR_NAME,
152 				 (dev->driver ? dev->driver->name : "unknown"),
153 				 (dev->bus ? dev->bus->name : "unknown"),
154 				 dev_name(dev));
155 		}
156 
157 		buffer += strlen(event_buffer);
158 		buflen -= strlen(event_buffer);
159 
160 		retval = vsnprintf(buffer, buflen, format, args);
161 		if (retval < 0) {
162 			spin_unlock_irqrestore(&event_buffer_lock, flags);
163 			return -1;
164 		}
165 
166 		/*
167 		 * Put a line break at the end of the formatted string so that
168 		 * we don't wind up with run-on messages.
169 		 */
170 		printk("%s\n", event_buffer);
171 
172 		spin_unlock_irqrestore(&event_buffer_lock, flags);
173 	}
174 
175 	return 0;
176 }
177 
178 /**
179  * formats and logs a message to the system log.
180  *
181  * @param [in] level  the event level of the message
182  * @param [in] format the formating string for the message
183  * @param [in] ...    the substitution arguments to the formatting string
184  *
185  * @return 0 on success, or -1 if an error occurred.
186  */
esas2r_log(const long level,const char * format,...)187 int esas2r_log(const long level, const char *format, ...)
188 {
189 	int retval = 0;
190 	va_list args;
191 
192 	va_start(args, format);
193 
194 	retval = esas2r_log_master(level, NULL, format, args);
195 
196 	va_end(args);
197 
198 	return retval;
199 }
200 
201 /**
202  * formats and logs a message to the system log.  this message will include
203  * device information.
204  *
205  * @param [in] level   the event level of the message
206  * @param [in] dev     the device information
207  * @param [in] format  the formatting string for the message
208  * @param [in] ...     the substitution arguments to the formatting string
209  *
210  * @return 0 on success, or -1 if an error occurred.
211  */
esas2r_log_dev(const long level,const struct device * dev,const char * format,...)212 int esas2r_log_dev(const long level,
213 		   const struct device *dev,
214 		   const char *format,
215 		   ...)
216 {
217 	int retval = 0;
218 	va_list args;
219 
220 	va_start(args, format);
221 
222 	retval = esas2r_log_master(level, dev, format, args);
223 
224 	va_end(args);
225 
226 	return retval;
227 }
228 
229 /**
230  * formats and logs a message to the system log.  this message will include
231  * device information.
232  *
233  * @param [in] level   the event level of the message
234  * @param [in] buf
235  * @param [in] len
236  *
237  * @return 0 on success, or -1 if an error occurred.
238  */
esas2r_log_hexdump(const long level,const void * buf,size_t len)239 int esas2r_log_hexdump(const long level,
240 		       const void *buf,
241 		       size_t len)
242 {
243 	if (level <= event_log_level) {
244 		print_hex_dump(translate_esas2r_event_level_to_kernel(level),
245 			       "", DUMP_PREFIX_OFFSET, 16, 1, buf,
246 			       len, true);
247 	}
248 
249 	return 1;
250 }
251