drivers/scsi/esas2r/esas2r_log.c

   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  */
  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  */
 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  */
 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  */
 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  */
 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 }