Hannes Reinecke | ded85c1 | 2015-01-08 07:43:42 +0100 | [diff] [blame^] | 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); |