linux/drivers/scsi/fnic/fnic_trace.c

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/*
* Copyright 2012 Cisco Systems, Inc. All rights reserved.
*
* This program is free software; you may redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include <linux/module.h>
#include <linux/mempool.h>
#include <linux/errno.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include "fnic_io.h"
#include "fnic.h"
unsigned int trace_max_pages;
static int fnic_max_trace_entries;
static unsigned long fnic_trace_buf_p;
static DEFINE_SPINLOCK(fnic_trace_lock);
static fnic_trace_dbg_t fnic_trace_entries;
int fnic_tracing_enabled = 1;
/*
* fnic_trace_get_buf - Give buffer pointer to user to fill up trace information
*
* Description:
* This routine gets next available trace buffer entry location @wr_idx
* from allocated trace buffer pages and give that memory location
* to user to store the trace information.
*
* Return Value:
* This routine returns pointer to next available trace entry
* @fnic_buf_head for user to fill trace information.
*/
fnic_trace_data_t *fnic_trace_get_buf(void)
{
unsigned long fnic_buf_head;
unsigned long flags;
spin_lock_irqsave(&fnic_trace_lock, flags);
/*
* Get next available memory location for writing trace information
* at @wr_idx and increment @wr_idx
*/
fnic_buf_head =
fnic_trace_entries.page_offset[fnic_trace_entries.wr_idx];
fnic_trace_entries.wr_idx++;
/*
* Verify if trace buffer is full then change wd_idx to
* start from zero
*/
if (fnic_trace_entries.wr_idx >= fnic_max_trace_entries)
fnic_trace_entries.wr_idx = 0;
/*
* Verify if write index @wr_idx and read index @rd_idx are same then
* increment @rd_idx to move to next entry in trace buffer
*/
if (fnic_trace_entries.wr_idx == fnic_trace_entries.rd_idx) {
fnic_trace_entries.rd_idx++;
if (fnic_trace_entries.rd_idx >= fnic_max_trace_entries)
fnic_trace_entries.rd_idx = 0;
}
spin_unlock_irqrestore(&fnic_trace_lock, flags);
return (fnic_trace_data_t *)fnic_buf_head;
}
/*
* fnic_get_trace_data - Copy trace buffer to a memory file
* @fnic_dbgfs_t: pointer to debugfs trace buffer
*
* Description:
* This routine gathers the fnic trace debugfs data from the fnic_trace_data_t
* buffer and dumps it to fnic_dbgfs_t. It will start at the rd_idx entry in
* the log and process the log until the end of the buffer. Then it will gather
* from the beginning of the log and process until the current entry @wr_idx.
*
* Return Value:
* This routine returns the amount of bytes that were dumped into fnic_dbgfs_t
*/
int fnic_get_trace_data(fnic_dbgfs_t *fnic_dbgfs_prt)
{
int rd_idx;
int wr_idx;
int len = 0;
unsigned long flags;
char str[KSYM_SYMBOL_LEN];
struct timespec val;
fnic_trace_data_t *tbp;
spin_lock_irqsave(&fnic_trace_lock, flags);
rd_idx = fnic_trace_entries.rd_idx;
wr_idx = fnic_trace_entries.wr_idx;
if (wr_idx < rd_idx) {
while (1) {
/* Start from read index @rd_idx */
tbp = (fnic_trace_data_t *)
fnic_trace_entries.page_offset[rd_idx];
if (!tbp) {
spin_unlock_irqrestore(&fnic_trace_lock, flags);
return 0;
}
/* Convert function pointer to function name */
if (sizeof(unsigned long) < 8) {
sprint_symbol(str, tbp->fnaddr.low);
jiffies_to_timespec(tbp->timestamp.low, &val);
} else {
sprint_symbol(str, tbp->fnaddr.val);
jiffies_to_timespec(tbp->timestamp.val, &val);
}
/*
* Dump trace buffer entry to memory file
* and increment read index @rd_idx
*/
len += snprintf(fnic_dbgfs_prt->buffer + len,
(trace_max_pages * PAGE_SIZE * 3) - len,
"%16lu.%16lu %-50s %8x %8x %16llx %16llx "
"%16llx %16llx %16llx\n", val.tv_sec,
val.tv_nsec, str, tbp->host_no, tbp->tag,
tbp->data[0], tbp->data[1], tbp->data[2],
tbp->data[3], tbp->data[4]);
rd_idx++;
/*
* If rd_idx is reached to maximum trace entries
* then move rd_idx to zero
*/
if (rd_idx > (fnic_max_trace_entries-1))
rd_idx = 0;
/*
* Continure dumpping trace buffer entries into
* memory file till rd_idx reaches write index
*/
if (rd_idx == wr_idx)
break;
}
} else if (wr_idx > rd_idx) {
while (1) {
/* Start from read index @rd_idx */
tbp = (fnic_trace_data_t *)
fnic_trace_entries.page_offset[rd_idx];
if (!tbp) {
spin_unlock_irqrestore(&fnic_trace_lock, flags);
return 0;
}
/* Convert function pointer to function name */
if (sizeof(unsigned long) < 8) {
sprint_symbol(str, tbp->fnaddr.low);
jiffies_to_timespec(tbp->timestamp.low, &val);
} else {
sprint_symbol(str, tbp->fnaddr.val);
jiffies_to_timespec(tbp->timestamp.val, &val);
}
/*
* Dump trace buffer entry to memory file
* and increment read index @rd_idx
*/
len += snprintf(fnic_dbgfs_prt->buffer + len,
(trace_max_pages * PAGE_SIZE * 3) - len,
"%16lu.%16lu %-50s %8x %8x %16llx %16llx "
"%16llx %16llx %16llx\n", val.tv_sec,
val.tv_nsec, str, tbp->host_no, tbp->tag,
tbp->data[0], tbp->data[1], tbp->data[2],
tbp->data[3], tbp->data[4]);
rd_idx++;
/*
* Continue dumpping trace buffer entries into
* memory file till rd_idx reaches write index
*/
if (rd_idx == wr_idx)
break;
}
}
spin_unlock_irqrestore(&fnic_trace_lock, flags);
return len;
}
/*
* fnic_trace_buf_init - Initialize fnic trace buffer logging facility
*
* Description:
* Initialize trace buffer data structure by allocating required memory and
* setting page_offset information for every trace entry by adding trace entry
* length to previous page_offset value.
*/
int fnic_trace_buf_init(void)
{
unsigned long fnic_buf_head;
int i;
int err = 0;
trace_max_pages = fnic_trace_max_pages;
fnic_max_trace_entries = (trace_max_pages * PAGE_SIZE)/
FNIC_ENTRY_SIZE_BYTES;
fnic_trace_buf_p = (unsigned long)vmalloc((trace_max_pages * PAGE_SIZE));
if (!fnic_trace_buf_p) {
printk(KERN_ERR PFX "Failed to allocate memory "
"for fnic_trace_buf_p\n");
err = -ENOMEM;
goto err_fnic_trace_buf_init;
}
memset((void *)fnic_trace_buf_p, 0, (trace_max_pages * PAGE_SIZE));
fnic_trace_entries.page_offset = vmalloc(fnic_max_trace_entries *
sizeof(unsigned long));
if (!fnic_trace_entries.page_offset) {
printk(KERN_ERR PFX "Failed to allocate memory for"
" page_offset\n");
if (fnic_trace_buf_p) {
vfree((void *)fnic_trace_buf_p);
fnic_trace_buf_p = 0;
}
err = -ENOMEM;
goto err_fnic_trace_buf_init;
}
memset((void *)fnic_trace_entries.page_offset, 0,
(fnic_max_trace_entries * sizeof(unsigned long)));
fnic_trace_entries.wr_idx = fnic_trace_entries.rd_idx = 0;
fnic_buf_head = fnic_trace_buf_p;
/*
* Set page_offset field of fnic_trace_entries struct by
* calculating memory location for every trace entry using
* length of each trace entry
*/
for (i = 0; i < fnic_max_trace_entries; i++) {
fnic_trace_entries.page_offset[i] = fnic_buf_head;
fnic_buf_head += FNIC_ENTRY_SIZE_BYTES;
}
err = fnic_trace_debugfs_init();
if (err < 0) {
printk(KERN_ERR PFX "Failed to initialize debugfs for tracing\n");
goto err_fnic_trace_debugfs_init;
}
printk(KERN_INFO PFX "Successfully Initialized Trace Buffer\n");
return err;
err_fnic_trace_debugfs_init:
fnic_trace_free();
err_fnic_trace_buf_init:
return err;
}
/*
* fnic_trace_free - Free memory of fnic trace data structures.
*/
void fnic_trace_free(void)
{
fnic_tracing_enabled = 0;
fnic_trace_debugfs_terminate();
if (fnic_trace_entries.page_offset) {
vfree((void *)fnic_trace_entries.page_offset);
fnic_trace_entries.page_offset = NULL;
}
if (fnic_trace_buf_p) {
vfree((void *)fnic_trace_buf_p);
fnic_trace_buf_p = 0;
}
printk(KERN_INFO PFX "Successfully Freed Trace Buffer\n");
}