linux/drivers/scsi/fnic/fnic_debugfs.c

315 lines
8.7 KiB
C

/*
* 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/errno.h>
#include <linux/debugfs.h>
#include "fnic.h"
static struct dentry *fnic_trace_debugfs_root;
static struct dentry *fnic_trace_debugfs_file;
static struct dentry *fnic_trace_enable;
/*
* fnic_trace_ctrl_open - Open the trace_enable file
* @inode: The inode pointer.
* @file: The file pointer to attach the trace enable/disable flag.
*
* Description:
* This routine opens a debugsfs file trace_enable.
*
* Returns:
* This function returns zero if successful.
*/
static int fnic_trace_ctrl_open(struct inode *inode, struct file *filp)
{
filp->private_data = inode->i_private;
return 0;
}
/*
* fnic_trace_ctrl_read - Read a trace_enable debugfs file
* @filp: The file pointer to read from.
* @ubuf: The buffer to copy the data to.
* @cnt: The number of bytes to read.
* @ppos: The position in the file to start reading from.
*
* Description:
* This routine reads value of variable fnic_tracing_enabled
* and stores into local @buf. It will start reading file at @ppos and
* copy up to @cnt of data to @ubuf from @buf.
*
* Returns:
* This function returns the amount of data that was read.
*/
static ssize_t fnic_trace_ctrl_read(struct file *filp,
char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
int len;
len = sprintf(buf, "%u\n", fnic_tracing_enabled);
return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
}
/*
* fnic_trace_ctrl_write - Write to trace_enable debugfs file
* @filp: The file pointer to write from.
* @ubuf: The buffer to copy the data from.
* @cnt: The number of bytes to write.
* @ppos: The position in the file to start writing to.
*
* Description:
* This routine writes data from user buffer @ubuf to buffer @buf and
* sets fnic_tracing_enabled value as per user input.
*
* Returns:
* This function returns the amount of data that was written.
*/
static ssize_t fnic_trace_ctrl_write(struct file *filp,
const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
char buf[64];
unsigned long val;
int ret;
if (cnt >= sizeof(buf))
return -EINVAL;
if (copy_from_user(&buf, ubuf, cnt))
return -EFAULT;
buf[cnt] = 0;
ret = kstrtoul(buf, 10, &val);
if (ret < 0)
return ret;
fnic_tracing_enabled = val;
(*ppos)++;
return cnt;
}
/*
* fnic_trace_debugfs_open - Open the fnic trace log
* @inode: The inode pointer
* @file: The file pointer to attach the log output
*
* Description:
* This routine is the entry point for the debugfs open file operation.
* It allocates the necessary buffer for the log, fills the buffer from
* the in-memory log and then returns a pointer to that log in
* the private_data field in @file.
*
* Returns:
* This function returns zero if successful. On error it will return
* a negative error value.
*/
static int fnic_trace_debugfs_open(struct inode *inode,
struct file *file)
{
fnic_dbgfs_t *fnic_dbg_prt;
fnic_dbg_prt = kzalloc(sizeof(fnic_dbgfs_t), GFP_KERNEL);
if (!fnic_dbg_prt)
return -ENOMEM;
fnic_dbg_prt->buffer = vmalloc((3*(trace_max_pages * PAGE_SIZE)));
if (!fnic_dbg_prt->buffer) {
kfree(fnic_dbg_prt);
return -ENOMEM;
}
memset((void *)fnic_dbg_prt->buffer, 0,
(3*(trace_max_pages * PAGE_SIZE)));
fnic_dbg_prt->buffer_len = fnic_get_trace_data(fnic_dbg_prt);
file->private_data = fnic_dbg_prt;
return 0;
}
/*
* fnic_trace_debugfs_lseek - Seek through a debugfs file
* @file: The file pointer to seek through.
* @offset: The offset to seek to or the amount to seek by.
* @howto: Indicates how to seek.
*
* Description:
* This routine is the entry point for the debugfs lseek file operation.
* The @howto parameter indicates whether @offset is the offset to directly
* seek to, or if it is a value to seek forward or reverse by. This function
* figures out what the new offset of the debugfs file will be and assigns
* that value to the f_pos field of @file.
*
* Returns:
* This function returns the new offset if successful and returns a negative
* error if unable to process the seek.
*/
static loff_t fnic_trace_debugfs_lseek(struct file *file,
loff_t offset,
int howto)
{
fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
loff_t pos = -1;
switch (howto) {
case 0:
pos = offset;
break;
case 1:
pos = file->f_pos + offset;
break;
case 2:
pos = fnic_dbg_prt->buffer_len - offset;
}
return (pos < 0 || pos > fnic_dbg_prt->buffer_len) ?
-EINVAL : (file->f_pos = pos);
}
/*
* fnic_trace_debugfs_read - Read a debugfs file
* @file: The file pointer to read from.
* @ubuf: The buffer to copy the data to.
* @nbytes: The number of bytes to read.
* @pos: The position in the file to start reading from.
*
* Description:
* This routine reads data from the buffer indicated in the private_data
* field of @file. It will start reading at @pos and copy up to @nbytes of
* data to @ubuf.
*
* Returns:
* This function returns the amount of data that was read (this could be
* less than @nbytes if the end of the file was reached).
*/
static ssize_t fnic_trace_debugfs_read(struct file *file,
char __user *ubuf,
size_t nbytes,
loff_t *pos)
{
fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
int rc = 0;
rc = simple_read_from_buffer(ubuf, nbytes, pos,
fnic_dbg_prt->buffer,
fnic_dbg_prt->buffer_len);
return rc;
}
/*
* fnic_trace_debugfs_release - Release the buffer used to store
* debugfs file data
* @inode: The inode pointer
* @file: The file pointer that contains the buffer to release
*
* Description:
* This routine frees the buffer that was allocated when the debugfs
* file was opened.
*
* Returns:
* This function returns zero.
*/
static int fnic_trace_debugfs_release(struct inode *inode,
struct file *file)
{
fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
vfree(fnic_dbg_prt->buffer);
kfree(fnic_dbg_prt);
return 0;
}
static const struct file_operations fnic_trace_ctrl_fops = {
.owner = THIS_MODULE,
.open = fnic_trace_ctrl_open,
.read = fnic_trace_ctrl_read,
.write = fnic_trace_ctrl_write,
};
static const struct file_operations fnic_trace_debugfs_fops = {
.owner = THIS_MODULE,
.open = fnic_trace_debugfs_open,
.llseek = fnic_trace_debugfs_lseek,
.read = fnic_trace_debugfs_read,
.release = fnic_trace_debugfs_release,
};
/*
* fnic_trace_debugfs_init - Initialize debugfs for fnic trace logging
*
* Description:
* When Debugfs is configured this routine sets up the fnic debugfs
* file system. If not already created, this routine will create the
* fnic directory. It will create file trace to log fnic trace buffer
* output into debugfs and it will also create file trace_enable to
* control enable/disable of trace logging into trace buffer.
*/
int fnic_trace_debugfs_init(void)
{
int rc = -1;
fnic_trace_debugfs_root = debugfs_create_dir("fnic", NULL);
if (!fnic_trace_debugfs_root) {
printk(KERN_DEBUG "Cannot create debugfs root\n");
return rc;
}
fnic_trace_enable = debugfs_create_file("tracing_enable",
S_IFREG|S_IRUGO|S_IWUSR,
fnic_trace_debugfs_root,
NULL, &fnic_trace_ctrl_fops);
if (!fnic_trace_enable) {
printk(KERN_DEBUG "Cannot create trace_enable file"
" under debugfs");
return rc;
}
fnic_trace_debugfs_file = debugfs_create_file("trace",
S_IFREG|S_IRUGO|S_IWUSR,
fnic_trace_debugfs_root,
NULL,
&fnic_trace_debugfs_fops);
if (!fnic_trace_debugfs_file) {
printk(KERN_DEBUG "Cannot create trace file under debugfs");
return rc;
}
rc = 0;
return rc;
}
/*
* fnic_trace_debugfs_terminate - Tear down debugfs infrastructure
*
* Description:
* When Debugfs is configured this routine removes debugfs file system
* elements that are specific to fnic trace logging.
*/
void fnic_trace_debugfs_terminate(void)
{
if (fnic_trace_debugfs_file) {
debugfs_remove(fnic_trace_debugfs_file);
fnic_trace_debugfs_file = NULL;
}
if (fnic_trace_enable) {
debugfs_remove(fnic_trace_enable);
fnic_trace_enable = NULL;
}
if (fnic_trace_debugfs_root) {
debugfs_remove(fnic_trace_debugfs_root);
fnic_trace_debugfs_root = NULL;
}
}