2 * Copyright 2012 Cisco Systems, Inc. All rights reserved.
4 * This program is free software; you may redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; version 2 of the License.
8 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
9 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
10 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
11 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
12 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
13 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
14 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
18 #include <linux/module.h>
19 #include <linux/errno.h>
20 #include <linux/debugfs.h>
23 static struct dentry *fnic_trace_debugfs_root;
24 static struct dentry *fnic_trace_debugfs_file;
25 static struct dentry *fnic_trace_enable;
28 * fnic_trace_ctrl_open - Open the trace_enable file
29 * @inode: The inode pointer.
30 * @file: The file pointer to attach the trace enable/disable flag.
33 * This routine opens a debugsfs file trace_enable.
36 * This function returns zero if successful.
38 static int fnic_trace_ctrl_open(struct inode *inode, struct file *filp)
40 filp->private_data = inode->i_private;
45 * fnic_trace_ctrl_read - Read a trace_enable debugfs file
46 * @filp: The file pointer to read from.
47 * @ubuf: The buffer to copy the data to.
48 * @cnt: The number of bytes to read.
49 * @ppos: The position in the file to start reading from.
52 * This routine reads value of variable fnic_tracing_enabled
53 * and stores into local @buf. It will start reading file at @ppos and
54 * copy up to @cnt of data to @ubuf from @buf.
57 * This function returns the amount of data that was read.
59 static ssize_t fnic_trace_ctrl_read(struct file *filp,
61 size_t cnt, loff_t *ppos)
65 len = sprintf(buf, "%u\n", fnic_tracing_enabled);
67 return simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
71 * fnic_trace_ctrl_write - Write to trace_enable debugfs file
72 * @filp: The file pointer to write from.
73 * @ubuf: The buffer to copy the data from.
74 * @cnt: The number of bytes to write.
75 * @ppos: The position in the file to start writing to.
78 * This routine writes data from user buffer @ubuf to buffer @buf and
79 * sets fnic_tracing_enabled value as per user input.
82 * This function returns the amount of data that was written.
84 static ssize_t fnic_trace_ctrl_write(struct file *filp,
85 const char __user *ubuf,
86 size_t cnt, loff_t *ppos)
92 if (cnt >= sizeof(buf))
95 if (copy_from_user(&buf, ubuf, cnt))
100 ret = kstrtoul(buf, 10, &val);
104 fnic_tracing_enabled = val;
111 * fnic_trace_debugfs_open - Open the fnic trace log
112 * @inode: The inode pointer
113 * @file: The file pointer to attach the log output
116 * This routine is the entry point for the debugfs open file operation.
117 * It allocates the necessary buffer for the log, fills the buffer from
118 * the in-memory log and then returns a pointer to that log in
119 * the private_data field in @file.
122 * This function returns zero if successful. On error it will return
123 * a negative error value.
125 static int fnic_trace_debugfs_open(struct inode *inode,
128 fnic_dbgfs_t *fnic_dbg_prt;
129 fnic_dbg_prt = kzalloc(sizeof(fnic_dbgfs_t), GFP_KERNEL);
133 fnic_dbg_prt->buffer = vmalloc((3*(trace_max_pages * PAGE_SIZE)));
134 if (!fnic_dbg_prt->buffer) {
138 memset((void *)fnic_dbg_prt->buffer, 0,
139 (3*(trace_max_pages * PAGE_SIZE)));
140 fnic_dbg_prt->buffer_len = fnic_get_trace_data(fnic_dbg_prt);
141 file->private_data = fnic_dbg_prt;
146 * fnic_trace_debugfs_lseek - Seek through a debugfs file
147 * @file: The file pointer to seek through.
148 * @offset: The offset to seek to or the amount to seek by.
149 * @howto: Indicates how to seek.
152 * This routine is the entry point for the debugfs lseek file operation.
153 * The @howto parameter indicates whether @offset is the offset to directly
154 * seek to, or if it is a value to seek forward or reverse by. This function
155 * figures out what the new offset of the debugfs file will be and assigns
156 * that value to the f_pos field of @file.
159 * This function returns the new offset if successful and returns a negative
160 * error if unable to process the seek.
162 static loff_t fnic_trace_debugfs_lseek(struct file *file,
166 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
174 pos = file->f_pos + offset;
177 pos = fnic_dbg_prt->buffer_len - offset;
179 return (pos < 0 || pos > fnic_dbg_prt->buffer_len) ?
180 -EINVAL : (file->f_pos = pos);
184 * fnic_trace_debugfs_read - Read a debugfs file
185 * @file: The file pointer to read from.
186 * @ubuf: The buffer to copy the data to.
187 * @nbytes: The number of bytes to read.
188 * @pos: The position in the file to start reading from.
191 * This routine reads data from the buffer indicated in the private_data
192 * field of @file. It will start reading at @pos and copy up to @nbytes of
196 * This function returns the amount of data that was read (this could be
197 * less than @nbytes if the end of the file was reached).
199 static ssize_t fnic_trace_debugfs_read(struct file *file,
204 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
206 rc = simple_read_from_buffer(ubuf, nbytes, pos,
207 fnic_dbg_prt->buffer,
208 fnic_dbg_prt->buffer_len);
213 * fnic_trace_debugfs_release - Release the buffer used to store
215 * @inode: The inode pointer
216 * @file: The file pointer that contains the buffer to release
219 * This routine frees the buffer that was allocated when the debugfs
223 * This function returns zero.
225 static int fnic_trace_debugfs_release(struct inode *inode,
228 fnic_dbgfs_t *fnic_dbg_prt = file->private_data;
230 vfree(fnic_dbg_prt->buffer);
235 static const struct file_operations fnic_trace_ctrl_fops = {
236 .owner = THIS_MODULE,
237 .open = fnic_trace_ctrl_open,
238 .read = fnic_trace_ctrl_read,
239 .write = fnic_trace_ctrl_write,
242 static const struct file_operations fnic_trace_debugfs_fops = {
243 .owner = THIS_MODULE,
244 .open = fnic_trace_debugfs_open,
245 .llseek = fnic_trace_debugfs_lseek,
246 .read = fnic_trace_debugfs_read,
247 .release = fnic_trace_debugfs_release,
251 * fnic_trace_debugfs_init - Initialize debugfs for fnic trace logging
254 * When Debugfs is configured this routine sets up the fnic debugfs
255 * file system. If not already created, this routine will create the
256 * fnic directory. It will create file trace to log fnic trace buffer
257 * output into debugfs and it will also create file trace_enable to
258 * control enable/disable of trace logging into trace buffer.
260 int fnic_trace_debugfs_init(void)
263 fnic_trace_debugfs_root = debugfs_create_dir("fnic", NULL);
264 if (!fnic_trace_debugfs_root) {
265 printk(KERN_DEBUG "Cannot create debugfs root\n");
268 fnic_trace_enable = debugfs_create_file("tracing_enable",
269 S_IFREG|S_IRUGO|S_IWUSR,
270 fnic_trace_debugfs_root,
271 NULL, &fnic_trace_ctrl_fops);
273 if (!fnic_trace_enable) {
274 printk(KERN_DEBUG "Cannot create trace_enable file"
279 fnic_trace_debugfs_file = debugfs_create_file("trace",
280 S_IFREG|S_IRUGO|S_IWUSR,
281 fnic_trace_debugfs_root,
283 &fnic_trace_debugfs_fops);
285 if (!fnic_trace_debugfs_file) {
286 printk(KERN_DEBUG "Cannot create trace file under debugfs");
294 * fnic_trace_debugfs_terminate - Tear down debugfs infrastructure
297 * When Debugfs is configured this routine removes debugfs file system
298 * elements that are specific to fnic trace logging.
300 void fnic_trace_debugfs_terminate(void)
302 if (fnic_trace_debugfs_file) {
303 debugfs_remove(fnic_trace_debugfs_file);
304 fnic_trace_debugfs_file = NULL;
306 if (fnic_trace_enable) {
307 debugfs_remove(fnic_trace_enable);
308 fnic_trace_enable = NULL;
310 if (fnic_trace_debugfs_root) {
311 debugfs_remove(fnic_trace_debugfs_root);
312 fnic_trace_debugfs_root = NULL;