[PATCH] staging: android: logger: Allocate logs dynamically at boot

From: Tim Bird
Date: Fri May 04 2012 - 19:33:14 EST


This changes the log initialization to be dynamic, but still
at boot time. These changes are a predecessor to implementing
runtime allocation and freeing of logs, to make the Android logger
less hard-coded.

This makes no ABI changes with user space.

Signed-off-by: Tim Bird <tim.bird@xxxxxxxxxxx>
---
drivers/staging/android/logger.c | 117 ++++++++++++++++++++++++--------------
1 file changed, 75 insertions(+), 42 deletions(-)

diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c
index ea69b6a..fa5fd71 100644
--- a/drivers/staging/android/logger.c
+++ b/drivers/staging/android/logger.c
@@ -25,6 +25,7 @@
#include <linux/poll.h>
#include <linux/slab.h>
#include <linux/time.h>
+#include <linux/vmalloc.h>
#include "logger.h"

#include <asm/ioctls.h>
@@ -564,81 +565,113 @@ static const struct file_operations logger_fops = {
.release = logger_release,
};

-/*
- * Defines a log structure with name 'NAME' and a size of 'SIZE' bytes, which
- * must be a power of two, greater than LOGGER_ENTRY_MAX_LEN, and less than
- * LONG_MAX minus LOGGER_ENTRY_MAX_LEN.
- */
-#define DEFINE_LOGGER_DEVICE(VAR, NAME, SIZE) \
-static unsigned char _buf_ ## VAR[SIZE]; \
-static struct logger_log VAR = { \
- .buffer = _buf_ ## VAR, \
- .misc = { \
- .minor = MISC_DYNAMIC_MINOR, \
- .name = NAME, \
- .fops = &logger_fops, \
- .parent = NULL, \
- }, \
- .wq = __WAIT_QUEUE_HEAD_INITIALIZER(VAR .wq), \
- .readers = LIST_HEAD_INIT(VAR .readers), \
- .mutex = __MUTEX_INITIALIZER(VAR .mutex), \
- .w_off = 0, \
- .head = 0, \
- .size = SIZE, \
-};
-
-DEFINE_LOGGER_DEVICE(log_main, LOGGER_LOG_MAIN, 256*1024)
-DEFINE_LOGGER_DEVICE(log_events, LOGGER_LOG_EVENTS, 256*1024)
-DEFINE_LOGGER_DEVICE(log_radio, LOGGER_LOG_RADIO, 256*1024)
-DEFINE_LOGGER_DEVICE(log_system, LOGGER_LOG_SYSTEM, 256*1024)
+#define MAX_LOGS 5
+struct logger_log *logs_array[MAX_LOGS];

static struct logger_log *get_log_from_minor(int minor)
{
- if (log_main.misc.minor == minor)
- return &log_main;
- if (log_events.misc.minor == minor)
- return &log_events;
- if (log_radio.misc.minor == minor)
- return &log_radio;
- if (log_system.misc.minor == minor)
- return &log_system;
+ int i;
+
+ for (i = 0; i < MAX_LOGS; i++) {
+ if (logs_array[i]->misc.minor == minor)
+ return logs_array[i];
+ }
return NULL;
}

-static int __init init_log(struct logger_log *log)
+static int __init add_log(struct logger_log *log)
{
- int ret;
+ int i;

+ for (i = 0; i < MAX_LOGS; i++) {
+ if (logs_array[i] == 0) {
+ logs_array[i] = log;
+ return 0;
+ }
+ }
+ return -1;
+}
+
+/*
+ * Log size must be a power of two, greater than LOGGER_ENTRY_MAX_LEN,
+ * and less than LONG_MAX minus LOGGER_ENTRY_MAX_LEN.
+ */
+static int __init create_log(char *log_name, int size)
+{
+ int ret = 0;
+ struct logger_log *log;
+ unsigned char *buffer;
+
+ buffer = vmalloc(size);
+ if (buffer == NULL)
+ return -1;
+
+ log = kzalloc(sizeof(struct logger_log), GFP_KERNEL);
+ if (log == NULL) {
+ ret = -1;
+ goto out_free_buffer;
+ }
+ log->buffer = buffer;
+
+ log->misc.minor = MISC_DYNAMIC_MINOR;
+ log->misc.name = kstrdup(log_name, GFP_KERNEL);
+ if (log->misc.name == NULL) {
+ ret = -1;
+ goto out_free_log;
+ }
+
+ log->misc.fops = &logger_fops;
+ log->misc.parent = NULL;
+
+ init_waitqueue_head(&log->wq);
+ INIT_LIST_HEAD(&log->readers);
+ mutex_init(&log->mutex);
+ log->w_off = 0;
+ log->head = 0;
+ log->size = size;
+
+ ret = add_log(log);
+ if (unlikely(ret))
+ goto out_free_log;
+
+ /* finally, initialize the misc device for this log */
ret = misc_register(&log->misc);
if (unlikely(ret)) {
printk(KERN_ERR "logger: failed to register misc "
"device for log '%s'!\n", log->misc.name);
- return ret;
+ goto out_free_log;
}

printk(KERN_INFO "logger: created %luK log '%s'\n",
(unsigned long) log->size >> 10, log->misc.name);

return 0;
+
+out_free_log:
+ kfree(log);
+
+out_free_buffer:
+ vfree(buffer);
+ return ret;
}

static int __init logger_init(void)
{
int ret;

- ret = init_log(&log_main);
+ ret = create_log(LOGGER_LOG_MAIN, 256*1024);
if (unlikely(ret))
goto out;

- ret = init_log(&log_events);
+ ret = create_log(LOGGER_LOG_EVENTS, 256*1024);
if (unlikely(ret))
goto out;

- ret = init_log(&log_radio);
+ ret = create_log(LOGGER_LOG_RADIO, 256*1024);
if (unlikely(ret))
goto out;

- ret = init_log(&log_system);
+ ret = create_log(LOGGER_LOG_SYSTEM, 256*1024);
if (unlikely(ret))
goto out;

--
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/