[ALSA] Make buffer size of proc text interface variable

Make the read/write buffer size of proc text interface variable.
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/info.h

@@ -27,9 +27,9 @@
 /* buffer for information */
 struct snd_info_buffer {
 	char *buffer;		/* pointer to begin of buffer */
-	char *curr;		/* current position in buffer */
-	unsigned long size;	/* current size */
-	unsigned long len;	/* total length of buffer */
+	unsigned int curr;	/* current position in buffer */
+	unsigned int size;	/* current size */
+	unsigned int len;	/* total length of buffer */
 	int stop;		/* stop flag */
 	int error;		/* error code */
 };

sound/core/info.c

@@ -21,7 +21,6 @@
 
 #include <sound/driver.h>
 #include <linux/init.h>
-#include <linux/vmalloc.h>
 #include <linux/time.h>
 #include <linux/smp_lock.h>
 #include <linux/string.h>
@@ -82,6 +81,24 @@ static int snd_info_version_init(void);
 static int snd_info_version_done(void);
 
 
+/* resize the proc r/w buffer */
+static int resize_info_buffer(struct snd_info_buffer *buffer,
+			      unsigned int nsize)
+{
+	char *nbuf;
+
+	nsize = PAGE_ALIGN(nsize);
+	nbuf = kmalloc(nsize, GFP_KERNEL);
+	if (! nbuf)
+		return -ENOMEM;
+
+	memcpy(nbuf, buffer->buffer, buffer->len);
+	kfree(buffer->buffer);
+	buffer->buffer = nbuf;
+	buffer->len = nsize;
+	return 0;
+}
+
 /**
  * snd_iprintf - printf on the procfs buffer
  * @buffer: the procfs buffer
@@ -95,17 +112,25 @@ int snd_iprintf(struct snd_info_buffer *buffer, char *fmt,...)
 {
 	va_list args;
 	int len, res;
+	int err = 0;
 
 	if (buffer->stop || buffer->error)
 		return 0;
 	len = buffer->len - buffer->size;
 	va_start(args, fmt);
-	res = vsnprintf(buffer->curr, len, fmt, args);
-	va_end(args);
-	if (res >= len) {
-		buffer->stop = 1;
-		return 0;
+	for (;;) {
+		res = vsnprintf(buffer->buffer + buffer->curr, len, fmt, args);
+		if (res < len)
+			break;
+		err = resize_info_buffer(buffer, buffer->len + PAGE_SIZE);
+		if (err < 0)
+			break;
+		len = buffer->len - buffer->size;
 	}
+	va_end(args);
+
+	if (err < 0)
+		return err;
 	buffer->curr += res;
 	buffer->size += res;
 	return res;
@@ -225,7 +250,7 @@ static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer
 	struct snd_info_private_data *data;
 	struct snd_info_entry *entry;
 	struct snd_info_buffer *buf;
-	size_t size = 0;
+	ssize_t size = 0;
 	loff_t pos;
 
 	data = file->private_data;
@@ -241,14 +266,20 @@ static ssize_t snd_info_entry_write(struct file *file, const char __user *buffer
 		buf = data->wbuffer;
 		if (buf == NULL)
 			return -EIO;
-		if (pos >= buf->len)
-			return -ENOMEM;
-		size = buf->len - pos;
-		size = min(count, size);
-		if (copy_from_user(buf->buffer + pos, buffer, size))
+		mutex_unlock(&entry->access);
+		if (pos + count >= buf->len) {
+			if (resize_info_buffer(buf, pos + count)) {
+				mutex_unlock(&entry->access);
+				return -ENOMEM;
+			}
+		}
+		if (copy_from_user(buf->buffer + pos, buffer, count)) {
+			mutex_unlock(&entry->access);
 			return -EFAULT;
-		if ((long)buf->size < pos + size)
-			buf->size = pos + size;
+		}
+		buf->size = pos + count;
+		mutex_unlock(&entry->access);
+		size = count;
 		break;
 	case SNDRV_INFO_CONTENT_DATA:
 		if (entry->c.ops->write)
@@ -283,18 +314,14 @@ static int snd_info_entry_open(struct inode *inode, struct file *file)
 	}
 	mode = file->f_flags & O_ACCMODE;
 	if (mode == O_RDONLY || mode == O_RDWR) {
-		if ((entry->content == SNDRV_INFO_CONTENT_TEXT &&
-		     !entry->c.text.read_size) ||
-		    (entry->content == SNDRV_INFO_CONTENT_DATA &&
+		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 		     entry->c.ops->read == NULL)) {
 		    	err = -ENODEV;
 		    	goto __error;
 		}
 	}
 	if (mode == O_WRONLY || mode == O_RDWR) {
-		if ((entry->content == SNDRV_INFO_CONTENT_TEXT &&
-		     !entry->c.text.write_size) ||
-		    (entry->content == SNDRV_INFO_CONTENT_DATA &&
+		if ((entry->content == SNDRV_INFO_CONTENT_DATA &&
 		     entry->c.ops->write == NULL)) {
 		    	err = -ENODEV;
 		    	goto __error;
@@ -310,49 +337,23 @@ static int snd_info_entry_open(struct inode *inode, struct file *file)
 	case SNDRV_INFO_CONTENT_TEXT:
 		if (mode == O_RDONLY || mode == O_RDWR) {
 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
-			if (buffer == NULL) {
-				kfree(data);
-				err = -ENOMEM;
-				goto __error;
-			}
-			buffer->len = (entry->c.text.read_size +
-				      (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
-			buffer->buffer = vmalloc(buffer->len);
-			if (buffer->buffer == NULL) {
-				kfree(buffer);
-				kfree(data);
-				err = -ENOMEM;
-				goto __error;
-			}
-			buffer->curr = buffer->buffer;
+			if (buffer == NULL)
+				goto __nomem;
 			data->rbuffer = buffer;
+			buffer->len = PAGE_SIZE;
+			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
+			if (buffer->buffer == NULL)
+				goto __nomem;
 		}
 		if (mode == O_WRONLY || mode == O_RDWR) {
 			buffer = kzalloc(sizeof(*buffer), GFP_KERNEL);
-			if (buffer == NULL) {
-				if (mode == O_RDWR) {
-					vfree(data->rbuffer->buffer);
-					kfree(data->rbuffer);
-				}
-				kfree(data);
-				err = -ENOMEM;
-				goto __error;
-			}
-			buffer->len = (entry->c.text.write_size +
-				      (PAGE_SIZE - 1)) & ~(PAGE_SIZE - 1);
-			buffer->buffer = vmalloc(buffer->len);
-			if (buffer->buffer == NULL) {
-				if (mode == O_RDWR) {
-					vfree(data->rbuffer->buffer);
-					kfree(data->rbuffer);
-				}
-				kfree(buffer);
-				kfree(data);
-				err = -ENOMEM;
-				goto __error;
-			}
-			buffer->curr = buffer->buffer;
+			if (buffer == NULL)
+				goto __nomem;
 			data->wbuffer = buffer;
+			buffer->len = PAGE_SIZE;
+			buffer->buffer = kmalloc(buffer->len, GFP_KERNEL);
+			if (buffer->buffer == NULL)
+				goto __nomem;
 		}
 		break;
 	case SNDRV_INFO_CONTENT_DATA:	/* data */
@@ -377,6 +378,17 @@ static int snd_info_entry_open(struct inode *inode, struct file *file)
 	}
 	return 0;
 
+ __nomem:
+	if (data->rbuffer) {
+		kfree(data->rbuffer->buffer);
+		kfree(data->rbuffer);
+	}
+	if (data->wbuffer) {
+		kfree(data->wbuffer->buffer);
+		kfree(data->wbuffer);
+	}
+	kfree(data);
+	err = -ENOMEM;
       __error:
 	module_put(entry->module);
       __error1:
@@ -395,11 +407,11 @@ static int snd_info_entry_release(struct inode *inode, struct file *file)
 	entry = data->entry;
 	switch (entry->content) {
 	case SNDRV_INFO_CONTENT_TEXT:
-		if (mode == O_RDONLY || mode == O_RDWR) {
-			vfree(data->rbuffer->buffer);
+		if (data->rbuffer) {
+			kfree(data->rbuffer->buffer);
 			kfree(data->rbuffer);
 		}
-		if (mode == O_WRONLY || mode == O_RDWR) {
+		if (data->wbuffer) {
 			if (entry->c.text.write) {
 				entry->c.text.write(entry, data->wbuffer);
 				if (data->wbuffer->error) {
@@ -408,7 +420,7 @@ static int snd_info_entry_release(struct inode *inode, struct file *file)
 						data->wbuffer->error);
 				}
 			}
-			vfree(data->wbuffer->buffer);
+			kfree(data->wbuffer->buffer);
 			kfree(data->wbuffer);
 		}
 		break;
@@ -668,24 +680,22 @@ int snd_info_get_line(struct snd_info_buffer *buffer, char *line, int len)
 	if (len <= 0 || buffer->stop || buffer->error)
 		return 1;
 	while (--len > 0) {
-		c = *buffer->curr++;
+		c = buffer->buffer[buffer->curr++];
 		if (c == '\n') {
-			if ((buffer->curr - buffer->buffer) >= (long)buffer->size) {
+			if (buffer->curr >= buffer->size)
 				buffer->stop = 1;
-			}
 			break;
 		}
 		*line++ = c;
-		if ((buffer->curr - buffer->buffer) >= (long)buffer->size) {
+		if (buffer->curr >= buffer->size) {
 			buffer->stop = 1;
 			break;
 		}
 	}
 	while (c != '\n' && !buffer->stop) {
-		c = *buffer->curr++;
-		if ((buffer->curr - buffer->buffer) >= (long)buffer->size) {
+		c = buffer->buffer[buffer->curr++];
+		if (buffer->curr >= buffer->size)
 			buffer->stop = 1;
-		}
 	}
 	*line = '\0';
 	return 0;
@@ -978,7 +988,6 @@ static int __init snd_info_version_init(void)
 	entry = snd_info_create_module_entry(THIS_MODULE, "version", NULL);
 	if (entry == NULL)
 		return -ENOMEM;
-	entry->c.text.read_size = 256;
 	entry->c.text.read = snd_info_version_read;
 	if (snd_info_register(entry) < 0) {
 		snd_info_free_entry(entry);