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Commit 19cba8ab authored by Latchesar Ionkov's avatar Latchesar Ionkov Committed by Linus Torvalds
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[PATCH] v9fs: remove additional buffer allocation from v9fs_file_read and v9fs_file_write 



v9fs_file_read and v9fs_file_write use kmalloc to allocate buffers as big
as the data buffer received as parameter.  kmalloc cannot be used to
allocate buffers bigger than 128K, so reading/writing data in chunks bigger
than 128k fails.

This patch reorganizes v9fs_file_read and v9fs_file_write to allocate only
buffers as big as the maximum data that can be sent in one 9P message.

Signed-off-by: default avatarLatchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ad6ce87e

fs/9p/vfs_file.c

+33 −81
Original line number Diff line number Diff line
@@ -175,16 +175,16 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl) 
}



/**

 * v9fs_read - read from a file (internal)

 * v9fs_file_read - read from a file

 * @filep: file pointer to read

 * @data: data buffer to read data into

 * @count: size of buffer

 * @offset: offset at which to read data

 *

 */



static ssize_t

v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)

v9fs_file_read(struct file *filp, char __user * data, size_t count,

	       loff_t * offset)

{

	struct inode *inode = filp->f_dentry->d_inode;

	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
@@ -194,6 +194,7 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) 
	int rsize = 0;

	int result = 0;

	int total = 0;

	int n;



	dprintk(DEBUG_VFS, "\n");
@@ -216,10 +217,15 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) 
		} else

			*offset += result;



		/* XXX - extra copy */

		memcpy(buffer, fcall->params.rread.data, result);

		n = copy_to_user(data, fcall->params.rread.data, result);

		if (n) {

			dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);

			kfree(fcall);

			return -EFAULT;

		}



		count -= result;

		buffer += result;

		data += result;

		total += result;



		kfree(fcall);
@@ -232,42 +238,7 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset) 
}



/**

 * v9fs_file_read - read from a file

 * @filep: file pointer to read

 * @data: data buffer to read data into

 * @count: size of buffer

 * @offset: offset at which to read data

 *

 */



static ssize_t

v9fs_file_read(struct file *filp, char __user * data, size_t count,

	       loff_t * offset)

{

	int retval = -1;

	int ret = 0;

	char *buffer;



	buffer = kmalloc(count, GFP_KERNEL);

	if (!buffer)

		return -ENOMEM;



	retval = v9fs_read(filp, buffer, count, offset);

	if (retval > 0) {

		if ((ret = copy_to_user(data, buffer, retval)) != 0) {

			dprintk(DEBUG_ERROR, "Problem copying to user %d\n",

				ret);

			retval = ret;

		}

	}



	kfree(buffer);



	return retval;

}



/**

 * v9fs_write - write to a file

 * v9fs_file_write - write to a file

 * @filep: file pointer to write

 * @data: data buffer to write data from

 * @count: size of buffer
@@ -276,7 +247,8 @@ v9fs_file_read(struct file *filp, char __user * data, size_t count, 
 */



static ssize_t

v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset)

v9fs_file_write(struct file *filp, const char __user * data,

		size_t count, loff_t * offset)

{

	struct inode *inode = filp->f_dentry->d_inode;

	struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
@@ -286,30 +258,42 @@ v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset) 
	int result = -EIO;

	int rsize = 0;

	int total = 0;

	char *buf;



	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count,

	dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,

		(int)*offset);

	rsize = v9ses->maxdata - V9FS_IOHDRSZ;

	if (v9fid->iounit != 0 && rsize > v9fid->iounit)

		rsize = v9fid->iounit;



	dump_data(buffer, count);

	buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL);

	if (!buf)

		return -ENOMEM;



	do {

		if (count < rsize)

			rsize = count;



		result =

		    v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall);

		result = copy_from_user(buf, data, rsize);

		if (result) {

			dprintk(DEBUG_ERROR, "Problem copying from user\n");

			kfree(buf);

			return -EFAULT;

		}



		dump_data(buf, rsize);

		result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall);

		if (result < 0) {

			eprintk(KERN_ERR, "error while writing: %s(%d)\n",

				FCALL_ERROR(fcall), result);

			kfree(fcall);

			kfree(buf);

			return result;

		} else

			*offset += result;



		kfree(fcall);

		fcall = NULL;



		if (result != rsize) {

			eprintk(KERN_ERR,
@@ -319,46 +303,14 @@ v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset) 
		}



		count -= result;

		buffer += result;

		data += result;

		total += result;

	} while (count);



	kfree(buf);

	return total;

}



/**

 * v9fs_file_write - write to a file

 * @filep: file pointer to write

 * @data: data buffer to write data from

 * @count: size of buffer

 * @offset: offset at which to write data

 *

 */



static ssize_t

v9fs_file_write(struct file *filp, const char __user * data,

		size_t count, loff_t * offset)

{

	int ret = -1;

	char *buffer;



	buffer = kmalloc(count, GFP_KERNEL);

	if (buffer == NULL)

		return -ENOMEM;



	ret = copy_from_user(buffer, data, count);

	if (ret) {

		dprintk(DEBUG_ERROR, "Problem copying from user\n");

		ret = -EFAULT;

	} else {

		ret = v9fs_write(filp, buffer, count, offset);

	}



	kfree(buffer);



	return ret;

}



struct file_operations v9fs_file_operations = {

	.llseek = generic_file_llseek,

	.read = v9fs_file_read,