[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: Latchesar Ionkov <lucho@ionkov.net> Cc: Eric Van Hensbergen <ericvh@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Latchesar Ionkov
Linus Torvalds
Родитель
ad6ce87e5b
Коммит
19cba8abd6
180
fs/9p/vfs_file.c
180
fs/9p/vfs_file.c
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@ -175,16 +175,16 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
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}
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/**
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* v9fs_read - read from a file (internal)
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* v9fs_file_read - read from a file
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* @filep: file pointer to read
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* @data: data buffer to read data into
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* @count: size of buffer
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* @offset: offset at which to read data
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*
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*/
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static ssize_t
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v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
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v9fs_file_read(struct file *filp, char __user * data, size_t count,
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loff_t * offset)
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{
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struct inode *inode = filp->f_dentry->d_inode;
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struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
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@ -194,6 +194,7 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
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int rsize = 0;
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int result = 0;
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int total = 0;
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int n;
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dprintk(DEBUG_VFS, "\n");
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@ -216,10 +217,15 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
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} else
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*offset += result;
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/* XXX - extra copy */
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memcpy(buffer, fcall->params.rread.data, result);
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n = copy_to_user(data, fcall->params.rread.data, result);
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if (n) {
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dprintk(DEBUG_ERROR, "Problem copying to user %d\n", n);
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kfree(fcall);
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return -EFAULT;
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}
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count -= result;
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buffer += result;
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data += result;
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total += result;
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kfree(fcall);
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@ -231,101 +237,6 @@ v9fs_read(struct file *filp, char *buffer, size_t count, loff_t * offset)
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return total;
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}
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/**
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* v9fs_file_read - read from a file
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* @filep: file pointer to read
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* @data: data buffer to read data into
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* @count: size of buffer
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* @offset: offset at which to read data
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*
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*/
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static ssize_t
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v9fs_file_read(struct file *filp, char __user * data, size_t count,
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loff_t * offset)
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{
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int retval = -1;
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int ret = 0;
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char *buffer;
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buffer = kmalloc(count, GFP_KERNEL);
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if (!buffer)
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return -ENOMEM;
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retval = v9fs_read(filp, buffer, count, offset);
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if (retval > 0) {
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if ((ret = copy_to_user(data, buffer, retval)) != 0) {
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dprintk(DEBUG_ERROR, "Problem copying to user %d\n",
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ret);
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retval = ret;
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}
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}
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kfree(buffer);
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return retval;
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}
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/**
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* v9fs_write - write to a file
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* @filep: file pointer to write
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* @data: data buffer to write data from
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* @count: size of buffer
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* @offset: offset at which to write data
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*
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*/
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static ssize_t
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v9fs_write(struct file *filp, char *buffer, size_t count, loff_t * offset)
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{
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struct inode *inode = filp->f_dentry->d_inode;
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struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
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struct v9fs_fid *v9fid = filp->private_data;
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struct v9fs_fcall *fcall;
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int fid = v9fid->fid;
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int result = -EIO;
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int rsize = 0;
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int total = 0;
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dprintk(DEBUG_VFS, "data %p count %d offset %x\n", buffer, (int)count,
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(int)*offset);
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rsize = v9ses->maxdata - V9FS_IOHDRSZ;
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if (v9fid->iounit != 0 && rsize > v9fid->iounit)
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rsize = v9fid->iounit;
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dump_data(buffer, count);
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do {
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if (count < rsize)
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rsize = count;
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result =
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v9fs_t_write(v9ses, fid, *offset, rsize, buffer, &fcall);
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if (result < 0) {
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eprintk(KERN_ERR, "error while writing: %s(%d)\n",
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FCALL_ERROR(fcall), result);
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kfree(fcall);
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return result;
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} else
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*offset += result;
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kfree(fcall);
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if (result != rsize) {
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eprintk(KERN_ERR,
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"short write: v9fs_t_write returned %d\n",
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result);
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break;
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}
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count -= result;
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buffer += result;
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total += result;
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} while (count);
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return total;
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}
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/**
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* v9fs_file_write - write to a file
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* @filep: file pointer to write
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@ -339,24 +250,65 @@ static ssize_t
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v9fs_file_write(struct file *filp, const char __user * data,
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size_t count, loff_t * offset)
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{
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int ret = -1;
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char *buffer;
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struct inode *inode = filp->f_dentry->d_inode;
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struct v9fs_session_info *v9ses = v9fs_inode2v9ses(inode);
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struct v9fs_fid *v9fid = filp->private_data;
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struct v9fs_fcall *fcall;
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int fid = v9fid->fid;
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int result = -EIO;
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int rsize = 0;
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int total = 0;
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char *buf;
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buffer = kmalloc(count, GFP_KERNEL);
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if (buffer == NULL)
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dprintk(DEBUG_VFS, "data %p count %d offset %x\n", data, (int)count,
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(int)*offset);
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rsize = v9ses->maxdata - V9FS_IOHDRSZ;
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if (v9fid->iounit != 0 && rsize > v9fid->iounit)
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rsize = v9fid->iounit;
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buf = kmalloc(v9ses->maxdata - V9FS_IOHDRSZ, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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ret = copy_from_user(buffer, data, count);
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if (ret) {
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dprintk(DEBUG_ERROR, "Problem copying from user\n");
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ret = -EFAULT;
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} else {
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ret = v9fs_write(filp, buffer, count, offset);
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}
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do {
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if (count < rsize)
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rsize = count;
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kfree(buffer);
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result = copy_from_user(buf, data, rsize);
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if (result) {
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dprintk(DEBUG_ERROR, "Problem copying from user\n");
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kfree(buf);
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return -EFAULT;
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}
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return ret;
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dump_data(buf, rsize);
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result = v9fs_t_write(v9ses, fid, *offset, rsize, buf, &fcall);
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if (result < 0) {
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eprintk(KERN_ERR, "error while writing: %s(%d)\n",
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FCALL_ERROR(fcall), result);
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kfree(fcall);
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kfree(buf);
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return result;
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} else
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*offset += result;
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kfree(fcall);
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fcall = NULL;
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if (result != rsize) {
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eprintk(KERN_ERR,
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"short write: v9fs_t_write returned %d\n",
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result);
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break;
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}
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count -= result;
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data += result;
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total += result;
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} while (count);
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kfree(buf);
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return total;
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}
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struct file_operations v9fs_file_operations = {
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