From 19cba8abd6ca09527c194864ae651db65cbacfe1 Mon Sep 17 00:00:00 2001
From: Latchesar Ionkov <lucho@ionkov.net>
Date: Tue, 11 Oct 2005 08:29:03 -0700
Subject: [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>
---
fs/9p/vfs_file.c | 114 ++++++++++++++++---------------------------------------
1 file changed, 33 insertions(+), 81 deletions(-)
(limited to 'fs/9p')
diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
index a4799e971d1c..bbc3cc63854f 100644
--- a/fs/9p/vfs_file.c
+++ b/fs/9p/vfs_file.c
@@ -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,
--
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