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Subject[patch] v2.5.31 nfsctl.c stack usage reduction
Heyo,

The patch below (which depends on the copy_from_user_kmalloc addition)
reduces the stack usage in nfsctl.c, which was allocating structures that
were 2KB or more on the stack.

-ben

:r ~/patches/v2.5/v2.5.31-stack-nfs.diff
diff -urN foo-v2.5.31/fs/nfsd/nfsctl.c bar-v2.5.31/fs/nfsd/nfsctl.c
--- foo-v2.5.31/fs/nfsd/nfsctl.c Tue Jul 30 10:24:17 2002
+++ bar-v2.5.31/fs/nfsd/nfsctl.c Thu Aug 15 17:26:09 2002
@@ -155,56 +155,47 @@
* payload - write methods
*/

+/* Rather than duplicate this many times, just use a funky macro. */
+#define WRITE_METHOD(type, fn) \
+ type *data; \
+ ssize_t ret; \
+ if (size < sizeof(*data)) \
+ return -EINVAL; \
+ data = copy_from_user_kmalloc(buf, size);\
+ if (IS_ERR(data)) \
+ return PTR_ERR(data); \
+ ret = fn; \
+ kfree(data); \
+ return ret;
+
static ssize_t write_svc(struct file *file, const char *buf, size_t size)
{
- struct nfsctl_svc data;
- if (size < sizeof(data))
- return -EINVAL;
- if (copy_from_user(&data, buf, size))
- return -EFAULT;
- return nfsd_svc(data.svc_port, data.svc_nthreads);
+ WRITE_METHOD(struct nfsctl_svc,
+ nfsd_svc(data->svc_port, data->svc_nthreads));
}

static ssize_t write_add(struct file *file, const char *buf, size_t size)
{
- struct nfsctl_client data;
- if (size < sizeof(data))
- return -EINVAL;
- if (copy_from_user(&data, buf, size))
- return -EFAULT;
- return exp_addclient(&data);
+ WRITE_METHOD(struct nfsctl_client, exp_addclient(data));
}

static ssize_t write_del(struct file *file, const char *buf, size_t size)
{
- struct nfsctl_client data;
- if (size < sizeof(data))
- return -EINVAL;
- if (copy_from_user(&data, buf, size))
- return -EFAULT;
- return exp_delclient(&data);
+ WRITE_METHOD(struct nfsctl_client, exp_delclient(data));
}

static ssize_t write_export(struct file *file, const char *buf, size_t size)
{
- struct nfsctl_export data;
- if (size < sizeof(data))
- return -EINVAL;
- if (copy_from_user(&data, buf, size))
- return -EFAULT;
- return exp_export(&data);
+ WRITE_METHOD(struct nfsctl_export, exp_export(data));
}

static ssize_t write_unexport(struct file *file, const char *buf, size_t size)
{
- struct nfsctl_export data;
- if (size < sizeof(data))
- return -EINVAL;
- if (copy_from_user(&data, buf, size))
- return -EFAULT;
- return exp_unexport(&data);
+ WRITE_METHOD(struct nfsctl_export, exp_unexport(data));
}

+#undef WRITE_METHOD
+
static ssize_t write_getfs(struct file *file, const char *buf, size_t size)
{
struct nfsctl_fsparm data;
-
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