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authorMichael Holzheu <holzheu@linux.vnet.ibm.com>2011-01-05 12:47:43 +0100
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2011-01-05 12:47:27 +0100
commit2fcb3686e1601cff992e026dceeab1b22dc81178 (patch)
tree6f2c62354f5fa445982f3e1575aac5e4758187ee /arch/s390/hypfs/hypfs_diag.c
parent[S390] current_thread_info optimization (diff)
downloadlinux-dev-2fcb3686e1601cff992e026dceeab1b22dc81178.tar.xz
linux-dev-2fcb3686e1601cff992e026dceeab1b22dc81178.zip
[S390] hypfs: Move buffer allocation from open to read
Currently the buffer for diagnose data is allocated in the open function of the debugfs file and is released in the close function. This has the drawback that a user (root) can pin that memory by not closing the file. This patch moves the buffer allocation to the read function. The buffer is automatically released after the buffer is copied to userspace. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/hypfs/hypfs_diag.c')
-rw-r--r--arch/s390/hypfs/hypfs_diag.c82
1 files changed, 20 insertions, 62 deletions
diff --git a/arch/s390/hypfs/hypfs_diag.c b/arch/s390/hypfs/hypfs_diag.c
index cd4a81be9cf8..6023c6dc1fb7 100644
--- a/arch/s390/hypfs/hypfs_diag.c
+++ b/arch/s390/hypfs/hypfs_diag.c
@@ -555,81 +555,38 @@ struct dbfs_d204 {
char buf[]; /* d204 buffer */
} __attribute__ ((packed));
-struct dbfs_d204_private {
- struct dbfs_d204 *d204; /* Aligned d204 data with header */
- void *base; /* Base pointer (needed for vfree) */
-};
-
-static int dbfs_d204_open(struct inode *inode, struct file *file)
+static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
{
- struct dbfs_d204_private *data;
struct dbfs_d204 *d204;
int rc, buf_size;
+ void *base;
- data = kzalloc(sizeof(*data), GFP_KERNEL);
- if (!data)
- return -ENOMEM;
buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
- data->base = vmalloc(buf_size);
- if (!data->base) {
- rc = -ENOMEM;
- goto fail_kfree_data;
+ base = vmalloc(buf_size);
+ if (!base)
+ return -ENOMEM;
+ memset(base, 0, buf_size);
+ d204 = page_align_ptr(base + sizeof(d204->hdr)) - sizeof(d204->hdr);
+ rc = diag204_do_store(d204->buf, diag204_buf_pages);
+ if (rc) {
+ vfree(base);
+ return rc;
}
- memset(data->base, 0, buf_size);
- d204 = page_align_ptr(data->base + sizeof(d204->hdr))
- - sizeof(d204->hdr);
- rc = diag204_do_store(&d204->buf, diag204_buf_pages);
- if (rc)
- goto fail_vfree_base;
d204->hdr.version = DBFS_D204_HDR_VERSION;
d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
d204->hdr.sc = diag204_store_sc;
- data->d204 = d204;
- file->private_data = data;
- return nonseekable_open(inode, file);
-
-fail_vfree_base:
- vfree(data->base);
-fail_kfree_data:
- kfree(data);
- return rc;
-}
-
-static int dbfs_d204_release(struct inode *inode, struct file *file)
-{
- struct dbfs_d204_private *data = file->private_data;
-
- vfree(data->base);
- kfree(data);
+ *data = d204;
+ *data_free_ptr = base;
+ *size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
return 0;
}
-static ssize_t dbfs_d204_read(struct file *file, char __user *buf,
- size_t size, loff_t *ppos)
-{
- struct dbfs_d204_private *data = file->private_data;
-
- return simple_read_from_buffer(buf, size, ppos, data->d204,
- data->d204->hdr.len +
- sizeof(data->d204->hdr));
-}
-
-static const struct file_operations dbfs_d204_ops = {
- .open = dbfs_d204_open,
- .read = dbfs_d204_read,
- .release = dbfs_d204_release,
- .llseek = no_llseek,
+static struct hypfs_dbfs_file dbfs_file_d204 = {
+ .name = "diag_204",
+ .data_create = dbfs_d204_create,
+ .data_free = vfree,
};
-static int hypfs_dbfs_init(void)
-{
- dbfs_d204_file = debugfs_create_file("diag_204", 0400, hypfs_dbfs_dir,
- NULL, &dbfs_d204_ops);
- if (IS_ERR(dbfs_d204_file))
- return PTR_ERR(dbfs_d204_file);
- return 0;
-}
-
__init int hypfs_diag_init(void)
{
int rc;
@@ -639,7 +596,7 @@ __init int hypfs_diag_init(void)
return -ENODATA;
}
if (diag204_info_type == INFO_EXT) {
- rc = hypfs_dbfs_init();
+ rc = hypfs_dbfs_create_file(&dbfs_file_d204);
if (rc)
return rc;
}
@@ -660,6 +617,7 @@ void hypfs_diag_exit(void)
debugfs_remove(dbfs_d204_file);
diag224_delete_name_table();
diag204_free_buffer();
+ hypfs_dbfs_remove_file(&dbfs_file_d204);
}
/*