rbd: don't allocate mon_addrs buffer in rbd_add()
The mon_addrs buffer in rbd_add is used to hold a copy of the
monitor IP addresses supplied via /sys/bus/rbd/add. That is
passed to rbd_get_client(), which never modifies it (nor do
any of the functions it gets passed to thereafter)--the mon_addr
parameter to rbd_get_client() is a pointer to constant data, so it
can't be modifed. Furthermore, rbd_get_client() has the length of
the mon_addrs buffer and that is used to ensure nothing goes beyond
its end.
Based on all this, there is no reason that a buffer needs to
be used to hold a copy of the mon_addrs provided via
/sys/bus/rbd/add. Instead, the location within that passed-in
buffer can be provided, along with the length of the "token"
therein which represents the monitor IP's.
A small change to rbd_add_parse_args() allows the address within the
buffer to be passed back, and the length is already returned. This
now means that, at least from the perspective of this interface,
there is no such thing as a list of monitor addresses that is too
long.
Signed-off-by: Alex Elder <elder@dreamhost.com>
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 2f2d194..641f098 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2284,7 +2284,7 @@
*/
static int rbd_add_parse_args(struct rbd_device *rbd_dev,
const char *buf,
- char *mon_addrs,
+ const char **mon_addrs,
size_t *mon_addrs_size,
char *options,
size_t options_size)
@@ -2293,10 +2293,13 @@
/* The first four tokens are required */
- len = copy_token(&buf, mon_addrs, *mon_addrs_size);
- if (!len || len >= *mon_addrs_size)
+ len = next_token(&buf);
+ if (!len)
return -EINVAL;
*mon_addrs_size = len + 1;
+ *mon_addrs = buf;
+
+ buf += len;
len = copy_token(&buf, options, options_size);
if (!len || len >= options_size)
@@ -2337,8 +2340,8 @@
size_t count)
{
struct rbd_device *rbd_dev;
- char *mon_addrs = NULL;
- size_t mon_addrs_size;
+ const char *mon_addrs = NULL;
+ size_t mon_addrs_size = 0;
char *options = NULL;
struct ceph_osd_client *osdc;
int rc = -ENOMEM;
@@ -2349,9 +2352,6 @@
rbd_dev = kzalloc(sizeof(*rbd_dev), GFP_KERNEL);
if (!rbd_dev)
goto err_nomem;
- mon_addrs = kmalloc(count, GFP_KERNEL);
- if (!mon_addrs)
- goto err_nomem;
options = kmalloc(count, GFP_KERNEL);
if (!options)
goto err_nomem;
@@ -2372,8 +2372,7 @@
sprintf(rbd_dev->name, "%s%d", RBD_DRV_NAME, rbd_dev->id);
/* parse add command */
- mon_addrs_size = count;
- rc = rbd_add_parse_args(rbd_dev, buf, mon_addrs, &mon_addrs_size,
+ rc = rbd_add_parse_args(rbd_dev, buf, &mon_addrs, &mon_addrs_size,
options, count);
if (rc)
goto err_put_id;
@@ -2420,7 +2419,6 @@
rbd_bus_del_dev(rbd_dev);
kfree(options);
- kfree(mon_addrs);
return rc;
err_out_blkdev:
@@ -2431,7 +2429,6 @@
rbd_id_put(rbd_dev);
err_nomem:
kfree(options);
- kfree(mon_addrs);
kfree(rbd_dev);
dout("Error adding device %s\n", buf);