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authorAlex Elder <elder@dreamhost.com>2012-02-02 08:13:30 -0600
committerAlex Elder <elder@dreamhost.com>2012-03-22 10:47:50 -0500
commit7ef3214af220515b8fe223ec92ec017d2e5607a7 (patch)
tree74911dc83a10f824d0e2cbd83896bb32b0fc566b
parent5214ecc45cf9b9f1365b189bcb63e441e3865334 (diff)
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>
-rw-r--r--drivers/block/rbd.c21
1 files changed, 9 insertions, 12 deletions
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 2f2d194ca3d..641f09898e1 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -2284,7 +2284,7 @@ static inline size_t copy_token(const char **buf,
*/
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 @@ static int rbd_add_parse_args(struct rbd_device *rbd_dev,
/* 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 @@ static ssize_t rbd_add(struct bus_type *bus,
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 @@ static ssize_t rbd_add(struct bus_type *bus,
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 @@ static ssize_t rbd_add(struct bus_type *bus,
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 @@ err_out_bus:
rbd_bus_del_dev(rbd_dev);
kfree(options);
- kfree(mon_addrs);
return rc;
err_out_blkdev:
@@ -2431,7 +2429,6 @@ err_put_id:
rbd_id_put(rbd_dev);
err_nomem:
kfree(options);
- kfree(mon_addrs);
kfree(rbd_dev);
dout("Error adding device %s\n", buf);