On 05/27/2019 12:44 AM, xiubli@xxxxxxxxxx wrote: > From: Xiubo Li <xiubli@xxxxxxxxxx> > > This will allow the blksize to be set zero and then use 1024 as > default. > > Signed-off-by: Xiubo Li <xiubli@xxxxxxxxxx> > --- > drivers/block/nbd.c | 21 ++++++++++++++++++--- > 1 file changed, 18 insertions(+), 3 deletions(-) > > diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c > index 053958a..4c1de1c 100644 > --- a/drivers/block/nbd.c > +++ b/drivers/block/nbd.c > @@ -135,6 +135,8 @@ struct nbd_cmd { > > #define NBD_MAGIC 0x68797548 > > +#define NBD_DEF_BLKSIZE 1024 > + > static unsigned int nbds_max = 16; > static int max_part = 16; > static struct workqueue_struct *recv_workqueue; > @@ -1237,6 +1239,14 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd, > nbd_config_put(nbd); > } > > +static bool nbd_is_valid_blksize(unsigned long blksize) > +{ > + if (!blksize || !is_power_of_2(blksize) || blksize < 512 || > + blksize > PAGE_SIZE) > + return false; > + return true; > +} > + > /* Must be called with config_lock held */ > static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, > unsigned int cmd, unsigned long arg) > @@ -1252,8 +1262,9 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, > case NBD_SET_SOCK: > return nbd_add_socket(nbd, arg, false); > case NBD_SET_BLKSIZE: > - if (!arg || !is_power_of_2(arg) || arg < 512 || > - arg > PAGE_SIZE) > + if (!arg) > + arg = NBD_DEF_BLKSIZE; > + if (!nbd_is_valid_blksize(arg)) > return -EINVAL; > nbd_size_set(nbd, arg, > div_s64(config->bytesize, arg)); > @@ -1333,7 +1344,7 @@ static struct nbd_config *nbd_alloc_config(void) > atomic_set(&config->recv_threads, 0); > init_waitqueue_head(&config->recv_wq); > init_waitqueue_head(&config->conn_wait); > - config->blksize = 1024; > + config->blksize = NBD_DEF_BLKSIZE; > atomic_set(&config->live_connections, 0); > try_module_get(THIS_MODULE); > return config; > @@ -1769,6 +1780,10 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info) > if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) { > u64 bsize = > nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]); > + if (!bsize) > + bsize = NBD_DEF_BLKSIZE; > + if (!nbd_is_valid_blksize(bsize)) > + return -EINVAL; You can't only return here. You need to also drop the mutex, do nbd_put, and drop config_refs reference. Maybe you want to move this check to the beginning of the function with the NBD_ATTR_SIZE_BYTES sanity check since the error handling is easier there. > nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize)); > } > if (info->attrs[NBD_ATTR_TIMEOUT]) { >