Re: [RFC PATCH 2/2] lightnvm: Append device name to target name

[Matias Bjørling]

On 05/23/2016 11:13 AM, Wenwei Tao wrote:
From: Wenwei Tao <ww.tao0...@gmail.com>
We may create targets with same name on different
backend devices, this is not what we want, so append
the device name to target name to make the new target
name unique in the system.

Signed-off-by: Wenwei Tao <ww.tao0...@gmail.com>
---
  drivers/lightnvm/gennvm.c | 13 +++++++++++--
  1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/lightnvm/gennvm.c b/drivers/lightnvm/gennvm.c
index 39ff0af..ecb09cb 100644
--- a/drivers/lightnvm/gennvm.c
+++ b/drivers/lightnvm/gennvm.c
@@ -43,9 +43,18 @@ static int gen_create_tgt(struct nvm_dev *dev, struct 
nvm_ioctl_create *create)
        struct gendisk *tdisk;
        struct nvm_tgt_type *tt;
        struct nvm_target *t;
+       char tgtname[DISK_NAME_LEN];
        void *targetdata;
        int ret = -ENOMEM;

+       if (strlen(dev->name) + strlen(create->tgtname) + 1 > DISK_NAME_LEN) {
+               pr_err("nvm: target name too long. %s:%s\n",
+                               dev->name, create->tgtname);
+               return -EINVAL;
+       }
+
+       sprintf(tgtname, "%s%s", dev->name, create->tgtname);
+
        tt = nvm_find_target_type(create->tgttype, 1);
        if (!tt) {
                pr_err("nvm: target type %s not found\n", create->tgttype);
@@ -53,7 +62,7 @@ static int gen_create_tgt(struct nvm_dev *dev, struct 
nvm_ioctl_create *create)
        }

        mutex_lock(&gn->lock);
-       t = gen_find_target(gn, create->tgtname);
+       t = gen_find_target(gn, tgtname);
        if (t) {
                pr_err("nvm: target name already exists.\n");
                ret = -EINVAL;
@@ -73,7 +82,7 @@ static int gen_create_tgt(struct nvm_dev *dev, struct 
nvm_ioctl_create *create)
        if (!tdisk)
                goto err_queue;

-       sprintf(tdisk->disk_name, "%s", create->tgtname);
+       sprintf(tdisk->disk_name, "%s", tgtname);
        tdisk->flags = GENHD_FL_EXT_DEVT;
        tdisk->major = 0;
        tdisk->first_minor = 0;


Hi Wenwei, what about the case where a target instance has multiple 
devices associated?

I am okay with having the user choosing a unique name for the target to 
be exposed.