usb: f_mass_storage: limit number of reported LUNs

Mass storage function created via configfs always reports eight LUNs
to the hosts even if only one LUN has been configured.  Adjust the
number when the USB function is allocated based on LUNs that user
has created.

Cc: <stable@vger.kernel.org>
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index d2259c6639960c55c76239401148bbcc2ec1f449..f936268d26c6aaa9a5601614adf2e90319e0d364 100644 (file)
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -2786,7 +2786,7 @@ int fsg_common_set_nluns(struct fsg_common *common, int nluns)
                return -EINVAL;
        }
 
-       curlun = kcalloc(nluns, sizeof(*curlun), GFP_KERNEL);
+       curlun = kcalloc(FSG_MAX_LUNS, sizeof(*curlun), GFP_KERNEL);
        if (unlikely(!curlun))
                return -ENOMEM;
 
@@ -2796,8 +2796,6 @@ int fsg_common_set_nluns(struct fsg_common *common, int nluns)
        common->luns = curlun;
        common->nluns = nluns;
 
-       pr_info("Number of LUNs=%d\n", common->nluns);
-
        return 0;
 }
 EXPORT_SYMBOL_GPL(fsg_common_set_nluns);
@@ -3563,14 +3561,26 @@ static struct usb_function *fsg_alloc(struct usb_function_instance *fi)
        struct fsg_opts *opts = fsg_opts_from_func_inst(fi);
        struct fsg_common *common = opts->common;
        struct fsg_dev *fsg;
+       unsigned nluns, i;
 
        fsg = kzalloc(sizeof(*fsg), GFP_KERNEL);
        if (unlikely(!fsg))
                return ERR_PTR(-ENOMEM);
 
        mutex_lock(&opts->lock);
+       if (!opts->refcnt) {
+               for (nluns = i = 0; i < FSG_MAX_LUNS; ++i)
+                       if (common->luns[i])
+                               nluns = i + 1;
+               if (!nluns)
+                       pr_warn("No LUNS defined, continuing anyway\n");
+               else
+                       common->nluns = nluns;
+               pr_info("Number of LUNs=%u\n", common->nluns);
+       }
        opts->refcnt++;
        mutex_unlock(&opts->lock);
+
        fsg->function.name      = FSG_DRIVER_DESC;
        fsg->function.bind      = fsg_bind;
        fsg->function.unbind    = fsg_unbind;