usb: f_mass_storage: limit number of reported LUNs

commit 8515bac01a983d277148e4fcc5f235bf603de577 upstream.

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.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 3cc109f3c9c803638b8a47ffc1aa4aabb8397a6b..15c3071550370c14b3274866eeb6b06711d85907 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;