On Fri, Jun 19 2015, Felipe Balbi wrote:
> the fact is that this needs to be configurable from configfs. If user
> sets up a single lun, then this should be as you said, however, if 2
> luns are configured, I still want to have those 2 working.
>
> From a user perspective, configfs should support N luns just fine as
> long as we have enough memory available.
Yes, sorry, you’re right. I didn’t fallow closely migration to configfs
based configuration and didn’t have the full picture.
After taking another look, I think the best solution is to have a loop
in fsg_alloc, something like the following (beware that this has not
been tested in any way):
>From 19ec2796009f8650c7db4358f7e16931ba96e4ee Mon Sep 17 00:00:00 2001
From: Michal Nazarewicz <mina86@xxxxxxxxxx>
Date: Fri, 19 Jun 2015 23:56:34 +0200
Subject: [PATCH] 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.
Signed-off-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
drivers/usb/gadget/function/f_mass_storage.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 3cc109f..8e26a12 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -3563,14 +3563,28 @@ 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 if (nluns != common->nluns) {
+ pr_info("Adjusting number of LUNs=%u (was %u)\n",
+ nluns, common->nluns);
+ common->nluns = nluns;
+ }
+ }
opts->refcnt++;
mutex_unlock(&opts->lock);
+
fsg->function.name = FSG_DRIVER_DESC;
fsg->function.bind = fsg_bind;
fsg->function.unbind = fsg_unbind;
--
2.4.3.573.g4eafbef
--
Best regards, _ _
.o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o
..o | Computer Science, Michał “mina86” Nazarewicz (o o)
ooo +--<mpn@xxxxxxxxxx>--<xmpp:mina86@xxxxxxxxxx>--ooO--(_)--Ooo--
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