[PATCH v2 3/4] usb: gadget: mass_storage: Ensure that lun ids are contiguous

From: Krzysztof Opasiak
Date: Wed Apr 08 2015 - 08:08:18 EST


Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx>
---
drivers/usb/gadget/function/f_mass_storage.c | 35 +++++++++++++++++++++++---
1 file changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/function/f_mass_storage.c b/drivers/usb/gadget/function/f_mass_storage.c
index 095b618..9d9fafb 100644
--- a/drivers/usb/gadget/function/f_mass_storage.c
+++ b/drivers/usb/gadget/function/f_mass_storage.c
@@ -3355,6 +3355,12 @@ static struct config_group *fsg_lun_make(struct config_group *group,
goto out;
}

+ if (!fsg_opts->common->luns[num - 1]) {
+ ret = -EINVAL;
+ pr_err("LUN ids should be contignous\n");
+ goto out;
+ }
+
opts = kzalloc(sizeof(*opts), GFP_KERNEL);
if (!opts) {
ret = -ENOMEM;
@@ -3364,12 +3370,17 @@ static struct config_group *fsg_lun_make(struct config_group *group,
memset(&config, 0, sizeof(config));
config.removable = true;

+ /* ensure that lun ids are contiguous */
+ ret = configfs_depend_item_unlocked(&(fsg_opts->lun_opts
+ [num - 1]->group.cg_item));
+ if (ret)
+ goto err_free_opts;
+
ret = fsg_common_create_lun(fsg_opts->common, &config, num, name,
(const char **)&group->cg_item.ci_name);
- if (ret) {
- kfree(opts);
- goto out;
- }
+ if (ret)
+ goto err_undepend_item;
+
opts->lun = fsg_opts->common->luns[num];
opts->lun_id = num;
BUG_ON(fsg_opts->lun_opts[num]);
@@ -3382,6 +3393,16 @@ static struct config_group *fsg_lun_make(struct config_group *group,
out:
mutex_unlock(&fsg_opts->lock);
return ERR_PTR(ret);
+
+err_undepend_item:
+ configfs_undepend_item_unlocked(&(fsg_opts->lun_opts
+ [num - 1]->group.cg_item));
+err_free_opts:
+ kfree(opts);
+
+ mutex_unlock(&fsg_opts->lock);
+ return ERR_PTR(ret);
+
}

static void fsg_lun_drop(struct config_group *group, struct config_item *item)
@@ -3400,10 +3421,16 @@ static void fsg_lun_drop(struct config_group *group, struct config_item *item)
unregister_gadget_item(gadget);
}

+
+ /* Allow to remove next one */
+ configfs_undepend_item_unlocked(&(fsg_opts->lun_opts
+ [lun_opts->lun_id - 1]->group.cg_item));
+
fsg_common_remove_lun(lun_opts->lun, fsg_opts->common->sysfs);
fsg_opts->common->luns[lun_opts->lun_id] = NULL;
fsg_opts->lun_opts[lun_opts->lun_id] = NULL;
lun_opts->lun_id = 0;
+
mutex_unlock(&fsg_opts->lock);

config_item_put(item);
--
1.7.9.5

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