Prepare for configfs integration. Use the new interface so that f_fs can be
made a module.
Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxx>
Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
---
drivers/usb/gadget/Kconfig | 1 +
drivers/usb/gadget/g_ffs.c | 190 ++++++++++++++++++++++++++++++-------------
2 files changed, 133 insertions(+), 58 deletions(-)
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 66444d0..2479644 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -862,6 +862,7 @@ config USB_GADGETFS
config USB_FUNCTIONFS
tristate "Function Filesystem"
select USB_LIBCOMPOSITE
+ select USB_F_FS
select USB_FUNCTIONFS_GENERIC if !(USB_FUNCTIONFS_ETH || USB_FUNCTIONFS_RNDIS)
help
The Function Filesystem (FunctionFS) lets one create USB
diff --git a/drivers/usb/gadget/g_ffs.c b/drivers/usb/gadget/g_ffs.c
index 7691395..316cd35 100644
--- a/drivers/usb/gadget/g_ffs.c
+++ b/drivers/usb/gadget/g_ffs.c
@@ -13,13 +13,7 @@
#define pr_fmt(fmt) "g_ffs: " fmt
#include <linux/module.h>
-/*
- * kbuild is not very cooperative with respect to linking separately
- * compiled library objects into one module. So for now we won't use
- * separate compilation ... ensuring init/exit sections work to shrink
- * the runtime footprint, and giving us at least some parts of what
- * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
- */
+
#if defined CONFIG_USB_FUNCTIONFS_ETH || defined CONFIG_USB_FUNCTIONFS_RNDIS
#include <linux/netdevice.h>
@@ -54,8 +48,7 @@ static struct usb_function *f_rndis;
# endif
#endif
-#define USB_FFS_INCLUDED
-#include "f_fs.c"
+#include "u_fs.h"
#define DRIVER_NAME "g_ffs"
#define DRIVER_DESC "USB Function Filesystem"
@@ -139,6 +132,7 @@ static struct usb_gadget_strings *gfs_dev_strings[] = {
struct gfs_configuration {
struct usb_configuration c;
int (*eth)(struct usb_configuration *c);
+ int num;
} gfs_configurations[] = {
#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
{
@@ -158,12 +152,15 @@ struct gfs_configuration {
#endif
};
+static void *functionfs_acquire_dev(struct ffs_dev *dev);
+static void functionfs_release_dev(struct ffs_dev *dev);
static int functionfs_ready_callback(struct ffs_data *ffs);
static void functionfs_closed_callback(struct ffs_data *ffs);
static int gfs_bind(struct usb_composite_dev *cdev);
static int gfs_unbind(struct usb_composite_dev *cdev);
static int gfs_do_config(struct usb_configuration *c);
+
static __refdata struct usb_composite_driver gfs_driver = {
.name = DRIVER_NAME,
.dev = &gfs_dev_desc,
@@ -176,10 +173,26 @@ static __refdata struct usb_composite_driver gfs_driver = {
static unsigned int missing_funcs;
static bool gfs_registered;
static bool gfs_single_func;
-static struct ffs_dev **ffs_tab;
+static struct usb_function_instance **fi_ffs;
+static struct usb_function **f_ffs[] = {
+#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
+ NULL,
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_ETH
+ NULL,
+#endif
+
+#ifdef CONFIG_USB_FUNCTIONFS_GENERIC
+ NULL,
+#endif
+};
+
+#define N_CONF ARRAY_SIZE(f_ffs)
static int __init gfs_init(void)
{
+ struct f_fs_opts *opts;
int i;
int ret = 0;
@@ -190,39 +203,89 @@ static int __init gfs_init(void)
func_num = 1;
}
- ffs_tab = kcalloc(func_num, sizeof(*ffs_tab), GFP_KERNEL);
- if (!ffs_tab)
- return -ENOMEM;
+ /*
+ * Allocate in one chunk for easier maintenance
+ */
+ f_ffs[0] = kcalloc(func_num * N_CONF, sizeof(*f_ffs), GFP_KERNEL);
+ if (!f_ffs[0]) {
+ ret = -ENOMEM;
+ goto no_func;
+ }
+ for (i = 1; i < N_CONF; ++i)
+ f_ffs[i] = f_ffs[0] + i * func_num;
+
+ fi_ffs = kcalloc(func_num, sizeof(*fi_ffs), GFP_KERNEL);
+ if (!fi_ffs) {
+ ret = -ENOMEM;
+ goto no_func;
+ }
- ffs_dev_lock();
for (i = 0; i < func_num; i++) {
- ffs_tab[i] = ffs_alloc_dev();
- if (IS_ERR(ffs_tab[i])) {
- ret = PTR_ERR(ffs_tab[i]);
- --i;
+ /*
+ * usb_get_function_instance() takes ffs_lock,
+ * so we must not take it here...
+ */
+ fi_ffs[i] = usb_get_function_instance("ffs");
+ if (IS_ERR(fi_ffs[i])) {
+ ret = PTR_ERR(fi_ffs[i]);
goto no_dev;
}
- ret = ffs_single_dev(ffs_tab[i], gfs_single_func);
+ /*
+ * ... but we need it below
+ *
+ * What happens if some thread of execution kicks in between
+ * usb_get_function_instance() above and ffs_dev_lock() below
+ * and (after taking the lock) accesses the devices list?
+ *
+ * The other thread can be a configfs-based gadget only,
+ * since we cannot load this (g_ffs) module twice.
+ *
+ * For the device to be used it needs so be acquired first.
+ * ffs_acquire_dev() finds the device by name and it will get
+ * some string to match against as a device name given for
+ * mount by the user. So devices which don't have their name set
+ * will never be matched, so our device just created above will
+ * not be abused.
+ *
+ * There is an exception to the matching rule: the g_ffs, if
+ * no functions= parameter is given on module load, will assume
+ * there is only one "device" and will accept any "device" name
+ * given for mount. If this is the case here, then the other
+ * thread potentially creates another device and the device list
+ * consists no more of a single device. Then setting the device
+ * created above as "single" will not succeed and g_ffs will
+ * refuse loading with EBUSY.
+ */
+ ffs_dev_lock();
+ opts = to_f_fs_opts(fi_ffs[i]);
+ ret = ffs_single_dev(opts->dev, gfs_single_func);
if (ret)
- goto no_dev;
+ goto no_dev_unlock;
if (!gfs_single_func) {
- ret = ffs_name_dev(ffs_tab[i], func_names[i]);
+ ret = ffs_name_dev(opts->dev, func_names[i]);
if (ret)
- goto no_dev;
+ goto no_dev_unlock;
}
- ffs_tab[i]->ffs_ready_callback = functionfs_ready_callback;
- ffs_tab[i]->ffs_closed_callback = functionfs_closed_callback;
+ opts->dev->ffs_ready_callback = functionfs_ready_callback;
+ opts->dev->ffs_closed_callback = functionfs_closed_callback;
+ opts->dev->ffs_acquire_dev_callback = functionfs_acquire_dev;
+ opts->dev->ffs_release_dev_callback = functionfs_release_dev;
+ opts->no_configfs = true;
+ ffs_dev_unlock();
}
- ffs_dev_unlock();
missing_funcs = func_num;
return 0;
+no_dev_unlock:
+ ffs_dev_unlock();
no_dev:
while (i >= 0)
- ffs_free_dev(ffs_tab[i--]);
- ffs_dev_unlock();
- kfree(ffs_tab);
+ usb_put_function_instance(fi_ffs[i]);
+ kfree(fi_ffs);
+ i = N_CONF;
+no_func:
+ kfree(f_ffs[0]);
return ret;
}
module_init(gfs_init);
@@ -232,19 +295,33 @@ static void __exit gfs_exit(void)
int i;
ENTER();
- ffs_dev_lock();
if (gfs_registered)
usb_composite_unregister(&gfs_driver);
gfs_registered = false;
+ kfree(f_ffs[0]);
+
for (i = 0; i < func_num; i++)
- ffs_free_dev(ffs_tab[i]);
- ffs_dev_unlock();
- kfree(ffs_tab);
+ usb_put_function_instance(fi_ffs[i]);
+
+ kfree(fi_ffs);
}
module_exit(gfs_exit);
+static void *functionfs_acquire_dev(struct ffs_dev *dev)
+{
+ if (!try_module_get(THIS_MODULE))
+ return ERR_PTR(-ENODEV);
+
+ return 0;
+}
+
+static void functionfs_release_dev(struct ffs_dev *dev)
+{
+ module_put(THIS_MODULE);
+}
+
/*
* The caller of this function takes ffs_lock
*/
@@ -361,20 +438,12 @@ static int gfs_bind(struct usb_composite_dev *cdev)
rndis_borrow_net(fi_rndis, net);
#endif
+ /* TODO: gstrings_attach? */
ret = usb_string_ids_tab(cdev, gfs_strings);
if (unlikely(ret < 0))
goto error_rndis;
gfs_dev_desc.iProduct = gfs_strings[USB_GADGET_PRODUCT_IDX].id;
- for (i = func_num; i--; ) {
- ret = functionfs_bind(ffs_tab[i]->ffs_data, cdev);
- if (unlikely(ret < 0)) {
- while (++i < func_num)
- functionfs_unbind(ffs_tab[i]->ffs_data);
- goto error_rndis;
- }
- }
-
for (i = 0; i < ARRAY_SIZE(gfs_configurations); ++i) {
struct gfs_configuration *c = gfs_configurations + i;
int sid = USB_GADGET_FIRST_AVAIL_IDX + i;
@@ -384,6 +453,8 @@ static int gfs_bind(struct usb_composite_dev *cdev)
c->c.bConfigurationValue = 1 + i;
c->c.bmAttributes = USB_CONFIG_ATT_SELFPOWER;
+ c->num = i;
+
ret = usb_add_config(cdev, &c->c, gfs_do_config);
if (unlikely(ret < 0))
goto error_unbind;
@@ -391,9 +462,8 @@ static int gfs_bind(struct usb_composite_dev *cdev)
usb_composite_overwrite_options(cdev, &coverwrite);
return 0;
+/* TODO */
error_unbind:
- for (i = 0; i < func_num; i++)
- functionfs_unbind(ffs_tab[i]->ffs_data);
error_rndis:
#ifdef CONFIG_USB_FUNCTIONFS_RNDIS
usb_put_function_instance(fi_rndis);
@@ -432,18 +502,8 @@ static int gfs_unbind(struct usb_composite_dev *cdev)
usb_put_function_instance(fi_geth);
}
#endif
-
- /*
- * We may have been called in an error recovery from
- * composite_bind() after gfs_unbind() failure so we need to
- * check if instance's ffs_data is not NULL since gfs_bind() handles
- * all error recovery itself. I'd rather we werent called
- * from composite on orror recovery, but what you're gonna
- * do...?
- */
- for (i = func_num; i--; )
- if (ffs_tab[i]->ffs_data)
- functionfs_unbind(ffs_tab[i]->ffs_data);
+ for (i = 0; i < N_CONF * func_num; ++i)
+ usb_put_function(*(f_ffs[0] + i));
return 0;
}
@@ -474,9 +534,16 @@ static int gfs_do_config(struct usb_configuration *c)
}
for (i = 0; i < func_num; i++) {
- ret = functionfs_bind_config(c->cdev, c, ffs_tab[i]->ffs_data);
- if (unlikely(ret < 0))
- return ret;
+ f_ffs[gc->num][i] = usb_get_function(fi_ffs[i]);
+ if (IS_ERR(f_ffs[gc->num][i])) {
+ ret = PTR_ERR(f_ffs[gc->num][i]);
+ goto error;
+ }
+ ret = usb_add_function(c, f_ffs[gc->num][i]);
+ if (ret < 0) {
+ usb_put_function(f_ffs[gc->num][i]);
+ goto error;
+ }
}
/*
@@ -493,6 +560,13 @@ static int gfs_do_config(struct usb_configuration *c)
c->interface[c->next_interface_id] = NULL;
return 0;
+error:
+ while (--i >= 0) {
+ if (!IS_ERR(f_ffs[gc->num][i]))
+ usb_remove_function(c, f_ffs[gc->num][i]);
+ usb_put_function(f_ffs[gc->num][i]);
+ }
+ return ret;
}
#ifdef CONFIG_USB_FUNCTIONFS_ETH
--
1.7.0.4
--
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