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Subject[PATCH/RFC 1/2] USB: gadget: f_mass_storage: split fsg_common_init() into two phases
This patch splits the fsg_common_init() into two phases.  The first
phase is a “early init” (carried by fsg_common_early_init() function)
and the second is binding to cdev (carried by
fsg_common_bind_cdev() function).

The second phase can be undone (by fsg_common_unbind_cdev()
function) and carried multiple times.

The “early init” needs only the configuration object (the fsg_config
structure) and does not depend on the composite device (the
usb_composite_dev structure). The second stage binds the instance
of the fsg_common structure with the composite device.

This division allows for binding the MSF to several composite
devices which are created when you first usb_composite_unregister()
one and usb_composite_register() another.

Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
drivers/usb/gadget/f_mass_storage.c | 302 ++++++++++++++++++++++-------------
1 files changed, 187 insertions(+), 115 deletions(-)

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 32cce02..2b5cb67 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -300,7 +300,7 @@
/*------------------------------------------------------------------------*/

#define FSG_DRIVER_DESC "Mass Storage Function"
-#define FSG_DRIVER_VERSION "2009/09/11"
+#define FSG_DRIVER_VERSION "2010/07/01"

static const char fsg_string_interface[] = "Mass Storage";

@@ -366,6 +366,7 @@ struct fsg_common {
unsigned int lun;
struct fsg_lun *luns;
struct fsg_lun *curlun;
+ const char *lun_name_format;

unsigned int bulk_out_maxpacket;
enum fsg_state state; /* For exception handling */
@@ -379,6 +380,7 @@ struct fsg_common {
u32 usb_amount_left;

unsigned int can_stall:1;
+ unsigned int cfg_can_stall:1;
unsigned int free_storage_on_release:1;
unsigned int phase_error:1;
unsigned int short_packet_received:1;
@@ -397,6 +399,7 @@ struct fsg_common {
/* Vendor (8 chars), product (16 chars), release (4
* hexadecimal digits) and NUL byte */
char inquiry_string[8 + 16 + 4 + 1];
+ u16 cfg_release;

struct kref ref;
};
@@ -445,17 +448,7 @@ struct fsg_dev {
};


-static inline int __fsg_is_set(struct fsg_common *common,
- const char *func, unsigned line)
-{
- if (common->fsg)
- return 1;
- ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
- WARN_ON(1);
- return 0;
-}
-
-#define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
+#define fsg_is_set(common) (!WARN_ON(!(common)->fsg))


static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
@@ -2685,21 +2678,29 @@ static inline void fsg_common_put(struct fsg_common *common)
}


-static struct fsg_common *fsg_common_init(struct fsg_common *common,
- struct usb_composite_dev *cdev,
- struct fsg_config *cfg)
+static struct fsg_common *fsg_common_early_init(struct fsg_common *common,
+ struct fsg_config *cfg)
{
- struct usb_gadget *gadget = cdev->gadget;
struct fsg_buffhd *bh;
struct fsg_lun *curlun;
struct fsg_lun_config *lcfg;
int nluns, i, rc;
char *pathbuf;

+ /*
+ * Do not use ERROR, WARNING, INFO, DBG and VDBG macros in
+ * this function. common->gadget is unset and usage of those
+ * macros here will cause a NULL pointer dereference. Instead
+ * fallback to plain pr_*.
+ *
+ * The L*() macros (for luns) are fine.
+ */
+
/* Find out how many LUNs there should be */
nluns = cfg->nluns;
if (nluns < 1 || nluns > FSG_MAX_LUNS) {
- dev_err(&gadget->dev, "invalid number of LUNs: %u\n", nluns);
+ pr_err("mass storage: invalid number of LUNs: %u\n",
+ nluns);
return ERR_PTR(-EINVAL);
}

@@ -2717,70 +2718,39 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
common->ops = cfg->ops;
common->private_data = cfg->private_data;

- common->gadget = gadget;
- common->ep0 = gadget->ep0;
- common->ep0req = cdev->req;
-
- /* Maybe allocate device-global string IDs, and patch descriptors */
- if (fsg_strings[FSG_STRING_INTERFACE].id == 0) {
- rc = usb_string_id(cdev);
- if (unlikely(rc < 0))
- goto error_release;
- fsg_strings[FSG_STRING_INTERFACE].id = rc;
- fsg_intf_desc.iInterface = rc;
- }
-
- /* Create the LUNs, open their backing files, and register the
- * LUN devices in sysfs. */
+ /* Create the LUNs, and open their backing files */
curlun = kzalloc(nluns * sizeof *curlun, GFP_KERNEL);
if (unlikely(!curlun)) {
rc = -ENOMEM;
- goto error_release;
+ goto error;
}
common->luns = curlun;
+ common->nluns = nluns;

init_rwsem(&common->filesem);

- for (i = 0, lcfg = cfg->luns; i < nluns; ++i, ++curlun, ++lcfg) {
+ common->lun_name_format = cfg->lun_name_format ?: "lun%d";
+
+ lcfg = cfg->luns;
+ i = 0;
+ do {
curlun->cdrom = !!lcfg->cdrom;
curlun->ro = lcfg->cdrom || lcfg->ro;
curlun->removable = lcfg->removable;
- curlun->dev.release = fsg_lun_release;
- curlun->dev.parent = &gadget->dev;
- /* curlun->dev.driver = &fsg_driver.driver; XXX */
- dev_set_drvdata(&curlun->dev, &common->filesem);
- dev_set_name(&curlun->dev,
- cfg->lun_name_format
- ? cfg->lun_name_format
- : "lun%d",
- i);

- rc = device_register(&curlun->dev);
- if (rc) {
- INFO(common, "failed to register LUN%d: %d\n", i, rc);
- common->nluns = i;
- goto error_release;
- }
-
- rc = device_create_file(&curlun->dev, &dev_attr_ro);
- if (rc)
- goto error_luns;
- rc = device_create_file(&curlun->dev, &dev_attr_file);
- if (rc)
- goto error_luns;
+ dev_set_name(&curlun->dev, common->lun_name_format, i);
+ dev_set_drvdata(&curlun->dev, &common->filesem);

if (lcfg->filename) {
rc = fsg_lun_open(curlun, lcfg->filename);
if (rc)
- goto error_luns;
+ goto error;
} else if (!curlun->removable) {
- ERROR(common, "no file given for LUN%d\n", i);
+ pr_err("mass storage: no file given for LUN%d\n", i);
rc = -EINVAL;
- goto error_luns;
+ goto error;
}
- }
- common->nluns = nluns;
-
+ } while (++curlun, ++lcfg, ++i < nluns);

/* Data buffers cyclic list */
bh = common->buffhds;
@@ -2793,44 +2763,12 @@ buffhds_first_it:
bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
if (unlikely(!bh->buf)) {
rc = -ENOMEM;
- goto error_release;
+ goto error;
}
} while (--i);
bh->next = common->buffhds;


- /* Prepare inquiryString */
- if (cfg->release != 0xffff) {
- i = cfg->release;
- } else {
- i = usb_gadget_controller_number(gadget);
- if (i >= 0) {
- i = 0x0300 + i;
- } else {
- WARNING(common, "controller '%s' not recognized\n",
- gadget->name);
- i = 0x0399;
- }
- }
-#define OR(x, y) ((x) ? (x) : (y))
- snprintf(common->inquiry_string, sizeof common->inquiry_string,
- "%-8s%-16s%04x",
- OR(cfg->vendor_name, "Linux "),
- /* Assume product name dependent on the first LUN */
- OR(cfg->product_name, common->luns->cdrom
- ? "File-Stor Gadget"
- : "File-CD Gadget "),
- i);
-
-
- /* Some peripheral controllers are known not to be able to
- * halt bulk endpoints correctly. If one of them is present,
- * disable stalls.
- */
- common->can_stall = cfg->can_stall &&
- !(gadget_is_at91(common->gadget));
-
-
spin_lock_init(&common->lock);
kref_init(&common->ref);

@@ -2838,19 +2776,18 @@ buffhds_first_it:
/* Tell the thread to start working */
common->thread_task =
kthread_create(fsg_main_thread, common,
- OR(cfg->thread_name, "file-storage"));
+ cfg->thread_name ?: "file-storage");
if (IS_ERR(common->thread_task)) {
rc = PTR_ERR(common->thread_task);
- goto error_release;
+ goto error;
}
init_completion(&common->thread_notifier);
init_waitqueue_head(&common->fsg_wait);
-#undef OR


/* Information */
- INFO(common, FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
- INFO(common, "Number of LUNs=%d\n", common->nluns);
+ pr_info(FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION
+ "\nNumber of LUNs=%d\n", common->nluns);

pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
for (i = 0, nluns = common->nluns, curlun = common->luns;
@@ -2874,28 +2811,167 @@ buffhds_first_it:
}
kfree(pathbuf);

- DBG(common, "I/O thread pid: %d\n", task_pid_nr(common->thread_task));
+ pr_debug(KERN_DEBUG "mass storage: I/O thread pid: %d\n", task_pid_nr(common->thread_task));

wake_up_process(common->thread_task);

- return common;
+ /* Prepare inquiryString */
+ /* Release will be later added in fsg_common_bind_cdev() */
+ snprintf(common->inquiry_string, sizeof common->inquiry_string,
+ "%-8s%-16s",
+ cfg->vendor_name ?: "Linux ",
+ /* Assume product name dependent on the first LUN */
+ cfg->product_name ?: (common->luns->cdrom
+ ? "File-Stor Gadget"
+ : "File-CD Gadget "));
+
+ common->cfg_release = cfg->release;
+ common->cfg_can_stall = cfg->can_stall;

+ return common;

-error_luns:
- common->nluns = i + 1;
-error_release:
+error:
common->state = FSG_STATE_TERMINATED; /* The thread is dead */
- /* Call fsg_common_release() directly, ref might be not
- * initialised */
+ /*
+ * Call fsg_common_release() directly, ref might be not
+ * initialised
+ */
fsg_common_release(&common->ref);
return ERR_PTR(rc);
}


+static void fsg_common_unbind_cdev(struct fsg_common *common)
+{
+ struct fsg_lun *curlun;
+ unsigned i, nluns;
+
+ if (!common->gadget)
+ return;
+
+ common->gadget = NULL;
+ common->ep0 = NULL;
+ common->ep0req = NULL;
+
+ curlun = common->luns;
+ if (unlikely(!curlun))
+ return;
+
+ nluns = common->nluns;
+ i = 0;
+ do {
+ if (!curlun->dev.parent)
+ continue;
+
+ device_remove_file(&curlun->dev, &dev_attr_ro);
+ device_remove_file(&curlun->dev, &dev_attr_file);
+ device_unregister(&curlun->dev);
+ memset(&curlun->dev, 0, sizeof curlun->dev);
+
+ dev_set_name(&curlun->dev, common->lun_name_format, i);
+ dev_set_drvdata(&curlun->dev, &common->filesem);
+ } while (++curlun, ++i < nluns);
+}
+
+static int fsg_common_bind_cdev(struct fsg_common *common,
+ struct usb_composite_dev *cdev)
+{
+ struct usb_gadget *gadget = cdev->gadget;
+ struct fsg_lun *curlun;
+ int i, rc;
+
+ /* Register string */
+ i = usb_string_id(cdev);
+ if (unlikely(i < 0))
+ return i;
+ fsg_strings[FSG_STRING_INTERFACE].id = i;
+ fsg_intf_desc.iInterface = i;
+
+ /* Save pointers */
+ common->gadget = gadget;
+ common->ep0 = gadget->ep0;
+ common->ep0req = cdev->req;
+
+ /* Register the LUN devices in sysfs. */
+ curlun = common->luns;
+ i = common->nluns;
+ do {
+ curlun->dev.parent = &gadget->dev;
+ curlun->dev.release = fsg_lun_release;
+ rc = device_register(&curlun->dev);
+ if (unlikely(rc)) {
+ curlun->dev.parent = NULL;
+ goto error;
+ }
+
+ rc = device_create_file(&curlun->dev, &dev_attr_ro);
+ if (unlikely(rc))
+ goto error;
+ rc = device_create_file(&curlun->dev, &dev_attr_file);
+ if (unlikely(rc))
+ goto error;
+ } while (++curlun, --i);
+
+ /* Save release in inquiryString */
+ /*
+ * The rest of the inquiryString is prepared in
+ * fsg_common_early_init().
+ */
+ if (common->cfg_release != 0xffff) {
+ i = common->cfg_release;
+ } else {
+ i = usb_gadget_controller_number(gadget);
+ i = i >= 0 ? 0x0300 + i : 0x0399;
+ }
+
+ snprintf(common->inquiry_string + 8 + 16,
+ sizeof common->inquiry_string - 8 - 16,
+ "%04x", i);
+
+ /*
+ * Some peripheral controllers are known not to be able to
+ * halt bulk endpoints correctly. If one of them is present,
+ * disable stalls.
+ */
+ common->can_stall = common->cfg_can_stall &&
+ !(gadget_is_at91(common->gadget));
+
+ return 0;
+
+error:
+ fsg_common_unbind_cdev(common);
+ return rc;
+}
+
+
+static struct fsg_common *fsg_common_init(struct fsg_common *common,
+ struct usb_composite_dev *cdev,
+ struct fsg_config *cfg)
+{
+ int ret;
+
+ common = fsg_common_early_init(common, cfg);
+ if (unlikely(IS_ERR(common)))
+ return common;
+
+ ret = fsg_common_bind_cdev(common, cdev);
+ if (unlikely(ret))
+ goto error;
+ return common;
+
+error:
+ fsg_common_release(&common->ref);
+ return ERR_PTR(ret);
+}
+
+
static void fsg_common_release(struct kref *ref)
{
struct fsg_common *common = container_of(ref, struct fsg_common, ref);

+ /* Unbind from cdev */
+ fsg_common_unbind_cdev(common);
+
/* If the thread isn't already dead, tell it to exit now */
if (common->state != FSG_STATE_TERMINATED) {
raise_exception(common, FSG_STATE_EXIT);
@@ -2906,16 +2982,12 @@ static void fsg_common_release(struct kref *ref)
}

if (likely(common->luns)) {
- struct fsg_lun *lun = common->luns;
+ struct fsg_lun *curlun = common->luns;
unsigned i = common->nluns;

- /* In error recovery common->nluns may be zero. */
- for (; i; --i, ++lun) {
- device_remove_file(&lun->dev, &dev_attr_ro);
- device_remove_file(&lun->dev, &dev_attr_file);
- fsg_lun_close(lun);
- device_unregister(&lun->dev);
- }
+ do {
+ fsg_lun_close(curlun);
+ } while (++curlun, --i);

kfree(common->luns);
}
--
1.7.1
--
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