3 files changed, 64 insertions, 7 deletions

diff --git a/Documentation/ABI/testing/sysfs-devices-platform-_UDC_-gadget b/Documentation/ABI/testing/sysfs-devices-platform-_UDC_-gadget
index 34034027b13c..d548eaac230a 100644
--- a/Documentation/ABI/testing/sysfs-devices-platform-_UDC_-gadget
+++ b/Documentation/ABI/testing/sysfs-devices-platform-_UDC_-gadget
@@ -7,3 +7,15 @@ Description:
                 0 -> resumed
 
                 (_UDC_ is the name of the USB Device Controller driver)
+
+What:           /sys/devices/platform/_UDC_/gadget/gadget-lunX/nofua
+Date:           July 2010
+Contact:        Andy Shevchenko <andy.shevchenko@gmail.com>
+Description:
+                Show or set the reaction on the FUA (Force Unit Access) bit in
+                the SCSI WRITE(10,12) commands when a gadget in USB Mass
+                Storage mode.
+
+                Possible values are:
+                        1 -> ignore the FUA flag
+                        0 -> obey the FUA flag
diff --git a/drivers/usb/gadget/file_storage.c b/drivers/usb/gadget/file_storage.c
index d57c09f764d6..88e5ad2bc710 100644
--- a/drivers/usb/gadget/file_storage.c
+++ b/drivers/usb/gadget/file_storage.c
@@ -93,6 +93,8 @@
  *      removable               Default false, boolean for removable media
  *      luns=N                  Default N = number of filenames, number of
  *                                      LUNs to support
+ *      nofua=b[,b...]          Default false, booleans for ignore FUA flag
+ *                                      in SCSI WRITE(10,12) commands
  *      stall                   Default determined according to the type of
  *                                      USB device controller (usually true),
  *                                      boolean to permit the driver to halt
@@ -112,12 +114,12 @@
  *                                      PAGE_CACHE_SIZE)
  *
  * If CONFIG_USB_FILE_STORAGE_TEST is not set, only the "file", "ro",
- * "removable", "luns", "stall", and "cdrom" options are available; default
- * values are used for everything else.
+ * "removable", "luns", "nofua", "stall", and "cdrom" options are available;
+ * default values are used for everything else.
  *
  * The pathnames of the backing files and the ro settings are available in
- * the attribute files "file" and "ro" in the lun<n> subdirectory of the
- * gadget's sysfs directory.  If the "removable" option is set, writing to
+ * the attribute files "file", "nofua", and "ro" in the lun<n> subdirectory of
+ * the gadget's sysfs directory.  If the "removable" option is set, writing to
  * these files will simulate ejecting/loading the medium (writing an empty
  * line means eject) and adjusting a write-enable tab.  Changes to the ro
  * setting are not allowed when the medium is loaded or if CD-ROM emulation
@@ -304,8 +306,10 @@ MODULE_LICENSE("Dual BSD/GPL");
 static struct {
         char            *file[FSG_MAX_LUNS];
         int             ro[FSG_MAX_LUNS];
+        int             nofua[FSG_MAX_LUNS];
         unsigned int    num_filenames;
         unsigned int    num_ros;
+        unsigned int    num_nofuas;
         unsigned int    nluns;
 
         int             removable;
@@ -345,6 +349,10 @@ MODULE_PARM_DESC(file, "names of backing files or devices");
 module_param_array_named(ro, mod_data.ro, bool, &mod_data.num_ros, S_IRUGO);
 MODULE_PARM_DESC(ro, "true to force read-only");
 
+module_param_array_named(nofua, mod_data.nofua, bool, &mod_data.num_nofuas,
+                S_IRUGO);
+MODULE_PARM_DESC(nofua, "true to ignore SCSI WRITE(10,12) FUA bit");
+
 module_param_named(luns, mod_data.nluns, uint, S_IRUGO);
 MODULE_PARM_DESC(luns, "number of LUNs");
 
@@ -1279,7 +1287,8 @@ static int do_write(struct fsg_dev *fsg)
                         curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
                         return -EINVAL;
                 }
-                if (fsg->cmnd[1] & 0x08) {      // FUA
+                /* FUA */
+                if (!curlun->nofua && (fsg->cmnd[1] & 0x08)) {
                         spin_lock(&curlun->filp->f_lock);
                         curlun->filp->f_flags |= O_DSYNC;
                         spin_unlock(&curlun->filp->f_lock);
@@ -3133,6 +3142,7 @@ static int fsg_main_thread(void *fsg_)
 
 /* The write permissions and store_xxx pointers are set in fsg_bind() */
 static DEVICE_ATTR(ro, 0444, fsg_show_ro, NULL);
+static DEVICE_ATTR(nofua, 0644, fsg_show_nofua, NULL);
 static DEVICE_ATTR(file, 0444, fsg_show_file, NULL);
 
 
@@ -3362,6 +3372,10 @@ static int __ref fsg_bind(struct usb_gadget *gadget)
                 }
         }
 
+        /* Only for removable media? */
+        dev_attr_nofua.attr.mode = 0644;
+        dev_attr_nofua.store = fsg_store_nofua;
+
         /* Find out how many LUNs there should be */
         i = mod_data.nluns;
         if (i == 0)
@@ -3387,6 +3401,7 @@ static int __ref fsg_bind(struct usb_gadget *gadget)
                 curlun->ro = mod_data.cdrom || mod_data.ro[i];
                 curlun->initially_ro = curlun->ro;
                 curlun->removable = mod_data.removable;
+                curlun->nofua = mod_data.nofua[i];
                 curlun->dev.release = lun_release;
                 curlun->dev.parent = &gadget->dev;
                 curlun->dev.driver = &fsg_driver.driver;
@@ -3401,6 +3416,8 @@ static int __ref fsg_bind(struct usb_gadget *gadget)
                 if ((rc = device_create_file(&curlun->dev,
                                         &dev_attr_ro)) != 0 ||
                                 (rc = device_create_file(&curlun->dev,
+                                        &dev_attr_nofua)) != 0 ||
+                                (rc = device_create_file(&curlun->dev,
                                         &dev_attr_file)) != 0) {
                         device_unregister(&curlun->dev);
                         goto out;
@@ -3525,8 +3542,8 @@ static int __ref fsg_bind(struct usb_gadget *gadget)
                                 if (IS_ERR(p))
                                         p = NULL;
                         }
-                        LINFO(curlun, "ro=%d, file: %s\n",
-                                        curlun->ro, (p ? p : "(error)"));
+                        LINFO(curlun, "ro=%d, nofua=%d, file: %s\n",
+                              curlun->ro, curlun->nofua, (p ? p : "(error)"));
                 }
         }
         kfree(pathbuf);
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 3bbddab72e57..484acfb1a7c5 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -284,6 +284,7 @@ struct fsg_lun {
         unsigned int    prevent_medium_removal:1;
         unsigned int    registered:1;
         unsigned int    info_valid:1;
+        unsigned int    nofua:1;
 
         u32             sense_data;
         u32             sense_data_info;
@@ -714,6 +715,14 @@ static ssize_t fsg_show_ro(struct device *dev, struct device_attribute *attr,
                                   : curlun->initially_ro);
 }
 
+static ssize_t fsg_show_nofua(struct device *dev, struct device_attribute *attr,
+                              char *buf)
+{
+        struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
+
+        return sprintf(buf, "%u\n", curlun->nofua);
+}
+
 static ssize_t fsg_show_file(struct device *dev, struct device_attribute *attr,
                              char *buf)
 {
@@ -770,6 +779,25 @@ static ssize_t fsg_store_ro(struct device *dev, struct device_attribute *attr,
         return rc;
 }
 
+static ssize_t fsg_store_nofua(struct device *dev,
+                               struct device_attribute *attr,
+                               const char *buf, size_t count)
+{
+        struct fsg_lun  *curlun = fsg_lun_from_dev(dev);
+        unsigned long   nofua;
+
+        if (strict_strtoul(buf, 2, &nofua))
+                return -EINVAL;
+
+        /* Sync data when switching from async mode to sync */
+        if (!nofua && curlun->nofua)
+                fsg_lun_fsync_sub(curlun);
+
+        curlun->nofua = nofua;
+
+        return count;
+}
+
 static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
                               const char *buf, size_t count)
 {