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authorAndy Shevchenko <andy.shevchenko@gmail.com>2010-07-22 17:53:56 +0300
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 14:35:42 -0700
commita93917d39fc388c4761d2530af82513e2d3bf9f6 (patch)
tree0e2f7bed30b16c70a2f71951adfadeab7a29a4a8
parent8156d158efa6370a8183f47327f122edbb4f2cb6 (diff)
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USB: gadget: storage: optional SCSI WRITE FUA bit
MS Windows mounts removable storage in "Removal optimized mode" by default. All the writes to the media are synchronous which is achieved by setting FUA (Force Unit Access) bit in SCSI WRITE(10,12) commands. This prevents I/O requests aggregation in block layer dramatically decreasing performance. This patch brings an option to accept or ignore mentioned bit a) via specifying module parameter "nofua", or b) through sysfs entry /sys/devices/platform/_UDC_/gadget/gadget-lunX/nofua (_UDC_ is the name of the USB Device Controller driver) Patch is based on the work that was done by Denis Karpov for Maemo 5 platform. Signed-off-by: Andy Shevchenko <ext-andriy.shevchenko@nokia.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Cc: Denis Karpov <ext-denis.2.karpov@nokia.com> Cc: Adrian Hunter <adrian.hunter@nokia.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--Documentation/ABI/testing/sysfs-devices-platform-_UDC_-gadget12
-rw-r--r--drivers/usb/gadget/file_storage.c31
-rw-r--r--drivers/usb/gadget/storage_common.c28
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 34034027b13..d548eaac230 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 d57c09f764d..88e5ad2bc71 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 3bbddab72e5..484acfb1a7c 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)
{