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Date: Fri, 23 Apr 2010 14:21:27 +0200
From: fabien.chouteau@...il.com
To: linux-usb@...r.kernel.org
Cc: Fabien Chouteau <fabien.chouteau@...co.com>,
David Brownell <dbrownell@...rs.sourceforge.net>,
Greg Kroah-Hartman <gregkh@...e.de>,
Michal Nazarewicz <m.nazarewicz@...sung.com>,
Peter Korsgaard <jacmet@...site.dk>,
linux-kernel@...r.kernel.org
Subject: [PATCH RESEND 2/2] Mass storage gadget: Handle eject request
From: Fabien Chouteau <fabien.chouteau@...co.com>
This patch adds handling of the "Start/Stop Unit" SCSI request to simulate media
ejection. A sysfs entry to get the "eject" state of a LUN is also added.
Signed-off-by: Fabien Chouteau <fabien.chouteau@...co.com>
---
drivers/usb/gadget/f_mass_storage.c | 57 +++++++++++++++++++++++++++++++++--
drivers/usb/gadget/storage_common.c | 11 +++++++
2 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index f4911c0..7b55435 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -163,6 +163,13 @@
* ro setting are not allowed when the medium is loaded or if CD-ROM
* emulation is being used.
*
+ * When a LUN receive an "eject" SCSI request (Start/Stop Unit),
+ * if the LUN is removable, the backing file is released to simulate
+ * ejection.
+ * The "eject" state of a LUN is available in the "ejected" file of the
+ * LUN's sysfs directory (see above). The "eject" state is only updated
+ * by SCSI request, not by user ejection.
+ *
*
* This function is heavily based on "File-backed Storage Gadget" by
* Alan Stern which in turn is heavily based on "Gadget Zero" by David
@@ -1385,12 +1392,51 @@ static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
static int do_start_stop(struct fsg_common *common)
{
- if (!common->curlun) {
+ struct fsg_lun *curlun = common->curlun;
+ int loej, start;
+
+ if (!curlun) {
return -EINVAL;
- } else if (!common->curlun->removable) {
- common->curlun->sense_data = SS_INVALID_COMMAND;
+ } else if (!curlun->removable) {
+ curlun->sense_data = SS_INVALID_COMMAND;
+ return -EINVAL;
+ }
+
+ loej = common->cmnd[4] & 0x02;
+ start = common->cmnd[4] & 0x01;
+
+ /* eject code from file_storage.c:do_start_stop() */
+
+ if ((common->cmnd[1] & ~0x01) != 0 || /* Mask away Immed */
+ (common->cmnd[4] & ~0x03) != 0) { /* Mask LoEj, Start */
+ curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
return -EINVAL;
}
+
+ if (!start) {
+ /* Are we allowed to unload the media? */
+ if (curlun->prevent_medium_removal) {
+ LDBG(curlun, "unload attempt prevented\n");
+ curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
+ return -EINVAL;
+ }
+ if (loej) { /* Simulate an unload/eject */
+ up_read(&common->filesem);
+ down_write(&common->filesem);
+ fsg_lun_close(curlun);
+ curlun->ejected = 1;
+ up_write(&common->filesem);
+ down_read(&common->filesem);
+ }
+ } else {
+
+ /* Our emulation doesn't support mounting; the medium is
+ * available for use as soon as it is loaded. */
+ if (!fsg_lun_is_open(curlun)) {
+ curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
+ return -EINVAL;
+ }
+ }
return 0;
}
@@ -2641,6 +2687,7 @@ static int fsg_main_thread(void *common_)
/* Write permission is checked per LUN in store_*() functions. */
static DEVICE_ATTR(ro, 0644, fsg_show_ro, fsg_store_ro);
static DEVICE_ATTR(file, 0644, fsg_show_file, fsg_store_file);
+static DEVICE_ATTR(ejected, 0444, fsg_show_ejected, NULL);
/****************************** FSG COMMON ******************************/
@@ -2747,6 +2794,9 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
rc = device_create_file(&curlun->dev, &dev_attr_file);
if (rc)
goto error_luns;
+ rc = device_create_file(&curlun->dev, &dev_attr_ejected);
+ if (rc)
+ goto error_luns;
if (lcfg->filename) {
rc = fsg_lun_open(curlun, lcfg->filename);
@@ -2887,6 +2937,7 @@ static void fsg_common_release(struct kref *ref)
for (; i; --i, ++lun) {
device_remove_file(&lun->dev, &dev_attr_ro);
device_remove_file(&lun->dev, &dev_attr_file);
+ device_remove_file(&lun->dev, &dev_attr_ejected);
fsg_lun_close(lun);
device_unregister(&lun->dev);
}
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 868d8ee..16ccebd 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -267,6 +267,7 @@ struct fsg_lun {
unsigned int removable:1;
unsigned int cdrom:1;
unsigned int prevent_medium_removal:1;
+ unsigned int ejected:1;
unsigned int registered:1;
unsigned int info_valid:1;
@@ -625,6 +626,7 @@ static int fsg_lun_open(struct fsg_lun *curlun, const char *filename)
curlun->filp = filp;
curlun->file_length = size;
curlun->num_sectors = num_sectors;
+ curlun->ejected = 0;
LDBG(curlun, "open backing file: %s\n", filename);
rc = 0;
@@ -776,3 +778,12 @@ static ssize_t fsg_store_file(struct device *dev, struct device_attribute *attr,
up_write(filesem);
return (rc < 0 ? rc : count);
}
+
+static ssize_t fsg_show_ejected(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct fsg_lun *curlun = fsg_lun_from_dev(dev);
+
+ return sprintf(buf, "%d\n", curlun->ejected);
+}
+
--
1.7.0.5
--
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