2 files changed, 74 insertions, 40 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index fa86b946dcd6..32cce029f65c 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -316,6 +316,27 @@ static const char fsg_string_interface[] = "Mass Storage";
 /*-------------------------------------------------------------------------*/
 
 struct fsg_dev;
+struct fsg_common;
+
+/* FSF callback functions */
+struct fsg_operations {
+        /* Callback function to call when thread exits.  If no
+         * callback is set or it returns value lower then zero MSF
+         * will force eject all LUNs it operates on (including those
+         * marked as non-removable or with prevent_medium_removal flag
+         * set). */
+        int (*thread_exits)(struct fsg_common *common);
+
+        /* Called prior to ejection.  Negative return means error,
+         * zero means to continue with ejection, positive means not to
+         * eject. */
+        int (*pre_eject)(struct fsg_common *common,
+                         struct fsg_lun *lun, int num);
+        /* Called after ejection.  Negative return means error, zero
+         * or positive is just a success. */
+        int (*post_eject)(struct fsg_common *common,
+                          struct fsg_lun *lun, int num);
+};
 
 
 /* Data shared by all the FSG instances. */
@@ -368,8 +389,8 @@ struct fsg_common {
         struct completion       thread_notifier;
         struct task_struct      *thread_task;
 
-        /* Callback function to call when thread exits. */
-        int                     (*thread_exits)(struct fsg_common *common);
+        /* Callback functions. */
+        const struct fsg_operations     *ops;
         /* Gadget's private data. */
         void                    *private_data;
 
@@ -393,12 +414,8 @@ struct fsg_config {
         const char              *lun_name_format;
         const char              *thread_name;
 
-        /* Callback function to call when thread exits.  If no
-         * callback is set or it returns value lower then zero MSF
-         * will force eject all LUNs it operates on (including those
-         * marked as non-removable or with prevent_medium_removal flag
-         * set). */
-        int                     (*thread_exits)(struct fsg_common *common);
+        /* Callback functions. */
+        const struct fsg_operations     *ops;
         /* Gadget's private data. */
         void                    *private_data;
 
@@ -434,6 +451,7 @@ static inline int __fsg_is_set(struct fsg_common *common,
         if (common->fsg)
                 return 1;
         ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
+        WARN_ON(1);
         return 0;
 }
 
@@ -1392,43 +1410,55 @@ static int do_start_stop(struct fsg_common *common)
         } 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 */
+        } else 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);
-                        up_write(&common->filesem);
-                        down_read(&common->filesem);
-                }
-        } else {
+        loej  = common->cmnd[4] & 0x02;
+        start = common->cmnd[4] & 0x01;
 
-                /* Our emulation doesn't support mounting; the medium is
-                 * available for use as soon as it is loaded. */
+        /* Our emulation doesn't support mounting; the medium is
+         * available for use as soon as it is loaded. */
+        if (start) {
                 if (!fsg_lun_is_open(curlun)) {
                         curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
                         return -EINVAL;
                 }
+                return 0;
         }
-        return 0;
+
+        /* 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)
+                return 0;
+
+        /* Simulate an unload/eject */
+        if (common->ops && common->ops->pre_eject) {
+                int r = common->ops->pre_eject(common, curlun,
+                                               curlun - common->luns);
+                if (unlikely(r < 0))
+                        return r;
+                else if (r)
+                        return 0;
+        }
+
+        up_read(&common->filesem);
+        down_write(&common->filesem);
+        fsg_lun_close(curlun);
+        up_write(&common->filesem);
+        down_read(&common->filesem);
+
+        return common->ops && common->ops->post_eject
+                ? min(0, common->ops->post_eject(common, curlun,
+                                                 curlun - common->luns))
+                : 0;
 }
 
 
@@ -2607,7 +2637,8 @@ static int fsg_main_thread(void *common_)
         common->thread_task = NULL;
         spin_unlock_irq(&common->lock);
 
-        if (!common->thread_exits || common->thread_exits(common) < 0) {
+        if (!common->ops || !common->ops->thread_exits
+         || common->ops->thread_exits(common) < 0) {
                 struct fsg_lun *curlun = common->luns;
                 unsigned i = common->nluns;
 
@@ -2683,6 +2714,7 @@ static struct fsg_common *fsg_common_init(struct fsg_common *common,
                 common->free_storage_on_release = 0;
         }
 
+        common->ops = cfg->ops;
         common->private_data = cfg->private_data;
 
         common->gadget = gadget;
@@ -2804,7 +2836,6 @@ buffhds_first_it:
 
 
         /* Tell the thread to start working */
-        common->thread_exits = cfg->thread_exits;
         common->thread_task =
                 kthread_create(fsg_main_thread, common,
                                OR(cfg->thread_name, "file-storage"));
@@ -3100,8 +3131,8 @@ fsg_config_from_params(struct fsg_config *cfg,
         cfg->product_name = 0;
         cfg->release = 0xffff;
 
-        cfg->thread_exits = 0;
-        cfg->private_data = 0;
+        cfg->ops = NULL;
+        cfg->private_data = NULL;
 
         /* Finalise */
         cfg->can_stall = params->stall;
diff --git a/drivers/usb/gadget/mass_storage.c b/drivers/usb/gadget/mass_storage.c
index 2b11e2079823..306098f2d924 100644
--- a/drivers/usb/gadget/mass_storage.c
+++ b/drivers/usb/gadget/mass_storage.c
@@ -143,6 +143,9 @@ static int msg_thread_exits(struct fsg_common *common)
 
 static int __init msg_do_config(struct usb_configuration *c)
 {
+        static const struct fsg_operations ops = {
+                .thread_exits = msg_thread_exits,
+        };
         static struct fsg_common common;
 
         struct fsg_common *retp;
@@ -155,7 +158,7 @@ static int __init msg_do_config(struct usb_configuration *c)
         }
 
         fsg_config_from_params(&config, &mod_data);
-        config.thread_exits = msg_thread_exits;
+        config.ops = &ops;
 
         retp = fsg_common_init(&common, c->cdev, &config);
         if (IS_ERR(retp))