usb: gadget: storage_common: pass filesem to fsg_store_cdrom

If cdrom flag is set ro flag is implied. Try setting the ro first, and
only if it succeeds set the cdrom flag.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

3 files changed, 39 insertions, 13 deletions

diff --git a/drivers/usb/gadget/f_mass_storage.c b/drivers/usb/gadget/f_mass_storage.c
index 6e5a6daf1a12..6b5f45144cdf 100644
--- a/drivers/usb/gadget/f_mass_storage.c
+++ b/drivers/usb/gadget/f_mass_storage.c
@@ -3281,7 +3281,12 @@ static ssize_t fsg_lun_opts_cdrom_show(struct fsg_lun_opts *opts, char *page)
 static ssize_t fsg_lun_opts_cdrom_store(struct fsg_lun_opts *opts,
                                        const char *page, size_t len)
 {
-        return fsg_store_cdrom(opts->lun, page, len);
+        struct fsg_opts *fsg_opts;
+
+        fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
+
+        return fsg_store_cdrom(opts->lun, &fsg_opts->common->filesem, page,
+                               len);
 }
 
 static struct fsg_lun_opts_attribute fsg_lun_opts_cdrom =
diff --git a/drivers/usb/gadget/storage_common.c b/drivers/usb/gadget/storage_common.c
index 8bd5f2d838db..ec20a1f50c2d 100644
--- a/drivers/usb/gadget/storage_common.c
+++ b/drivers/usb/gadget/storage_common.c
@@ -371,6 +371,23 @@ ssize_t fsg_show_removable(struct fsg_lun *curlun, char *buf)
 }
 EXPORT_SYMBOL(fsg_show_removable);
 
+/*
+ * The caller must hold fsg->filesem for reading when calling this function.
+ */
+static ssize_t _fsg_store_ro(struct fsg_lun *curlun, bool ro)
+{
+        if (fsg_lun_is_open(curlun)) {
+                LDBG(curlun, "read-only status change prevented\n");
+                return -EBUSY;
+        }
+
+        curlun->ro = ro;
+        curlun->initially_ro = ro;
+        LDBG(curlun, "read-only status set to %d\n", curlun->ro);
+
+        return 0;
+}
+
 ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
                      const char *buf, size_t count)
 {
@@ -386,16 +403,11 @@ ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
          * backing file is closed.
          */
         down_read(filesem);
-        if (fsg_lun_is_open(curlun)) {
-                LDBG(curlun, "read-only status change prevented\n");
-                rc = -EBUSY;
-        } else {
-                curlun->ro = ro;
-                curlun->initially_ro = ro;
-                LDBG(curlun, "read-only status set to %d\n", curlun->ro);
+        rc = _fsg_store_ro(curlun, ro);
+        if (!rc)
                 rc = count;
-        }
         up_read(filesem);
+
         return rc;
 }
 EXPORT_SYMBOL(fsg_store_ro);
@@ -450,7 +462,8 @@ ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 }
 EXPORT_SYMBOL(fsg_store_file);
 
-ssize_t fsg_store_cdrom(struct fsg_lun *curlun, const char *buf, size_t count)
+ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
+                        const char *buf, size_t count)
 {
         bool            cdrom;
         int             ret;
@@ -459,9 +472,16 @@ ssize_t fsg_store_cdrom(struct fsg_lun *curlun, const char *buf, size_t count)
         if (ret)
                 return ret;
 
-        curlun->cdrom = cdrom;
+        down_read(filesem);
+        ret = cdrom ? _fsg_store_ro(curlun, true) : 0;
 
-        return count;
+        if (!ret) {
+                curlun->cdrom = cdrom;
+                ret = count;
+        }
+        up_read(filesem);
+
+        return ret;
 }
 EXPORT_SYMBOL(fsg_store_cdrom);
 
diff --git a/drivers/usb/gadget/storage_common.h b/drivers/usb/gadget/storage_common.h
index e0f7aa69c7ed..c74c2fdbd56e 100644
--- a/drivers/usb/gadget/storage_common.h
+++ b/drivers/usb/gadget/storage_common.h
@@ -221,7 +221,8 @@ ssize_t fsg_store_ro(struct fsg_lun *curlun, struct rw_semaphore *filesem,
 ssize_t fsg_store_nofua(struct fsg_lun *curlun, const char *buf, size_t count);
 ssize_t fsg_store_file(struct fsg_lun *curlun, struct rw_semaphore *filesem,
                        const char *buf, size_t count);
-ssize_t fsg_store_cdrom(struct fsg_lun *curlun, const char *buf, size_t count);
+ssize_t fsg_store_cdrom(struct fsg_lun *curlun, struct rw_semaphore *filesem,
+                        const char *buf, size_t count);
 ssize_t fsg_store_removable(struct fsg_lun *curlun, const char *buf,
                             size_t count);