UBI: handle attach ioctl
Actually implement the MTD device attach/detach handlers.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 403c10a..70c0b9a 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -621,18 +621,19 @@
/**
* ubi_attach_mtd_dev - attach an MTD device.
* @mtd_dev: MTD device description object
+ * @ubi_num: number to assign to the new UBI device
* @vid_hdr_offset: VID header offset
*
- * This function attaches an MTD device to UBI. It first treats @mtd_dev as the
- * MTD device name, and tries to open it by this name. If it is unable to open,
- * it tries to convert @mtd_dev to an integer and open the MTD device by its
- * number. Returns new UBI device's number in case of success and a negative
- * error code in case of failure.
+ * This function attaches MTD device @mtd_dev to UBI and assign @ubi_num number
+ * to the newly created UBI device, unless @ubi_num is %UBI_DEV_NUM_AUTO, in
+ * which case this function finds a vacant device nubert and assings it
+ * automatically. Returns the new UBI device number in case of success and a
+ * negative error code in case of failure.
*
* Note, the invocations of this function has to be serialized by the
* @ubi_devices_mutex.
*/
-int ubi_attach_mtd_dev(struct mtd_info *mtd, int vid_hdr_offset)
+int ubi_attach_mtd_dev(struct mtd_info *mtd, int ubi_num, int vid_hdr_offset)
{
struct ubi_device *ubi;
int i, err;
@@ -643,22 +644,47 @@
* Note, this function assumes that UBI devices creations and deletions
* are serialized, so it does not take the &ubi_devices_lock.
*/
- for (i = 0; i < UBI_MAX_DEVICES; i++)
+ for (i = 0; i < UBI_MAX_DEVICES; i++) {
ubi = ubi_devices[i];
if (ubi && mtd->index == ubi->mtd->index) {
- ubi_err("mtd%d is already attached to ubi%d",
+ dbg_err("mtd%d is already attached to ubi%d",
mtd->index, i);
- return -EINVAL;
+ return -EEXIST;
}
+ }
- /* Search for an empty slot in the @ubi_devices array */
- for (i = 0; i < UBI_MAX_DEVICES; i++)
- if (!ubi_devices[i])
- break;
+ /*
+ * Make sure this MTD device is not emulated on top of an UBI volume
+ * already. Well, generally this recursion works fine, but there are
+ * different problems like the UBI module takes a reference to itself
+ * by attaching (and thus, opening) the emulated MTD device. This
+ * results in inability to unload the module. And in general it makes
+ * no sense to attach emulated MTD devices, so we prohibit this.
+ */
+ if (mtd->type == MTD_UBIVOLUME) {
+ ubi_err("refuse attaching mtd%d - it is already emulated on "
+ "top of UBI", mtd->index);
+ return -EINVAL;
+ }
- if (i == UBI_MAX_DEVICES) {
- ubi_err("only %d UBI devices may be created", UBI_MAX_DEVICES);
- return -ENFILE;
+ if (ubi_num == UBI_DEV_NUM_AUTO) {
+ /* Search for an empty slot in the @ubi_devices array */
+ for (ubi_num = 0; ubi_num < UBI_MAX_DEVICES; ubi_num++)
+ if (!ubi_devices[ubi_num])
+ break;
+ if (ubi_num == UBI_MAX_DEVICES) {
+ dbg_err("only %d UBI devices may be created", UBI_MAX_DEVICES);
+ return -ENFILE;
+ }
+ } else {
+ if (ubi_num >= UBI_MAX_DEVICES)
+ return -EINVAL;
+
+ /* Make sure ubi_num is not busy */
+ if (ubi_devices[ubi_num]) {
+ dbg_err("ubi%d already exists", ubi_num);
+ return -EEXIST;
+ }
}
ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
@@ -666,11 +692,11 @@
return -ENOMEM;
ubi->mtd = mtd;
- ubi->ubi_num = i;
+ ubi->ubi_num = ubi_num;
ubi->vid_hdr_offset = vid_hdr_offset;
dbg_msg("attaching mtd%d to ubi%d: VID header offset %d",
- mtd->index, ubi->ubi_num, vid_hdr_offset);
+ mtd->index, ubi_num, vid_hdr_offset);
err = io_init(ubi);
if (err)
@@ -710,7 +736,7 @@
goto out_uif;
}
- ubi_msg("attached mtd%d to ubi%d", mtd->index, ubi->ubi_num);
+ ubi_msg("attached mtd%d to ubi%d", mtd->index, ubi_num);
ubi_msg("MTD device name: \"%s\"", mtd->name);
ubi_msg("MTD device size: %llu MiB", ubi->flash_size >> 20);
ubi_msg("physical eraseblock size: %d bytes (%d KiB)",
@@ -739,8 +765,8 @@
wake_up_process(ubi->bgt_thread);
}
- ubi_devices[ubi->ubi_num] = ubi;
- return ubi->ubi_num;
+ ubi_devices[ubi_num] = ubi;
+ return ubi_num;
out_uif:
uif_close(ubi);
@@ -781,23 +807,24 @@
spin_lock(&ubi_devices_lock);
ubi = ubi_devices[ubi_num];
if (!ubi) {
- spin_lock(&ubi_devices_lock);
+ spin_unlock(&ubi_devices_lock);
return -EINVAL;
}
if (ubi->ref_count) {
if (!anyway) {
- spin_lock(&ubi_devices_lock);
+ spin_unlock(&ubi_devices_lock);
return -EBUSY;
}
/* This may only happen if there is a bug */
ubi_err("%s reference count %d, destroy anyway",
ubi->ubi_name, ubi->ref_count);
}
- ubi_devices[ubi->ubi_num] = NULL;
+ ubi_devices[ubi_num] = NULL;
spin_unlock(&ubi_devices_lock);
- dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi->ubi_num);
+ ubi_assert(ubi_num == ubi->ubi_num);
+ dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
/*
* Before freeing anything, we have to stop the background thread to
@@ -935,7 +962,8 @@
}
mutex_lock(&ubi_devices_mutex);
- err = ubi_attach_mtd_dev(mtd, p->vid_hdr_offs);
+ err = ubi_attach_mtd_dev(mtd, UBI_DEV_NUM_AUTO,
+ p->vid_hdr_offs);
mutex_unlock(&ubi_devices_mutex);
if (err < 0) {
put_mtd_device(mtd);
