UBI: make gluebi a separate module
[Artem: re-worked the patch: made it release resources when the
module is unloaded, made it do module referencing, made it really
independent on UBI, tested it with the UBI test-suite which can
be found in ubi-2.6.git/tests/ubi-tests, re-named most of the
funcs/variables to get rid of the "ubi" word and make names
consistent.]
Signed-off-by: Dmitry Pervushin <dpervushin@embeddedalley.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
diff --git a/drivers/mtd/ubi/Kconfig b/drivers/mtd/ubi/Kconfig
index 3f06310..b1cd7a1 100644
--- a/drivers/mtd/ubi/Kconfig
+++ b/drivers/mtd/ubi/Kconfig
@@ -49,15 +49,16 @@
reserved. Leave the default value if unsure.
config MTD_UBI_GLUEBI
- bool "Emulate MTD devices"
+ tristate "MTD devices emulation driver (gluebi)"
default n
depends on MTD_UBI
help
- This option enables MTD devices emulation on top of UBI volumes: for
- each UBI volumes an MTD device is created, and all I/O to this MTD
- device is redirected to the UBI volume. This is handy to make
- MTD-oriented software (like JFFS2) work on top of UBI. Do not enable
- this if no legacy software will be used.
+ This option enables gluebi - an additional driver which emulates MTD
+ devices on top of UBI volumes: for each UBI volumes an MTD device is
+ created, and all I/O to this MTD device is redirected to the UBI
+ volume. This is handy to make MTD-oriented software (like JFFS2)
+ work on top of UBI. Do not enable this unless you use legacy
+ software.
source "drivers/mtd/ubi/Kconfig.debug"
endmenu
diff --git a/drivers/mtd/ubi/Makefile b/drivers/mtd/ubi/Makefile
index dd834e0..c9302a5 100644
--- a/drivers/mtd/ubi/Makefile
+++ b/drivers/mtd/ubi/Makefile
@@ -4,4 +4,4 @@
ubi-y += misc.o
ubi-$(CONFIG_MTD_UBI_DEBUG) += debug.o
-ubi-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
+obj-$(CONFIG_MTD_UBI_GLUEBI) += gluebi.o
diff --git a/drivers/mtd/ubi/gluebi.c b/drivers/mtd/ubi/gluebi.c
index 49cd55a..95aaac0 100644
--- a/drivers/mtd/ubi/gluebi.c
+++ b/drivers/mtd/ubi/gluebi.c
@@ -19,17 +19,71 @@
*/
/*
- * This file includes implementation of fake MTD devices for each UBI volume.
- * This sounds strange, but it is in fact quite useful to make MTD-oriented
- * software (including all the legacy software) to work on top of UBI.
+ * This is a small driver which implements fake MTD devices on top of UBI
+ * volumes. This sounds strange, but it is in fact quite useful to make
+ * MTD-oriented software (including all the legacy software) work on top of
+ * UBI.
*
* Gluebi emulates MTD devices of "MTD_UBIVOLUME" type. Their minimal I/O unit
- * size (mtd->writesize) is equivalent to the UBI minimal I/O unit. The
+ * size (@mtd->writesize) is equivalent to the UBI minimal I/O unit. The
* eraseblock size is equivalent to the logical eraseblock size of the volume.
*/
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/sched.h>
#include <linux/math64.h>
-#include "ubi.h"
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/mtd/ubi.h>
+#include <linux/mtd/mtd.h>
+#include "ubi-media.h"
+
+#define err_msg(fmt, ...) \
+ printk(KERN_DEBUG "gluebi (pid %d): %s: " fmt "\n", \
+ current->pid, __func__, ##__VA_ARGS__)
+
+/**
+ * struct gluebi_device - a gluebi device description data structure.
+ * @mtd: emulated MTD device description object
+ * @refcnt: gluebi device reference count
+ * @desc: UBI volume descriptor
+ * @ubi_num: UBI device number this gluebi device works on
+ * @vol_id: ID of UBI volume this gluebi device works on
+ * @list: link in a list of gluebi devices
+ */
+struct gluebi_device {
+ struct mtd_info mtd;
+ int refcnt;
+ struct ubi_volume_desc *desc;
+ int ubi_num;
+ int vol_id;
+ struct list_head list;
+};
+
+/* List of all gluebi devices */
+static LIST_HEAD(gluebi_devices);
+static DEFINE_MUTEX(devices_mutex);
+
+/**
+ * find_gluebi_nolock - find a gluebi device.
+ * @ubi_num: UBI device number
+ * @vol_id: volume ID
+ *
+ * This function seraches for gluebi device corresponding to UBI device
+ * @ubi_num and UBI volume @vol_id. Returns the gluebi device description
+ * object in case of success and %NULL in case of failure. The caller has to
+ * have the &devices_mutex locked.
+ */
+static struct gluebi_device *find_gluebi_nolock(int ubi_num, int vol_id)
+{
+ struct gluebi_device *gluebi;
+
+ list_for_each_entry(gluebi, &gluebi_devices, list)
+ if (gluebi->ubi_num == ubi_num && gluebi->vol_id == vol_id)
+ return gluebi;
+ return NULL;
+}
/**
* gluebi_get_device - get MTD device reference.
@@ -41,15 +95,18 @@
*/
static int gluebi_get_device(struct mtd_info *mtd)
{
- struct ubi_volume *vol;
+ struct gluebi_device *gluebi;
+ int ubi_mode = UBI_READONLY;
- vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
+ if (!try_module_get(THIS_MODULE))
+ return -ENODEV;
- /*
- * We do not introduce locks for gluebi reference count because the
- * get_device()/put_device() calls are already serialized at MTD.
- */
- if (vol->gluebi_refcount > 0) {
+ if (mtd->flags & MTD_WRITEABLE)
+ ubi_mode = UBI_READWRITE;
+
+ gluebi = container_of(mtd, struct gluebi_device, mtd);
+ mutex_lock(&devices_mutex);
+ if (gluebi->refcnt > 0) {
/*
* The MTD device is already referenced and this is just one
* more reference. MTD allows many users to open the same
@@ -58,7 +115,8 @@
* open the UBI volume again - just increase the reference
* counter and return.
*/
- vol->gluebi_refcount += 1;
+ gluebi->refcnt += 1;
+ mutex_unlock(&devices_mutex);
return 0;
}
@@ -66,11 +124,15 @@
* This is the first reference to this UBI volume via the MTD device
* interface. Open the corresponding volume in read-write mode.
*/
- vol->gluebi_desc = ubi_open_volume(vol->ubi->ubi_num, vol->vol_id,
- UBI_READWRITE);
- if (IS_ERR(vol->gluebi_desc))
- return PTR_ERR(vol->gluebi_desc);
- vol->gluebi_refcount += 1;
+ gluebi->desc = ubi_open_volume(gluebi->ubi_num, gluebi->vol_id,
+ ubi_mode);
+ if (IS_ERR(gluebi->desc)) {
+ mutex_unlock(&devices_mutex);
+ module_put(THIS_MODULE);
+ return PTR_ERR(gluebi->desc);
+ }
+ gluebi->refcnt += 1;
+ mutex_unlock(&devices_mutex);
return 0;
}
@@ -83,13 +145,15 @@
*/
static void gluebi_put_device(struct mtd_info *mtd)
{
- struct ubi_volume *vol;
+ struct gluebi_device *gluebi;
- vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
- vol->gluebi_refcount -= 1;
- ubi_assert(vol->gluebi_refcount >= 0);
- if (vol->gluebi_refcount == 0)
- ubi_close_volume(vol->gluebi_desc);
+ gluebi = container_of(mtd, struct gluebi_device, mtd);
+ mutex_lock(&devices_mutex);
+ gluebi->refcnt -= 1;
+ if (gluebi->refcnt == 0)
+ ubi_close_volume(gluebi->desc);
+ module_put(THIS_MODULE);
+ mutex_unlock(&devices_mutex);
}
/**
@@ -107,16 +171,12 @@
size_t *retlen, unsigned char *buf)
{
int err = 0, lnum, offs, total_read;
- struct ubi_volume *vol;
- struct ubi_device *ubi;
-
- dbg_gen("read %zd bytes from offset %lld", len, from);
+ struct gluebi_device *gluebi;
if (len < 0 || from < 0 || from + len > mtd->size)
return -EINVAL;
- vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
- ubi = vol->ubi;
+ gluebi = container_of(mtd, struct gluebi_device, mtd);
lnum = div_u64_rem(from, mtd->erasesize, &offs);
total_read = len;
@@ -126,7 +186,7 @@
if (to_read > total_read)
to_read = total_read;
- err = ubi_eba_read_leb(ubi, vol, lnum, buf, offs, to_read, 0);
+ err = ubi_read(gluebi->desc, lnum, buf, offs, to_read);
if (err)
break;
@@ -152,21 +212,17 @@
* case of failure.
*/
static int gluebi_write(struct mtd_info *mtd, loff_t to, size_t len,
- size_t *retlen, const u_char *buf)
+ size_t *retlen, const u_char *buf)
{
int err = 0, lnum, offs, total_written;
- struct ubi_volume *vol;
- struct ubi_device *ubi;
-
- dbg_gen("write %zd bytes to offset %lld", len, to);
+ struct gluebi_device *gluebi;
if (len < 0 || to < 0 || len + to > mtd->size)
return -EINVAL;
- vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
- ubi = vol->ubi;
+ gluebi = container_of(mtd, struct gluebi_device, mtd);
- if (ubi->ro_mode)
+ if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
lnum = div_u64_rem(to, mtd->erasesize, &offs);
@@ -181,8 +237,7 @@
if (to_write > total_written)
to_write = total_written;
- err = ubi_eba_write_leb(ubi, vol, lnum, buf, offs, to_write,
- UBI_UNKNOWN);
+ err = ubi_write(gluebi->desc, lnum, buf, offs, to_write);
if (err)
break;
@@ -207,41 +262,36 @@
static int gluebi_erase(struct mtd_info *mtd, struct erase_info *instr)
{
int err, i, lnum, count;
- struct ubi_volume *vol;
- struct ubi_device *ubi;
-
- dbg_gen("erase %llu bytes at offset %llu", (unsigned long long)instr->len,
- (unsigned long long)instr->addr);
+ struct gluebi_device *gluebi;
if (instr->addr < 0 || instr->addr > mtd->size - mtd->erasesize)
return -EINVAL;
-
if (instr->len < 0 || instr->addr + instr->len > mtd->size)
return -EINVAL;
-
if (mtd_mod_by_ws(instr->addr, mtd) || mtd_mod_by_ws(instr->len, mtd))
return -EINVAL;
lnum = mtd_div_by_eb(instr->addr, mtd);
count = mtd_div_by_eb(instr->len, mtd);
- vol = container_of(mtd, struct ubi_volume, gluebi_mtd);
- ubi = vol->ubi;
+ gluebi = container_of(mtd, struct gluebi_device, mtd);
- if (ubi->ro_mode)
+ if (!(mtd->flags & MTD_WRITEABLE))
return -EROFS;
- for (i = 0; i < count; i++) {
- err = ubi_eba_unmap_leb(ubi, vol, lnum + i);
+ for (i = 0; i < count - 1; i++) {
+ err = ubi_leb_unmap(gluebi->desc, lnum + i);
if (err)
goto out_err;
}
-
/*
* MTD erase operations are synchronous, so we have to make sure the
* physical eraseblock is wiped out.
+ *
+ * Thus, perform leb_erase instead of leb_unmap operation - leb_erase
+ * will wait for the end of operations
*/
- err = ubi_wl_flush(ubi);
+ err = ubi_leb_erase(gluebi->desc, lnum + i);
if (err)
goto out_err;
@@ -256,28 +306,38 @@
}
/**
- * ubi_create_gluebi - initialize gluebi for an UBI volume.
- * @ubi: UBI device description object
- * @vol: volume description object
+ * gluebi_create - create a gluebi device for an UBI volume.
+ * @di: UBI device description object
+ * @vi: UBI volume description object
*
- * This function is called when an UBI volume is created in order to create
+ * This function is called when a new UBI volume is created in order to create
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
-int ubi_create_gluebi(struct ubi_device *ubi, struct ubi_volume *vol)
+static int gluebi_create(struct ubi_device_info *di,
+ struct ubi_volume_info *vi)
{
- struct mtd_info *mtd = &vol->gluebi_mtd;
+ struct gluebi_device *gluebi, *g;
+ struct mtd_info *mtd;
- mtd->name = kmemdup(vol->name, vol->name_len + 1, GFP_KERNEL);
- if (!mtd->name)
+ gluebi = kzalloc(sizeof(struct gluebi_device), GFP_KERNEL);
+ if (!gluebi)
return -ENOMEM;
+ mtd = &gluebi->mtd;
+ mtd->name = kmemdup(vi->name, vi->name_len + 1, GFP_KERNEL);
+ if (!mtd->name) {
+ kfree(gluebi);
+ return -ENOMEM;
+ }
+
+ gluebi->vol_id = vi->vol_id;
mtd->type = MTD_UBIVOLUME;
- if (!ubi->ro_mode)
+ if (!di->ro_mode)
mtd->flags = MTD_WRITEABLE;
- mtd->writesize = ubi->min_io_size;
mtd->owner = THIS_MODULE;
- mtd->erasesize = vol->usable_leb_size;
+ mtd->writesize = di->min_io_size;
+ mtd->erasesize = vi->usable_leb_size;
mtd->read = gluebi_read;
mtd->write = gluebi_write;
mtd->erase = gluebi_erase;
@@ -285,60 +345,196 @@
mtd->put_device = gluebi_put_device;
/*
- * In case of dynamic volume, MTD device size is just volume size. In
+ * In case of dynamic a volume, MTD device size is just volume size. In
* case of a static volume the size is equivalent to the amount of data
* bytes.
*/
- if (vol->vol_type == UBI_DYNAMIC_VOLUME)
- mtd->size = (long long)vol->usable_leb_size * vol->reserved_pebs;
+ if (vi->vol_type == UBI_DYNAMIC_VOLUME)
+ mtd->size = (unsigned long long)vi->usable_leb_size * vi->size;
else
- mtd->size = vol->used_bytes;
+ mtd->size = vi->used_bytes;
+
+ /* Just a sanity check - make sure this gluebi device does not exist */
+ mutex_lock(&devices_mutex);
+ g = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
+ if (g)
+ err_msg("gluebi MTD device %d form UBI device %d volume %d "
+ "already exists", g->mtd.index, vi->ubi_num,
+ vi->vol_id);
+ mutex_unlock(&devices_mutex);
if (add_mtd_device(mtd)) {
- ubi_err("cannot not add MTD device");
+ err_msg("cannot add MTD device");
kfree(mtd->name);
+ kfree(gluebi);
return -ENFILE;
}
- dbg_gen("added mtd%d (\"%s\"), size %llu, EB size %u",
- mtd->index, mtd->name, (unsigned long long)mtd->size, mtd->erasesize);
+ mutex_lock(&devices_mutex);
+ list_add_tail(&gluebi->list, &gluebi_devices);
+ mutex_unlock(&devices_mutex);
return 0;
}
/**
- * ubi_destroy_gluebi - close gluebi for an UBI volume.
- * @vol: volume description object
+ * gluebi_remove - remove a gluebi device.
+ * @vi: UBI volume description object
*
- * This function is called when an UBI volume is removed in order to remove
+ * This function is called when an UBI volume is removed and it removes
* corresponding fake MTD device. Returns zero in case of success and a
* negative error code in case of failure.
*/
-int ubi_destroy_gluebi(struct ubi_volume *vol)
+static int gluebi_remove(struct ubi_volume_info *vi)
{
- int err;
- struct mtd_info *mtd = &vol->gluebi_mtd;
+ int err = 0;
+ struct mtd_info *mtd;
+ struct gluebi_device *gluebi;
- dbg_gen("remove mtd%d", mtd->index);
- err = del_mtd_device(mtd);
+ mutex_lock(&devices_mutex);
+ gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
+ if (!gluebi) {
+ err_msg("got remove notification for unknown UBI device %d "
+ "volume %d", vi->ubi_num, vi->vol_id);
+ err = -ENOENT;
+ } else if (gluebi->refcnt)
+ err = -EBUSY;
+ else
+ list_del(&gluebi->list);
+ mutex_unlock(&devices_mutex);
if (err)
return err;
+
+ mtd = &gluebi->mtd;
+ err = del_mtd_device(mtd);
+ if (err) {
+ err_msg("cannot remove fake MTD device %d, UBI device %d, "
+ "volume %d, error %d", mtd->index, gluebi->ubi_num,
+ gluebi->vol_id, err);
+ mutex_lock(&devices_mutex);
+ list_add_tail(&gluebi->list, &gluebi_devices);
+ mutex_unlock(&devices_mutex);
+ return err;
+ }
+
kfree(mtd->name);
+ kfree(gluebi);
return 0;
}
/**
- * ubi_gluebi_updated - UBI volume was updated notifier.
- * @vol: volume description object
+ * gluebi_updated - UBI volume was updated notifier.
+ * @vi: volume info structure
*
- * This function is called every time an UBI volume is updated. This function
- * does nothing if volume @vol is dynamic, and changes MTD device size if the
+ * This function is called every time an UBI volume is updated. It does nothing
+ * if te volume @vol is dynamic, and changes MTD device size if the
* volume is static. This is needed because static volumes cannot be read past
- * data they contain.
+ * data they contain. This function returns zero in case of success and a
+ * negative error code in case of error.
*/
-void ubi_gluebi_updated(struct ubi_volume *vol)
+static int gluebi_updated(struct ubi_volume_info *vi)
{
- struct mtd_info *mtd = &vol->gluebi_mtd;
+ struct gluebi_device *gluebi;
- if (vol->vol_type == UBI_STATIC_VOLUME)
- mtd->size = vol->used_bytes;
+ mutex_lock(&devices_mutex);
+ gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
+ if (!gluebi) {
+ mutex_unlock(&devices_mutex);
+ err_msg("got update notification for unknown UBI device %d "
+ "volume %d", vi->ubi_num, vi->vol_id);
+ return -ENOENT;
+ }
+
+ if (vi->vol_type == UBI_STATIC_VOLUME)
+ gluebi->mtd.size = vi->used_bytes;
+ mutex_unlock(&devices_mutex);
+ return 0;
}
+
+/**
+ * gluebi_resized - UBI volume was re-sized notifier.
+ * @vi: volume info structure
+ *
+ * This function is called every time an UBI volume is re-size. It changes the
+ * corresponding fake MTD device size. This function returns zero in case of
+ * success and a negative error code in case of error.
+ */
+static int gluebi_resized(struct ubi_volume_info *vi)
+{
+ struct gluebi_device *gluebi;
+
+ mutex_lock(&devices_mutex);
+ gluebi = find_gluebi_nolock(vi->ubi_num, vi->vol_id);
+ if (!gluebi) {
+ mutex_unlock(&devices_mutex);
+ err_msg("got update notification for unknown UBI device %d "
+ "volume %d", vi->ubi_num, vi->vol_id);
+ return -ENOENT;
+ }
+ gluebi->mtd.size = vi->used_bytes;
+ mutex_unlock(&devices_mutex);
+ return 0;
+}
+
+/**
+ * gluebi_notify - UBI notification handler.
+ * @nb: registered notifier block
+ * @l: notification type
+ * @ptr: pointer to the &struct ubi_notification object
+ */
+static int gluebi_notify(struct notifier_block *nb, unsigned long l,
+ void *ns_ptr)
+{
+ struct ubi_notification *nt = ns_ptr;
+
+ switch (l) {
+ case UBI_VOLUME_ADDED:
+ gluebi_create(&nt->di, &nt->vi);
+ break;
+ case UBI_VOLUME_REMOVED:
+ gluebi_remove(&nt->vi);
+ break;
+ case UBI_VOLUME_RESIZED:
+ gluebi_resized(&nt->vi);
+ break;
+ case UBI_VOLUME_UPDATED:
+ gluebi_updated(&nt->vi);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block gluebi_notifier = {
+ .notifier_call = gluebi_notify,
+};
+
+static int __init ubi_gluebi_init(void)
+{
+ return ubi_register_volume_notifier(&gluebi_notifier, 0);
+}
+
+static void __exit ubi_gluebi_exit(void)
+{
+ struct gluebi_device *gluebi, *g;
+
+ list_for_each_entry_safe(gluebi, g, &gluebi_devices, list) {
+ int err;
+ struct mtd_info *mtd = &gluebi->mtd;
+
+ err = del_mtd_device(mtd);
+ if (err)
+ err_msg("error %d while removing gluebi MTD device %d, "
+ "UBI device %d, volume %d - ignoring", err,
+ mtd->index, gluebi->ubi_num, gluebi->vol_id);
+ kfree(mtd->name);
+ kfree(gluebi);
+ }
+ ubi_unregister_volume_notifier(&gluebi_notifier);
+}
+
+module_init(ubi_gluebi_init);
+module_exit(ubi_gluebi_exit);
+MODULE_DESCRIPTION("MTD emulation layer over UBI volumes");
+MODULE_AUTHOR("Artem Bityutskiy, Joern Engel");
+MODULE_LICENSE("GPL");