Skip to content

Commit

Permalink
UBI: prepare attach and detach functions
Browse files Browse the repository at this point in the history 
Prepare the attach and detach functions to by used outside of
module initialization:

* detach function checks reference count before detaching
* it kills the background thread as well

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
  • Loading branch information
Artem Bityutskiy authored and Artem Bityutskiy committed Dec 26, 2007
1 parent e73f445 commit cdfa788
Show file tree
Hide file tree
Showing 3 changed files with 169 additions and 87 deletions.
235 changes: 162 additions & 73 deletions drivers/mtd/ubi/build.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@
#include <linux/stat.h>
#include <linux/miscdevice.h>
#include <linux/log2.h>
#include <linux/kthread.h>
#include "ubi.h"

/* Maximum length of the 'mtd=' parameter */
Expand Down Expand Up @@ -83,6 +84,9 @@ static struct miscdevice ubi_ctrl_cdev = {
/* All UBI devices in system */
static struct ubi_device *ubi_devices[UBI_MAX_DEVICES];

/* Serializes UBI devices creations and removals */
DEFINE_MUTEX(ubi_devices_mutex);

/* Protects @ubi_devices and @ubi->ref_count */
static DEFINE_SPINLOCK(ubi_devices_lock);

Expand Down Expand Up @@ -192,7 +196,7 @@ struct ubi_device *ubi_get_by_major(int major)
* @major: major number
*
* This function searches UBI device number object by its major number. If UBI
* device was not found, this function returns -ENODEV, othewise the UBI device
* device was not found, this function returns -ENODEV, otherwise the UBI device
* number is returned.
*/
int ubi_major2num(int major)
Expand Down Expand Up @@ -485,9 +489,9 @@ static int attach_by_scanning(struct ubi_device *ubi)
* assumed:
* o EC header is always at offset zero - this cannot be changed;
* o VID header starts just after the EC header at the closest address
* aligned to @io->@hdrs_min_io_size;
* aligned to @io->hdrs_min_io_size;
* o data starts just after the VID header at the closest address aligned to
* @io->@min_io_size
* @io->min_io_size
*
* This function returns zero in case of success and a negative error code in
* case of failure.
Expand All @@ -508,6 +512,9 @@ static int io_init(struct ubi_device *ubi)
return -EINVAL;
}

if (ubi->vid_hdr_offset < 0 || ubi->leb_start < ubi->vid_hdr_offset)
return -EINVAL;

/*
* Note, in this implementation we support MTD devices with 0x7FFFFFFF
* physical eraseblocks maximum.
Expand Down Expand Up @@ -616,84 +623,62 @@ static int io_init(struct ubi_device *ubi)
}

/**
* attach_mtd_dev - attach an MTD device.
* @mtd_dev: MTD device name or number string
* ubi_attach_mtd_dev - attach an MTD device.
* @mtd_dev: MTD device description object
* @vid_hdr_offset: VID header offset
* @data_offset: data 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 zero in case of success and a negative error code in case of
* failure.
* number. Returns new UBI device's 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.
*/
static int attach_mtd_dev(const char *mtd_dev, int vid_hdr_offset,
int data_offset)
int ubi_attach_mtd_dev(struct mtd_info *mtd, int vid_hdr_offset,
int data_offset)
{
struct ubi_device *ubi;
struct mtd_info *mtd;
int i, err;

mtd = get_mtd_device_nm(mtd_dev);
if (IS_ERR(mtd)) {
int mtd_num;
char *endp;

if (PTR_ERR(mtd) != -ENODEV)
return PTR_ERR(mtd);

/*
* Probably this is not MTD device name but MTD device number -
* check this out.
*/
mtd_num = simple_strtoul(mtd_dev, &endp, 0);
if (*endp != '\0' || mtd_dev == endp) {
ubi_err("incorrect MTD device: \"%s\"", mtd_dev);
return -ENODEV;
}

mtd = get_mtd_device(NULL, mtd_num);
if (IS_ERR(mtd))
return PTR_ERR(mtd);
}

/* Check if we already have the same MTD device attached */
/*
* Check if we already have the same MTD device attached.
*
* 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++)
ubi = ubi_devices[i];
if (ubi && ubi->mtd->index == mtd->index) {
if (ubi && mtd->index == ubi->mtd->index) {
ubi_err("mtd%d is already attached to ubi%d",
mtd->index, i);
err = -EINVAL;
goto out_mtd;
return -EINVAL;
}

ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
if (!ubi) {
err = -ENOMEM;
goto out_mtd;
}

ubi->mtd = mtd;

/* Search for an empty slot in the @ubi_devices array */
ubi->ubi_num = -1;
for (i = 0; i < UBI_MAX_DEVICES; i++)
if (!ubi_devices[i]) {
ubi->ubi_num = i;
if (!ubi_devices[i])
break;
}

if (ubi->ubi_num == -1) {
if (i == UBI_MAX_DEVICES) {
ubi_err("only %d UBI devices may be created", UBI_MAX_DEVICES);
err = -ENFILE;
goto out_free;
return -ENFILE;
}

dbg_msg("attaching mtd%d to ubi%d: VID header offset %d data offset %d",
ubi->mtd->index, ubi->ubi_num, vid_hdr_offset, data_offset);
ubi = kzalloc(sizeof(struct ubi_device), GFP_KERNEL);
if (!ubi)
return -ENOMEM;

ubi->mtd = mtd;
ubi->ubi_num = i;
ubi->vid_hdr_offset = vid_hdr_offset;
ubi->leb_start = data_offset;

dbg_msg("attaching mtd%d to ubi%d: VID header offset %d data offset %d",
mtd->index, ubi->ubi_num, vid_hdr_offset, data_offset);

err = io_init(ubi);
if (err)
goto out_free;
Expand Down Expand Up @@ -724,8 +709,16 @@ static int attach_mtd_dev(const char *mtd_dev, int vid_hdr_offset,
if (err)
goto out_detach;

ubi_msg("attached mtd%d to ubi%d", ubi->mtd->index, ubi->ubi_num);
ubi_msg("MTD device name: \"%s\"", ubi->mtd->name);
ubi->bgt_thread = kthread_create(ubi_thread, ubi, ubi->bgt_name);
if (IS_ERR(ubi->bgt_thread)) {
err = PTR_ERR(ubi->bgt_thread);
ubi_err("cannot spawn \"%s\", error %d", ubi->bgt_name,
err);
goto out_uif;
}

ubi_msg("attached mtd%d to ubi%d", mtd->index, ubi->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)",
ubi->peb_size, ubi->peb_size >> 10);
Expand Down Expand Up @@ -754,8 +747,10 @@ static int attach_mtd_dev(const char *mtd_dev, int vid_hdr_offset,
}

ubi_devices[ubi->ubi_num] = ubi;
return 0;
return ubi->ubi_num;

out_uif:
uif_close(ubi);
out_detach:
ubi_eba_close(ubi);
ubi_wl_close(ubi);
Expand All @@ -767,21 +762,57 @@ static int attach_mtd_dev(const char *mtd_dev, int vid_hdr_offset,
vfree(ubi->dbg_peb_buf);
#endif
kfree(ubi);
out_mtd:
put_mtd_device(mtd);
return err;
}

/**
* detach_mtd_dev - detach an MTD device.
* @ubi: UBI device description object
* ubi_detach_mtd_dev - detach an MTD device.
* @ubi_num: UBI device number to detach from
* @anyway: detach MTD even if device reference count is not zero
*
* This function destroys an UBI device number @ubi_num and detaches the
* underlying MTD device. Returns zero in case of success and %-EBUSY if the
* UBI device is busy and cannot be destroyed, and %-EINVAL if it does not
* exist.
*
* Note, the invocations of this function has to be serialized by the
* @ubi_devices_mutex.
*/
static void detach_mtd_dev(struct ubi_device *ubi)
int ubi_detach_mtd_dev(int ubi_num, int anyway)
{
int ubi_num = ubi->ubi_num, mtd_num = ubi->mtd->index;
struct ubi_device *ubi;

if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES)
return -EINVAL;

spin_lock(&ubi_devices_lock);
ubi = ubi_devices[ubi_num];
if (!ubi) {
spin_lock(&ubi_devices_lock);
return -EINVAL;
}

if (ubi->ref_count) {
if (!anyway) {
spin_lock(&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;
spin_unlock(&ubi_devices_lock);

dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi->ubi_num);

/*
* Before freeing anything, we have to stop the background thread to
* prevent it from doing anything on this device while we are freeing.
*/
if (ubi->bgt_thread)
kthread_stop(ubi->bgt_thread);

dbg_msg("detaching mtd%d from ubi%d", ubi->mtd->index, ubi_num);
ubi_assert(ubi->ref_count == 0);
uif_close(ubi);
ubi_eba_close(ubi);
ubi_wl_close(ubi);
Expand All @@ -792,9 +823,9 @@ static void detach_mtd_dev(struct ubi_device *ubi)
#ifdef CONFIG_MTD_UBI_DEBUG
vfree(ubi->dbg_peb_buf);
#endif
kfree(ubi_devices[ubi_num]);
ubi_devices[ubi_num] = NULL;
ubi_msg("mtd%d is detached from ubi%d", mtd_num, ubi_num);
ubi_msg("mtd%d is detached from ubi%d", ubi->mtd->index, ubi->ubi_num);
kfree(ubi);
return 0;
}

/**
Expand All @@ -811,6 +842,46 @@ static void ltree_entry_ctor(struct kmem_cache *cache, void *obj)
init_rwsem(&le->mutex);
}

/**
* find_mtd_device - open an MTD device by its name or number.
* @mtd_dev: name or number of the device
*
* This function tries to open and MTD device with name @mtd_dev, and if it
* fails, then it tries to interpret the @mtd_dev string as an ASCII-coded
* integer and open an MTD device with this number. Returns MTD device
* description object in case of success and a negative error code in case of
* failure.
*/
static struct mtd_info * __init open_mtd_device(const char *mtd_dev)
{
struct mtd_info *mtd;

mtd = get_mtd_device_nm(mtd_dev);
if (IS_ERR(mtd)) {
int mtd_num;
char *endp;

if (PTR_ERR(mtd) != -ENODEV)
return mtd;

/*
* Probably this is not MTD device name but MTD device number -
* check this out.
*/
mtd_num = simple_strtoul(mtd_dev, &endp, 0);
if (*endp != '\0' || mtd_dev == endp) {
ubi_err("incorrect MTD device: \"%s\"", mtd_dev);
return ERR_PTR(-ENODEV);
}

mtd = get_mtd_device(NULL, mtd_num);
if (IS_ERR(mtd))
return mtd;
}

return mtd;
}

static int __init ubi_init(void)
{
int err, i, k;
Expand Down Expand Up @@ -860,10 +931,21 @@ static int __init ubi_init(void)
/* Attach MTD devices */
for (i = 0; i < mtd_devs; i++) {
struct mtd_dev_param *p = &mtd_dev_param[i];
struct mtd_info *mtd;

cond_resched();
err = attach_mtd_dev(p->name, p->vid_hdr_offs, p->data_offs);
if (err) {

mtd = open_mtd_device(p->name);
if (IS_ERR(mtd)) {
err = PTR_ERR(mtd);
goto out_detach;
}

mutex_lock(&ubi_devices_mutex);
err = ubi_attach_mtd_dev(mtd, p->vid_hdr_offs, p->data_offs);
mutex_unlock(&ubi_devices_mutex);
if (err < 0) {
put_mtd_device(mtd);
printk(KERN_ERR "UBI error: cannot attach %s\n",
p->name);
goto out_detach;
Expand All @@ -874,7 +956,11 @@ static int __init ubi_init(void)

out_detach:
for (k = 0; k < i; k++)
detach_mtd_dev(ubi_devices[k]);
if (ubi_devices[k]) {
mutex_lock(&ubi_devices_mutex);
ubi_detach_mtd_dev(ubi_devices[k]->ubi_num, 1);
mutex_unlock(&ubi_devices_mutex);
}
kmem_cache_destroy(ubi_wl_entry_slab);
out_ltree:
kmem_cache_destroy(ubi_ltree_slab);
Expand All @@ -895,8 +981,11 @@ static void __exit ubi_exit(void)
int i;

for (i = 0; i < UBI_MAX_DEVICES; i++)
if (ubi_devices[i])
detach_mtd_dev(ubi_devices[i]);
if (ubi_devices[i]) {
mutex_lock(&ubi_devices_mutex);
ubi_detach_mtd_dev(ubi_devices[i]->ubi_num, 1);
mutex_unlock(&ubi_devices_mutex);
}
kmem_cache_destroy(ubi_wl_entry_slab);
kmem_cache_destroy(ubi_ltree_slab);
misc_deregister(&ubi_ctrl_cdev);
Expand Down
5 changes: 5 additions & 0 deletions drivers/mtd/ubi/ubi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -404,6 +404,7 @@ extern struct file_operations ubi_ctrl_cdev_operations;
extern struct file_operations ubi_cdev_operations;
extern struct file_operations ubi_vol_cdev_operations;
extern struct class *ubi_class;
extern struct mutex ubi_devices_mutex;

/* vtbl.c */
int ubi_change_vtbl_record(struct ubi_device *ubi, int idx,
Expand Down Expand Up @@ -462,6 +463,7 @@ int ubi_wl_flush(struct ubi_device *ubi);
int ubi_wl_scrub_peb(struct ubi_device *ubi, int pnum);
int ubi_wl_init_scan(struct ubi_device *ubi, struct ubi_scan_info *si);
void ubi_wl_close(struct ubi_device *ubi);
int ubi_thread(void *u);

/* io.c */
int ubi_io_read(const struct ubi_device *ubi, void *buf, int pnum, int offset,
Expand All @@ -481,6 +483,9 @@ int ubi_io_write_vid_hdr(struct ubi_device *ubi, int pnum,
struct ubi_vid_hdr *vid_hdr);

/* build.c */
int ubi_attach_mtd_dev(struct mtd_info *mtd, int vid_hdr_offset,
int data_offset);
int ubi_detach_mtd_dev(int ubi_num, int anyway);
struct ubi_device *ubi_get_device(int ubi_num);
void ubi_put_device(struct ubi_device *ubi);
struct ubi_device *ubi_get_by_major(int major);
Expand Down
Loading

0 comments on commit cdfa788

Please sign in to comment.