[PATCH v2 16/17] UBI: hide EBA internals

From: Boris Brezillon
Date: Mon Sep 05 2016 - 11:06:34 EST

Create a private ubi_eba_table struct to hide EBA internals and provide
helpers to allocate, destroy, copy and assing an EBA table to a volume.

Now that external EBA users are using helpers to query/modify the EBA
state we can safely change the internal representation, which will be
needed to support the LEB consolidation concept.

Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
---
drivers/mtd/ubi/build.c | 2 +-
drivers/mtd/ubi/eba.c | 166 ++++++++++++++++++++++++++++++++++++++++--------
drivers/mtd/ubi/ubi.h | 8 ++-
drivers/mtd/ubi/vmt.c | 40 +++++-------
4 files changed, 165 insertions(+), 51 deletions(-)

diff --git a/drivers/mtd/ubi/build.c b/drivers/mtd/ubi/build.c
index 0680516bb472..45ea1ddebc5c 100644
--- a/drivers/mtd/ubi/build.c
+++ b/drivers/mtd/ubi/build.c
@@ -574,7 +574,7 @@ void ubi_free_internal_volumes(struct ubi_device *ubi)

for (i = ubi->vtbl_slots;
i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
- kfree(ubi->volumes[i]->eba_tbl);
+ ubi_eba_set_table(ubi->volumes[i], NULL);
kfree(ubi->volumes[i]);
}
}
diff --git a/drivers/mtd/ubi/eba.c b/drivers/mtd/ubi/eba.c
index bdb9bf5d4e3f..ed7f79a3c1b7 100644
--- a/drivers/mtd/ubi/eba.c
+++ b/drivers/mtd/ubi/eba.c
@@ -50,6 +50,30 @@
#define EBA_RESERVED_PEBS 1

/**
+ * struct ubi_eba_entry - structure encoding a single LEB -> PEB association
+ * @pnum: the physical eraseblock number attached to the LEB
+ *
+ * This structure is encoding a LEB -> PEB association. Note that the LEB
+ * number is not stored here, because it is the index used to access the
+ * entries table.
+ */
+struct ubi_eba_entry {
+ int pnum;
+};
+
+/**
+ * struct ubi_eba_table - LEB -> PEB association information
+ * @entries: the LEB to PEB mapping (one entry per LEB).
+ *
+ * This structure is private to the EBA logic and should be kept here.
+ * It is encoding the LEB to PEB association table, and is subject to
+ * changes.
+ */
+struct ubi_eba_table {
+ struct ubi_eba_entry *entries;
+};
+
+/**
* next_sqnum - get next sequence number.
* @ubi: UBI device description object
*
@@ -97,7 +121,94 @@ void ubi_eba_get_ldesc(struct ubi_volume *vol, int lnum,
struct ubi_eba_leb_desc *ldesc)
{
ldesc->lnum = lnum;
- ldesc->pnum = vol->eba_tbl[lnum];
+ ldesc->pnum = vol->eba_tbl->entries[lnum].pnum;
+}
+
+/**
+ * ubi_eba_create_table - allocate a new EBA table and initialize it with all
+ * LEBs unmapped
+ * @vol: volume containing the EBA table to copy
+ * @nentries: number of entries in the table
+ *
+ * Allocate a new EBA table and initialize it with all LEBs unmapped.
+ * Returns a valid pointer if it succeed, an ERR_PTR() otherwise.
+ */
+struct ubi_eba_table *ubi_eba_create_table(struct ubi_volume *vol,
+ int nentries)
+{
+ struct ubi_eba_table *tbl;
+ int err = -ENOMEM;
+ int i;
+
+ tbl = kzalloc(sizeof(*tbl), GFP_KERNEL);
+ if (!tbl)
+ return ERR_PTR(-ENOMEM);
+
+ tbl->entries = kmalloc_array(nentries, sizeof(*tbl->entries),
+ GFP_KERNEL);
+ if (!tbl->entries)
+ goto err;
+
+ for (i = 0; i < nentries; i++)
+ tbl->entries[i].pnum = UBI_LEB_UNMAPPED;
+
+ return tbl;
+
+err:
+ kfree(tbl->entries);
+ kfree(tbl);
+
+ return ERR_PTR(err);
+}
+
+/**
+ * ubi_eba_destroy_table - destroy an EBA table
+ * @tbl: the table to destroy
+ *
+ * Destroy an EBA table.
+ */
+void ubi_eba_destroy_table(struct ubi_eba_table *tbl)
+{
+ if (!tbl)
+ return;
+
+ kfree(tbl->entries);
+ kfree(tbl);
+}
+
+/**
+ * ubi_eba_copy_table - copy the EBA table attached to vol into another table
+ * @vol: volume containing the EBA table to copy
+ * @dst: destination
+ * @nentries: number of entries to copy
+ *
+ * Copy the EBA table stored in vol into the one pointed by dst.
+ */
+void ubi_eba_copy_table(struct ubi_volume *vol, struct ubi_eba_table *dst,
+ int nentries)
+{
+ struct ubi_eba_table *src;
+ int i;
+
+ ubi_assert(dst && vol && vol->eba_tbl);
+
+ src = vol->eba_tbl;
+
+ for (i = 0; i < nentries; i++)
+ dst->entries[i].pnum = src->entries[i].pnum;
+}
+
+/**
+ * ubi_eba_set_table - assign a new EBA table to a volume
+ * @vol: volume containing the EBA table to copy
+ * @tbl: new EBA table
+ *
+ * Assign a new EBA table to the volume and release the old one.
+ */
+void ubi_eba_set_table(struct ubi_volume *vol, struct ubi_eba_table *tbl)
+{
+ ubi_eba_destroy_table(vol->eba_tbl);
+ vol->eba_tbl = tbl;
}

/**
@@ -337,7 +448,7 @@ static void leb_write_unlock(struct ubi_device *ubi, int vol_id, int lnum)
*/
bool ubi_eba_is_mapped(struct ubi_volume *vol, int lnum)
{
- return vol->eba_tbl[lnum] >= 0;
+ return vol->eba_tbl->entries[lnum].pnum >= 0;
}

/**
@@ -362,7 +473,7 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
if (err)
return err;

- pnum = vol->eba_tbl[lnum];
+ pnum = vol->eba_tbl->entries[lnum].pnum;
if (pnum < 0)
/* This logical eraseblock is already unmapped */
goto out_unlock;
@@ -370,7 +481,7 @@ int ubi_eba_unmap_leb(struct ubi_device *ubi, struct ubi_volume *vol,
dbg_eba("erase LEB %d:%d, PEB %d", vol_id, lnum, pnum);

down_read(&ubi->fm_eba_sem);
- vol->eba_tbl[lnum] = UBI_LEB_UNMAPPED;
+ vol->eba_tbl->entries[lnum].pnum = UBI_LEB_UNMAPPED;
up_read(&ubi->fm_eba_sem);
err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 0);

@@ -409,7 +520,7 @@ int ubi_eba_read_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
if (err)
return err;

- pnum = vol->eba_tbl[lnum];
+ pnum = vol->eba_tbl->entries[lnum].pnum;
if (pnum < 0) {
/*
* The logical eraseblock is not mapped, fill the whole buffer
@@ -651,7 +762,7 @@ out_unlock:
mutex_unlock(&ubi->buf_mutex);

if (!err)
- vol->eba_tbl[lnum] = new_pnum;
+ vol->eba_tbl->entries[lnum].pnum = new_pnum;

out_put:
up_read(&ubi->fm_eba_sem);
@@ -740,7 +851,7 @@ static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
goto out_put;
}

- opnum = vol->eba_tbl[lnum];
+ opnum = vol->eba_tbl->entries[lnum].pnum;

dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);
@@ -762,7 +873,7 @@ static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
}
}

- vol->eba_tbl[lnum] = pnum;
+ vol->eba_tbl->entries[lnum].pnum = pnum;

out_put:
up_read(&ubi->fm_eba_sem);
@@ -803,7 +914,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
if (err)
return err;

- pnum = vol->eba_tbl[lnum];
+ pnum = vol->eba_tbl->entries[lnum].pnum;
if (pnum >= 0) {
dbg_eba("write %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);
@@ -921,7 +1032,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
vid_hdr->used_ebs = cpu_to_be32(used_ebs);
vid_hdr->data_crc = cpu_to_be32(crc);

- ubi_assert(vol->eba_tbl[lnum] < 0);
+ ubi_assert(vol->eba_tbl->entries[lnum].pnum < 0);

for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
err = try_write_vid_and_data(vol, lnum, vid_hdr, buf, 0, len);
@@ -1131,9 +1242,9 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
* probably waiting on @ubi->move_mutex. No need to continue the work,
* cancel it.
*/
- if (vol->eba_tbl[lnum] != from) {
+ if (vol->eba_tbl->entries[lnum].pnum != from) {
dbg_wl("LEB %d:%d is no longer mapped to PEB %d, mapped to PEB %d, cancel",
- vol_id, lnum, from, vol->eba_tbl[lnum]);
+ vol_id, lnum, from, vol->eba_tbl->entries[lnum].pnum);
err = MOVE_CANCEL_RACE;
goto out_unlock_leb;
}
@@ -1218,9 +1329,9 @@ int ubi_eba_copy_leb(struct ubi_device *ubi, int from, int to,
cond_resched();
}

- ubi_assert(vol->eba_tbl[lnum] == from);
+ ubi_assert(vol->eba_tbl->entries[lnum].pnum == from);
down_read(&ubi->fm_eba_sem);
- vol->eba_tbl[lnum] = to;
+ vol->eba_tbl->entries[lnum].pnum = to;
up_read(&ubi->fm_eba_sem);

out_unlock_buf:
@@ -1377,7 +1488,7 @@ out_free:
*/
int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
{
- int i, j, err, num_volumes;
+ int i, err, num_volumes;
struct ubi_ainf_volume *av;
struct ubi_volume *vol;
struct ubi_ainf_peb *aeb;
@@ -1393,35 +1504,39 @@ int ubi_eba_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
num_volumes = ubi->vtbl_slots + UBI_INT_VOL_COUNT;

for (i = 0; i < num_volumes; i++) {
+ struct ubi_eba_table *tbl;
+
vol = ubi->volumes[i];
if (!vol)
continue;

cond_resched();

- vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int),
- GFP_KERNEL);
- if (!vol->eba_tbl) {
- err = -ENOMEM;
+ tbl = ubi_eba_create_table(vol, vol->reserved_pebs);
+ if (IS_ERR(tbl)) {
+ err = PTR_ERR(tbl);
goto out_free;
}

- for (j = 0; j < vol->reserved_pebs; j++)
- vol->eba_tbl[j] = UBI_LEB_UNMAPPED;
+ ubi_eba_set_table(vol, tbl);

av = ubi_find_av(ai, idx2vol_id(ubi, i));
if (!av)
continue;

ubi_rb_for_each_entry(rb, aeb, &av->root, u.rb) {
- if (aeb->lnum >= vol->reserved_pebs)
+ if (aeb->lnum >= vol->reserved_pebs) {
/*
* This may happen in case of an unclean reboot
* during re-size.
*/
ubi_move_aeb_to_list(av, aeb, &ai->erase);
- else
- vol->eba_tbl[aeb->lnum] = aeb->pnum;
+ } else {
+ struct ubi_eba_entry *entry;
+
+ entry = &vol->eba_tbl->entries[aeb->lnum];
+ entry->pnum = aeb->pnum;
+ }
}
}

@@ -1458,8 +1573,7 @@ out_free:
for (i = 0; i < num_volumes; i++) {
if (!ubi->volumes[i])
continue;
- kfree(ubi->volumes[i]->eba_tbl);
- ubi->volumes[i]->eba_tbl = NULL;
+ ubi_eba_set_table(ubi->volumes[i], NULL);
}
return err;
}
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index c14b8e71d388..e645be172243 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -359,7 +359,7 @@ struct ubi_volume {
long long upd_received;
void *upd_buf;

- int *eba_tbl;
+ struct ubi_eba_table *eba_tbl;
unsigned int checked:1;
unsigned int corrupted:1;
unsigned int upd_marker:1;
@@ -864,6 +864,12 @@ static inline bool ubi_leb_valid(struct ubi_volume *vol, int lnum)
}

/* eba.c */
+struct ubi_eba_table *ubi_eba_create_table(struct ubi_volume *vol,
+ int nentries);
+void ubi_eba_destroy_table(struct ubi_eba_table *tbl);
+void ubi_eba_copy_table(struct ubi_volume *vol, struct ubi_eba_table *dst,
+ int nentries);
+void ubi_eba_set_table(struct ubi_volume *vol, struct ubi_eba_table *tbl);
void ubi_eba_get_ldesc(struct ubi_volume *vol, int lnum,
struct ubi_eba_leb_desc *ldesc);
bool ubi_eba_is_mapped(struct ubi_volume *vol, int lnum);
diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index 0138f526474a..21b8c5aca2da 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -138,7 +138,7 @@ static void vol_release(struct device *dev)
{
struct ubi_volume *vol = container_of(dev, struct ubi_volume, dev);

- kfree(vol->eba_tbl);
+ ubi_eba_set_table(vol, NULL);
kfree(vol);
}

@@ -158,6 +158,7 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
int i, err, vol_id = req->vol_id, do_free = 1;
struct ubi_volume *vol;
struct ubi_vtbl_record vtbl_rec;
+ struct ubi_eba_table *eba_tbl = NULL;
dev_t dev;

if (ubi->ro_mode)
@@ -241,14 +242,13 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
if (err)
goto out_acc;

- vol->eba_tbl = kmalloc(vol->reserved_pebs * sizeof(int), GFP_KERNEL);
- if (!vol->eba_tbl) {
- err = -ENOMEM;
+ eba_tbl = ubi_eba_create_table(vol, vol->reserved_pebs);
+ if (IS_ERR(eba_tbl)) {
+ err = PTR_ERR(eba_tbl);
goto out_acc;
}

- for (i = 0; i < vol->reserved_pebs; i++)
- vol->eba_tbl[i] = UBI_LEB_UNMAPPED;
+ ubi_eba_set_table(vol, eba_tbl);

if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
vol->used_ebs = vol->reserved_pebs;
@@ -329,7 +329,7 @@ out_cdev:
cdev_del(&vol->cdev);
out_mapping:
if (do_free)
- kfree(vol->eba_tbl);
+ ubi_eba_destroy_table(eba_tbl);
out_acc:
spin_lock(&ubi->volumes_lock);
ubi->rsvd_pebs -= vol->reserved_pebs;
@@ -427,10 +427,11 @@ out_unlock:
*/
int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
{
- int i, err, pebs, *new_mapping;
+ int i, err, pebs;
struct ubi_volume *vol = desc->vol;
struct ubi_device *ubi = vol->ubi;
struct ubi_vtbl_record vtbl_rec;
+ struct ubi_eba_table *new_eba_tbl = NULL;
int vol_id = vol->vol_id;

if (ubi->ro_mode)
@@ -450,12 +451,9 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
if (reserved_pebs == vol->reserved_pebs)
return 0;

- new_mapping = kmalloc(reserved_pebs * sizeof(int), GFP_KERNEL);
- if (!new_mapping)
- return -ENOMEM;
-
- for (i = 0; i < reserved_pebs; i++)
- new_mapping[i] = UBI_LEB_UNMAPPED;
+ new_eba_tbl = ubi_eba_create_table(vol, reserved_pebs);
+ if (IS_ERR(new_eba_tbl))
+ return PTR_ERR(new_eba_tbl);

spin_lock(&ubi->volumes_lock);
if (vol->ref_count > 1) {
@@ -481,10 +479,8 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
}
ubi->avail_pebs -= pebs;
ubi->rsvd_pebs += pebs;
- for (i = 0; i < vol->reserved_pebs; i++)
- new_mapping[i] = vol->eba_tbl[i];
- kfree(vol->eba_tbl);
- vol->eba_tbl = new_mapping;
+ ubi_eba_copy_table(vol, new_eba_tbl, vol->reserved_pebs);
+ ubi_eba_set_table(vol, new_eba_tbl);
spin_unlock(&ubi->volumes_lock);
}

@@ -498,10 +494,8 @@ int ubi_resize_volume(struct ubi_volume_desc *desc, int reserved_pebs)
ubi->rsvd_pebs += pebs;
ubi->avail_pebs -= pebs;
ubi_update_reserved(ubi);
- for (i = 0; i < reserved_pebs; i++)
- new_mapping[i] = vol->eba_tbl[i];
- kfree(vol->eba_tbl);
- vol->eba_tbl = new_mapping;
+ ubi_eba_copy_table(vol, new_eba_tbl, reserved_pebs);
+ ubi_eba_set_table(vol, new_eba_tbl);
spin_unlock(&ubi->volumes_lock);
}

@@ -543,7 +537,7 @@ out_acc:
spin_unlock(&ubi->volumes_lock);
}
out_free:
- kfree(new_mapping);
+ kfree(new_eba_tbl);
return err;
}

--
2.7.4