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UBI: simplify LEB write and atomic LEB change code
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ubi_eba_write_leb(), ubi_eba_write_leb_st() and
ubi_eba_atomic_leb_change() are using a convoluted retry/exit path.
Add the try_write_vid_and_data() function to simplify the retry logic
and make sure we have a single exit path instead of manually releasing
the resources in each error path.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
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Boris Brezillon authored and Richard Weinberger committed Oct 2, 2016
1 parent f036dfe commit 2d78aee
Showing 1 changed file with 115 additions and 170 deletions.
285 changes: 115 additions & 170 deletions drivers/mtd/ubi/eba.c
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Original file line number Diff line number Diff line change
Expand Up @@ -692,6 +692,69 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
return err;
}

/**
* try_write_vid_and_data - try to write VID header and data to a new PEB.
* @vol: volume description object
* @lnum: logical eraseblock number
* @vid_hdr: VID header to write
* @buf: buffer containing the data
* @offset: where to start writing data
* @len: how many bytes should be written
*
* This function tries to write VID header and data belonging to logical
* eraseblock @lnum of volume @vol to a new physical eraseblock. Returns zero
* in case of success and a negative error code in case of failure.
* In case of error, it is possible that something was still written to the
* flash media, but may be some garbage.
*/
static int try_write_vid_and_data(struct ubi_volume *vol, int lnum,
struct ubi_vid_hdr *vid_hdr, const void *buf,
int offset, int len)
{
struct ubi_device *ubi = vol->ubi;
int pnum, opnum, err, vol_id = vol->vol_id;

pnum = ubi_wl_get_peb(ubi);
if (pnum < 0) {
err = pnum;
goto out_put;
}

opnum = vol->eba_tbl[lnum];

dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);

err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
goto out_put;
}

if (len) {
err = ubi_io_write_data(ubi, buf, pnum, offset, len);
if (err) {
ubi_warn(ubi,
"failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);
goto out_put;
}
}

vol->eba_tbl[lnum] = pnum;

out_put:
up_read(&ubi->fm_eba_sem);

if (err && pnum >= 0)
err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
else if (!err && opnum >= 0)
err = ubi_wl_put_peb(ubi, vol_id, lnum, opnum, 0);

return err;
}

/**
* ubi_eba_write_leb - write data to dynamic volume.
* @ubi: UBI device description object
Expand All @@ -705,11 +768,12 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
* @vol. Returns zero in case of success and a negative error code in case
* of failure. In case of error, it is possible that something was still
* written to the flash media, but may be some garbage.
* This function retries %UBI_IO_RETRIES times before giving up.
*/
int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
const void *buf, int offset, int len)
{
int err, pnum, tries = 0, vol_id = vol->vol_id;
int err, pnum, tries, vol_id = vol->vol_id;
struct ubi_vid_hdr *vid_hdr;

if (ubi->ro_mode)
Expand All @@ -730,11 +794,9 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
if (err == -EIO && ubi->bad_allowed)
err = recover_peb(ubi, pnum, vol_id, lnum, buf,
offset, len);
if (err)
ubi_ro_mode(ubi);
}
leb_write_unlock(ubi, vol_id, lnum);
return err;

goto out;
}

/*
Expand All @@ -754,67 +816,31 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
vid_hdr->compat = ubi_get_compat(ubi, vol_id);
vid_hdr->data_pad = cpu_to_be32(vol->data_pad);

retry:
pnum = ubi_wl_get_peb(ubi);
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
up_read(&ubi->fm_eba_sem);
return pnum;
}

dbg_eba("write VID hdr and %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);

err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
}
for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
err = try_write_vid_and_data(vol, lnum, vid_hdr, buf, offset,
len);
if (err != -EIO || !ubi->bad_allowed)
break;

if (len) {
err = ubi_io_write_data(ubi, buf, pnum, offset, len);
if (err) {
ubi_warn(ubi, "failed to write %d bytes at offset %d of LEB %d:%d, PEB %d",
len, offset, vol_id, lnum, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
}
/*
* Fortunately, this is the first write operation to this
* physical eraseblock, so just put it and request a new one.
* We assume that if this physical eraseblock went bad, the
* erase code will handle that.
*/
vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
}

vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_eba_sem);

leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return 0;

write_error:
if (err != -EIO || !ubi->bad_allowed) {
out:
if (err)
ubi_ro_mode(ubi);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}

/*
* Fortunately, this is the first write operation to this physical
* eraseblock, so just put it and request a new one. We assume that if
* this physical eraseblock went bad, the erase code will handle that.
*/
err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
if (err || ++tries > UBI_IO_RETRIES) {
ubi_ro_mode(ubi);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
leb_write_unlock(ubi, vol_id, lnum);

vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
goto retry;
return err;
}

/**
Expand Down Expand Up @@ -842,7 +868,7 @@ int ubi_eba_write_leb(struct ubi_device *ubi, struct ubi_volume *vol, int lnum,
int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
int lnum, const void *buf, int len, int used_ebs)
{
int err, pnum, tries = 0, data_size = len, vol_id = vol->vol_id;
int err, tries, data_size = len, vol_id = vol->vol_id;
struct ubi_vid_hdr *vid_hdr;
uint32_t crc;

Expand All @@ -860,10 +886,8 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
return -ENOMEM;

err = leb_write_lock(ubi, vol_id, lnum);
if (err) {
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
if (err)
goto out;

vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
vid_hdr->vol_id = cpu_to_be32(vol_id);
Expand All @@ -877,66 +901,26 @@ 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);

retry:
pnum = ubi_wl_get_peb(ubi);
if (pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
leb_write_unlock(ubi, vol_id, lnum);
up_read(&ubi->fm_eba_sem);
return pnum;
}

dbg_eba("write VID hdr and %d bytes at LEB %d:%d, PEB %d, used_ebs %d",
len, vol_id, lnum, pnum, used_ebs);
ubi_assert(vol->eba_tbl[lnum] < 0);

err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
}
for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
err = try_write_vid_and_data(vol, lnum, vid_hdr, buf, 0, len);
if (err != -EIO || !ubi->bad_allowed)
break;

err = ubi_io_write_data(ubi, buf, pnum, 0, len);
if (err) {
ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
len, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
}

ubi_assert(vol->eba_tbl[lnum] < 0);
vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_eba_sem);
if (err)
ubi_ro_mode(ubi);

leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return 0;

write_error:
if (err != -EIO || !ubi->bad_allowed) {
/*
* This flash device does not admit of bad eraseblocks or
* something nasty and unexpected happened. Switch to read-only
* mode just in case.
*/
ubi_ro_mode(ubi);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}

err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
if (err || ++tries > UBI_IO_RETRIES) {
ubi_ro_mode(ubi);
leb_write_unlock(ubi, vol_id, lnum);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}
out:
ubi_free_vid_hdr(ubi, vid_hdr);

vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
goto retry;
return err;
}

/*
Expand All @@ -959,7 +943,7 @@ int ubi_eba_write_leb_st(struct ubi_device *ubi, struct ubi_volume *vol,
int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
int lnum, const void *buf, int len)
{
int err, pnum, old_pnum, tries = 0, vol_id = vol->vol_id;
int err, tries, vol_id = vol->vol_id;
struct ubi_vid_hdr *vid_hdr;
uint32_t crc;

Expand Down Expand Up @@ -998,70 +982,31 @@ int ubi_eba_atomic_leb_change(struct ubi_device *ubi, struct ubi_volume *vol,
vid_hdr->copy_flag = 1;
vid_hdr->data_crc = cpu_to_be32(crc);

retry:
pnum = ubi_wl_get_peb(ubi);
if (pnum < 0) {
err = pnum;
up_read(&ubi->fm_eba_sem);
goto out_leb_unlock;
}

dbg_eba("change LEB %d:%d, PEB %d, write VID hdr to PEB %d",
vol_id, lnum, vol->eba_tbl[lnum], pnum);
dbg_eba("change LEB %d:%d", vol_id, lnum);

err = ubi_io_write_vid_hdr(ubi, pnum, vid_hdr);
if (err) {
ubi_warn(ubi, "failed to write VID header to LEB %d:%d, PEB %d",
vol_id, lnum, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
}
for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
err = try_write_vid_and_data(vol, lnum, vid_hdr, buf, 0, len);
if (err != -EIO || !ubi->bad_allowed)
break;

err = ubi_io_write_data(ubi, buf, pnum, 0, len);
if (err) {
ubi_warn(ubi, "failed to write %d bytes of data to PEB %d",
len, pnum);
up_read(&ubi->fm_eba_sem);
goto write_error;
vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
}

old_pnum = vol->eba_tbl[lnum];
vol->eba_tbl[lnum] = pnum;
up_read(&ubi->fm_eba_sem);

if (old_pnum >= 0) {
err = ubi_wl_put_peb(ubi, vol_id, lnum, old_pnum, 0);
if (err)
goto out_leb_unlock;
}
/*
* This flash device does not admit of bad eraseblocks or
* something nasty and unexpected happened. Switch to read-only
* mode just in case.
*/
if (err)
ubi_ro_mode(ubi);

out_leb_unlock:
leb_write_unlock(ubi, vol_id, lnum);

out_mutex:
mutex_unlock(&ubi->alc_mutex);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;

write_error:
if (err != -EIO || !ubi->bad_allowed) {
/*
* This flash device does not admit of bad eraseblocks or
* something nasty and unexpected happened. Switch to read-only
* mode just in case.
*/
ubi_ro_mode(ubi);
goto out_leb_unlock;
}

err = ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
if (err || ++tries > UBI_IO_RETRIES) {
ubi_ro_mode(ubi);
goto out_leb_unlock;
}

vid_hdr->sqnum = cpu_to_be64(ubi_next_sqnum(ubi));
ubi_msg(ubi, "try another PEB");
goto retry;
}

/**
Expand Down

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