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UBI: simplify recover_peb() code
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recover_peb() is using a convoluted retry/exit path. Add try_recover_peb()
to simplify the retry logic and make sure we have a single exit path
instead of manually releasing the resource 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 7b6b749 commit f036dfe
Showing 1 changed file with 77 additions and 53 deletions.
130 changes: 77 additions & 53 deletions drivers/mtd/ubi/eba.c
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Original file line number Diff line number Diff line change
Expand Up @@ -554,39 +554,37 @@ int ubi_eba_read_leb_sg(struct ubi_device *ubi, struct ubi_volume *vol,
}

/**
* recover_peb - recover from write failure.
* @ubi: UBI device description object
* try_recover_peb - try to recover from write failure.
* @vol: volume description object
* @pnum: the physical eraseblock to recover
* @vol_id: volume ID
* @lnum: logical eraseblock number
* @buf: data which was not written because of the write failure
* @offset: offset of the failed write
* @len: how many bytes should have been written
* @vid: VID header
* @retry: whether the caller should retry in case of failure
*
* This function is called in case of a write failure and moves all good data
* from the potentially bad physical eraseblock to a good physical eraseblock.
* This function also writes the data which was not written due to the failure.
* Returns new physical eraseblock number in case of success, and a negative
* error code in case of failure.
* Returns 0 in case of success, and a negative error code in case of failure.
* In case of failure, the %retry parameter is set to false if this is a fatal
* error (retrying won't help), and true otherwise.
*/
static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
const void *buf, int offset, int len)
static int try_recover_peb(struct ubi_volume *vol, int pnum, int lnum,
const void *buf, int offset, int len,
struct ubi_vid_hdr *vid_hdr, bool *retry)
{
int err, idx = vol_id2idx(ubi, vol_id), new_pnum, data_size, tries = 0;
struct ubi_volume *vol = ubi->volumes[idx];
struct ubi_vid_hdr *vid_hdr;
struct ubi_device *ubi = vol->ubi;
int new_pnum, err, vol_id = vol->vol_id, data_size;
uint32_t crc;

vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
if (!vid_hdr)
return -ENOMEM;
*retry = false;

retry:
new_pnum = ubi_wl_get_peb(ubi);
if (new_pnum < 0) {
ubi_free_vid_hdr(ubi, vid_hdr);
up_read(&ubi->fm_eba_sem);
return new_pnum;
err = new_pnum;
goto out_put;
}

ubi_msg(ubi, "recover PEB %d, move data to PEB %d",
Expand All @@ -596,7 +594,6 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
if (err && err != UBI_IO_BITFLIPS) {
if (err > 0)
err = -EIO;
up_read(&ubi->fm_eba_sem);
goto out_put;
}

Expand All @@ -608,12 +605,12 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
/* Read everything before the area where the write failure happened */
if (offset > 0) {
err = ubi_io_read_data(ubi, ubi->peb_buf, pnum, 0, offset);
if (err && err != UBI_IO_BITFLIPS) {
up_read(&ubi->fm_eba_sem);
if (err && err != UBI_IO_BITFLIPS)
goto out_unlock;
}
}

*retry = true;

memcpy(ubi->peb_buf + offset, buf, len);

data_size = offset + len;
Expand All @@ -623,49 +620,76 @@ static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
vid_hdr->data_size = cpu_to_be32(data_size);
vid_hdr->data_crc = cpu_to_be32(crc);
err = ubi_io_write_vid_hdr(ubi, new_pnum, vid_hdr);
if (err) {
mutex_unlock(&ubi->buf_mutex);
up_read(&ubi->fm_eba_sem);
goto write_error;
}
if (err)
goto out_unlock;

err = ubi_io_write_data(ubi, ubi->peb_buf, new_pnum, 0, data_size);
if (err) {
mutex_unlock(&ubi->buf_mutex);
up_read(&ubi->fm_eba_sem);
goto write_error;
}

out_unlock:
mutex_unlock(&ubi->buf_mutex);
ubi_free_vid_hdr(ubi, vid_hdr);

vol->eba_tbl[lnum] = new_pnum;
if (!err)
vol->eba_tbl[lnum] = new_pnum;

out_put:
up_read(&ubi->fm_eba_sem);
ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);

ubi_msg(ubi, "data was successfully recovered");
return 0;
if (!err) {
ubi_wl_put_peb(ubi, vol_id, lnum, pnum, 1);
ubi_msg(ubi, "data was successfully recovered");
} else if (new_pnum >= 0) {
/*
* Bad luck? This physical eraseblock is bad too? Crud. Let's
* try to get another one.
*/
ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
ubi_warn(ubi, "failed to write to PEB %d", new_pnum);
}

out_unlock:
mutex_unlock(&ubi->buf_mutex);
out_put:
ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
}

write_error:
/*
* Bad luck? This physical eraseblock is bad too? Crud. Let's try to
* get another one.
*/
ubi_warn(ubi, "failed to write to PEB %d", new_pnum);
ubi_wl_put_peb(ubi, vol_id, lnum, new_pnum, 1);
if (++tries > UBI_IO_RETRIES) {
ubi_free_vid_hdr(ubi, vid_hdr);
return err;
/**
* recover_peb - recover from write failure.
* @ubi: UBI device description object
* @pnum: the physical eraseblock to recover
* @vol_id: volume ID
* @lnum: logical eraseblock number
* @buf: data which was not written because of the write failure
* @offset: offset of the failed write
* @len: how many bytes should have been written
*
* This function is called in case of a write failure and moves all good data
* from the potentially bad physical eraseblock to a good physical eraseblock.
* This function also writes the data which was not written due to the failure.
* Returns 0 in case of success, and a negative error code in case of failure.
* This function tries %UBI_IO_RETRIES before giving up.
*/
static int recover_peb(struct ubi_device *ubi, int pnum, int vol_id, int lnum,
const void *buf, int offset, int len)
{
int err, idx = vol_id2idx(ubi, vol_id), tries;
struct ubi_volume *vol = ubi->volumes[idx];
struct ubi_vid_hdr *vid_hdr;

vid_hdr = ubi_zalloc_vid_hdr(ubi, GFP_NOFS);
if (!vid_hdr)
return -ENOMEM;

for (tries = 0; tries <= UBI_IO_RETRIES; tries++) {
bool retry;

err = try_recover_peb(vol, pnum, lnum, buf, offset, len,
vid_hdr, &retry);
if (!err || !retry)
break;

ubi_msg(ubi, "try again");
}
ubi_msg(ubi, "try again");
goto retry;

ubi_free_vid_hdr(ubi, vid_hdr);

return err;
}

/**
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