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author | 2020-03-31 09:31:59 +0800 | |
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committer | 2020-06-05 10:16:14 +0200 | |
commit | 5788ccf3c84f5587418a80128a3653aa35abf00b (patch) | |
tree | 105543ba94960667a75ade8fdcbbdc5d09e40b65 /drivers/mtd/mtdblock.c | |
parent | mtd: parser: cmdline: Support MTD names containing one or more colons (diff) | |
download | linux-5788ccf3c84f5587418a80128a3653aa35abf00b.tar.gz linux-5788ccf3c84f5587418a80128a3653aa35abf00b.tar.bz2 linux-5788ccf3c84f5587418a80128a3653aa35abf00b.zip |
mtd: clear cache_state to avoid writing to bad blocks repeatedly
The function call process is as follows:
mtd_blktrans_work()
while (1)
do_blktrans_request()
mtdblock_writesect()
do_cached_write()
write_cached_data() /*if cache_state is STATE_DIRTY*/
erase_write()
write_cached_data() returns failure without modifying cache_state
and cache_offset. So when do_cached_write() is called again,
write_cached_data() will be called again to perform erase_write()
on the same cache_offset.
But if this cache_offset points to a bad block, erase_write() will
always return -EIO. Writing to this mtdblk is equivalent to losing
the current data, and repeatedly writing to the bad block.
Repeatedly writing a bad block has no real benefits,
but brings some negative effects:
1 Lost subsequent data
2 Loss of flash device life
3 erase_write() bad blocks are very time-consuming. For example:
the function do_erase_oneblock() in chips/cfi_cmdset_0020.c or
chips/cfi_cmdset_0002.c may take more than 20 seconds to return
Therefore, when erase_write() returns -EIO in write_cached_data(),
clear cache_state to avoid writing to bad blocks repeatedly.
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'drivers/mtd/mtdblock.c')
-rw-r--r-- | drivers/mtd/mtdblock.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c index 078e0f67377d..32e52d83b961 100644 --- a/drivers/mtd/mtdblock.c +++ b/drivers/mtd/mtdblock.c @@ -89,8 +89,6 @@ static int write_cached_data (struct mtdblk_dev *mtdblk) ret = erase_write (mtd, mtdblk->cache_offset, mtdblk->cache_size, mtdblk->cache_data); - if (ret) - return ret; /* * Here we could arguably set the cache state to STATE_CLEAN. @@ -98,9 +96,14 @@ static int write_cached_data (struct mtdblk_dev *mtdblk) * be notified if this content is altered on the flash by other * means. Let's declare it empty and leave buffering tasks to * the buffer cache instead. + * + * If this cache_offset points to a bad block, data cannot be + * written to the device. Clear cache_state to avoid writing to + * bad blocks repeatedly. */ - mtdblk->cache_state = STATE_EMPTY; - return 0; + if (ret == 0 || ret == -EIO) + mtdblk->cache_state = STATE_EMPTY; + return ret; } |