On 11/03/2016 12:39 PM, Sandeep Jain wrote: > Dear Maintainers, > Requesting for your attention for patch review/merge. > > Thanks & Regards, > Sandeep Jain > > On Thu, Aug 04, 2016 at 07:46:33PM +0530, Sandeep Jain wrote: >> From: Vladimir Zapolskiy <[email protected]> >> >> The change controls module users counter, which prevents to get >> accidental oops on module unload while it is in use by mtd subsystem: >> >> % dd if=/dev/mtd0 of=/dev/null & >> % rmmod m25p80 >> >> Removing MTD device #0 (spi32766.0) with use count 1 >> Unable to handle kernel paging request at virtual address 7f4fb7f8 >> pgd = bd094000 >> [7f4fb7f8] *pgd=4cb66811, *pte=00000000, *ppte=00000000 >> Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM >> >> Signed-off-by: Vladimir Zapolskiy <[email protected]> >> Signed-off-by: Sandeep Jain <[email protected]> >> --- >> drivers/mtd/devices/m25p80.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c >> index 9cf7fcd..2eb1530 100644 >> --- a/drivers/mtd/devices/m25p80.c >> +++ b/drivers/mtd/devices/m25p80.c >> @@ -185,6 +185,19 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t >> from, size_t len, >> return ret; >> } >> >> +static void m25p80_put(struct mtd_info *mtd) >> +{ >> + module_put(THIS_MODULE); >> +} >> + >> +static int m25p80_get(struct mtd_info *mtd) >> +{ >> + if (!try_module_get(THIS_MODULE)) >> + return -ENODEV; >> + >> + return 0; >> +} >> + >> /* >> * board specific setup should have ensured the SPI clock used here >> * matches what the READ command supports, at least until this driver >> @@ -212,6 +225,8 @@ static int m25p_probe(struct spi_device *spi) >> nor->write = m25p80_write; >> nor->write_reg = m25p80_write_reg; >> nor->read_reg = m25p80_read_reg; >> + nor->mtd._put_device = m25p80_put; >> + nor->mtd._get_device = m25p80_get; >> >> nor->dev = &spi->dev; >> spi_nor_set_flash_node(nor, spi->dev.of_node);
This makes me ponder how many other drivers suffer from this issue and whether you shouldn't fix this in the core code instead. What do you think? -- Best regards, Marek Vasut
