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author | Dan Ehrenberg <dehrenberg@chromium.org> | 2015-04-03 00:15:10 +0200 |
---|---|---|
committer | Brian Norris <computersforpeace@gmail.com> | 2015-04-06 02:44:01 +0200 |
commit | 727dc612c46b8f3858537ea23805b3e897cf127e (patch) | |
tree | 5bcda420d5f0071fc8d8c8c02dc68166256323e7 /drivers/mtd/mtdpart.c | |
parent | mtd: ts5500_flash: Fix typo in MODULE_DESCRIPTION in ts5500_flash.c (diff) | |
download | linux-727dc612c46b8f3858537ea23805b3e897cf127e.tar.xz linux-727dc612c46b8f3858537ea23805b3e897cf127e.zip |
mtd: part: Create the master device node when partitioned
For many use cases, it helps to have a device node for the entire
MTD device as well as device nodes for the individual partitions.
For example, this allows querying the entire device's properties.
A common idiom is to create an additional partition which spans
over the whole device.
This patch makes a config option, CONFIG_MTD_PARTITIONED_MASTER,
which makes the master partition present even when the device is
partitioned. This isn't turned on by default since it presents
a backwards-incompatible device numbering.
The patch also makes the parent of a partition device be the master,
if the config flag is set, now that the master is a full device.
Signed-off-by: Dan Ehrenberg <dehrenberg@chromium.org>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Diffstat (limited to 'drivers/mtd/mtdpart.c')
-rw-r--r-- | drivers/mtd/mtdpart.c | 18 |
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/mtd/mtdpart.c b/drivers/mtd/mtdpart.c index e779de315ade..a19ec5a4e409 100644 --- a/drivers/mtd/mtdpart.c +++ b/drivers/mtd/mtdpart.c @@ -30,6 +30,7 @@ #include <linux/mtd/mtd.h> #include <linux/mtd/partitions.h> #include <linux/err.h> +#include <linux/kconfig.h> #include "mtdcore.h" @@ -379,10 +380,17 @@ static struct mtd_part *allocate_partition(struct mtd_info *master, slave->mtd.name = name; slave->mtd.owner = master->owner; - /* NOTE: we don't arrange MTDs as a tree; it'd be error-prone - * to have the same data be in two different partitions. + /* NOTE: Historically, we didn't arrange MTDs as a tree out of + * concern for showing the same data in multiple partitions. + * However, it is very useful to have the master node present, + * so the MTD_PARTITIONED_MASTER option allows that. The master + * will have device nodes etc only if this is set, so make the + * parent conditional on that option. Note, this is a way to + * distinguish between the master and the partition in sysfs. */ - slave->mtd.dev.parent = master->dev.parent; + slave->mtd.dev.parent = IS_ENABLED(CONFIG_MTD_PARTITIONED_MASTER) ? + &master->dev : + master->dev.parent; slave->mtd._read = part_read; slave->mtd._write = part_write; @@ -631,8 +639,8 @@ EXPORT_SYMBOL_GPL(mtd_del_partition); * and registers slave MTD objects which are bound to the master according to * the partition definitions. * - * We don't register the master, or expect the caller to have done so, - * for reasons of data integrity. + * For historical reasons, this function's caller only registers the master + * if the MTD_PARTITIONED_MASTER config option is set. */ int add_mtd_partitions(struct mtd_info *master, |