If partition parsers need to clean up their resources, we shouldn't
assume that all memory will fit in a single kmalloc() that the caller
can kfree(). We should allow the parser to provide a proper cleanup
routine.

Note that this means we need to keep a hold on the parser's module for a
bit longer, and release it later with mtd_part_parser_put().

Alongside this, define a default callback that we'll automatically use
if the parser doesn't provide one, so we can still retain the old
behavior.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

For some of the core partitioning code, it helps to keep info about the
parsed partition (and who parsed them) together in one place.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The use of kmemdup() complicates the error handling a bit. We don't
actually need to allocate new memory, since this reference is treated as
const, and it is copied into new memory by the partition registration
code anyway. So remove it.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

We're going to reuse put_partition_parser(), so let's fix up the prefix
naming a bit, to hopefully be more consistent. Also make convert to a
true C function instead of a macro.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

We can guard against reorganization of struct mtd_part by using
container_of(). We can also make sure we're using the right pointer
types by making this a static inline function instead of a macro.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

This can help eliminate some boilerplate by generating the module_init()
and module_exit() functions, and by automatically assigning the module
owner.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>

It's easier to guarantee we've cleared out all unused fields with
memset() than by manually initializing each field.

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Due to wrong assumption in ofpart ofpart fails on Exynos on SPI chips
with no partitions because the subnode containing controller data
confuses the ofpart parser.

Thus compiling in ofpart support automatically fails probing any SPI NOR
flash without partitions on Exynos.

Compiling in a partitioning scheme should not cause probe of otherwise
valid device to fail.

Instead, let's do the following:
 * try parsers until one succeeds
 * if no parser succeeds, report the first error we saw
 * even in the failure case, allow MTD to probe, with fallback
   partitions or no partitions at all -- the master device will still be
   registered

Issue report and comments initially by Michal Suchanek.

Reported-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

The probe of a mtd device can fail when a partition parser returns
error. The failure due to partition parsing can be quite mysterious when
multiple partitioning schemes are compiled in and any of them can fail
the probe.

Add debug prints which show what parsers were tried and what they
returned.

Signed-off-by: Michal Suchanek <hramrach@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

If we fail to allocate a partition structure in the middle of the partition
creation process, the already allocated partitions are never removed, which
means they are still present in the partition list and their resources are
never freed.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: stable@vger.kernel.org
Signed-off-by: Brian Norris <computersforpeace@gmail.com>