Re: [PATCH 2/5] mmc: block: Refactor mmc_blk_part_switch()

On Mon, Jun 19, 2017 at 9:53 PM, Tomas Winkler [off-list ref] wrote:

On Thu, Jun 15, 2017 at 3:12 PM, Linus Walleij [off-list ref] wrote:

quoted

Instead of passing a struct mmc_blk_data * to mmc_blk_part_switch()
let's pass the actual partition type we want to switch to. This
is necessary in order not to have a block device with a backing
mmc_blk_data and request queue and all for every hardware partition,
such as RPMB.

Signed-off-by: Linus Walleij <redacted>
---
 drivers/mmc/core/block.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index d1b824e65590..94b97f97be1a 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c

@@ -127,7 +127,7 @@ module_param(perdev_minors, int, 0444);
 MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");

 static inline int mmc_blk_part_switch(struct mmc_card *card,
-                                     struct mmc_blk_data *md);
+                                     unsigned int part_type);

Maybe it's time to change this misleading 'part_type' name, this a bit
that represent  the actual  partition to
access and not a type of an partition. Maybe part_to_access will more
reflect the spec wording.
Need to change also  in mmc_blk_data;

That would be a separate patch I think (one patch, one technical step)
what about target_partition or something?

quoted

                /* Always switch back to main area after RPMB access */
                if (md->area_type & MMC_BLK_DATA_AREA_RPMB)
-                       mmc_blk_part_switch(card, dev_get_drvdata(&card->dev));
+                       mmc_blk_part_switch(card, main_md->part_type);

Actually this switch back should be probably done for any partition
which is not user data area.
so this should be
 if (md->area_type != MMC_BLK_DATA_AREA_MAIN)

That is another technical step so it should be a separate patch as
well.

Actually I think this code is broken in several ways, especially if
you do something crazy like access the main partition, both boot
partitions and the RPMB partition at the same time. It will invariably
screw something up.

I am trying to rework this to use the block layer properly, RPMB is
just the first step...

Yours,
Linus Walleij