4.4-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 382c55f88ffeb218c446bf0c46d0fc25d2795fe2 ]
It is quite common for Android devices to utilize more then 8 partitions on internal eMMC storage.
The vanilla kernel can support this via CONFIG_MMC_BLOCK_MINORS, however that solution caps the system to 256 minors total, which limits the number of mmc cards the system can support.
This patch, which has been carried for quite awhile in the AOSP common tree, provides an alternative solution that doesn't seem to limit the total card count. So I wanted to submit it for consideration upstream.
This patch sets the GENHD_FL_EXT_DEVT flag, which will allocate minor number in major 259 for partitions past disk->minors.
It also removes the use of disk_devt to determine devidx from md->disk. md->disk->first_minor is always initialized from devidx and can always be used to recover it.
Cc: Ulf Hansson ulf.hansson@linaro.org Cc: Adrian Hunter adrian.hunter@intel.com Cc: Ben Hutchings ben@decadent.org.uk Cc: Chuanxiao Dong chuanxiao.dong@intel.com Cc: Shawn Lin shawn.lin@rock-chips.com Cc: Austin S Hemmelgarn ahferroin7@gmail.com Cc: Arnd Bergmann arnd@arndb.de Cc: Android Kernel Team kernel-team@android.com Cc: linux-mmc@vger.kernel.org Signed-off-by: Colin Cross ccross@android.com [jstultz: Added context to commit message] Signed-off-by: John Stultz john.stultz@linaro.org Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/mmc/card/block.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index f2b733275a0a..c15b879c3070 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -171,11 +171,7 @@ static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
static inline int mmc_get_devidx(struct gendisk *disk) { - int devmaj = MAJOR(disk_devt(disk)); - int devidx = MINOR(disk_devt(disk)) / perdev_minors; - - if (!devmaj) - devidx = disk->first_minor / perdev_minors; + int devidx = disk->first_minor / perdev_minors; return devidx; }
@@ -2252,6 +2248,7 @@ static struct mmc_blk_data *mmc_blk_alloc_req(struct mmc_card *card, md->disk->queue = md->queue.queue; md->disk->driverfs_dev = parent; set_disk_ro(md->disk, md->read_only || default_ro); + md->disk->flags = GENHD_FL_EXT_DEVT; if (area_type & (MMC_BLK_DATA_AREA_RPMB | MMC_BLK_DATA_AREA_BOOT)) md->disk->flags |= GENHD_FL_NO_PART_SCAN;