• Colin Cross's avatar
    mmc: block: Allow more than 8 partitions per card · 382c55f8
    Colin Cross authored
    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: default avatarColin Cross <ccross@android.com>
    [jstultz: Added context to commit message]
    Signed-off-by: default avatarJohn Stultz <john.stultz@linaro.org>
    Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
    382c55f8
block.c 67.3 KB