From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965405AbbJVRA6 (ORCPT ); Thu, 22 Oct 2015 13:00:58 -0400 Received: from mail-pa0-f41.google.com ([209.85.220.41]:35139 "EHLO mail-pa0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965331AbbJVRAv (ORCPT ); Thu, 22 Oct 2015 13:00:51 -0400 From: John Stultz To: linux-kernel@vger.kernel.org Cc: Colin Cross , Ulf Hansson , Adrian Hunter , Ben Hutchings , Chuanxiao Dong , Shawn Lin , Austin S Hemmelgarn , Arnd Bergmann , Android Kernel Team , linux-mmc@vger.kernel.org, John Stultz Subject: [RFC][PATCH v2] mmc_block: Allow more than 8 partitions per card Date: Thu, 22 Oct 2015 10:00:41 -0700 Message-Id: <1445533241-10292-1-git-send-email-john.stultz@linaro.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Colin Cross 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. Thoughts or feedback would be greatly appreciated. Cc: Ulf Hansson Cc: Adrian Hunter Cc: Ben Hutchings Cc: Chuanxiao Dong Cc: Shawn Lin Cc: Austin S Hemmelgarn Cc: Arnd Bergmann Cc: Android Kernel Team Cc: linux-mmc@vger.kernel.org Signed-off-by: Colin Cross [jstultz: Added context to commit message] Signed-off-by: John Stultz --- v2: Added context to commit message about CONFIG_MMC_BLOCK_MINORS and its limitations. 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 c742cfd..564436e 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -172,11 +172,7 @@ 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; } @@ -2162,6 +2158,7 @@ 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; -- 1.9.1