linux-kernel - [PATCH] mmc: block: remove the check for whole block device for ioctl.

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Date:	Tue, 15 Mar 2016 11:26:07 -0400
From:	"Yin, Fengwei" <fengwei.yin@...aro.org>
To:	jonathanh@...dia.com, ulf.hansson@...aro.org,
	linux-kernel@...r.kernel.org
Cc:	fengwei.yin@...aro.org
Subject: [PATCH] mmc: block: remove the check for whole block device for ioctl.

From: Fengwei Yin <fengwei.yin@...aro.org>

a5f5774c55a2e3ed75f4d6c5556b7bfcb726e6f0 introduced the whole block
device checking for MMC_IOC_CMD while the old code has no such check.

It breaks some ioctl call like BLKROSET from user space. An example
is "adb remount" cmd. It prints out following error message:
"remount of /system failed; couldn't make block device XXXX writable: \
Operation not permitted."
while the command worked fine.

This change move the whole block device checking only for MMC_IOC_MULTI_CMD.

Signed-off-by: Fengwei Yin <fengwei.yin@...aro.org>
---
 drivers/mmc/card/block.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
index fe207e5..72b9053 100644
--- a/drivers/mmc/card/block.c
+++ b/drivers/mmc/card/block.c
@@ -693,7 +693,7 @@ static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,
 	 * whole block device, not on a partition.  This prevents overspray
 	 * between sibling partitions.
 	 */
-	if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
+	if (!capable(CAP_SYS_RAWIO))
 		return -EPERM;
 
 	switch (cmd) {
@@ -701,6 +701,9 @@ static int mmc_blk_ioctl(struct block_device *bdev, fmode_t mode,
 		return mmc_blk_ioctl_cmd(bdev,
 				(struct mmc_ioc_cmd __user *)arg);
 	case MMC_IOC_MULTI_CMD:
+        if (bdev != bdev->bd_contains)
+            return -EPERM;
+
 		return mmc_blk_ioctl_multi_cmd(bdev,
 				(struct mmc_ioc_multi_cmd __user *)arg);
 	default:
-- 
2.1.4