ANDROID: dm: Rebase on top of 4.9

1. "dm: optimize use SRCU and RCU" removes the use of dm_table_put.
2. "dm: remove request-based logic from make_request_fn wrapper" necessitates
    calling dm_setup_md_queue or else the request_queue's make_request_fn
    pointer ends being unset.

[    7.711600] Internal error: Oops - bad mode: 0 [raspberrypi#1] PREEMPT SMP
[    7.717519] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W       4.1.15-02273-gb057d16-dirty raspberrypi#33
[    7.726559] Hardware name: HiKey Development Board (DT)
[    7.731779] task: ffffffc005f8acc0 ti: ffffffc005f8c000 task.ti: ffffffc005f8c000
[    7.739257] PC is at 0x0
[    7.741787] LR is at generic_make_request+0x8c/0x108
....
[    9.082931] Call trace:
[    9.085372] [<          (null)>]           (null)
[    9.090074] [<ffffffc0003f4ac0>] submit_bio+0x98/0x1e0
[    9.095212] [<ffffffc0001e2618>] _submit_bh+0x120/0x1f0
[    9.096165] cfg80211: Calling CRDA to update world regulatory domain
[    9.106781] [<ffffffc0001e5450>] __bread_gfp+0x94/0x114
[    9.112004] [<ffffffc00024a748>] ext4_fill_super+0x18c/0x2d64
[    9.117750] [<ffffffc0001b275c>] mount_bdev+0x194/0x1c0
[    9.122973] [<ffffffc0002450dc>] ext4_mount+0x14/0x1c
[    9.128021] [<ffffffc0001b29a0>] mount_fs+0x3c/0x194
[    9.132985] [<ffffffc0001d059c>] vfs_kern_mount+0x4c/0x134
[    9.138467] [<ffffffc0001d2168>] do_mount+0x204/0xbbc
[    9.143514] [<ffffffc0001d2ec4>] SyS_mount+0x94/0xe8
[    9.148479] [<ffffffc000c54074>] mount_block_root+0x120/0x24c
[    9.154222] [<ffffffc000c543e8>] mount_root+0x110/0x12c
[    9.159443] [<ffffffc000c54574>] prepare_namespace+0x170/0x1b8
[    9.165273] [<ffffffc000c53d98>] kernel_init_freeable+0x23c/0x260
[    9.171365] [<ffffffc0009b1748>] kernel_init+0x10/0x118
[    9.176589] Code: bad PC value
[    9.179807] ---[ end trace 75e1bc52ba364d13 ]---

Bug: 27175947

Signed-off-by: Badhri Jagan Sridharan <[email protected]>
Change-Id: I952d86fd1475f0825f9be1386e3497b36127abd0

Author: Badhri Jagan Sridharan

init/do_mounts_dm.c

@@ -10,6 +10,7 @@
 #include <linux/string.h>
 
 #include "do_mounts.h"
+#include "../drivers/md/dm.h"
 
 #define DM_MAX_NAME 32
 #define DM_MAX_UUID 129
@@ -333,6 +334,7 @@ static void __init dm_setup_drive(void)
 		goto dm_table_create_fail;
 	}
 
+	dm_lock_md_type(md);
 	target = dm_setup_args.target;
 	while (target) {
 		DMINFO("adding target '%llu %llu %s %s'",
@@ -352,6 +354,17 @@ static void __init dm_setup_drive(void)
 		goto table_complete_fail;
 	}
 
+	if (dm_get_md_type(md) == DM_TYPE_NONE) {
+		dm_set_md_type(md, dm_table_get_type(table));
+		if (dm_setup_md_queue(md, table)) {
+			DMWARN("unable to set up device queue for new table.");
+			goto setup_md_queue_fail;
+		}
+	} else if (dm_get_md_type(md) != dm_table_get_type(table)) {
+		DMWARN("can't change device type after initial table load.");
+		goto setup_md_queue_fail;
+        }
+
 	/* Suspend the device so that we can bind it to the table. */
 	if (dm_suspend(md, 0)) {
 		DMDEBUG("failed to suspend the device pre-bind");
@@ -380,16 +393,18 @@ static void __init dm_setup_drive(void)
 	}
 	printk(KERN_INFO "dm: dm-%d is ready\n", dm_setup_args.minor);
 
+	dm_unlock_md_type(md);
 	dm_setup_cleanup();
 	return;
 
 export_fail:
 resume_fail:
 table_bind_fail:
 suspend_fail:
+setup_md_queue_fail:
 table_complete_fail:
 add_target_fail:
-	dm_table_put(table);
+	dm_unlock_md_type(md);
 dm_table_create_fail:
 	dm_put(md);
 dm_create_fail: