[PATCH] raid5: After bio_reset, it must set some parameter of struct bio.

[majianpeng <majianpeng@gmail.com>]

In commit 2f6db2a7073452b1, raid5 used bio_reset.But Kent Overstreet 
leak some fields of bio to set.So it will cause bugs:
[  355.746233] md/raid:md0: raid level 5 active with 3 out of 4 devices, algorithm 2
[  355.783651] ------------[ cut here ]------------
[  355.783707] kernel BUG at drivers/scsi/scsi_lib.c:1196!
[  355.783756] invalid opcode: 0000 [#1] SMP 
[  355.783846] Modules linked in: raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx netconsole configfs e1000e btrfs xor raid6_pq
[  355.784208] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.0-rc1+ #158
[  355.784261] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS 080015  11/09/2011
[  355.784336] task: ffffffff81c10440 ti: ffffffff81c00000 task.ti: ffffffff81c00000
[  355.784386] RIP: 0010:[<ffffffff81428fd2>]  [<ffffffff81428fd2>] scsi_setup_fs_cmnd+0x92/0xa0
[  355.784469] RSP: 0018:ffff8800bd203c48  EFLAGS: 00010046
[  355.784517] RAX: 0000000000000000 RBX: ffff880036e1a000 RCX: 0000000000000002
[  355.784571] RDX: ffffffff812afab0 RSI: ffff8800b5d75178 RDI: ffff880036e1a000
[  355.784593] RBP: ffff8800bd203c58 R08: ffff8800b5d74738 R09: 0000000000000001
[  355.784593] R10: 0000000000000000 R11: 0000000000012a00 R12: ffff8800b5d75178
[  355.784593] R13: ffff880036e1a000 R14: ffff8800b583a800 R15: 0000000000040000
[  355.784593] FS:  0000000000000000(0000) GS:ffff8800bd200000(0000) knlGS:0000000000000000
[  355.784593] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[  355.784593] CR2: 0000000001dfa008 CR3: 00000000b6d11000 CR4: 00000000000407f0
[  355.784593] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  355.784593] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[  355.784593] Stack:
[  355.784593]  ffff8800b5d75178 ffff8800b58f0000 ffff8800bd203ca8 ffffffff81439453
[  355.784593]  ffffffff821f2100 000000010000d993 ffff880000080000 ffff8800b58f0000
[  355.784593]  ffff8800b5d75178 ffffffff81c01fd8 ffffffff81c01fd8 ffff880036e1a000
[  355.784593] Call Trace:
[  355.784593]  <IRQ> 
[  355.784593]  [<ffffffff81439453>] sd_prep_fn+0xf3/0x810
[  355.784593]  [<ffffffff8129e186>] blk_peek_request+0x126/0x230
[  355.784593]  [<ffffffff814297ce>] scsi_request_fn+0x4e/0x4e0
[  355.784593]  [<ffffffff8129cce4>] ? blk_run_queue+0x24/0x50
[  355.784593]  [<ffffffff8129c773>] __blk_run_queue+0x33/0x40
[  355.784593]  [<ffffffff8129ccef>] blk_run_queue+0x2f/0x50
[  355.784593]  [<ffffffff81429361>] scsi_run_queue+0x151/0x2f0
[  355.784593]  [<ffffffff81409d97>] ? put_device+0x17/0x20
[  355.784593]  [<ffffffff814228c4>] ? __scsi_put_command+0x64/0xa0
[  355.784593]  [<ffffffff8142a852>] scsi_next_command+0x42/0x60
[  355.784593]  [<ffffffff8142a9a2>] scsi_io_completion+0xd2/0x6e0
[  355.784593]  [<ffffffff8109e6ed>] ? trace_hardirqs_on+0xd/0x10
[  355.784593]  [<ffffffff81421dcc>] scsi_finish_command+0xac/0xf0
[  355.784593]  [<ffffffff8142a753>] scsi_softirq_done+0xa3/0x140
[  355.784593]  [<ffffffff812a3aeb>] blk_done_softirq+0x7b/0x90
[  355.784593]  [<ffffffff81046970>] __do_softirq+0x100/0x280
[  355.784593]  [<ffffffff81046c95>] irq_exit+0xb5/0xc0
[  355.784593]  [<ffffffff81696443>] do_IRQ+0x63/0xe0
[  355.784593]  [<ffffffff8168c4af>] common_interrupt+0x6f/0x6f
[  355.784593]  <EOI> 
[  355.784593]  [<ffffffff8100a576>] ? default_idle+0x26/0x100
[  355.784593]  [<ffffffff8100ae56>] arch_cpu_idle+0x26/0x30
[  355.784593]  [<ffffffff8108ffae>] cpu_startup_entry+0x8e/0x270
[  355.784593]  [<ffffffff8166ba03>] rest_init+0xd3/0xe0
[  355.784593]  [<ffffffff8166b935>] ? rest_init+0x5/0xe0
[  355.784593]  [<ffffffff81ecbe1b>] start_kernel+0x3b5/0x3c2
[  355.784593]  [<ffffffff81ecb86e>] ? repair_env_string+0x5e/0x5e
[  355.784593]  [<ffffffff81ecb5a3>] x86_64_start_reservations+0x2a/0x2c
[  355.784593]  [<ffffffff81ecb671>] x86_64_start_kernel+0xcc/0xcf
[  355.784593] Code: c3 48 8b 00 48 85 c0 74 b7 48 8b 40 48 48 85 c0 74 ae 4c 89 e6 48 89 df ff d0 85 c0 74 a2 eb dc b8 02 00 00 00 0f 1f 40 00 eb d1 <0f> 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90 55 48 
[  355.784593] RIP  [<ffffffff81428fd2>] scsi_setup_fs_cmnd+0x92/0xa0
[  355.784593]  RSP <ffff8800bd203c48>

Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
---
 drivers/md/raid5.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 9359828..66314b5 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -642,8 +642,10 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
  md_sync_acct(rdev->bdev, STRIPE_SECTORS);

  set_bit(STRIPE_IO_STARTED, &sh->state);
-
  bio_reset(bi);
+
+ bi->bi_vcnt = bi->bi_max_vecs = 1;
+ bi->bi_io_vec = &(sh->dev[i].vec);
  bi->bi_bdev = rdev->bdev;
  bi->bi_rw = rw;
  bi->bi_end_io = (rw & WRITE)
@@ -663,7 +665,6 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
   + rdev->data_offset);
  if (test_bit(R5_ReadNoMerge, &sh->dev[i].flags))
  bi->bi_rw |= REQ_FLUSH;
-
  bi->bi_io_vec[0].bv_len = STRIPE_SIZE;
  bi->bi_io_vec[0].bv_offset = 0;
  bi->bi_size = STRIPE_SIZE;
@@ -684,6 +685,9 @@ static void ops_run_io(struct stripe_head *sh, struct stripe_head_state *s)
  set_bit(STRIPE_IO_STARTED, &sh->state);

  bio_reset(rbi);
+
+ rbi->bi_vcnt = rbi->bi_max_vecs = 1;
+ rbi->bi_io_vec = &(sh->dev[i].rvec);
  rbi->bi_bdev = rrdev->bdev;
  rbi->bi_rw = rw;
  BUG_ON(!(rw & WRITE));
-- 
1.8.3.rc1.44.gb387c77


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majianpeng