[SHDCI] Heavy (thousands) DMA leaks

[Jiri Slaby <jslaby@suse.cz>]

Hi,

after
commit 348487cb28e66b032bae1b38424d81bf5b444408
Author: Haibo Chen <haibo.chen@freescale.com>
Date:   Tue Dec 9 17:04:05 2014 +0800

    mmc: sdhci: use pipeline mmc requests to improve performance

I see heavy DMA leaks which result in warnings of the dma api debug code:
WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:509 add_dma_entry+0x138/0x150()
DMA-API: exceeded 7 overlapping mappings of cacheline 0x000000000b20ec00



And mainly this one upon sdhci module removal. It is over 4000 leaked
mappings during one card transfer.
mmc0: card e624 removed
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1263 at lib/dma-debug.c:974
dma_debug_device_change+0x158/0x1c0()
pci 0000:02:00.0: DMA-API: device driver has pending DMA allocations
while released from device [count=4041]
One of leaked entries details: [device address=0x00000000ddff0000]
[size=65536 bytes] [mapped with DMA_FROM_DEVICE] [mapped as scather-gather]
Modules linked in:
CPU: 2 PID: 1263 Comm: bash Tainted: G        W       4.2.0-rc4 #12
Hardware name: LENOVO 23252SG/23252SG, BIOS G2ET33WW (1.13 ) 07/24/2012
 ffffffff81cc5e32 ffff8800d03c3b68 ffffffff81820938 0000000000000000
 ffff8800d03c3bb8 ffff8800d03c3ba8 ffffffff810b827a 0000000100260021
 ffff88030e500000 0000000000000fc9 ffff88030d95aeb8 ffff88030e4ddd68
Call Trace:
 [<ffffffff81820938>] dump_stack+0x4c/0x6e
 [<ffffffff810b827a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff810b82f6>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff813248c8>] dma_debug_device_change+0x158/0x1c0
 [<ffffffff810d4e9d>] notifier_call_chain+0x4d/0x80
 [<ffffffff810d51fd>] __blocking_notifier_call_chain+0x4d/0x70
 [<ffffffff810d5236>] blocking_notifier_call_chain+0x16/0x20
 [<ffffffff814db395>] __device_release_driver+0x105/0x130
 [<ffffffff814db3e3>] device_release_driver+0x23/0x30
 [<ffffffff814d95ca>] unbind_store+0xba/0xe0
 [<ffffffff8123c638>] ? kernfs_fop_write+0xe8/0x170
 [<ffffffff814d8ac4>] drv_attr_store+0x24/0x30
 [<ffffffff8123ce4a>] sysfs_kf_write+0x3a/0x50
 [<ffffffff8123c670>] kernfs_fop_write+0x120/0x170
 [<ffffffff811ce9e8>] __vfs_write+0x28/0xe0
 [<ffffffff811d1209>] ? __sb_start_write+0x49/0xe0
 [<ffffffff810e3ba5>] ? local_clock+0x25/0x30
 [<ffffffff811cf041>] vfs_write+0xa1/0x170
 [<ffffffff810e43c4>] ? vtime_account_user+0x54/0x60
 [<ffffffff811cfce6>] SyS_write+0x46/0xa0
 [<ffffffff81180f83>] ? context_tracking_user_exit+0x13/0x20
 [<ffffffff8182a017>] entry_SYSCALL_64_fastpath+0x12/0x6a
---[ end trace 398181ad32332b33 ]---
Mapped at:
 [<ffffffff81324492>] debug_dma_map_sg+0x122/0x140
 [<ffffffff81616dd3>] sdhci_pre_dma_transfer+0xc3/0x1b0
 [<ffffffff81616f02>] sdhci_pre_req+0x42/0x70
 [<ffffffff81601492>] mmc_pre_req+0x42/0x60
 [<ffffffff8160290e>] mmc_start_req+0x3e/0x400

I already fixed one symptom -- memory corruption. Could you revisit the
commit once again, as there is surely at least one more bug?

thanks,
-- 
js
suse labs