Re: [PATCH V9 3/4] scsi: Align block queue to dma_get_cache_alignment()

[kbuild test robot]

Hi Huacai,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on linus/master]
[also build test ERROR on v4.14-rc7]
[cannot apply to next-20171103]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Huacai-Chen/dma-mapping-Rework-dma_get_cache_alignment/20171023-154436
config: m68k-sun3_defconfig (attached as .config)
compiler: m68k-linux-gcc (GCC) 4.9.0
reproduce:
wget 
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O 
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=m68k 

All errors (new ones prefixed by >>):

   drivers//scsi/scsi_lib.c: In function '__scsi_init_queue':
>> drivers//scsi/scsi_lib.c:2139:2: error: implicit declaration of function 
>> 'dma_get_cache_alignment' [-Werror=implicit-function-declaration]
 blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment(dev)) - 1);
 ^
   cc1: some warnings being treated as errors

vim +/dma_get_cache_alignment +2139 drivers//scsi/scsi_lib.c

  2103  
  2104  void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
  2105  {
  2106  struct device *dev = shost->dma_dev;
  2107  
  2108  queue_flag_set_unlocked(QUEUE_FLAG_SCSI_PASSTHROUGH, q);
  2109  
  2110  /*
  2111   * this limit is imposed by hardware restrictions
  2112   */
  2113  blk_queue_max_segments(q, min_t(unsigned short, 
shost->sg_tablesize,
  2114  SG_MAX_SEGMENTS));
  2115  
  2116  if (scsi_host_prot_dma(shost)) {
  2117  shost->sg_prot_tablesize =
  2118  min_not_zero(shost->sg_prot_tablesize,
  2119   (unsigned 
short)SCSI_MAX_PROT_SG_SEGMENTS);
  2120  BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
  2121  blk_queue_max_integrity_segments(q, 
shost->sg_prot_tablesize);
  2122  }
  2123  
  2124  blk_queue_max_hw_sectors(q, shost->max_sectors);
  2125  blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
  2126  blk_queue_segment_boundary(q, shost->dma_boundary);
  2127  dma_set_seg_boundary(dev, shost->dma_boundary);
  2128  
  2129  blk_queue_max_segment_size(q, dma_get_max_seg_size(dev));
  2130  
  2131  if (!shost->use_clustering)
  2132  q->limits.cluster = 0;
  2133  
  2134  /*
  2135   * set a reasonable default alignment on word/cacheline 
boundaries:
  2136   * the host and device may alter it using
  2137   * blk_queue_update_dma_alignment() later.
  2138   */
> 2139  blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment(dev)) 
> - 1);
  2140  }
  2141  EXPORT_SYMBOL_GPL(__scsi_init_queue);
  2142  

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: application/gzip

[PATCH V9 3/4] scsi: Align block queue to dma_get_cache_alignment()

[Huacai Chen]

In non-coherent DMA mode, kernel uses cache flushing operations to
maintain I/O coherency, so scsi's block queue should be aligned to
ARCH_DMA_MINALIGN. Otherwise, If a DMA buffer and a kernel structure
share a same cache line, and if the kernel structure has dirty data,
cache_invalidate (no writeback) will cause data corruption.

Cc: sta...@vger.kernel.org
Signed-off-by: Huacai Chen 
---
 drivers/scsi/scsi_lib.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 9cf6a80..19abc2e 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2132,11 +2132,11 @@ void __scsi_init_queue(struct Scsi_Host *shost, struct 
request_queue *q)
q->limits.cluster = 0;
 
/*
-* set a reasonable default alignment on word boundaries: the
-* host and device may alter it using
+* set a reasonable default alignment on word/cacheline boundaries:
+* the host and device may alter it using
 * blk_queue_update_dma_alignment() later.
 */
-   blk_queue_dma_alignment(q, 0x03);
+   blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment(dev)) - 1);
 }
 EXPORT_SYMBOL_GPL(__scsi_init_queue);
 
-- 
2.7.0