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| author | Vaughan Cao <vaughan.cao@oracle.com> | 2014-06-03 17:37:30 +0800 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2014-07-17 22:07:31 +0200 |
| commit | cb2fb68d064c16a559483651132815cc378fd1f9 (patch) | |
| tree | be186c470b27cfa9af56d464423cb3655bdacf1a /drivers/scsi/sd.c | |
| parent | 6bb5e6e772f5f71413e290eb9c6a475e9a6d39e2 (diff) | |
| download | linux-cb2fb68d064c16a559483651132815cc378fd1f9.tar.bz2 | |
sd: notify block layer when using temporary change to cache_type
This is a fix for commit 39c60a0948cc06139e2fbfe084f83cb7e7deae3b
"sd: fix array cache flushing bug causing performance problems"
We must notify the block layer via q->flush_flags after a temporary change
of the cache_type to write through. Without this, a SYNCHRONIZE CACHE
command will still be generated. This patch factors out a helper that
can be called from sd_revalidate_disk and cache_type_store.
Signed-off-by: Vaughan Cao <vaughan.cao@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'drivers/scsi/sd.c')
| -rw-r--r-- | drivers/scsi/sd.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 14ec8f521ae8..4056004102ae 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -134,6 +134,19 @@ static const char *sd_cache_types[] = { "write back, no read (daft)" }; +static void sd_set_flush_flag(struct scsi_disk *sdkp) +{ + unsigned flush = 0; + + if (sdkp->WCE) { + flush |= REQ_FLUSH; + if (sdkp->DPOFUA) + flush |= REQ_FUA; + } + + blk_queue_flush(sdkp->disk->queue, flush); +} + static ssize_t cache_type_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) @@ -177,6 +190,7 @@ cache_type_store(struct device *dev, struct device_attribute *attr, if (sdkp->cache_override) { sdkp->WCE = wce; sdkp->RCD = rcd; + sd_set_flush_flag(sdkp); return count; } @@ -2698,7 +2712,6 @@ static int sd_revalidate_disk(struct gendisk *disk) struct scsi_disk *sdkp = scsi_disk(disk); struct scsi_device *sdp = sdkp->device; unsigned char *buffer; - unsigned flush = 0; SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_revalidate_disk\n")); @@ -2744,13 +2757,7 @@ static int sd_revalidate_disk(struct gendisk *disk) * We now have all cache related info, determine how we deal * with flush requests. */ - if (sdkp->WCE) { - flush |= REQ_FLUSH; - if (sdkp->DPOFUA) - flush |= REQ_FUA; - } - - blk_queue_flush(sdkp->disk->queue, flush); + sd_set_flush_flag(sdkp); set_capacity(disk, sdkp->capacity); sd_config_write_same(sdkp); |