linux.git/drivers/scsi/scsi_debug.c, branch v3.17

scsi_debug: support scsi-mq, queues and locks

2014-07-26T15:55:35+00:00

 - add host_lock option whose default value is 0 which removes the
   host_lock around all queued commands
 - accept delay=-1 (_hi_) or -2 which use a tasklet to invoke
   the scsi_done callback into the mid-layer. The default
   is still delay=1 which uses a timer to delay 1 jiffy
 - wire .change_queue_depth and .change_queue_type
   functions to better simulate queueing in a modern LLD
 - add SCSI_DEBUG_OPT_Q_NOISE (0x200) mask to only produce
   debug output associated with queue full, plus from
   .change_queue_depth and .change_queue_type functions
 - add SCSI_DEBUG_OPT_ALL_TSF (0x400) mask which reports
   all queued_arr fulls at TASK_SET_FULL, otherwise
   SCSI_MLQUEUE_HOST_BUSY is returned
 - add SCSI_DEBUG_OPT_RARE_TSF (0x800) mask which works
   together with the every_nth option (> 0) to count
   occurrences of num_in_q==queue_depth. When every_nth
   is reached the victim (a command) yields TASK SET FULL
 - clean up many debug messages.
 - add ndelay= option that uses high resolution
   timers; active if > 0 and then overrides delay= option
 - expand Unit Attention handling: POR, BUS_RESET and
   MODE PARAMETERS CHANGED
 - support .eh_target_reset_handler and drop .bios_param
 - add OPT_N_WCE mask so caching page yields WCE=0
 - add OPT_RESET_NOISE mask to log aborts and resets
 - add OPT_NO_CDB_NOISE mask to not log each cdb
 - MODE SELECT support for changing caching page's WCE
 - name common ioctls in log
 - when fake_rw=1, do not vmalloc fake store; make
   UNMAP and WRITE SAME obey fake_rw
 - more logging and code improvements including better
   sense buffer handling

With fio and four (pseudo) devices I have observed 1.2 M IOPS
on my equipment. Rob Elliott who has done much testing and made
numerous suggestions, has better IOPS results than mine.

Signed-off-by: Douglas Gilbert 
Reviewed-by: Robert Elliott 
Tested-by: Robert Elliott 
Signed-off-by: Christoph Hellwig

scsi: use 64-bit LUNs

2014-07-17T20:07:37+00:00

The SCSI standard defines 64-bit values for LUNs, and large arrays
employing large or hierarchical LUN numbers become more and more
common.

So update the linux SCSI stack to use 64-bit LUN numbers.

Signed-off-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ewan Milne 
Signed-off-by: Christoph Hellwig

scsi_debug: allow huge transfer length for read/write commands

2014-07-17T20:07:31+00:00

This change enables to test read/write commands with huge transfer
length such as 1GB.  For example:

	# modprobe scsi_debug dev_size_mb=1024 clustering=1 opts=1
	# cat /sys/block/$DEV/queue/max_hw_sectors_kb > \
		/sys/block/$DEV/queue/max_sectors_kb
	# fio --name=test --rw=write --bs=1g --size=1g --filename=/dev/$DEV \
		--mem=mmaphuge  --direct=1

The data type of max_sectors in scsi_host_template has been extended
to unsigned int by the previous change.  So we can increase it from
0xffff to 0xffffffff to allow such huge transfer length.

Also, this increases sg_tablesize and max_segment_size, otherwise the
maximum transfer length is limited to 64MB.
(sg_tablesize * max_segment_size = 256 * 256KB)

Signed-off-by: Akinobu Mita 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Martin K. Petersen 
Acked by: Douglas Gilbert 
Signed-off-by: Christoph Hellwig

scsi_debug: simple short transfer injection

2014-05-19T17:57:31+00:00

Add an option to only transfer half the data for every n-th command.

Signed-off-by: Christoph Hellwig 
Acked-by: Douglas Gilbert 
Reviewed-by: Nicholas Bellinger

[SCSI] scsi_debug: add ability to enable clustering

2014-03-19T22:04:37+00:00

This adds a module parameter to enable clustering.

Without enabling clustering support, the transfer length for read and
write scsi commands is limited upto 8MB when page size is 4KB and
sg_tablesize is 2048 (= SCSI_MAX_SG_CHAIN_SEGMENTS).  I would like to
test commands with more than that transfer length.

Signed-off-by: Akinobu Mita 
Reviewed-by: Douglas Gilbert 
Reviewed-by: Martin K. Petersen 
Signed-off-by: James Bottomley

[SCSI] scsi_debug: protect device access with atomic_rw lock

2014-03-19T22:04:30+00:00

This change ensures that concurrent device access including ramdisk
storage, protection info, and provisioning map by read, write, and
unmap commands are protected with atomic_rw spinlock.

Signed-off-by: Akinobu Mita 
Reviewed-by: Douglas Gilbert 
Reviewed-by: Martin K. Petersen 
Signed-off-by: James Bottomley

[SCSI] scsi_debug: prepare to enable clustering

2014-03-19T19:21:02+00:00

Currently, clustering support for scsi_debug is disabled.  This is
because there are for_each_sg() loops which assume that each sg list
element is consisted with a single page.  But enabling clustering
support, each sg list element for scsi commands can be consisted with
multiple pages.

This replaces these for_each_sg() loops with sg mapping iterator which
is capable of handling each sg list element is consisted with multiple
pages.

Signed-off-by: Akinobu Mita 
Reviewed-by: Douglas Gilbert 
Reviewed-by: Martin K. Petersen 
Signed-off-by: James Bottomley

[SCSI] scsi_debug: fix resp_xdwriteread() return value when running out of memory

2014-03-19T19:15:03+00:00

When resp_xdwriteread() can't allocate temporary buffer, it returns -1.
But the return value is used as scsi status code and -1 is not
interpreted as correct code.

target_core_mod has similar xdwriteread emulation code. So this mimics
what target_core_mod does for xdwriteread when running out of memory.

Signed-off-by: Akinobu Mita 
Reviewed-by: Douglas Gilbert 
Reviewed-by: Martin K. Petersen 
Signed-off-by: James Bottomley

[SCSI] scsi_debug: fix duplicate dif_errors increment

2014-03-19T18:42:52+00:00

It is unnecessary to increase dif_errors in dif_verify(), because the
caller will increment it when dif_verify() detects failure.

This bug was introduced by commit beb40ea42bd6 ("[SCSI] scsi_debug:
reduce duplication between prot_verify_read and prot_verify_write")

Signed-off-by: Akinobu Mita 
Acked-by: Martin K. Petersen 
Reviewed-by: Douglas Gilbert 
Signed-off-by: James Bottomley

[SCSI] scsi_debug: make pseudo_primary static

2014-03-19T18:35:57+00:00

As pseudo_primary is only used in scsi_debug.c, it should be static.

Signed-off-by: Akinobu Mita 
Reviewed-by: Douglas Gilbert 
Reviewed-by: Martin K. Petersen 
Signed-off-by: James Bottomley