Commit f3f62a38 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi 

Pull SCSI updates from James Bottomley:
 "This patch is the usual mix of driver updates (srp, ipr, scsi_debug,
  NCR5380, fnic, 53c974, ses, wd719x, hpsa, megaraid_sas).

  Of those, wd7a9x is new and 53c974 is a rewrite of the old tmscsim
  driver and the extensive work by Finn Thain rewrites all the NCR5380
  based drivers.

  There's also extensive infrastructure updates: a new logging
  infrastructure for sense information and a rewrite of the tagged
  command queue API and an assortment of minor updates"

* tag 'scsi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (183 commits)
  scsi: set fmt to NULL scsi_extd_sense_format() by default
  libsas: remove task_collector mode
  wd719x: remove dma_cache_sync call
  scsi_debug: add Report supported opcodes+tmfs; Compare and write
  scsi_debug: change SCSI command parser to table driven
  scsi_debug: add Capacity Changed Unit Attention
  scsi_debug: append inject error flags onto scsi_cmnd object
  scsi_debug: pinpoint invalid field in sense data
  wd719x: Add firmware documentation
  wd719x: Introduce Western Digital WD7193/7197/7296 PCI SCSI card driver
  eeprom-93cx6: Add (read-only) support for 8-bit mode
  esas2r: fix an oversight in setting return value
  esas2r: fix an error path in esas2r_ioctl_handler
  esas2r: fir error handling in do_fm_api
  scsi: add SPC-3 command definitions
  scsi: rename SERVICE_ACTION_IN to SERVICE_ACTION_IN_16
  scsi: remove scsi_driver owner field
  scsi: move scsi_dispatch_cmd to scsi_lib.c
  scsi: stop passing a gfp_mask argument down the command setup path
  scsi: remove scsi_next_command
  ...
parents 140dfc92 096cbc35

Documentation/ABI/stable/sysfs-driver-ib_srp

+19 −6
Original line number Diff line number Diff line
@@ -55,12 +55,12 @@ Description: Interface for making ib_srp connect to a new target. 
		  only safe with partial memory descriptor list support enabled

		  (allow_ext_sg=1).

		* comp_vector, a number in the range 0..n-1 specifying the

		  MSI-X completion vector. Some HCA's allocate multiple (n)

		  MSI-X vectors per HCA port. If the IRQ affinity masks of

		  these interrupts have been configured such that each MSI-X

		  interrupt is handled by a different CPU then the comp_vector

		  parameter can be used to spread the SRP completion workload

		  over multiple CPU's.

		  MSI-X completion vector of the first RDMA channel. Some

		  HCA's allocate multiple (n) MSI-X vectors per HCA port. If

		  the IRQ affinity masks of these interrupts have been

		  configured such that each MSI-X interrupt is handled by a

		  different CPU then the comp_vector parameter can be used to

		  spread the SRP completion workload over multiple CPU's.

		* tl_retry_count, a number in the range 2..7 specifying the

		  IB RC retry count.

		* queue_size, the maximum number of commands that the
@@ -88,6 +88,13 @@ Description: Whether ib_srp is allowed to include a partial memory 
		descriptor list in an SRP_CMD when communicating with an SRP

		target.



What:		/sys/class/scsi_host/host<n>/ch_count

Date:		April 1, 2015

KernelVersion:	3.19

Contact:	linux-rdma@vger.kernel.org

Description:	Number of RDMA channels used for communication with the SRP

		target.



What:		/sys/class/scsi_host/host<n>/cmd_sg_entries

Date:		May 19, 2011

KernelVersion:	2.6.39
@@ -95,6 +102,12 @@ Contact: linux-rdma@vger.kernel.org 
Description:	Maximum number of data buffer descriptors that may be sent to

		the target in a single SRP_CMD request.



What:		/sys/class/scsi_host/host<n>/comp_vector

Date:		September 2, 2013

KernelVersion:	3.11

Contact:	linux-rdma@vger.kernel.org

Description:	Completion vector used for the first RDMA channel.



What:		/sys/class/scsi_host/host<n>/dgid

Date:		June 17, 2006

KernelVersion:	2.6.17

Documentation/block/biodoc.txt

+0 −4
Original line number Diff line number Diff line
@@ -827,10 +827,6 @@ but in the event of any barrier requests in the tag queue we need to ensure 
that requests are restarted in the order they were queue. This may happen

if the driver needs to use blk_queue_invalidate_tags().



Tagging also defines a new request flag, REQ_QUEUED. This is set whenever

a request is currently tagged. You should not use this flag directly,

blk_rq_tagged(rq) is the portable way to do so.



3.3 I/O Submission



The routine submit_bio() is used to submit a single io. Higher level i/o

Documentation/scsi/libsas.txt

+4 −78
Original line number Diff line number Diff line
@@ -226,9 +226,6 @@ static int register_sas_ha(struct my_sas_ha *my_ha) 
	my_ha->sas_ha.lldd_dev_found = my_dev_found;

	my_ha->sas_ha.lldd_dev_gone = my_dev_gone;



	my_ha->sas_ha.lldd_max_execute_num = lldd_max_execute_num; (1)



	my_ha->sas_ha.lldd_queue_size = ha_can_queue;

	my_ha->sas_ha.lldd_execute_task = my_execute_task;



	my_ha->sas_ha.lldd_abort_task     = my_abort_task;
@@ -247,28 +244,6 @@ static int register_sas_ha(struct my_sas_ha *my_ha) 
	return sas_register_ha(&my_ha->sas_ha);

}



(1) This is normally a LLDD parameter, something of the

lines of a task collector.  What it tells the SAS Layer is

whether the SAS layer should run in Direct Mode (default:

value 0 or 1) or Task Collector Mode (value greater than 1).



In Direct Mode, the SAS Layer calls Execute Task as soon as

it has a command to send to the SDS, _and_ this is a single

command, i.e. not linked.



Some hardware (e.g. aic94xx) has the capability to DMA more

than one task at a time (interrupt) from host memory.  Task

Collector Mode is an optional feature for HAs which support

this in their hardware.  (Again, it is completely optional

even if your hardware supports it.)



In Task Collector Mode, the SAS Layer would do _natural_

coalescing of tasks and at the appropriate moment it would

call your driver to DMA more than one task in a single HA

interrupt. DMBS may want to use this by insmod/modprobe

setting the lldd_max_execute_num to something greater than

1.



(2) SAS 1.1 does not define I_T Nexus Reset TMF.



Events
@@ -325,71 +300,22 @@ PHYE_SPINUP_HOLD -- SATA is present, COMWAKE not sent. 


The Execute Command SCSI RPC:



	int (*lldd_execute_task)(struct sas_task *, int num,

				 unsigned long gfp_flags);

	int (*lldd_execute_task)(struct sas_task *, gfp_t gfp_flags);



Used to queue a task to the SAS LLDD.  @task is the tasks to

be executed.  @num should be the number of tasks being

queued at this function call (they are linked listed via

task::list), @gfp_mask should be the gfp_mask defining the

context of the caller.

Used to queue a task to the SAS LLDD.  @task is the task to be executed.

@gfp_mask is the gfp_mask defining the context of the caller.



This function should implement the Execute Command SCSI RPC,

or if you're sending a SCSI Task as linked commands, you

should also use this function.



That is, when lldd_execute_task() is called, the command(s)

That is, when lldd_execute_task() is called, the command

go out on the transport *immediately*.  There is *no*

queuing of any sort and at any level in a SAS LLDD.



The use of task::list is two-fold, one for linked commands,

the other discussed below.



It is possible to queue up more than one task at a time, by

initializing the list element of struct sas_task, and

passing the number of tasks enlisted in this manner in num.



Returns: -SAS_QUEUE_FULL, -ENOMEM, nothing was queued;

	 0, the task(s) were queued.



If you want to pass num > 1, then either

A) you're the only caller of this function and keep track

   of what you've queued to the LLDD, or

B) you know what you're doing and have a strategy of

   retrying.



As opposed to queuing one task at a time (function call),

batch queuing of tasks, by having num > 1, greatly

simplifies LLDD code, sequencer code, and _hardware design_,

and has some performance advantages in certain situations

(DBMS).



The LLDD advertises if it can take more than one command at

a time at lldd_execute_task(), by setting the

lldd_max_execute_num parameter (controlled by "collector"

module parameter in aic94xx SAS LLDD).



You should leave this to the default 1, unless you know what

you're doing.



This is a function of the LLDD, to which the SAS layer can

cater to.



int lldd_queue_size

	The host adapter's queue size.  This is the maximum

number of commands the lldd can have pending to domain

devices on behalf of all upper layers submitting through

lldd_execute_task().



You really want to set this to something (much) larger than

1.



This _really_ has absolutely nothing to do with queuing.

There is no queuing in SAS LLDDs.



struct sas_task {

	dev -- the device this task is destined to

	list -- must be initialized (INIT_LIST_HEAD)

	task_proto -- _one_ of enum sas_proto

	scatter -- pointer to scatter gather list array

	num_scatter -- number of elements in scatter

Documentation/scsi/scsi_mid_low_api.txt

+13 −53
Original line number Diff line number Diff line
@@ -149,7 +149,7 @@ scsi_add_host() ----> 
scsi_scan_host()  -------+

                         |

                    slave_alloc()

                    slave_configure() -->  scsi_adjust_queue_depth()

                    slave_configure() -->  scsi_change_queue_depth()

                         |

                    slave_alloc()

                    slave_configure()
@@ -159,7 +159,7 @@ scsi_scan_host() -------+ 
------------------------------------------------------------



If the LLD wants to adjust the default queue settings, it can invoke

scsi_adjust_queue_depth() in its slave_configure() routine.

scsi_change_queue_depth() in its slave_configure() routine.



*** For scsi devices that the mid level tries to scan but do not

    respond, a slave_alloc(), slave_destroy() pair is called.
@@ -203,7 +203,7 @@ LLD mid level LLD 
scsi_add_device()  ------+

                         |

                    slave_alloc()

                    slave_configure()   [--> scsi_adjust_queue_depth()]

                    slave_configure()   [--> scsi_change_queue_depth()]

------------------------------------------------------------



In a similar fashion, an LLD may become aware that a SCSI device has been
@@ -261,7 +261,7 @@ init_this_scsi_driver() ----+ 
                            |                scsi_register()

                            |

                      slave_alloc()

                      slave_configure()  -->  scsi_adjust_queue_depth()

                      slave_configure()  -->  scsi_change_queue_depth()

                      slave_alloc()   ***

                      slave_destroy() ***

                            |
@@ -271,9 +271,9 @@ init_this_scsi_driver() ----+ 
                      slave_destroy() ***

------------------------------------------------------------



The mid level invokes scsi_adjust_queue_depth() with tagged queuing off and

"cmd_per_lun" for that host as the queue length. These settings can be

overridden by a slave_configure() supplied by the LLD.

The mid level invokes scsi_change_queue_depth() with "cmd_per_lun" for that

host as the queue length. These settings can be overridden by a

slave_configure() supplied by the LLD.



*** For scsi devices that the mid level tries to scan but do not

    respond, a slave_alloc(), slave_destroy() pair is called.
@@ -366,13 +366,11 @@ is initialized. The functions below are listed alphabetically and their 
names all start with "scsi_".



Summary:

   scsi_activate_tcq - turn on tag command queueing

   scsi_add_device - creates new scsi device (lu) instance

   scsi_add_host - perform sysfs registration and set up transport class

   scsi_adjust_queue_depth - change the queue depth on a SCSI device

   scsi_change_queue_depth - change the queue depth on a SCSI device

   scsi_bios_ptable - return copy of block device's partition table

   scsi_block_requests - prevent further commands being queued to given host

   scsi_deactivate_tcq - turn off tag command queueing

   scsi_host_alloc - return a new scsi_host instance whose refcount==1

   scsi_host_get - increments Scsi_Host instance's refcount

   scsi_host_put - decrements Scsi_Host instance's refcount (free if 0)
@@ -389,24 +387,6 @@ Summary: 


Details:



/**

 * scsi_activate_tcq - turn on tag command queueing ("ordered" task attribute)

 * @sdev:       device to turn on TCQ for

 * @depth:      queue depth

 *

 *      Returns nothing

 *

 *      Might block: no

 *

 *      Notes: Eventually, it is hoped depth would be the maximum depth

 *      the device could cope with and the real queue depth

 *      would be adjustable from 0 to depth.

 *

 *      Defined (inline) in: include/scsi/scsi_tcq.h

 **/

void scsi_activate_tcq(struct scsi_device *sdev, int depth)





/**

 * scsi_add_device - creates new scsi device (lu) instance

 * @shost:   pointer to scsi host instance
@@ -456,11 +436,8 @@ int scsi_add_host(struct Scsi_Host *shost, struct device * dev) 




/**

 * scsi_adjust_queue_depth - allow LLD to change queue depth on a SCSI device

 * scsi_change_queue_depth - allow LLD to change queue depth on a SCSI device

 * @sdev:       pointer to SCSI device to change queue depth on

 * @tagged:     0 - no tagged queuing

 *              MSG_SIMPLE_TAG - simple tagged queuing

 *              MSG_ORDERED_TAG - ordered tagged queuing

 * @tags        Number of tags allowed if tagged queuing enabled,

 *              or number of commands the LLD can queue up

 *              in non-tagged mode (as per cmd_per_lun).
@@ -471,15 +448,12 @@ int scsi_add_host(struct Scsi_Host *shost, struct device * dev) 
 *

 *      Notes: Can be invoked any time on a SCSI device controlled by this

 *      LLD. [Specifically during and after slave_configure() and prior to

 *      slave_destroy().] Can safely be invoked from interrupt code. Actual

 *      queue depth change may be delayed until the next command is being

 *      processed. See also scsi_activate_tcq() and scsi_deactivate_tcq().

 *      slave_destroy().] Can safely be invoked from interrupt code.

 *

 *      Defined in: drivers/scsi/scsi.c [see source code for more notes]

 *

 **/

void scsi_adjust_queue_depth(struct scsi_device * sdev, int tagged, 

                             int tags)

int scsi_change_queue_depth(struct scsi_device *sdev, int tags)





/**
@@ -514,20 +488,6 @@ unsigned char *scsi_bios_ptable(struct block_device *dev) 
void scsi_block_requests(struct Scsi_Host * shost)





/**

 * scsi_deactivate_tcq - turn off tag command queueing

 * @sdev:       device to turn off TCQ for

 * @depth:      queue depth (stored in sdev)

 *

 *      Returns nothing

 *

 *      Might block: no

 *

 *      Defined (inline) in: include/scsi/scsi_tcq.h

 **/

void scsi_deactivate_tcq(struct scsi_device *sdev, int depth)





/**

 * scsi_host_alloc - create a scsi host adapter instance and perform basic

 *                   initialization.
@@ -1254,7 +1214,7 @@ of interest: 
                   for disk firmware uploads.

    cmd_per_lun  - maximum number of commands that can be queued on devices

                   controlled by the host. Overridden by LLD calls to

                   scsi_adjust_queue_depth().

                   scsi_change_queue_depth().

    unchecked_isa_dma - 1=>only use bottom 16 MB of ram (ISA DMA addressing

                   restriction), 0=>can use full 32 bit (or better) DMA

                   address space
@@ -1294,7 +1254,7 @@ struct scsi_cmnd 
Instances of this structure convey SCSI commands to the LLD and responses

back to the mid level. The SCSI mid level will ensure that no more SCSI

commands become queued against the LLD than are indicated by

scsi_adjust_queue_depth() (or struct Scsi_Host::cmd_per_lun). There will

scsi_change_queue_depth() (or struct Scsi_Host::cmd_per_lun). There will

be at least one instance of struct scsi_cmnd available for each SCSI device.

Members of interest:

    cmnd         - array containing SCSI command

Documentation/scsi/st.txt

+5 −3
Original line number Diff line number Diff line
@@ -506,9 +506,11 @@ user does not request data that far.) 


DEBUGGING HINTS



To enable debugging messages, edit st.c and #define DEBUG 1. As seen

above, debugging can be switched off with an ioctl if debugging is

compiled into the driver. The debugging output is not voluminous.

Debugging code is now compiled in by default but debugging is turned off

with the kernel module parameter debug_flag defaulting to 0.  Debugging

can still be switched on and off with an ioctl.  To enable debug at

module load time add debug_flag=1 to the module load options, the

debugging output is not voluminous.



If the tape seems to hang, I would be very interested to hear where

the driver is waiting. With the command 'ps -l' you can see the state

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