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

devices.

.. kernel-doc:: drivers/scsi/scsi_devinfo.c

   :internal:

   :export:

drivers/scsi/scsi_ioctl.c

~~~~~~~~~~~~~~~~~~~~~~~~~~

plumbing to manage /proc/scsi/\*

.. kernel-doc:: drivers/scsi/scsi_proc.c

   :internal:

drivers/scsi/scsi_netlink.c

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

is seen that cannot have a device attached to it.

.. kernel-doc:: drivers/scsi/scsi_scan.c

   :internal:

   :export:

drivers/scsi/scsi_sysctl.c

~~~~~~~~~~~~~~~~~~~~~~~~~~~

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

For all non-EH commands, scsi_done() is the completion callback.  It

just calls blk_complete_request() to delete the block layer timer and

raise SCSI_SOFTIRQ

just calls blk_mq_complete_request() to delete the block layer timer and

raise BLOCK_SOFTIRQ.

SCSI_SOFTIRQ handler scsi_softirq calls scsi_decide_disposition() to

determine what to do with the command.  scsi_decide_disposition()

looks at the scmd->result value and sense data to determine what to do

with the command.

The BLOCK_SOFTIRQ indirectly calls scsi_complete(), which calls

scsi_decide_disposition() to determine what to do with the command.

scsi_decide_disposition() looks at the scmd->result value and sense

data to determine what to do with the command.

 - SUCCESS

    retry which failed), when retries are exceeded, or when the EH deadline is

    expired. In these cases Step #3 is taken.

 3. scsi_eh_scmd_add(scmd, SCSI_EH_CANCEL_CMD) is invoked for the

 3. scsi_eh_scmd_add(scmd) is invoked for the

    command.  See [1-4] for more information.

1.3 Asynchronous command aborts

    :ACTION: scsi_eh_finish_cmd() is invoked to EH-finish scmd

	- scsi_setup_cmd_retry()

	- move from local eh_work_q to local eh_done_q

    :LOCKING: none

    ``scsi_eh_get_sense``

	This action is taken for each error-completed

	(!SCSI_EH_CANCEL_CMD) commands without valid sense data.  Most

	command without valid sense data.  Most

	SCSI transports/LLDDs automatically acquire sense data on

	command failures (autosense).  Autosense is recommended for

	performance reasons and as sense information could get out of

	   - otherwise

		No action.

    3. If !list_empty(&eh_work_q), invoke scsi_eh_abort_cmds().

    ``scsi_eh_abort_cmds``

	This action is taken for each timed out command when

	no_async_abort is enabled in the host template.

	hostt->eh_abort_handler() is invoked for each scmd.  The

	handler returns SUCCESS if it has succeeded to make LLDD and

	all related hardware forget about the scmd.

	If a timedout scmd is successfully aborted and the sdev is

	either offline or ready, scsi_eh_finish_cmd() is invoked for

	the scmd.  Otherwise, the scmd is left in eh_work_q for

	higher-severity actions.

	Note that both offline and ready status mean that the sdev is

	ready to process new scmds, where processing also implies

	immediate failing; thus, if a sdev is in one of the two

	states, no further recovery action is needed.

	Device readiness is tested using scsi_eh_tur() which issues

	TEST_UNIT_READY command.  Note that the scmd must have been

	aborted successfully before reusing it for TEST_UNIT_READY.

    4. If !list_empty(&eh_work_q), invoke scsi_eh_ready_devs()

    ``scsi_eh_ready_devs``

	    For each sdev which has failed scmds with valid sense data

	    of which scsi_check_sense()'s verdict is FAILED,

	    START_STOP_UNIT command is issued w/ start=1.  Note that

	    START STOP UNIT command is issued w/ start=1.  Note that

	    as we explicitly choose error-completed scmds, it is known

	    that lower layers have forgotten about the scmd and we can

	    reuse it for STU.

 - shost->host_failed is zero.

 - Each scmd is in such a state that scsi_setup_cmd_retry() on the

   scmd doesn't make any difference.

 - shost->eh_cmd_q is cleared.

 - Each scmd->eh_entry is cleared.

Those functions in group b) are listed in a section entitled "Interface

functions" below. Their function pointers are placed in the members of

"struct scsi_host_template", an instance of which is passed to

scsi_host_alloc() [#]_.  Those interface functions that the LLD does not

scsi_host_alloc().  Those interface functions that the LLD does not

wish to supply should have NULL placed in the corresponding member of

struct scsi_host_template.  Defining an instance of struct

scsi_host_template at file scope will cause NULL to be  placed in function

that are shared with the mid level and other layers.

All functions defined within an LLD and all data defined at file scope

should be static. For example the slave_alloc() function in an LLD

should be static. For example the sdev_init() function in an LLD

called "xxx" could be defined as

``static int xxx_slave_alloc(struct scsi_device * sdev) { /* code */ }``

.. [#] the scsi_host_alloc() function is a replacement for the rather vaguely

       named scsi_register() function in most situations.

``static int xxx_sdev_init(struct scsi_device * sdev) { /* code */ }``

Hotplug initialization model

    scsi_add_host()  ---->

    scsi_scan_host()  -------+

			    |

			slave_alloc()

			slave_configure() -->  scsi_change_queue_depth()

			sdev_init()

			sdev_configure() -->  scsi_change_queue_depth()

			    |

			slave_alloc()

			slave_configure()

			sdev_init()

			sdev_configure()

			    |

			slave_alloc()   ***

			slave_destroy() ***

			sdev_init()   ***

			sdev_destroy() ***

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

	respond, a slave_alloc(), slave_destroy() pair is called.

	respond, a sdev_init(), sdev_destroy() pair is called.

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

scsi_change_queue_depth() in its slave_configure() routine.

scsi_change_queue_depth() in its sdev_configure() routine.

When an HBA is being removed it could be as part of an orderly shutdown

associated with the LLD module being unloaded (e.g. with the "rmmod"

    ===----------------------=========-----------------===------

    scsi_remove_host() ---------+

				|

			slave_destroy()

			slave_destroy()

			sdev_destroy()

			sdev_destroy()

    scsi_host_put()

It may be useful for a LLD to keep track of struct Scsi_Host instances

    ===-------------------=========--------------------===------

    scsi_add_device()  ------+

			    |

			slave_alloc()

			slave_configure()   [--> scsi_change_queue_depth()]

			sdev_init()

			sdev_configure()   [--> scsi_change_queue_depth()]

In a similar fashion, an LLD may become aware that a SCSI device has been

removed (unplugged) or the connection to it has been interrupted. Some

    ===----------------------=========-----------------===------

    scsi_remove_device() -------+

				|

			slave_destroy()

			sdev_destroy()

It may be useful for an LLD to keep track of struct scsi_device instances

(a pointer is passed as the parameter to slave_alloc() and

slave_configure() callbacks). Such instances are "owned" by the mid-level.

struct scsi_device instances are freed after slave_destroy().

(a pointer is passed as the parameter to sdev_init() and

sdev_configure() callbacks). Such instances are "owned" by the mid-level.

struct scsi_device instances are freed after sdev_destroy().

Reference Counting

  - 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)

  - scsi_register - create and register a scsi host adapter instance.

  - scsi_remove_device - detach and remove a SCSI device

  - scsi_remove_host - detach and remove all SCSI devices owned by host

  - scsi_report_bus_reset - report scsi _bus_ reset observed

  - scsi_scan_host - scan SCSI bus

  - scsi_track_queue_full - track successive QUEUE_FULL events

  - scsi_unblock_requests - allow further commands to be queued to given host

  - scsi_unregister - [calls scsi_host_put()]

Details::

    *      bus scan when an HBA is added (i.e. scsi_scan_host()). So it

    *      should only be called if the HBA becomes aware of a new scsi

    *      device (lu) after scsi_scan_host() has completed. If successful

    *      this call can lead to slave_alloc() and slave_configure() callbacks

    *      this call can lead to sdev_init() and sdev_configure() callbacks

    *      into the LLD.

    *

    *      Defined in: drivers/scsi/scsi_scan.c

    *      Might block: no

    *

    *      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.

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

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

    *

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

    *

    void scsi_host_put(struct Scsi_Host *shost)

    /**

    * scsi_register - create and register a scsi host adapter instance.

    * @sht:        pointer to scsi host template

    * @privsize:   extra bytes to allocate in hostdata array (which is the

    *              last member of the returned Scsi_Host instance)

    *

    *      Returns pointer to new Scsi_Host instance or NULL on failure

    *

    *      Might block: yes

    *

    *      Notes: When this call returns to the LLD, the SCSI bus scan on

    *      this host has _not_ yet been done.

    *      The hostdata array (by default zero length) is a per host scratch

    *      area for the LLD.

    *

    *      Defined in: drivers/scsi/hosts.c .

    **/

    struct Scsi_Host * scsi_register(struct scsi_host_template * sht,

				    int privsize)

    /**

    * scsi_remove_device - detach and remove a SCSI device

    * @sdev:      a pointer to a scsi device instance

    *      Notes: If an LLD becomes aware that a scsi device (lu) has

    *      been removed but its host is still present then it can request

    *      the removal of that scsi device. If successful this call will

    *      lead to the slave_destroy() callback being invoked. sdev is an

    *      lead to the sdev_destroy() callback being invoked. sdev is an

    *      invalid pointer after this call.

    *

    *      Defined in: drivers/scsi/scsi_sysfs.c .

    *

    *      Notes: Should only be invoked if the "hotplug initialization

    *      model" is being used. It should be called _prior_ to

    *      scsi_unregister().

    *      calling scsi_host_put().

    *

    *      Defined in: drivers/scsi/hosts.c .

    **/

    void scsi_unblock_requests(struct Scsi_Host * shost)

    /**

    * scsi_unregister - unregister and free memory used by host instance

    * @shp:        pointer to scsi host instance to unregister.

    *

    *      Returns nothing

    *

    *      Might block: no

    *

    *      Notes: Should not be invoked if the "hotplug initialization

    *      model" is being used. Called internally by exit_this_scsi_driver()

    *      in the "passive initialization model". Hence a LLD has no need to

    *      call this function directly.

    *

    *      Defined in: drivers/scsi/hosts.c .

    **/

    void scsi_unregister(struct Scsi_Host * shp)

Interface Functions

===================

Interface functions are supplied (defined) by LLDs and their function

pointers are placed in an instance of struct scsi_host_template which

is passed to scsi_host_alloc() [or scsi_register() / init_this_scsi_driver()].

is passed to scsi_host_alloc().

Some are mandatory. Interface functions should be declared static. The

accepted convention is that driver "xyz" will declare its slave_configure()

accepted convention is that driver "xyz" will declare its sdev_configure()

function as::

    static int xyz_slave_configure(struct scsi_device * sdev);

    static int xyz_sdev_configure(struct scsi_device * sdev);

and so forth for all interface functions listed below.

A pointer to this function should be placed in the 'slave_configure' member

A pointer to this function should be placed in the 'sdev_configure' member

of a "struct scsi_host_template" instance. A pointer to such an instance

should be passed to the mid level's scsi_host_alloc() [or scsi_register() /

init_this_scsi_driver()].

should be passed to the mid level's scsi_host_alloc().

.

The interface functions are also described in the include/scsi/scsi_host.h

file immediately above their definition point in "struct scsi_host_template".

  - ioctl - driver can respond to ioctls

  - proc_info - supports /proc/scsi/{driver_name}/{host_no}

  - queuecommand - queue scsi command, invoke 'done' on completion

  - slave_alloc - prior to any commands being sent to a new device

  - slave_configure - driver fine tuning for given device after attach

  - slave_destroy - given device is about to be shut down

  - sdev_init - prior to any commands being sent to a new device

  - sdev_configure - driver fine tuning for given device after attach

  - sdev_destroy - given device is about to be shut down

Details::

    *

    *      Calling context: kernel thread

    *

    *      Notes: If 'no_async_abort' is defined this callback

    *  	will be invoked from scsi_eh thread. No other commands

    *	will then be queued on current host during eh.

    *	Otherwise it will be called whenever scsi_timeout()

    *      is called due to a command timeout.

    *      Notes: This is called only for a command that has timed out.

    *

    *      Optionally defined in: LLD

    **/

    *      The SCSI_IOCTL_PROBE_HOST ioctl yields the string returned by this

    *      function (or struct Scsi_Host::name if this function is not

    *      available).

    *      In a similar manner, init_this_scsi_driver() outputs to the console

    *      each host's "info" (or name) for the driver it is registering.

    *      Also if proc_info() is not supplied, the output of this function

    *      is used instead.

    *

    *      Optionally defined in: LLD

    **/

    /**

    *      slave_alloc -   prior to any commands being sent to a new device

    *      sdev_init -   prior to any commands being sent to a new device

    *                      (i.e. just prior to scan) this call is made

    *      @sdp: pointer to new device (about to be scanned)

    *

    *      prior to its initial scan. The corresponding scsi device may not

    *      exist but the mid level is just about to scan for it (i.e. send

    *      and INQUIRY command plus ...). If a device is found then

    *      slave_configure() will be called while if a device is not found

    *      slave_destroy() is called.

    *      sdev_configure() will be called while if a device is not found

    *      sdev_destroy() is called.

    *      For more details see the include/scsi/scsi_host.h file.

    *

    *      Optionally defined in: LLD

    **/

	int slave_alloc(struct scsi_device *sdp)

	int sdev_init(struct scsi_device *sdp)

    /**

    *      slave_configure - driver fine tuning for given device just after it

    *      sdev_configure - driver fine tuning for given device just after it

    *                     has been first scanned (i.e. it responded to an

    *                     INQUIRY)

    *      @sdp: device that has just been attached

    *

    *      Returns 0 if ok. Any other return is assumed to be an error and

    *      the device is taken offline. [offline devices will _not_ have

    *      slave_destroy() called on them so clean up resources.]

    *      sdev_destroy() called on them so clean up resources.]

    *

    *      Locks: none

    *

    *

    *      Optionally defined in: LLD

    **/

	int slave_configure(struct scsi_device *sdp)

	int sdev_configure(struct scsi_device *sdp)

    /**

    *      slave_destroy - given device is about to be shut down. All

    *      sdev_destroy - given device is about to be shut down. All

    *                      activity has ceased on this device.

    *      @sdp: device that is about to be shut down

    *

    *      by this driver for given device should be freed now. No further

    *      commands will be sent for this sdp instance. [However the device

    *      could be re-attached in the future in which case a new instance

    *      of struct scsi_device would be supplied by future slave_alloc()

    *      and slave_configure() calls.]

    *      of struct scsi_device would be supplied by future sdev_init()

    *      and sdev_configure() calls.]

    *

    *      Optionally defined in: LLD

    **/

	void slave_destroy(struct scsi_device *sdp)

	void sdev_destroy(struct scsi_device *sdp)

There is one "struct scsi_host_template" instance per LLD [#]_. It is

typically initialized as a file scope static in a driver's header file. That

way members that are not explicitly initialized will be set to 0 or NULL.

Member of interest:

Members of interest:

    name

		 - name of driver (may contain spaces, please limit to

		 - primary callback that the mid level uses to inject

                   SCSI commands into an LLD.

    vendor_id

		 - a unique value that identifies the vendor supplying

                   the LLD for the Scsi_Host.  Used most often in validating

                   vendor-specific message requests.  Value consists of an

                   identifier type and a vendor-specific value.

                   See scsi_netlink.h for a description of valid formats.

The structure is defined and commented in include/scsi/scsi_host.h

.. [#] In extreme situations a single driver may have several instances

		 - maximum number of commands that can be queued on devices

                   controlled by the host. Overridden by LLD calls to

                   scsi_change_queue_depth().

    no_async_abort

		 - 1=>Asynchronous aborts are not supported

		 - 0=>Timed-out commands will be aborted asynchronously

    hostt

		 - pointer to driver's struct scsi_host_template from which

                   this struct Scsi_Host instance was spawned

    transportt

		 - pointer to driver's struct scsi_transport_template instance

                   (if any). FC and SPI transports currently supported.

    sh_list

		 - a double linked list of pointers to all struct Scsi_Host

                   instances (currently ordered by ascending host_no)

    my_devices

		 - a double linked list of pointers to struct scsi_device

                   instances that belong to this host.

    hostdata[0]

		 - area reserved for LLD at end of struct Scsi_Host. Size

                   is set by the second argument (named 'xtr_bytes') to

                   scsi_host_alloc() or scsi_register().

    vendor_id

		 - a unique value that identifies the vendor supplying

                   the LLD for the Scsi_Host.  Used most often in validating

                   vendor-specific message requests.  Value consists of an

                   identifier type and a vendor-specific value.

                   See scsi_netlink.h for a description of valid formats.

                   is set by the second argument (named 'privsize') to

                   scsi_host_alloc().

The scsi_host structure is defined in include/scsi/scsi_host.h

    cmnd

		 - array containing SCSI command

    cmnd_len

    cmd_len

		 - length (in bytes) of SCSI command

    sc_data_direction

		 - direction of data transfer in data phase. See

                   "enum dma_data_direction" in include/linux/dma-mapping.h

    request_bufflen

		 - number of data bytes to transfer (0 if no data phase)

    use_sg

		 - ==0 -> no scatter gather list, hence transfer data

                          to/from request_buffer

                 - >0 ->  scatter gather list (actually an array) in

                          request_buffer with use_sg elements

    request_buffer

		   - either contains data buffer or scatter gather list

                     depending on the setting of use_sg. Scatter gather

                     elements are defined by 'struct scatterlist' found

                     in include/linux/scatterlist.h .

    done

		 - function pointer that should be invoked by LLD when the

                   SCSI command is completed (successfully or otherwise).

                   Should only be called by an LLD if the LLD has accepted

                   the command (i.e. queuecommand() returned or will return

                   0). The LLD may invoke 'done'  prior to queuecommand()

                   finishing.

    result

		 - should be set by LLD prior to calling 'done'. A value

                   of 0 implies a successfully completed command (and all

    device

		 - pointer to scsi_device object that this command is

                   associated with.

    resid

    resid_len   (access by calling scsi_set_resid() / scsi_get_resid())

		 - an LLD should set this unsigned integer to the requested

                   transfer length (i.e. 'request_bufflen') less the number

                   of bytes that are actually transferred. 'resid' is

                   of bytes that are actually transferred. 'resid_len' is

                   preset to 0 so an LLD can ignore it if it cannot detect

                   underruns (overruns should not be reported). An LLD

                   should set 'resid' prior to invoking 'done'. The most

                   should set 'resid_len' prior to invoking 'done'. The most

                   interesting case is data transfers from a SCSI target

                   device (e.g. READs) that underrun.

    underflow

                   figure. Not many LLDs implement this check and some that

                   do just output an error message to the log rather than

                   report a DID_ERROR. Better for an LLD to implement

                   'resid'.

                   'resid_len'.

It is recommended that a LLD set 'resid' on data transfers from a SCSI

target device (e.g. READs). It is especially important that 'resid' is set

It is recommended that a LLD set 'resid_len' on data transfers from a SCSI

target device (e.g. READs). It is especially important that 'resid_len' is set

when such data transfers have sense keys of MEDIUM ERROR and HARDWARE ERROR

(and possibly RECOVERED ERROR). In these cases if a LLD is in doubt how much

data has been received then the safest approach is to indicate no bytes have

    scsi_set_resid(SCpnt, scsi_bufflen(SCpnt));

where 'SCpnt' is a pointer to a scsi_cmnd object. To indicate only three 512

bytes blocks has been received 'resid' could be set like this::

bytes blocks have been received 'resid_len' could be set like this::

    scsi_set_resid(SCpnt, scsi_bufflen(SCpnt) - (3 * 512));

F:	include/linux/mfd/intel_pmc_bxt.h

INTEL C600 SERIES SAS CONTROLLER DRIVER

M:	Artur Paszkiewicz <artur.paszkiewicz@intel.com>

L:	linux-scsi@vger.kernel.org

S:	Supported

S:	Orphan

T:	git git://git.code.sf.net/p/intel-sas/isci

F:	drivers/scsi/isci/

F:	drivers/s390/crypto/

S390 ZFCP DRIVER

M:	Steffen Maier <maier@linux.ibm.com>

M:	Benjamin Block <bblock@linux.ibm.com>

M:	Nihar Panda <niharp@linux.ibm.com>

L:	linux-s390@vger.kernel.org

S:	Supported

F:	drivers/s390/scsi/zfcp_*

	.sdev_groups		= ahci_sdev_groups,			\

	.change_queue_depth     = ata_scsi_change_queue_depth,		\

	.tag_alloc_policy_rr	= true,					\

	.device_configure	= ata_scsi_device_configure

	.sdev_configure		= ata_scsi_sdev_configure

extern struct ata_port_operations ahci_ops;

extern struct ata_port_operations ahci_platform_ops;