linux_dsm_epyc7002/include/scsi/scsi_host.h

937 lines
28 KiB
C
Raw Normal View History

#ifndef _SCSI_SCSI_HOST_H
#define _SCSI_SCSI_HOST_H
#include <linux/device.h>
#include <linux/list.h>
#include <linux/types.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/seq_file.h>
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
#include <linux/blk-mq.h>
#include <scsi/scsi.h>
struct request_queue;
struct block_device;
struct completion;
struct module;
struct scsi_cmnd;
struct scsi_device;
struct scsi_host_cmd_pool;
struct scsi_target;
struct Scsi_Host;
struct scsi_host_cmd_pool;
struct scsi_transport_template;
struct blk_queue_tags;
/*
* The various choices mean:
* NONE: Self evident. Host adapter is not capable of scatter-gather.
* ALL: Means that the host adapter module can do scatter-gather,
* and that there is no limit to the size of the table to which
* we scatter/gather data. The value we set here is the maximum
* single element sglist. To use chained sglists, the adapter
* has to set a value beyond ALL (and correctly use the chain
* handling API.
* Anything else: Indicates the maximum number of chains that can be
* used in one scatter-gather request.
*/
#define SG_NONE 0
#define SG_ALL SCSI_MAX_SG_SEGMENTS
#define MODE_UNKNOWN 0x00
#define MODE_INITIATOR 0x01
#define MODE_TARGET 0x02
#define DISABLE_CLUSTERING 0
#define ENABLE_CLUSTERING 1
struct scsi_host_template {
struct module *module;
const char *name;
/*
* Used to initialize old-style drivers. For new-style drivers
* just perform all work in your module initialization function.
*
* Status: OBSOLETE
*/
int (* detect)(struct scsi_host_template *);
/*
* Used as unload callback for hosts with old-style drivers.
*
* Status: OBSOLETE
*/
int (* release)(struct Scsi_Host *);
/*
* The info function will return whatever useful information the
* developer sees fit. If not provided, then the name field will
* be used instead.
*
* Status: OPTIONAL
*/
const char *(* info)(struct Scsi_Host *);
/*
* Ioctl interface
*
* Status: OPTIONAL
*/
int (* ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
#ifdef CONFIG_COMPAT
/*
* Compat handler. Handle 32bit ABI.
* When unknown ioctl is passed return -ENOIOCTLCMD.
*
* Status: OPTIONAL
*/
int (* compat_ioctl)(struct scsi_device *dev, int cmd, void __user *arg);
#endif
/*
* The queuecommand function is used to queue up a scsi
* command block to the LLDD. When the driver finished
* processing the command the done callback is invoked.
*
* If queuecommand returns 0, then the HBA has accepted the
* command. The done() function must be called on the command
* when the driver has finished with it. (you may call done on the
* command before queuecommand returns, but in this case you
* *must* return 0 from queuecommand).
*
* Queuecommand may also reject the command, in which case it may
* not touch the command and must not call done() for it.
*
* There are two possible rejection returns:
*
* SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but
* allow commands to other devices serviced by this host.
*
* SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this
* host temporarily.
*
* For compatibility, any other non-zero return is treated the
* same as SCSI_MLQUEUE_HOST_BUSY.
*
* NOTE: "temporarily" means either until the next command for#
* this device/host completes, or a period of time determined by
* I/O pressure in the system if there are no other outstanding
* commands.
*
* STATUS: REQUIRED
*/
int (* queuecommand)(struct Scsi_Host *, struct scsi_cmnd *);
/*
* This is an error handling strategy routine. You don't need to
* define one of these if you don't want to - there is a default
* routine that is present that should work in most cases. For those
* driver authors that have the inclination and ability to write their
* own strategy routine, this is where it is specified. Note - the
* strategy routine is *ALWAYS* run in the context of the kernel eh
* thread. Thus you are guaranteed to *NOT* be in an interrupt
* handler when you execute this, and you are also guaranteed to
* *NOT* have any other commands being queued while you are in the
* strategy routine. When you return from this function, operations
* return to normal.
*
* See scsi_error.c scsi_unjam_host for additional comments about
* what this function should and should not be attempting to do.
*
* Status: REQUIRED (at least one of them)
*/
int (* eh_abort_handler)(struct scsi_cmnd *);
int (* eh_device_reset_handler)(struct scsi_cmnd *);
int (* eh_target_reset_handler)(struct scsi_cmnd *);
int (* eh_bus_reset_handler)(struct scsi_cmnd *);
int (* eh_host_reset_handler)(struct scsi_cmnd *);
/*
* Before the mid layer attempts to scan for a new device where none
* currently exists, it will call this entry in your driver. Should
* your driver need to allocate any structs or perform any other init
* items in order to send commands to a currently unused target/lun
* combo, then this is where you can perform those allocations. This
* is specifically so that drivers won't have to perform any kind of
* "is this a new device" checks in their queuecommand routine,
* thereby making the hot path a bit quicker.
*
* Return values: 0 on success, non-0 on failure
*
* Deallocation: If we didn't find any devices at this ID, you will
* get an immediate call to slave_destroy(). If we find something
* here then you will get a call to slave_configure(), then the
* device will be used for however long it is kept around, then when
* the device is removed from the system (or * possibly at reboot
* time), you will then get a call to slave_destroy(). This is
* assuming you implement slave_configure and slave_destroy.
* However, if you allocate memory and hang it off the device struct,
* then you must implement the slave_destroy() routine at a minimum
* in order to avoid leaking memory
* each time a device is tore down.
*
* Status: OPTIONAL
*/
int (* slave_alloc)(struct scsi_device *);
/*
* Once the device has responded to an INQUIRY and we know the
* device is online, we call into the low level driver with the
* struct scsi_device *. If the low level device driver implements
* this function, it *must* perform the task of setting the queue
* depth on the device. All other tasks are optional and depend
* on what the driver supports and various implementation details.
*
* Things currently recommended to be handled at this time include:
*
* 1. Setting the device queue depth. Proper setting of this is
* described in the comments for scsi_change_queue_depth.
* 2. Determining if the device supports the various synchronous
* negotiation protocols. The device struct will already have
* responded to INQUIRY and the results of the standard items
* will have been shoved into the various device flag bits, eg.
* device->sdtr will be true if the device supports SDTR messages.
* 3. Allocating command structs that the device will need.
* 4. Setting the default timeout on this device (if needed).
* 5. Anything else the low level driver might want to do on a device
* specific setup basis...
* 6. Return 0 on success, non-0 on error. The device will be marked
* as offline on error so that no access will occur. If you return
* non-0, your slave_destroy routine will never get called for this
* device, so don't leave any loose memory hanging around, clean
* up after yourself before returning non-0
*
* Status: OPTIONAL
*/
int (* slave_configure)(struct scsi_device *);
/*
* Immediately prior to deallocating the device and after all activity
* has ceased the mid layer calls this point so that the low level
* driver may completely detach itself from the scsi device and vice
* versa. The low level driver is responsible for freeing any memory
* it allocated in the slave_alloc or slave_configure calls.
*
* Status: OPTIONAL
*/
void (* slave_destroy)(struct scsi_device *);
/*
* Before the mid layer attempts to scan for a new device attached
* to a target where no target currently exists, it will call this
* entry in your driver. Should your driver need to allocate any
* structs or perform any other init items in order to send commands
* to a currently unused target, then this is where you can perform
* those allocations.
*
* Return values: 0 on success, non-0 on failure
*
* Status: OPTIONAL
*/
int (* target_alloc)(struct scsi_target *);
/*
* Immediately prior to deallocating the target structure, and
* after all activity to attached scsi devices has ceased, the
* midlayer calls this point so that the driver may deallocate
* and terminate any references to the target.
*
* Status: OPTIONAL
*/
void (* target_destroy)(struct scsi_target *);
/*
* If a host has the ability to discover targets on its own instead
* of scanning the entire bus, it can fill in this function and
* call scsi_scan_host(). This function will be called periodically
* until it returns 1 with the scsi_host and the elapsed time of
* the scan in jiffies.
*
* Status: OPTIONAL
*/
int (* scan_finished)(struct Scsi_Host *, unsigned long);
/*
* If the host wants to be called before the scan starts, but
* after the midlayer has set up ready for the scan, it can fill
* in this function.
*
* Status: OPTIONAL
*/
void (* scan_start)(struct Scsi_Host *);
/*
* Fill in this function to allow the queue depth of this host
* to be changeable (on a per device basis). Returns either
* the current queue depth setting (may be different from what
* was passed in) or an error. An error should only be
* returned if the requested depth is legal but the driver was
* unable to set it. If the requested depth is illegal, the
* driver should set and return the closest legal queue depth.
*
* Status: OPTIONAL
*/
int (* change_queue_depth)(struct scsi_device *, int);
/*
* This function determines the BIOS parameters for a given
* harddisk. These tend to be numbers that are made up by
* the host adapter. Parameters:
* size, device, list (heads, sectors, cylinders)
*
* Status: OPTIONAL
*/
int (* bios_param)(struct scsi_device *, struct block_device *,
sector_t, int []);
/*
* This function is called when one or more partitions on the
* device reach beyond the end of the device.
*
* Status: OPTIONAL
*/
void (*unlock_native_capacity)(struct scsi_device *);
/*
* Can be used to export driver statistics and other infos to the
* world outside the kernel ie. userspace and it also provides an
* interface to feed the driver with information.
*
* Status: OBSOLETE
*/
int (*show_info)(struct seq_file *, struct Scsi_Host *);
int (*write_info)(struct Scsi_Host *, char *, int);
/*
* This is an optional routine that allows the transport to become
* involved when a scsi io timer fires. The return value tells the
* timer routine how to finish the io timeout handling:
* EH_HANDLED: I fixed the error, please complete the command
* EH_RESET_TIMER: I need more time, reset the timer and
* begin counting again
* EH_NOT_HANDLED Begin normal error recovery
*
* Status: OPTIONAL
*/
enum blk_eh_timer_return (*eh_timed_out)(struct scsi_cmnd *);
/* This is an optional routine that allows transport to initiate
* LLD adapter or firmware reset using sysfs attribute.
*
* Return values: 0 on success, -ve value on failure.
*
* Status: OPTIONAL
*/
int (*host_reset)(struct Scsi_Host *shost, int reset_type);
#define SCSI_ADAPTER_RESET 1
#define SCSI_FIRMWARE_RESET 2
/*
* Name of proc directory
*/
const char *proc_name;
/*
* Used to store the procfs directory if a driver implements the
* show_info method.
*/
struct proc_dir_entry *proc_dir;
/*
* This determines if we will use a non-interrupt driven
* or an interrupt driven scheme. It is set to the maximum number
* of simultaneous commands a given host adapter will accept.
*/
int can_queue;
/*
* In many instances, especially where disconnect / reconnect are
* supported, our host also has an ID on the SCSI bus. If this is
* the case, then it must be reserved. Please set this_id to -1 if
* your setup is in single initiator mode, and the host lacks an
* ID.
*/
int this_id;
/*
* This determines the degree to which the host adapter is capable
* of scatter-gather.
*/
unsigned short sg_tablesize;
unsigned short sg_prot_tablesize;
/*
* Set this if the host adapter has limitations beside segment count.
*/
unsigned int max_sectors;
/*
* DMA scatter gather segment boundary limit. A segment crossing this
* boundary will be split in two.
*/
unsigned long dma_boundary;
/*
* This specifies "machine infinity" for host templates which don't
* limit the transfer size. Note this limit represents an absolute
* maximum, and may be over the transfer limits allowed for
* individual devices (e.g. 256 for SCSI-1).
*/
#define SCSI_DEFAULT_MAX_SECTORS 1024
/*
* True if this host adapter can make good use of linked commands.
* This will allow more than one command to be queued to a given
* unit on a given host. Set this to the maximum number of command
* blocks to be provided for each device. Set this to 1 for one
* command block per lun, 2 for two, etc. Do not set this to 0.
* You should make sure that the host adapter will do the right thing
* before you try setting this above 1.
*/
short cmd_per_lun;
/*
* present contains counter indicating how many boards of this
* type were found when we did the scan.
*/
unsigned char present;
/* If use block layer to manage tags, this is tag allocation policy */
int tag_alloc_policy;
/*
* Let the block layer assigns tags to all commands.
*/
unsigned use_blk_tags:1;
/*
* Track QUEUE_FULL events and reduce queue depth on demand.
*/
unsigned track_queue_depth:1;
/*
* This specifies the mode that a LLD supports.
*/
unsigned supported_mode:2;
/*
* True if this host adapter uses unchecked DMA onto an ISA bus.
*/
unsigned unchecked_isa_dma:1;
/*
* True if this host adapter can make good use of clustering.
* I originally thought that if the tablesize was large that it
* was a waste of CPU cycles to prepare a cluster list, but
* it works out that the Buslogic is faster if you use a smaller
* number of segments (i.e. use clustering). I guess it is
* inefficient.
*/
unsigned use_clustering:1;
/*
* True for emulated SCSI host adapters (e.g. ATAPI).
*/
unsigned emulated:1;
/*
* True if the low-level driver performs its own reset-settle delays.
*/
unsigned skip_settle_delay:1;
/* True if the controller does not support WRITE SAME */
unsigned no_write_same:1;
/*
* True if asynchronous aborts are not supported
*/
unsigned no_async_abort:1;
/*
* Countdown for host blocking with no commands outstanding.
*/
unsigned int max_host_blocked;
/*
* Default value for the blocking. If the queue is empty,
* host_blocked counts down in the request_fn until it restarts
* host operations as zero is reached.
*
* FIXME: This should probably be a value in the template
*/
#define SCSI_DEFAULT_HOST_BLOCKED 7
/*
* Pointer to the sysfs class properties for this host, NULL terminated.
*/
struct device_attribute **shost_attrs;
/*
* Pointer to the SCSI device properties for this host, NULL terminated.
*/
struct device_attribute **sdev_attrs;
/*
* List of hosts per template.
*
* This is only for use by scsi_module.c for legacy templates.
* For these access to it is synchronized implicitly by
* module_init/module_exit.
*/
struct list_head legacy_hosts;
[SCSI] FC Pass Thru support Attached is the ELS/CT pass-thru patch for the FC Transport. The patch creates a generic framework that lays on top of bsg and the SGIO v4 ioctl in order to pass transaction requests to LLDD's. The interface supports the following operations: On an fc_host basis: Request login to the specified N_Port_ID, creating an fc_rport. Request logout of the specified N_Port_ID, deleting an fc_rport Send ELS request to specified N_Port_ID w/o requiring a login, and wait for ELS response. Send CT request to specified N_Port_ID and wait for CT response. Login is required, but LLDD is allowed to manage login and decide whether it stays in place after the request is satisfied. Vendor-Unique request. Allows a LLDD-specific request to be passed to the LLDD, and the passing of a response back to the application. On an fc_rport basis: Send ELS request to nport and wait for ELS response. Send CT request to nport and wait for CT response. The patch also exports several headers from include/scsi such that they can be available to user-space applications: include/scsi/scsi.h include/scsi/scsi_netlink.h include/scsi/scsi_netlink_fc.h include/scsi/scsi_bsg_fc.h For further information, refer to the last RFC: http://marc.info/?l=linux-scsi&m=123436574018579&w=2 Note: Documentation is still spotty and will be added later. [bharrosh@panasas.com: update for new block API] Signed-off-by: James Smart <james.smart@emulex.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-03-27 00:33:19 +07:00
/*
* Vendor Identifier associated with the host
*
* Note: When specifying vendor_id, be sure to read the
* Vendor Type and ID formatting requirements specified in
* scsi_netlink.h
*/
u64 vendor_id;
/*
* Additional per-command data allocated for the driver.
*/
unsigned int cmd_size;
struct scsi_host_cmd_pool *cmd_pool;
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
/* temporary flag to disable blk-mq I/O path */
bool disable_blk_mq;
};
/*
* Temporary #define for host lock push down. Can be removed when all
* drivers have been updated to take advantage of unlocked
* queuecommand.
*
*/
#define DEF_SCSI_QCMD(func_name) \
int func_name(struct Scsi_Host *shost, struct scsi_cmnd *cmd) \
{ \
unsigned long irq_flags; \
int rc; \
spin_lock_irqsave(shost->host_lock, irq_flags); \
scsi_cmd_get_serial(shost, cmd); \
rc = func_name##_lck (cmd, cmd->scsi_done); \
spin_unlock_irqrestore(shost->host_lock, irq_flags); \
return rc; \
}
/*
* shost state: If you alter this, you also need to alter scsi_sysfs.c
* (for the ascii descriptions) and the state model enforcer:
* scsi_host_set_state()
*/
enum scsi_host_state {
SHOST_CREATED = 1,
SHOST_RUNNING,
SHOST_CANCEL,
SHOST_DEL,
SHOST_RECOVERY,
SHOST_CANCEL_RECOVERY,
SHOST_DEL_RECOVERY,
};
struct Scsi_Host {
/*
* __devices is protected by the host_lock, but you should
* usually use scsi_device_lookup / shost_for_each_device
* to access it and don't care about locking yourself.
* In the rare case of being in irq context you can use
* their __ prefixed variants with the lock held. NEVER
* access this list directly from a driver.
*/
struct list_head __devices;
struct list_head __targets;
struct scsi_host_cmd_pool *cmd_pool;
spinlock_t free_list_lock;
struct list_head free_list; /* backup store of cmd structs */
struct list_head starved_list;
spinlock_t default_lock;
spinlock_t *host_lock;
struct mutex scan_mutex;/* serialize scanning activity */
struct list_head eh_cmd_q;
struct task_struct * ehandler; /* Error recovery thread. */
struct completion * eh_action; /* Wait for specific actions on the
host. */
wait_queue_head_t host_wait;
struct scsi_host_template *hostt;
struct scsi_transport_template *transportt;
/*
* Area to keep a shared tag map (if needed, will be
* NULL if not).
*/
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
union {
struct blk_queue_tag *bqt;
struct blk_mq_tag_set tag_set;
};
atomic_t host_busy; /* commands actually active on low-level */
atomic_t host_blocked;
unsigned int host_failed; /* commands that failed.
protected by host_lock */
unsigned int host_eh_scheduled; /* EH scheduled without command */
unsigned int host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */
/* next two fields are used to bound the time spent in error handling */
int eh_deadline;
unsigned long last_reset;
/*
* These three parameters can be used to allow for wide scsi,
* and for host adapters that support multiple busses
* The last two should be set to 1 more than the actual max id
* or lun (e.g. 8 for SCSI parallel systems).
*/
unsigned int max_channel;
unsigned int max_id;
u64 max_lun;
/*
* This is a unique identifier that must be assigned so that we
* have some way of identifying each detected host adapter properly
* and uniquely. For hosts that do not support more than one card
* in the system at one time, this does not need to be set. It is
* initialized to 0 in scsi_register.
*/
unsigned int unique_id;
/*
* The maximum length of SCSI commands that this host can accept.
* Probably 12 for most host adapters, but could be 16 for others.
* or 260 if the driver supports variable length cdbs.
* For drivers that don't set this field, a value of 12 is
* assumed.
*/
unsigned short max_cmd_len;
int this_id;
int can_queue;
short cmd_per_lun;
short unsigned int sg_tablesize;
short unsigned int sg_prot_tablesize;
unsigned int max_sectors;
unsigned long dma_boundary;
/*
* In scsi-mq mode, the number of hardware queues supported by the LLD.
*
* Note: it is assumed that each hardware queue has a queue depth of
* can_queue. In other words, the total queue depth per host
* is nr_hw_queues * can_queue.
*/
unsigned nr_hw_queues;
/*
* Used to assign serial numbers to the cmds.
* Protected by the host lock.
*/
unsigned long cmd_serial_number;
unsigned active_mode:2;
unsigned unchecked_isa_dma:1;
unsigned use_clustering:1;
/*
* Host has requested that no further requests come through for the
* time being.
*/
unsigned host_self_blocked:1;
/*
* Host uses correct SCSI ordering not PC ordering. The bit is
* set for the minority of drivers whose authors actually read
* the spec ;).
*/
unsigned reverse_ordering:1;
/* Task mgmt function in progress */
unsigned tmf_in_progress:1;
/* Asynchronous scan in progress */
unsigned async_scan:1;
/* Don't resume host in EH */
unsigned eh_noresume:1;
/* The controller does not support WRITE SAME */
unsigned no_write_same:1;
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
unsigned use_blk_mq:1;
unsigned use_cmd_list:1;
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
/*
* Optional work queue to be utilized by the transport
*/
char work_q_name[20];
struct workqueue_struct *work_q;
/*
* Task management function work queue
*/
struct workqueue_struct *tmf_work_q;
scsi: don't store LUN bits in CDB[1] for USB mass-storage devices The SCSI specification requires that the second Command Data Byte should contain the LUN value in its high-order bits if the recipient device reports SCSI level 2 or below. Nevertheless, some USB mass-storage devices use those bits for other purposes in vendor-specific commands. Currently Linux has no way to send such commands, because the SCSI stack always overwrites the LUN bits. Testing shows that Windows 7 and XP do not store the LUN bits in the CDB when sending commands to a USB device. This doesn't matter if the device uses the Bulk-Only or UAS transports (which virtually all modern USB mass-storage devices do), as these have a separate mechanism for sending the LUN value. Therefore this patch introduces a flag in the Scsi_Host structure to inform the SCSI midlayer that a transport does not require the LUN bits to be stored in the CDB, and it makes usb-storage set this flag for all devices using the Bulk-Only transport. (UAS is handled by a separate driver, but it doesn't really matter because no SCSI-2 or lower device is at all likely to use UAS.) The patch also cleans up the code responsible for storing the LUN value by adding a bitflag to the scsi_device structure. The test for whether to stick the LUN value in the CDB can be made when the device is probed, and stored for future use rather than being made over and over in the fast path. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Reported-by: Tiziano Bacocco <tiziano.bacocco@gmail.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Acked-by: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-09-02 22:35:50 +07:00
/* The transport requires the LUN bits NOT to be stored in CDB[1] */
unsigned no_scsi2_lun_in_cdb:1;
/*
* Value host_blocked counts down from
*/
unsigned int max_host_blocked;
/* Protection Information */
unsigned int prot_capabilities;
unsigned char prot_guard_type;
/*
* q used for scsi_tgt msgs, async events or any other requests that
* need to be processed in userspace
*/
struct request_queue *uspace_req_q;
/* legacy crap */
unsigned long base;
unsigned long io_port;
unsigned char n_io_port;
unsigned char dma_channel;
unsigned int irq;
enum scsi_host_state shost_state;
/* ldm bits */
struct device shost_gendev, shost_dev;
/*
* List of hosts per template.
*
* This is only for use by scsi_module.c for legacy templates.
* For these access to it is synchronized implicitly by
* module_init/module_exit.
*/
struct list_head sht_legacy_list;
/*
* Points to the transport data (if any) which is allocated
* separately
*/
void *shost_data;
/*
* Points to the physical bus device we'd use to do DMA
* Needed just in case we have virtual hosts.
*/
struct device *dma_dev;
/*
* We should ensure that this is aligned, both for better performance
* and also because some compilers (m68k) don't automatically force
* alignment to a long boundary.
*/
unsigned long hostdata[0] /* Used for storage of host specific stuff */
__attribute__ ((aligned (sizeof(unsigned long))));
};
#define class_to_shost(d) \
container_of(d, struct Scsi_Host, shost_dev)
#define shost_printk(prefix, shost, fmt, a...) \
dev_printk(prefix, &(shost)->shost_gendev, fmt, ##a)
static inline void *shost_priv(struct Scsi_Host *shost)
{
return (void *)shost->hostdata;
}
int scsi_is_host_device(const struct device *);
static inline struct Scsi_Host *dev_to_shost(struct device *dev)
{
while (!scsi_is_host_device(dev)) {
if (!dev->parent)
return NULL;
dev = dev->parent;
}
return container_of(dev, struct Scsi_Host, shost_gendev);
}
static inline int scsi_host_in_recovery(struct Scsi_Host *shost)
{
return shost->shost_state == SHOST_RECOVERY ||
shost->shost_state == SHOST_CANCEL_RECOVERY ||
shost->shost_state == SHOST_DEL_RECOVERY ||
shost->tmf_in_progress;
}
scsi: add support for a blk-mq based I/O path. This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-01-17 18:06:53 +07:00
extern bool scsi_use_blk_mq;
static inline bool shost_use_blk_mq(struct Scsi_Host *shost)
{
return shost->use_blk_mq;
}
extern int scsi_queue_work(struct Scsi_Host *, struct work_struct *);
extern void scsi_flush_work(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *, int);
extern int __must_check scsi_add_host_with_dma(struct Scsi_Host *,
struct device *,
struct device *);
extern void scsi_scan_host(struct Scsi_Host *);
extern void scsi_rescan_device(struct device *);
extern void scsi_remove_host(struct Scsi_Host *);
extern struct Scsi_Host *scsi_host_get(struct Scsi_Host *);
extern void scsi_host_put(struct Scsi_Host *t);
extern struct Scsi_Host *scsi_host_lookup(unsigned short);
extern const char *scsi_host_state_name(enum scsi_host_state);
extern void scsi_cmd_get_serial(struct Scsi_Host *, struct scsi_cmnd *);
static inline int __must_check scsi_add_host(struct Scsi_Host *host,
struct device *dev)
{
return scsi_add_host_with_dma(host, dev, dev);
}
static inline struct device *scsi_get_device(struct Scsi_Host *shost)
{
return shost->shost_gendev.parent;
}
/**
* scsi_host_scan_allowed - Is scanning of this host allowed
* @shost: Pointer to Scsi_Host.
**/
static inline int scsi_host_scan_allowed(struct Scsi_Host *shost)
{
2011-08-25 12:36:38 +07:00
return shost->shost_state == SHOST_RUNNING ||
shost->shost_state == SHOST_RECOVERY;
}
extern void scsi_unblock_requests(struct Scsi_Host *);
extern void scsi_block_requests(struct Scsi_Host *);
struct class_container;
extern struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
void (*) (struct request_queue *));
/*
* These two functions are used to allocate and free a pseudo device
* which will connect to the host adapter itself rather than any
* physical device. You must deallocate when you are done with the
* thing. This physical pseudo-device isn't real and won't be available
* from any high-level drivers.
*/
extern void scsi_free_host_dev(struct scsi_device *);
extern struct scsi_device *scsi_get_host_dev(struct Scsi_Host *);
/*
* DIF defines the exchange of protection information between
* initiator and SBC block device.
*
* DIX defines the exchange of protection information between OS and
* initiator.
*/
enum scsi_host_prot_capabilities {
SHOST_DIF_TYPE1_PROTECTION = 1 << 0, /* T10 DIF Type 1 */
SHOST_DIF_TYPE2_PROTECTION = 1 << 1, /* T10 DIF Type 2 */
SHOST_DIF_TYPE3_PROTECTION = 1 << 2, /* T10 DIF Type 3 */
SHOST_DIX_TYPE0_PROTECTION = 1 << 3, /* DIX between OS and HBA only */
SHOST_DIX_TYPE1_PROTECTION = 1 << 4, /* DIX with DIF Type 1 */
SHOST_DIX_TYPE2_PROTECTION = 1 << 5, /* DIX with DIF Type 2 */
SHOST_DIX_TYPE3_PROTECTION = 1 << 6, /* DIX with DIF Type 3 */
};
/*
* SCSI hosts which support the Data Integrity Extensions must
* indicate their capabilities by setting the prot_capabilities using
* this call.
*/
static inline void scsi_host_set_prot(struct Scsi_Host *shost, unsigned int mask)
{
shost->prot_capabilities = mask;
}
static inline unsigned int scsi_host_get_prot(struct Scsi_Host *shost)
{
return shost->prot_capabilities;
}
static inline int scsi_host_prot_dma(struct Scsi_Host *shost)
{
return shost->prot_capabilities >= SHOST_DIX_TYPE0_PROTECTION;
}
static inline unsigned int scsi_host_dif_capable(struct Scsi_Host *shost, unsigned int target_type)
{
static unsigned char cap[] = { 0,
SHOST_DIF_TYPE1_PROTECTION,
SHOST_DIF_TYPE2_PROTECTION,
SHOST_DIF_TYPE3_PROTECTION };
if (target_type >= ARRAY_SIZE(cap))
return 0;
return shost->prot_capabilities & cap[target_type] ? target_type : 0;
}
static inline unsigned int scsi_host_dix_capable(struct Scsi_Host *shost, unsigned int target_type)
{
#if defined(CONFIG_BLK_DEV_INTEGRITY)
static unsigned char cap[] = { SHOST_DIX_TYPE0_PROTECTION,
SHOST_DIX_TYPE1_PROTECTION,
SHOST_DIX_TYPE2_PROTECTION,
SHOST_DIX_TYPE3_PROTECTION };
if (target_type >= ARRAY_SIZE(cap))
return 0;
return shost->prot_capabilities & cap[target_type];
#endif
return 0;
}
/*
* All DIX-capable initiators must support the T10-mandated CRC
* checksum. Controllers can optionally implement the IP checksum
* scheme which has much lower impact on system performance. Note
* that the main rationale for the checksum is to match integrity
* metadata with data. Detecting bit errors are a job for ECC memory
* and buses.
*/
enum scsi_host_guard_type {
SHOST_DIX_GUARD_CRC = 1 << 0,
SHOST_DIX_GUARD_IP = 1 << 1,
};
static inline void scsi_host_set_guard(struct Scsi_Host *shost, unsigned char type)
{
shost->prot_guard_type = type;
}
static inline unsigned char scsi_host_get_guard(struct Scsi_Host *shost)
{
return shost->prot_guard_type;
}
/* legacy interfaces */
extern struct Scsi_Host *scsi_register(struct scsi_host_template *, int);
extern void scsi_unregister(struct Scsi_Host *);
extern int scsi_host_set_state(struct Scsi_Host *, enum scsi_host_state);
#endif /* _SCSI_SCSI_HOST_H */