summaryrefslogtreecommitdiff
path: root/Documentation/scsi
diff options
context:
space:
mode:
authorChristoph Hellwig <hch@lst.de>2018-03-19 10:37:53 +0300
committerMartin K. Petersen <martin.petersen@oracle.com>2018-03-20 05:54:47 +0300
commit83c9f08e6c6a6dc668384882de4dcf5ef4ae0ba7 (patch)
tree6751b9993669a3ac2739378d3a5c1a3c00910de2 /Documentation/scsi
parent616434e2aa7091f0fc5f7838af0f8bc809c8cf85 (diff)
downloadlinux-83c9f08e6c6a6dc668384882de4dcf5ef4ae0ba7.tar.xz
scsi: remove the old scsi_module.c initialization model
After more than 15 years all users of this legacy interface are finally gone. Rest in peace! Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'Documentation/scsi')
-rw-r--r--Documentation/scsi/scsi_mid_low_api.txt122
1 files changed, 1 insertions, 121 deletions
diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt
index 2c31d9ee6776..177c031763c0 100644
--- a/Documentation/scsi/scsi_mid_low_api.txt
+++ b/Documentation/scsi/scsi_mid_low_api.txt
@@ -114,9 +114,7 @@ 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. The scsi_register()
-and scsi_unregister() functions remain to support legacy LLDs that use
-the passive initialization model.
+named scsi_register() function in most situations.
Hotplug initialization model
@@ -228,79 +226,6 @@ slave_configure() callbacks). Such instances are "owned" by the mid-level.
struct scsi_device instances are freed after slave_destroy().
-Passive initialization model
-============================
-These older LLDs include a file called "scsi_module.c" [yes the ".c" is a
-little surprising] in their source code. For that file to work an
-instance of struct scsi_host_template with the name "driver_template"
-needs to be defined. Here is a typical code sequence used in this model:
- static struct scsi_host_template driver_template = {
- ...
- };
- #include "scsi_module.c"
-
-The scsi_module.c file contains two functions:
- - init_this_scsi_driver() which is executed when the LLD is
- initialized (i.e. boot time or module load time)
- - exit_this_scsi_driver() which is executed when the LLD is shut
- down (i.e. module unload time)
-Note: since these functions are tagged with __init and __exit qualifiers
-an LLD should not call them explicitly (since the kernel does that).
-
-Here is an example of an initialization sequence when two hosts are
-detected (so detect() returns 2) and the SCSI bus scan on each host
-finds 1 SCSI device (and a second device does not respond).
-
-LLD mid level LLD
-===----------------------=========-----------------===------
-init_this_scsi_driver() ----+
- |
- detect() -----------------+
- | |
- | scsi_register()
- | scsi_register()
- |
- slave_alloc()
- slave_configure() --> scsi_change_queue_depth()
- slave_alloc() ***
- slave_destroy() ***
- |
- slave_alloc()
- slave_configure()
- slave_alloc() ***
- slave_destroy() ***
-------------------------------------------------------------
-
-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.
-
-Here is an LLD shutdown sequence:
-
-LLD mid level LLD
-===----------------------=========-----------------===------
-exit_this_scsi_driver() ----+
- |
- slave_destroy()
- release() --> scsi_unregister()
- |
- slave_destroy()
- release() --> scsi_unregister()
-------------------------------------------------------------
-
-An LLD need not define slave_destroy() (i.e. it is optional).
-
-The shortcoming of the "passive initialization model" is that host
-registration and de-registration are (typically) tied to LLD initialization
-and shutdown. Once the LLD is initialized then a new host that appears
-(e.g. via hotplugging) cannot easily be added without a redundant
-driver shutdown and re-initialization. It may be possible to write an LLD
-that uses both initialization models.
-
-
Reference Counting
==================
The Scsi_Host structure has had reference counting infrastructure added.
@@ -738,7 +663,6 @@ The interface functions are listed below in alphabetical order.
Summary:
bios_param - fetch head, sector, cylinder info for a disk
- detect - detects HBAs this driver wants to control
eh_timed_out - notify the host that a command timer expired
eh_abort_handler - abort given command
eh_bus_reset_handler - issue SCSI bus reset
@@ -748,7 +672,6 @@ Summary:
ioctl - driver can respond to ioctls
proc_info - supports /proc/scsi/{driver_name}/{host_no}
queuecommand - queue scsi command, invoke 'done' on completion
- release - release all resources associated with given host
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
@@ -785,28 +708,6 @@ Details:
/**
- * detect - detects HBAs this driver wants to control
- * @shtp: host template for this driver.
- *
- * Returns number of hosts this driver wants to control. 0 means no
- * suitable hosts found.
- *
- * Locks: none held
- *
- * Calling context: process [invoked from init_this_scsi_driver()]
- *
- * Notes: First function called from the SCSI mid level on this
- * driver. Upper level drivers (e.g. sd) may not (yet) be present.
- * For each host found, this method should call scsi_register()
- * [see hosts.c].
- *
- * Defined in: LLD (required if "passive initialization mode" is used,
- * not invoked in "hotplug initialization mode")
- **/
- int detect(struct scsi_host_template * shtp)
-
-
-/**
* eh_timed_out - The timer for the command has just fired
* @scp: identifies command timing out
*
@@ -1074,27 +975,6 @@ Details:
/**
- * release - release all resources associated with given host
- * @shp: host to be released.
- *
- * Return value ignored (could soon be a function returning void).
- *
- * Locks: none held
- *
- * Calling context: process
- *
- * Notes: Invoked from scsi_module.c's exit_this_scsi_driver().
- * LLD's implementation of this function should call
- * scsi_unregister(shp) prior to returning.
- * Only needed for old-style host templates.
- *
- * Defined in: LLD (required in "passive initialization model",
- * should not be defined in hotplug model)
- **/
- int release(struct Scsi_Host * shp)
-
-
-/**
* slave_alloc - 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)