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2010-02-26[S390] dasd: correct offline processingStefan Haberland
Flushing the dasd ccw request queue may stop the processing of the block device request queue. Destroy partitions may wait for outstanding requests and thus hang. Swapping dasd_destroy_partitions and dasd_flush_request_queue so that the request queue is empty before dasd_destroy_partitions is called. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26[S390] dasd: fix refcounting.Stefan Haberland
The function dasd_device_from_cdev returns a reference to the dasd device and increases the refcount by one. If an exception occurs, the refcount was not decreased in all cases e.g. in dasd_discipline_show. Prevent the offline processing from hang by correcting two functions to decrease the refcount even if an error occured. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26[S390] dasd: fix online/offline raceStefan Haberland
Setting a DASD online and offline in quick succession may cause a kernel panic or let the chhccwdev command wait forever. The Online process is split into two parts. After the first part is finished the offline process may be called. This may result in a situation where the second online processing part tries to set the DASD offline as well. Use a mutex to protect online and offline against each other. Also correct some checking. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-02-26block: Consolidate phys_segment and hw_segment limitsMartin K. Petersen
Except for SCSI no device drivers distinguish between physical and hardware segment limits. Consolidate the two into a single segment limit. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26block: Rename blk_queue_max_sectors to blk_queue_max_hw_sectorsMartin K. Petersen
The block layer calling convention is blk_queue_<limit name>. blk_queue_max_sectors predates this practice, leading to some confusion. Rename the function to appropriately reflect that its intended use is to set max_hw_sectors. Also introduce a temporary wrapper for backwards compability. This can be removed after the merge window is closed. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-27[S390] dasd: fix possible NULL pointer errorsStefan Haberland
Fix possible NULL pointer in DASD messages and correct discipline checking. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-01-13[S390] dasd: add proper compat pointer conversion for symmetrix ioctlHeiko Carstens
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-01-13[S390] dasd: add missing compat ptr conversionHeiko Carstens
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-18[S390] dasd: PTR_ERR return of wrong pointer inRoel Kluin
Return the PTR_ERR of the correct pointer. Signed-off-by: Roel Kluin <roel.kluin@gmail.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-18[S390] dasd: move dasd-diag kmsg to dasdStefan Haberland
The DIAG discipline does not have a own driver name. It shows up as dasd-eckd or dasd-fba. So messages for dasd-diag are moved to the generic dasd part. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-15tree-wide: convert open calls to remove spaces to skip_spaces() lib functionAndré Goddard Rosa
Makes use of skip_spaces() defined in lib/string.c for removing leading spaces from strings all over the tree. It decreases lib.a code size by 47 bytes and reuses the function tree-wide: text data bss dec hex filename 64688 584 592 65864 10148 (TOTALS-BEFORE) 64641 584 592 65817 10119 (TOTALS-AFTER) Also, while at it, if we see (*str && isspace(*str)), we can be sure to remove the first condition (*str) as the second one (isspace(*str)) also evaluates to 0 whenever *str == 0, making it redundant. In other words, "a char equals zero is never a space". Julia Lawall tried the semantic patch (http://coccinelle.lip6.fr) below, and found occurrences of this pattern on 3 more files: drivers/leds/led-class.c drivers/leds/ledtrig-timer.c drivers/video/output.c @@ expression str; @@ ( // ignore skip_spaces cases while (*str && isspace(*str)) { \(str++;\|++str;\) } | - *str && isspace(*str) ) Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com> Cc: Julia Lawall <julia@diku.dk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Dike <jdike@addtoit.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Richard Purdie <rpurdie@rpsys.net> Cc: Neil Brown <neilb@suse.de> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: David Howells <dhowells@redhat.com> Cc: <linux-ext4@vger.kernel.org> Cc: Samuel Ortiz <samuel@sortiz.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-15const: constify remaining dev_pm_opsAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-09Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits) tree-wide: fix misspelling of "definition" in comments reiserfs: fix misspelling of "journaled" doc: Fix a typo in slub.txt. inotify: remove superfluous return code check hdlc: spelling fix in find_pvc() comment doc: fix regulator docs cut-and-pasteism mtd: Fix comment in Kconfig doc: Fix IRQ chip docs tree-wide: fix assorted typos all over the place drivers/ata/libata-sff.c: comment spelling fixes fix typos/grammos in Documentation/edac.txt sysctl: add missing comments fs/debugfs/inode.c: fix comment typos sgivwfb: Make use of ARRAY_SIZE. sky2: fix sky2_link_down copy/paste comment error tree-wide: fix typos "couter" -> "counter" tree-wide: fix typos "offest" -> "offset" fix kerneldoc for set_irq_msi() spidev: fix double "of of" in comment comment typo fix: sybsystem -> subsystem ...
2009-12-07[S390] dasd: remove BKL from extended error reporting codeMartin Schwidefsky
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: let device initialization wait for LCU setupStefan Weinhuber
The first DASD that is set online for a specific logical control unit has to do certain setup steps on the storage server to make full use of it, for example it will enable PAV. The features and characteristics reported by the storage server will depend on this setup, so all other devices on the same LCU will need to wait for the setup to be finished. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: remove strings from s390dbfStefan Haberland
Remove strings from s390 debugfeature entries that could lead to a crash when the data is read from dbf because the strings do not exist any more. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: improve error recovery for internal I/OStefan Weinhuber
Most of the error conditions reported by a FICON storage server indicate situations which can be recovered. Sometimes the host just needs to retry an I/O request, but sometimes the recovery is more complex and requires the device driver to wait, choose a different path, etc. The DASD device driver has a fully featured error recovery for normal block layer I/O, but not for internal I/O request which are for example used during the device bring up. This can lead to situations where the IPL of a system fails because DASD devices are not properly recognized. This patch will extend the internal I/O handling to use the existing error recovery procedures. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: enable prefix independent of pav supportStefan Weinhuber
The DASD device driver needs to explicitly enable the prefix command on the storage server, before it can be used. Originally we enabled this command along with others only if we wanted to support PAV. However, today we require this command for other features like High Performance FICON as well, so we need to always enable prefix. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: remove dead codeChristian Borntraeger
the todclk.h header file is dead code. Remove it. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] dasd: support DIAG access for read-only devicesStefan Weinhuber
When a DASD device is used with the DIAG discipline, the DIAG initialization will indicate success or error with a respective return code. So far we have interpreted a return code of 4 as error, but it actually means that the initialization was successful, but the device is read-only. To allow read-only devices to be used with DIAG we need to accept a return code of 4 as success. Re-initialization of the DIAG access is also part of the DIAG error recovery. If we find that the access mode of a device has been changed from writable to read-only while the device was in use, we print an error message. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-07[S390] cio: split PGID settings and statusPeter Oberparleiter
Split setting (driver wants feature enabled) and status (feature setup was successful) for PGID related ccw device features so that setup errors can be detected. Previously, incorrectly handled setup errors could in rare cases lead to erratic I/O behavior and permanently unusuable devices. Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-04tree-wide: fix typos "couter" -> "counter"Uwe Kleine-König
This patch was generated by git grep -E -i -l 'couter' | xargs -r perl -p -i -e 's/couter/counter/' Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-10-14[S390] dasd: use idal for device characteristicsStefan Haberland
If the rdc_buffer is above 2G we need indirect addresssing so we have to use an idaw to give the rdc_buffer to the ccw. If the rdc_buffer is under 2G nothing changes. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-14[S390] dasd: fix locking bugStefan Haberland
Replace spin_lock with spin_lock_irqsave in dasd_eckd_restore_device. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-10-06[S390] dasd: fix race condition in resume codeStefan Haberland
There is a race while re-reading the device characteristics. After cleaning the memory area a cqr is build which reads the device characteristics. This may take a rather long time and the device characteristics structure is zero during this. Now it could be possible that the block tasklet starts working and a new cqr will be build. The build_cp command refers to the device characteristics structure and this may lead into a divide by zero exception. Fix this by re-reading the device characteristics into a temporary structur and copy the data to the original structure. Also take the ccwdev_lock. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-23Merge branch 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6Linus Torvalds
* 'for-linus' of git://git390.marist.edu/pub/scm/linux-2.6: (22 commits) [S390] Update default configuration. [S390] hibernate: Do real CPU swap at resume time [S390] dasd: tolerate devices that have no feature codes [S390] zcrypt: Do not add/remove devices in s/r callbacks [S390] hibernate: make sure pfn_is_nosave handles lowcore pages [S390] smp: introduce LC_ORDER and simplify lowcore handling [S390] ptrace: use common code for simple peek/poke operations [S390] fix disabled_wait inline assembly clobber list [S390] Change kernel_page_present coding style. [S390] hibernation: reset system after resume [S390] hibernation: fix guest page hinting related crash [S390] Get rid of init_module/delete_module compat functions. [S390] Convert sys_execve to function with parameters. [S390] Convert sys_clone to function with parameters. [S390] qdio: change state of all primed input buffers [S390] qdio: reduce per device debug messages [S390] cio: introduce consistent subchannel scanning [S390] cio: idset use actual number of ssids [S390] cio: dont kfree vmalloced memory [S390] cio: introduce css_settle ...
2009-09-22[S390] dasd: tolerate devices that have no feature codesStefan Weinhuber
The DASD device driver reads the feature codes of a device during device initialization. These codes are later used to determine the availability of advanced features like PAV or High Performance FICON. Some very old devices do not support the command to read feature codes and the initialization routine fails. As the feature codes are not necessary for basic DASD operations, we can support such devices by just ignoring missing feature codes. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-22Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits) trivial: fix typo in aic7xxx comment trivial: fix comment typo in drivers/ata/pata_hpt37x.c trivial: typo in kernel-parameters.txt trivial: fix typo in tracing documentation trivial: add __init/__exit macros in drivers/gpio/bt8xxgpio.c trivial: add __init macro/ fix of __exit macro location in ipmi_poweroff.c trivial: remove unnecessary semicolons trivial: Fix duplicated word "options" in comment trivial: kbuild: remove extraneous blank line after declaration of usage() trivial: improve help text for mm debug config options trivial: doc: hpfall: accept disk device to unload as argument trivial: doc: hpfall: reduce risk that hpfall can do harm trivial: SubmittingPatches: Fix reference to renumbered step trivial: fix typos "man[ae]g?ment" -> "management" trivial: media/video/cx88: add __init/__exit macros to cx88 drivers trivial: fix typo in CONFIG_DEBUG_FS in gcov doc trivial: fix missing printk space in amd_k7_smp_check trivial: fix typo s/ketymap/keymap/ in comment trivial: fix typo "to to" in multiple files trivial: fix typos in comments s/DGBU/DBGU/ ...
2009-09-22const: make block_device_operations constAlexey Dobriyan
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-21trivial: remove unnecessary semicolonsJoe Perches
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-09-11[S390] xpram: Remove checksum validation for suspend/resumeMichael Holzheu
Currently in the suspend process checksums for the XPRAM partitions are created and stored. During the resume process it is checked, if the checksums are still the same. If this is not the case, a kernel panic is triggered. Unfortunately this prevents XPRAM from beeing used as suspend device, because in this case after the checksum has been created, the memory image is written to XPRAM and therefore the contents of the suspend partition is changed. In order to allow XPRAM to be used as suspend device, this patch removes the checksum validation. Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-11[S390] dasd: fix message namingStefan Haberland
This patch fixes message naming so that generic dasd messages do not contain the device discipline. For this purpose the dev_ makros are replaced by pr_ makros for generic dasd messages. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-11[S390] dasd: optimize cpu usage in goodcaseStefan Haberland
remove unnecessary dbf call, remove string operations for magic Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-11[S390] dasd: fail requests when device state is less then readyStefan Weinhuber
A DASD device that is not ready or online has no defined disk layout, so all requests that arrive in such a state need to be returned as failed. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-08-23[S390] drivers/s390: put NULL test before dereferenceJulia Lawall
If the NULL test on block is needed, it should be before the dereference of the base field. The semantic match that finds this problem is as follows: (http://coccinelle.lip6.fr/) // <smpl> @r@ expression E1,E2; identifier fld; statement S1,S2; @@ E1 = E2->fld; ( if (E1 == NULL) S1 else S2 | *if (E2 == NULL) S1 else S2 ) // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-12headers: smp_lock.h reduxAlexey Dobriyan
* Remove smp_lock.h from files which don't need it (including some headers!) * Add smp_lock.h to files which do need it * Make smp_lock.h include conditional in hardirq.h It's needed only for one kernel_locked() usage which is under CONFIG_PREEMPT This will make hardirq.h inclusion cheaper for every PREEMPT=n config (which includes allmodconfig/allyesconfig, BTW) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-07[S390] improve suspend/resume error messagesChristian Borntraeger
From: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-07-07[S390] dasd: correct debugfeature sense dumpStefan Haberland
remove loop, add some debug data and use get_sense function Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-22[S390] dasd: fix refcounting in dasd_change_stateSebastian Ott
To set a dasd online dasd_change_state is called twice. The first cycle will schedule initial analysis of the device, set the rc to -EAGAIN and will not touch the device state any more. The initial analysis will in turn call dasd_change_state to increase the state to the final DASD_STATE_ONLINE. If the dasd_change_state on the second thread outruns the other one both finish with the state set to DASD_STATE_ONLINE and the device refcount will be decreased by 2. Fix this by leaving dasd_change_state on rc == -EAGAIN so that the refcount will always be decreased by 1. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-22[S390] dasd_pm: fix stop flag handlingStefan Haberland
The stop flags are handled in the generic restore function so the stop flag is removed also for FBA and DIAG devices. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-16[S390] pm: dcssblk power management callbacks.Gerald Schaefer
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-16[S390] pm: xpram driver power management callbacksMichael Holzheu
Signed-off-by: Michael Holzheu <holzheu@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-16[S390] pm: dasd power management callbacks.Stefan Haberland
Introduce the power management callbacks to the dasd driver. On suspend the dasd devices are stopped and removed from the focus of alias management. On resume they are reinitialized by rereading the device characteristics and adding the device to the alias management. In case the device has gone away during suspend it will caught in the suspend state with stopped flag set to UNRESUMED. After it appears again the restore function is called again. Signed-off-by: Stefan Haberland <stefan.haberland@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12[S390] dasd: forward internal errors to dasd_sleep_on callerStefan Weinhuber
If a DASD requests is started with dasd_sleep_on and fails, then the calling function may need to know the reason for the failure. In cases of hardware errors it can inspect the sense data in the irb, but when the reason is internal (e.g. start_IO failed) then it needs a meaningfull return code. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12[S390] dasd: sync after async probeSebastian Ott
Some functions called as a late_initcall depend on completely initialized devices. Since commit f3445a1a656bc26b07946cc6d20de1ef07c8d116 the dasd driver uses the new async framework and relies on the fact that synchronization is done in prepare_namespace which is called after the late_initcalls. Fix this by calling async_synchronize_full at the end of the related init functions. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12[S390] dasd: check_characteristics cleanupSebastian Ott
Fix a broken memset (sizeof pointer vs sizeof the underlying structure) by cleaning up the involved functions. Signed-off-by: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12[S390] dasd: no High Performance FICON in 31-bit modeStefan Weinhuber
The High Performance FICON feature is not supported in 31-bit mode, no matter what the various flags say. So we need to check for the CONFIG_64BIT option as well. Signed-off-by: Stefan Weinhuber <wein@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12[S390] dcssblk: revert devt conversionGerald Schaefer
git commit f331c0296f2a9fee0d396a70598b954062603015 changed users of ->first_minor to devt. This broke device handling in dcssblk, so that no additional devices could be added after the first one. This patch reverts the devt conversion to the previous ->first_minor handling. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-05-22block: Do away with the notion of hardsect_sizeMartin K. Petersen
Until now we have had a 1:1 mapping between storage device physical block size and the logical block sized used when addressing the device. With SATA 4KB drives coming out that will no longer be the case. The sector size will be 4KB but the logical block size will remain 512-bytes. Hence we need to distinguish between the physical block size and the logical ditto. This patch renames hardsect_size to logical_block_size. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11block: implement and enforce request peek/start/fetchTejun Heo
Till now block layer allowed two separate modes of request execution. A request is always acquired from the request queue via elv_next_request(). After that, drivers are free to either dequeue it or process it without dequeueing. Dequeue allows elv_next_request() to return the next request so that multiple requests can be in flight. Executing requests without dequeueing has its merits mostly in allowing drivers for simpler devices which can't do sg to deal with segments only without considering request boundary. However, the benefit this brings is dubious and declining while the cost of the API ambiguity is increasing. Segment based drivers are usually for very old or limited devices and as converting to dequeueing model isn't difficult, it doesn't justify the API overhead it puts on block layer and its more modern users. Previous patches converted all block low level drivers to dequeueing model. This patch completes the API transition by... * renaming elv_next_request() to blk_peek_request() * renaming blkdev_dequeue_request() to blk_start_request() * adding blk_fetch_request() which is combination of peek and start * disallowing completion of queued (not started) requests * applying new API to all LLDs Renamings are for consistency and to break out of tree code so that it's apparent that out of tree drivers need updating. [ Impact: block request issue API cleanup, no functional change ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Mike Miller <mike.miller@hp.com> Cc: unsik Kim <donari75@gmail.com> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Cc: David S. Miller <davem@davemloft.net> Cc: Laurent Vivier <Laurent@lvivier.info> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: Pierre Ossman <drzeus@drzeus.cx> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: Stefan Weinhuber <wein@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>