- 11 May, 2009 29 commits
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Tejun Heo authored
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>
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Tejun Heo authored
gdrom already dequeues and fully completes requests on normal path and the error paths can be easily converted to do so too. Clean it up and dequeue requests on error paths too. While at it remove superflous blk_fs_request() && !blk_rq_sectors() condition check. [ Impact: dequeue in-flight request, cleanup ] Signed-off-by:
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Tejun Heo authored
plat-omap/mailbox, floppy, viocd, mspro_block, i2o_block and mmc/card/queue are already pretty close to dequeueing model and can be converted with simple changes. Convert them. While at it, * xen-blkfront: !fs check moved downwards to share dequeue call with normal path. * mspro_block: __blk_end_request(..., blk_rq_cur_byte()) converted to __blk_end_request_cur() * mmc/card/queue: loop of __blk_end_request() converted to __blk_end_request_all() [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
z2ram processes requests one-by-one synchronously and can be easily converted to dequeueing model. Convert it. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
jsflash processes requests one-by-one synchronously from a kthread and can be easily converted to dequeueing model. Convert it. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
mtd_blkdevs processes requests one-by-one synchronously from a kthread and can be easily converted to dequeueing model. Convert it. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
xd processes requests one-by-one synchronously and can be easily converted to dequeueing model. Convert it. While at it, use rq_cur_bytes instead of rq_bytes when checking for sector overflow. This is for for consistency and better behavior for merged requests. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
swim processes requests one-by-one synchronously and can easily be converted to dequeuing model. Convert it. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
Request processing in amiflop is done sequentially in redo_fd_request() proper and redo_fd_request() can easily be converted to track in-flight request. Remove CURRENT, track in-flight request directly and dequeue it when processing starts. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
Other than in issue error paths, ps3disk always completely finishes fetched requests. With full completion on error paths, it can be easily converted to dequeueing model. * After L1 r/w call failure, ps3disk_submit_request_sg() now fails the whole request. Issue failure isn't likely to benefit from partial retry anyway and ps3disk uses full failure in completion error path too, so I don't think this amounts to any meaningful functionality loss. * flush completion is converted to _all for consistency. It doesn't make any functional difference. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
pd/pf/pcd have track in-flight request by pd/pf/pcd_req. They can be converted to dequeueing model by updating fetching and completion paths. Convert them. Note that removal of elv_next_request() call from pf_next_buf() doesn't make any functional difference. The path is traveled only during partial completion of a request and elv_next_request() call must return the same request anyway. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
xsysace already tracks in-flight request using ace->req. Converting to dequeueing model is mostly a matter of adding dequeueing call after request fetching. The only tricky part is handling CF removal which should complete both in flight and on queue requests. Convert to dequeueing model. While at it, remove explicit blk_rq_cur_bytes() and use __blk_end_request_cur() instead. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
swim3 has at most single request in flight and already tracks it using fd_req. Convert it to dequeuing model by updating request fetching and wrapping completion function. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
ataflop has single request in flight. Till now, whenever it needs to access the in-flight request it called elv_next_request(). This patch makes ataflop track the in-flight request directly and dequeue it when processing starts. The added complexity is minimal and this will help future block layer changes. [ Impact: dequeue in-flight request, one elv_next_request() per request ] Signed-off-by:
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Tejun Heo authored
hd has at most single request in flight. Till now, whenever it needs to access the in-flight request it called elv_next_request(). This patch makes hd track the in-flight request directly and dequeue it when processing starts. The added complexity is minimal and this will help future block layer changes. [ Impact: dequeue in-flight request, one elv_next_request() per request ] Signed-off-by:
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Tejun Heo authored
mg_disk has at most single request in flight per device. Till now, whenever it needs to access the in-flight request it called elv_next_request(). This patch makes mg_disk track the in-flight request directly using mg_host->req and dequeue it when processing starts. q->queuedata is set to mg_host so that mg_host can be determined without fetching request from the queue. [ Impact: dequeue in-flight request, one elv_next_request() per request ] Signed-off-by:
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Tejun Heo authored
Both request functions in mg_disk simply return when they encounter a !fs request, which means the request will never be cleared from the queue causing queue hang and indefinite retry of the request. Fix it. While at it, flatten condition checks and add unlikely to !fs tests. [ Impact: fix possible queue hang / infinite retry of !fs requests ] Signed-off-by:
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Tejun Heo authored
ide generally has single request in flight and tracks it using hwif->rq and all state handlers follow the following convention. * ide_started is returned if the request is in flight. * ide_stopped is returned if the queue needs to be restarted. The request might or might not have been processed fully or partially. * hwif->rq is set to NULL, when an issued request completes. So, dequeueing model can be implemented by dequeueing after fetch, requeueing if hwif->rq isn't NULL on ide_stopped return and doing about the same thing on completion / port unlock paths. These changes can be made in ide-io proper. In addition to the above main changes, the following updates are necessary. * ide-cd shouldn't dequeue a request when issuing REQUEST SENSE for it as the request is already dequeued. * ide-atapi uses request queue as stack when issuing REQUEST SENSE to put the REQUEST SENSE in front of the failed request. This now needs to be done using requeueing. [ Impact: dequeue in-flight request ] Signed-off-by:
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Tejun Heo authored
With the previous changes, the followings are now guaranteed for all requests in any valid state. * blk_rq_sectors() == blk_rq_bytes() >> 9 * blk_rq_cur_sectors() == blk_rq_cur_bytes() >> 9 Clean up accessor usages. Notable changes are * nbd,i2o_block: end_all used instead of explicit byte count * scsi_lib: unnecessary conditional on request type removed [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
Block low level drivers for some reason have been pretty good at abusing block layer API. Especially struct request's fields tend to get violated in all possible ways. Make it clear that low level drivers MUST NOT access or manipulate rq->sector and rq->data_len directly by prefixing them with double underscores. This change is also necessary to break build of out-of-tree codes which assume the previous block API where internal fields can be manipulated and rq->data_len carries residual count on completion. [ Impact: hide internal fields, block API change ] Signed-off-by:
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Tejun Heo authored
With recent unification of fields, it's now guaranteed that rq->data_len always equals blk_rq_bytes(). Convert all direct users to accessors. [ Impact: convert direct rq->data_len usages to blk_rq_bytes() ] Signed-off-by:
Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by:
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Tejun Heo authored
With recent unification of fields, it's now guaranteed that rq->data_len always equals blk_rq_bytes(). Convert all non-IDE direct users to accessors. IDE will be converted in a separate patch. Boaz: spotted incorrect data_len/resid_len conversion in osd. [ Impact: convert direct rq->data_len usages to blk_rq_bytes() ] Signed-off-by:
Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: Darrick J. Wong <djwong@us.ibm.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by:
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Tejun Heo authored
struct request has had a few different ways to represent some properties of a request. ->hard_* represent block layer's view of the request progress (completion cursor) and the ones without the prefix are supposed to represent the issue cursor and allowed to be updated as necessary by the low level drivers. The thing is that as block layer supports partial completion, the two cursors really aren't necessary and only cause confusion. In addition, manual management of request detail from low level drivers is cumbersome and error-prone at the very least. Another interesting duplicate fields are rq->[hard_]nr_sectors and rq->{hard_cur|current}_nr_sectors against rq->data_len and rq->bio->bi_size. This is more convoluted than the hard_ case. rq->[hard_]nr_sectors are initialized for requests with bio but blk_rq_bytes() uses it only for !pc requests. rq->data_len is initialized for all request but blk_rq_bytes() uses it only for pc requests. This causes good amount of confusion throughout block layer and its drivers and determining the request length has been a bit of black magic which may or may not work depending on circumstances and what the specific LLD is actually doing. rq->{hard_cur|current}_nr_sectors represent the number of sectors in the contiguous data area at the front. This is mainly used by drivers which transfers data by walking request segment-by-segment. This value always equals rq->bio->bi_size >> 9. However, data length for pc requests may not be multiple of 512 bytes and using this field becomes a bit confusing. In general, having multiple fields to represent the same property leads only to confusion and subtle bugs. With recent block low level driver cleanups, no driver is accessing or manipulating these duplicate fields directly. Drop all the duplicates. Now rq->sector means the current sector, rq->data_len the current total length and rq->bio->bi_size the current segment length. Everything else is defined in terms of these three and available only through accessors. * blk_recalc_rq_sectors() is collapsed into blk_update_request() and now handles pc and fs requests equally other than rq->sector update. This means that now pc requests can use partial completion too (no in-kernel user yet tho). * bio_cur_sectors() is replaced with bio_cur_bytes() as block layer now uses byte count as the primary data length. * blk_rq_pos() is now guranteed to be always correct. In-block users converted. * blk_rq_bytes() is now guaranteed to be always valid as is blk_rq_sectors(). In-block users converted. * blk_rq_sectors() is now guaranteed to equal blk_rq_bytes() >> 9. More convenient one is used. * blk_rq_bytes() and blk_rq_cur_bytes() are now inlined and take const pointer to request. [ Impact: API cleanup, single way to represent one property of a request ] Signed-off-by: -
Tejun Heo authored
ide doesn't manipulate request fields anymore and thus all hard and their soft equivalents are always equal. Convert all references to accessors. [ Impact: use pos and nr_sectors accessors ] Signed-off-by:
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Tejun Heo authored
With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by:
Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by:
Grant Likely <grant.likely@secretlab.ca> Acked-by:
Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by:
Mike Miller <mike.miller@hp.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Dario Ballabio <ballabio_dario@emc.com> Cc: David S. Miller <davem@davemloft.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: unsik Kim <donari75@gmail.com> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by:
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Tejun Heo authored
Implement accessors - blk_rq_pos(), blk_rq_sectors() and blk_rq_cur_sectors() which return rq->hard_sector, rq->hard_nr_sectors and rq->hard_cur_sectors respectively and convert direct references of the said fields to the accessors. This is in preparation of request data length handling cleanup. Geert : suggested adding const to struct request * parameter to accessors Sergei : spotted error in patch description [ Impact: cleanup ] Signed-off-by:
Stephen Rothwell <sfr@canb.auug.org.au> Tested-by:
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Tejun Heo authored
rq->data_len served two purposes - the length of data buffer on issue and the residual count on completion. This duality creates some headaches. First of all, block layer and low level drivers can't really determine what rq->data_len contains while a request is executing. It could be the total request length or it coulde be anything else one of the lower layers is using to keep track of residual count. This complicates things because blk_rq_bytes() and thus [__]blk_end_request_all() relies on rq->data_len for PC commands. Drivers which want to report residual count should first cache the total request length, update rq->data_len and then complete the request with the cached data length. Secondly, it makes requests default to reporting full residual count, ie. reporting that no data transfer occurred. The residual count is an exception not the norm; however, the driver should clear rq->data_len to zero to signify the normal cases while leaving it alone means no data transfer occurred at all. This reverse default behavior complicates code unnecessarily and renders block PC on some drivers (ide-tape/floppy) unuseable. This patch adds rq->resid_len which is used only for residual count. While at it, remove now unnecessasry blk_rq_bytes() caching in ide_pc_intr() as rq->data_len is not changed anymore. Boaz : spotted missing conversion in osd Sergei : spotted too early conversion to blk_rq_bytes() in ide-tape [ Impact: cleanup residual count handling, report 0 resid by default ] Signed-off-by:
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Tejun Heo authored
rq->sector is set to the tape->first_frame but it's never actually used and not even in the correct unit (512 byte sectors). Don't set it. [ Impact: cleanup ] Signed-off-by:
Borislav Petkov <petkovbb@gmail.com> Acked-by:
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Tejun Heo authored
There's no reason to clear rq->sector and nr_sectors after calling blk_rq_init(). They're guaranteed to be clear. Drop unnecessary clearing. [ Impact: cleanup ] Signed-off-by:
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- 28 Apr, 2009 11 commits
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Bartlomiej Zolnierkiewicz authored
While at it: - remove MG_REG_HEAD_MUST_BE_ON define - remove MG_REG_CTRL_INTR_ENABLE define - remove MG_REG_HEAD_LBA_MODE define - remove unused defines Cc: unsik Kim <donari75@gmail.com> Signed-off-by:
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Bartlomiej Zolnierkiewicz authored
Add local copies of ata_id_string() and ata_id_c_string() to mg_disk so there is no need for the driver to depend on ATA and SCSI. [ Impact: break dependency on libata by copying ata id string functions ] Cc: unsik Kim <donari75@gmail.com> Signed-off-by:
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Tejun Heo authored
mg_disk implements its own partial completion. Convert to standard block layer partial completion. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
include/linux/mg_disk.h is used only by drivers/block/mg_disk.c. No reason to put it in a separate header. Fold it into mg_disk.c. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
swim curiously tries to update request parameters before calling __blk_end_request() when __blk_end_request() will do it anyway and unnecessarily checks whether current_nr_sectors is zero right after fetching. Drop unnecessary stuff and use standard block layer mechanisms. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
swim3 curiously tries to update request parameters before calling __blk_end_request() when __blk_end_request() will do it anyway, and it updates request for partial completion manually instead of using blk_update_request(). Also, it does some spurious checks on rq such as testing whether rq->sector is negative or current_nr_sectors is zero right after fetching. Drop unnecessary stuff and use standard block layer mechanisms. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
hd read/write_intr() functions manually manipulate request to incrementally complete it, which block layer already supports. Simply use block layer completion routines instead of manual partial completion. While at it, clear unnecessary elv_next_request() check at the tail of read_intr(). This also makes read and write_intr() more consistent. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
ubd curiously updates rq->sector while issuing the request in multiple pieces. Don't do it and simply use local copy of sector. [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
ubd had its own block request partial completion mechanism, which is unnecessary as block layer already does it. Kill ubd_end_request() and ubd_finish() and replace them with direct call to blk_end_request(). [ Impact: cleanup ] Signed-off-by:
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Tejun Heo authored
vdc_end_request() is a thin silly wrapper on top of __blk_end_request(). Kill it. [ Impact: cleanup ] Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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Tejun Heo authored
ps3disk_interrupt() always completes requests fully but it uses rq->hard_cur_sectors for FLUSH requests for some reason. Drop them and simply use __blk_end_request_all(). [ Impact: cleanup ] Signed-off-by:
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