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* block: drop request->hard_* and *nr_sectorsTejun Heo2009-05-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <tj@kernel.org> Cc: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ide: convert to rq pos and nr_sectors accessorsTejun Heo2009-05-11
| | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: convert to pos and nr_sectors accessorsTejun Heo2009-05-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> 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: Jens Axboe <jens.axboe@oracle.com>
* block: implement blk_rq_pos/[cur_]sectors() and convert obvious onesTejun Heo2009-05-11
| | | | | | | | | | | | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Acked-by: Stephen Rothwell <sfr@canb.auug.org.au> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Ackec-by: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: add rq->resid_lenTejun Heo2009-05-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> 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: Mike Miller <mike.miller@hp.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: Doug Gilbert <dgilbert@interlog.com> Cc: Mike Miller <mike.miller@hp.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Darrick J. Wong <djwong@us.ibm.com> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ide-tape: don't initialize rq->sector for rw requestsTejun Heo2009-05-11
| | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Acked-by: Borislav Petkov <petkovbb@gmail.com> Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* nbd: don't clear rq->sector and nr_sectors unnecessarilyTejun Heo2009-05-11
| | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: Paul Clements <paul.clements@steeleye.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* mg_disk: use defines from <linux/ata.h>Bartlomiej Zolnierkiewicz2009-04-28
| | | | | | | | | | | | | 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: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* mg_disk: fix dependency on libataBartlomiej Zolnierkiewicz2009-04-28
| | | | | | | | | | | | 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: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* mg_disk: clean up request completion pathsTejun Heo2009-04-28
| | | | | | | | | | | mg_disk implements its own partial completion. Convert to standard block layer partial completion. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: unsik Kim <donari75@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* mg_disk: fold mg_disk.h into mg_disk.cTejun Heo2009-04-28
| | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: unsik Kim <donari75@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* swim: clean up request completion pathsTejun Heo2009-04-28
| | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* swim3: clean up request completion pathsTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* hd: clean up request completion pathsTejun Heo2009-04-28
| | | | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ubd: drop unnecessary rq->sector manipulationTejun Heo2009-04-28
| | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ubd: cleanup completion pathTejun Heo2009-04-28
| | | | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Cc: Jeff Dike <jdike@linux.intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* sunvdc: kill vdc_end_request()Tejun Heo2009-04-28
| | | | | | | | | | | vdc_end_request() is a thin silly wrapper on top of __blk_end_request(). Kill it. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ps3disk: simplify request completionTejun Heo2009-04-28
| | | | | | | | | | | 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: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* amiflop,ataflop,xd,mg_disk: clean up unnecessary stuff from block driversTejun Heo2009-04-28
| | | | | | | | | | | | | | | rq_data_dir() can only be READ or WRITE and rq->sector and nr_sectors are always automatically updated after partial request completion. Don't worry about rq_data_dir() not being either READ or WRITE or manually update sector and nr_sectors. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jörg Dorchain <joerg@dorchain.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: unsik Kim <donari75@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: don't init rq fields unnecessarilyTejun Heo2009-04-28
| | | | | | | | | | blk_get_request() always returns properly zeroed requests. Don't set fields to zero/NULL unnecessarily. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: make blk_end_request_cur() return boolTejun Heo2009-04-28
| | | | | | | | | | | In the process of mindlessly copying [__]blk_end_request_all(), [__]blk_end_request_cur() ended up returning void even though they're partial completion functions. Fix it. [ Impact: fix braindead API ] Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: catch trying to use more bits than request->cmd_flags hasNikanth Karthikesan2009-04-28
| | | | | Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: include discard requests in IO accountingJens Axboe2009-04-28
| | | | | | | | | | | | | We currently don't do merging on discard requests, but we potentially could. If we do, then we need to include discard requests in the IO accounting, or merging would end up decrementing in_flight IO counters for an IO which never incremented them. So enable accounting for discard requests. Problem found by Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: make blk_do_io_stat() do the full "is this rq accountable" checksJens Axboe2009-04-28
| | | | | | | We currently check for file system requests outside of blk_do_io_stat(rq), but we may as well just include it. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: kill rq->dataTejun Heo2009-04-28
| | | | | | | | | | | | Now that all block request data transfer is done via bio, rq->data isn't used. Kill it. While at it, make the roles of rq->special and buffer clear. [ Impact: drop now unncessary field from struct request ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Boaz Harrosh <bharrosh@panasas.com>
* arm-omap: don't abuse rq->dataTejun Heo2009-04-28
| | | | | | | | | | | | | omap mailbox uses rq->data as the second opaque pointer to carry mbox_msg_t and rq->special message argument which is needed only for tx. Add and use omap_msg_tx_data struct for tx and use rq->special for mbox_msg_t for rx such that only rq->special is used as opaque pointer. [ Impact: cleanup rq->data usage, extra kmalloc in msg_send ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk>
* block: replace end_request() with [__]blk_end_request_cur()Tejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | end_request() has been kept around for backward compatibility; however, it's about time for it to go away. * There aren't too many users left. * Its use of @updtodate is pretty confusing. * In some cases, newer code ends up using mixture of end_request() and [__]blk_end_request[_all](), which is way too confusing. So, add [__]blk_end_request_cur() and replace end_request() with it. Most conversions are straightforward. Noteworthy ones are... * paride/pcd: next_request() updated to take 0/-errno instead of 1/0. * paride/pf: pf_end_request() and next_request() updated to take 0/-errno instead of 1/0. * xd: xd_readwrite() updated to return 0/-errno instead of 1/0. * mtd/mtd_blkdevs: blktrans_discard_request() updated to return 0/-errno instead of 1/0. Unnecessary local variable res initialization removed from mtd_blktrans_thread(). [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Joerg Dorchain <joerg@dorchain.net> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Laurent Vivier <Laurent@lvivier.info> Cc: Tim Waugh <tim@cyberelk.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Markus Lidel <Markus.Lidel@shadowconnect.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: unsik Kim <donari75@gmail.com>
* block: implement and use [__]blk_end_request_all()Tejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are many [__]blk_end_request() call sites which call it with full request length and expect full completion. Many of them ensure that the request actually completes by doing BUG_ON() the return value, which is awkward and error-prone. This patch adds [__]blk_end_request_all() which takes @rq and @error and fully completes the request. BUG_ON() is added to to ensure that this actually happens. Most conversions are simple but there are a few noteworthy ones. * cdrom/viocd: viocd_end_request() replaced with direct calls to __blk_end_request_all(). * s390/block/dasd: dasd_end_request() replaced with direct calls to __blk_end_request_all(). * s390/char/tape_block: tapeblock_end_request() replaced with direct calls to blk_end_request_all(). [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Mike Miller <mike.miller@hp.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
* block: move rq->start_time initialization to blk_rq_init()Tejun Heo2009-04-28
| | | | | | | | | | | | | | rq->start_time was initialized in init_request_from_bio() so special requests didn't have start_time set. This has been okay as start_time has been used only for fs requests; however, there is no indication of this actually is the case or not. Set rq->start_time in blk_rq_init() and guarantee that all initialized rq's have its start_time set. This improves consistency at virtually no cost and future changes will make use of the timestamp for !bio requests. [ Impact: rq->start_time is valid for all requests ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: clean up request completion APITejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Request completion has gone through several changes and became a bit messy over the time. Clean it up. 1. end_that_request_data() is a thin wrapper around end_that_request_data_first() which checks whether bio is NULL before doing anything and handles bidi completion. blk_update_request() is a thin wrapper around end_that_request_data() which clears nr_sectors on the last iteration but doesn't use the bidi completion. Clean it up by moving the initial bio NULL check and nr_sectors clearing on the last iteration into end_that_request_data() and renaming it to blk_update_request(), which makes blk_end_io() the only user of end_that_request_data(). Collapse end_that_request_data() into blk_end_io(). 2. There are four visible completion variants - blk_end_request(), __blk_end_request(), blk_end_bidi_request() and end_request(). blk_end_request() and blk_end_bidi_request() uses blk_end_request() as the backend but __blk_end_request() and end_request() use separate implementation in __blk_end_request() due to different locking rules. blk_end_bidi_request() is identical to blk_end_io(). Collapse blk_end_io() into blk_end_bidi_request(), separate out request update into internal helper blk_update_bidi_request() and add __blk_end_bidi_request(). Redefine [__]blk_end_request() as thin inline wrappers around [__]blk_end_bidi_request(). 3. As the whole request issue/completion usages are about to be modified and audited, it's a good chance to convert completion functions return bool which better indicates the intended meaning of return values. 4. The function name end_that_request_last() is from the days when it was a public interface and slighly confusing. Give it a proper internal name - blk_finish_request(). 5. Add description explaning that blk_end_bidi_request() can be safely used for uni requests as suggested by Boaz Harrosh. The only visible behavior change is from #1. nr_sectors counts are cleared after the final iteration no matter which function is used to complete the request. I couldn't find any place where the code assumes those nr_sectors counters contain the values for the last segment and this change is good as it makes the API much more consistent as the end result is now same whether a request is completed using [__]blk_end_request() alone or in combination with blk_update_request(). API further cleaned up per Christoph's suggestion. [ Impact: cleanup, rq->*nr_sectors always updated after req completion ] Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Boaz Harrosh <bharrosh@panasas.com> Cc: Christoph Hellwig <hch@infradead.org>
* block: kill blk_end_request_callback()Tejun Heo2009-04-28
| | | | | | | | | With recent IDE updates, blk_end_request_callback() doesn't have any user now. Kill it. [ Impact: removal of unused convoluted interface ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: reorganize request fetching functionsTejun Heo2009-04-28
| | | | | | | | | | | | | | | Impact: code reorganization elv_next_request() and elv_dequeue_request() are public block layer interface than actual elevator implementation. They mostly deal with how requests interact with block layer and low level drivers at the beginning of rqeuest processing whereas __elv_next_request() is the actual eleveator request fetching interface. Move the two functions to blk-core.c. This prepares for further interface cleanup. Signed-off-by: Tejun Heo <tj@kernel.org>
* block: reorder request completion functionsTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | Reorder request completion functions such that * All request completion functions are located together. * Functions which are used by only one caller is put right above the caller. * end_request() is put after other completion functions but before blk_update_request(). This change is for completion function cleanup which will follow. [ Impact: cleanup, code reorganization ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: clean up misc stuff after block layer timeout conversionTejun Heo2009-04-28
| | | | | | | | | | * In blk_rq_timed_out_timer(), else { if } to else if * In blk_add_timer(), simplify if/else block [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: cleanup REQ_SOFTBARRIER usagesTejun Heo2009-04-28
| | | | | | | | | | blk_insert_request() doesn't need to worry about REQ_SOFTBARRIER. Don't set it. Combined with recent ide updates, REQ_SOFTBARRIER is now only used in elevator proper and for discard requests. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: don't set REQ_NOMERGE unnecessarilyTejun Heo2009-04-28
| | | | | | | | | | | | RQ_NOMERGE_FLAGS already clears defines which REQ flags aren't mergeable. There is no reason to specify it superflously. It only adds to confusion. Don't set REQ_NOMERGE for barriers and requests with specific queueing directive. REQ_NOMERGE is now exclusively used by the merging code. [ Impact: cleanup ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: kill blk_start_queueing()Tejun Heo2009-04-28
| | | | | | | | | | | blk_start_queueing() is identical to __blk_run_queue() except that it doesn't check for recursion. None of the current users depends on blk_start_queueing() running request_fn directly. Replace usages of blk_start_queueing() with [__]blk_run_queue() and kill it. [ Impact: removal of mostly duplicate interface function ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: merge blk_invoke_request_fn() into __blk_run_queue()Tejun Heo2009-04-28
| | | | | | | | | | | | | | | | __blk_run_queue wraps blk_invoke_request_fn() such that it additionally removes plug and bails out early if the queue is empty. Both extra operations have their own pending mechanisms and don't cause any harm correctness-wise when they are done superflously. The only user of blk_invoke_request_fn() being blk_start_queue(), there isn't much reason to keep both functions around. Merge blk_invoke_request_fn() into __blk_run_queue() and make blk_start_queue() use __blk_run_queue() instead. [ Impact: merge two subtly different internal functions ] Signed-off-by: Tejun Heo <tj@kernel.org>
* block: implement blkdev_readpagesJeff Moyer2009-04-28
| | | | | | | | Doing a proper block dev ->readpages() speeds up the crazy dump(8) approach of using interleaved process IO. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: enable by default support for large devices and files on 32-bit archsBartlomiej Zolnierkiewicz2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | Enable by default support for large devices and files (CONFIG_LBD): - With 1TB disks being a commodity hardware it is quite easy to hit 2TB limitation while building RAIDs etc. and many distros have been using CONFIG_LBD=y by default already (at least Fedora 10 and openSUSE 11.1). - This should also prevent a subtle ext4 filesystem compatibility issue: mke2fs.ext4 defaults to creating filesystems with huge_files feature enabled and such filesystems cannot be later mounted read-write on machines with CONFIG_LBD=n (it should be quite easy to hit this issue when trying to use filesystem created using distro kernel on system running the self-build kernel, think about USB disk enclosures & co.). While at it: - Clarify config option help text w.r.t. mounting ext4 filesystems (they can be mounted with CONFIG_LBD=n but in the read-only mode). Cc: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* ide-dma: don't reset request fields on dma_timeout_retry()Tejun Heo2009-04-28
| | | | | | | | | | | Impact: drop unnecessary code Now that everything uses bio and block operations, there is no need to reset request fields manually when retrying a request. Every field is guaranteed to be always valid. Drop unnecessary request field resetting from ide_dma_timeout_retry(). Signed-off-by: Tejun Heo <tj@kernel.org>
* ide: drop rq->data handling from ide_map_sg()Tejun Heo2009-04-28
| | | | | | | | | | Impact: remove code path which is no longer necessary All IDE data transfers now use rq->bio. Simplify ide_map_sg() accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk>
* ide-atapi: kill unused fields and callbacksTejun Heo2009-04-28
| | | | | | | | | | | | | Impact: remove fields and code paths which are no longer necessary Now that ide-tape uses standard mechanisms to transfer data, special case handling for bh handling can be dropped from ide-atapi. Drop the followings. * pc->cur_pos, b_count, bh and b_data * drive->pc_update_buffers() and pc_io_buffers(). Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-tape: simplify read/write functionsTejun Heo2009-04-28
| | | | | | | | | | | Impact: cleanup idetape_chrdev_read/write() functions are unnecessarily complex when everything can be handled in a single loop. Collapse idetape_add_chrdev_read/write_request() into the rw functions and simplify the implementation. Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-tape: use byte size instead of sectors on rw issue functionsTejun Heo2009-04-28
| | | | | | | | | | | | | | Impact: cleanup Byte size is what most issue functions deal with, make idetape_queue_rw_tail() and its wrappers take byte size instead of sector counts. idetape_chrdev_read() and write() functions are converted to use tape->buffer_size instead of ctl from tape->cap. This cleans up code a little bit and will ease the next r/w reimplementation. Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-tape: unify r/w init pathsTejun Heo2009-04-28
| | | | | | | | | Impact: cleanup Read and write init paths are almost identical. Unify them into idetape_init_rw(). Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-tape: kill idetape_bhTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | Impact: kill now unnecessary idetape_bh With everything using standard mechanisms, there is no need for idetape_bh anymore. Kill it and use tape->buf, cur and valid to describe data buffer instead. Changes worth mentioning are... * idetape_queue_rq_tail() now always queue tape->buf and and adjusts buffer state properly before completion. * idetape_pad_zeros() clears the buffer only once. Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-tape: use standard data transfer mechanismTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: use standard way to transfer data ide-tape uses rq in an interesting way. For r/w requests, rq->special is used to carry a private buffer management structure idetape_bh and rq->nr_sectors and current_nr_sectors are initialized to the number of idetape blocks which isn't necessary 512 bytes. Also, rq->current_nr_sectors is used to report back the residual count in units of idetape blocks. This peculiarity taxes both block layer and ide. ide-atapi has different paths and hooks to accomodate it and what a rq means becomes quite confusing and making changes at the block layer becomes quite difficult and error-prone. This patch makes ide-tape use bio instead. With the previous patch, ide-tape currently is using single contiguos buffer so replacing it isn't difficult. Data buffer is mapped into bio using blk_rq_map_kern() in idetape_queue_rw_tail(). idetape_io_buffers() and idetape_update_buffers() are dropped and pc->bh is set to null to tell ide-atapi to use standard data transfer mechanism and idetape_bh byte counts are updated by the issuer on completion using the residual count. This change also nicely removes the FIXME in ide_pc_intr() where ide-tape rqs need to be completed using ide_rq_bytes() instead of blk_rq_bytes() (although this didn't really matter as the request didn't have bio). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <jens.axboe@oracle.com>
* ide-tape: use single continuous bufferTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: simpler buffer allocation and handling, kills OOM, fix DMA transfers ide-tape has its own multiple buffer mechanism using struct idetape_bh. It allocates buffer with decreasing order-of-two allocations so that it results in minimum number of segments. However, the implementation is quite complex and works in a way that no other block or ide driver works necessitating a lot of special case handling. The benefit this complex allocation scheme brings is questionable as PIO or DMA the number of segments (16 maximum) doesn't make any noticeable difference and it also doesn't negate the need for multiple order allocation which can fail under memory pressure or high fragmentation although it does lower the highest order necessary by one when the buffer size isn't power of two. As the first step to remove the custom buffer management, this patch makes ide-tape allocate single continous buffer. The maximum order is four. I doubt the change would cause any trouble but if it ever matters, it should be converted to regular sg mechanism like everyone else and even in that case dropping custom buffer handling and moving to standard mechanism first make sense as an intermediate step. This patch makes the first bh to contain the whole buffer and drops multi bh handling code. Following patches will make further changes. This patch has the side effect of killing OOM triggered by allocation path and fixing DMA transfers. Previously, bug in alloc path triggered OOM on command issue and commands were passed to DMA engine without DMA-mapping all the segments. Signed-off-by: Tejun Heo <tj@kernel.org>
* ide-atapi,tape,floppy: allow ->pc_callback() to change rq->data_lenTejun Heo2009-04-28
| | | | | | | | | | | | | | | | | | | | | | Impact: allow residual count implementation in ->pc_callback() rq->data_len has two duties - carrying the number of input bytes on issue and carrying residual count back to the issuer on completion. ide-atapi completion callback ->pc_callback() is the right place to do this but currently ide-atapi depends on rq->data_len carrying the original request size after calling ->pc_callback() to complete the pc request. This patch makes ide_pc_intr(), ide_tape_issue_pc() and ide_floppy_issue_pc() cache length to complete before calling ->pc_callback() so that it can modify rq->data_len as necessary. Note: As using rq->data_len for two purposes can make cases like this incorrect in subtle ways, future changes will introduce separate field for residual count. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <jens.axboe@oracle.com>