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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: Tejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: Tejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: Tejun Heo <tj@kernel.org>
Cc: 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>
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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: Tejun Heo <tj@kernel.org>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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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: 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>
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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: Tejun Heo <tj@kernel.org>
Acked-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: Jens Axboe <jens.axboe@oracle.com>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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Impact: cleanup
Read and write init paths are almost identical. Unify them into
idetape_init_rw().
Signed-off-by: Tejun Heo <tj@kernel.org>
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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>
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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>
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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>
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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>
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Impact: fix infinite retry loop
After a command failed, ide-tape and floppy inserts REQUEST_SENSE in
front of the failed command and according to the result, sets
pc->retries, flags and errors. After REQUEST_SENSE is complete, the
failed command is again at the front of the queue and if the verdict
was to terminate the request, the issue functions tries to complete it
directly by calling drive->pc_callback() and returning ide_stopped.
However, drive->pc_callback() doesn't complete a request. It only
prepares for completion of the request. As a result, this creates an
infinite loop where the failed request is retried perpetually.
Fix it by actually ending the request by calling ide_complete_rq().
Signed-off-by: Tejun Heo <tj@kernel.org>
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Impact: cleanup rq->data usage
ide-pm uses rq->data to carry pointer to struct request_pm_state
through request queue and rq->special is used to carray pointer to
local struct ide_cmd, which isn't necessary. Use rq->special for
request_pm_state instead and use local ide_cmd in
ide_start_power_step().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Impact: unify request data buffer handling
rq->data is used mostly to pass kernel buffer through request queue
without using bio. There are only a couple of places which still do
this in kernel and converting to bio isn't difficult.
This patch converts ide-cd and atapi to use bio instead of rq->data
for request sense and internal pc commands. With previous change to
unify sense request handling, this is relatively easily achieved by
adding blk_rq_map_kern() during sense_rq prep and PC issue.
If blk_rq_map_kern() fails for sense, the error is deferred till sense
issue and aborts the failed command which triggered the sense. Note
that this is a slim possibility as sense prep is done on each command
issue, so for the above condition to actually trigger, all preps since
the last sense issue till the issue of the request which would require
a sense should fail.
* do_request functions might sleep now. This should be okay as ide
request_fn - do_ide_request() - is invoked only from make_request
and plug work. Make sure this is the case by adding might_sleep()
to do_ide_request().
* Functions which access the read sense data before the sense request
is complete now should access bio_data(sense_rq->bio) as the sense
buffer might have been copied during blk_rq_map_kern().
* ide-tape updated to map sg.
* cdrom_do_block_pc() now doesn't have to deal with REQ_TYPE_ATA_PC
special case. Simplified.
* tp_ops->output/input_data path dropped from ide_pc_intr().
Signed-off-by: Tejun Heo <tj@kernel.org>
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Since we're issuing REQ_TYPE_SENSE now we need to allow those types of
rqs in the ->do_request callbacks. As a future improvement, sense_len
assignment might be unified across all ATAPI devices. Borislav to
check with specs and test.
As a result, get rid of ide_queue_pc_head() and
drive->request_sense_rq.
tj: * Init request sense ide_atapi_pc from sense request. In the
longer timer, it would probably better to fold
ide_create_request_sense_cmd() into its only current user -
ide_floppy_get_format_progress().
* ide_retry_pc() no longer takes @disk.
CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Preallocate a sense request in the ->do_request method and reinitialize
it only on demand, in case it's been consumed in the IRQ handler path.
The reason for this is that we don't want to be mapping rq to bio in
the IRQ path and introduce all kinds of unnecessary hacks to the block
layer.
tj: * Both user and kernel PC requests expect sense data to be stored
in separate storage other than drive->sense_data. Copy sense
data to rq->sense on completion if rq->sense is not NULL. This
fixes bogus sense data on PC requests.
As a result, remove cdrom_queue_request_sense.
CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This is in preparation of removing the queueing of a sense request out
of the IRQ handler path.
Use struct request_sense as a general sense buffer for all ATAPI
devices ide-{floppy,tape,cd}.
tj: * blk_get_request(__GFP_WAIT) can't be called from do_request() as
it can cause deadlock. Converted to use inline struct request
and blk_rq_init().
* Added xfer / cdb len selection depending on device type.
* All sense prep logics folded into ide_prep_sense() which never
fails.
* hwif->rq clearing and sense_rq used handling moved into
ide_queue_sense_rq().
* blk_rq_map_kern() conversion is moved to later patch.
CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Impact: rq->buffer usage cleanup
ide-cd uses rq->buffer to carry pointer to the original request when
issuing REQUEST_SENSE. Use rq->special instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Impact: rq->buffer usage cleanup
ide-atapi uses rq->buffer as private opaque value for internal special
requests. rq->special isn't used for these cases (the only case where
rq->special is used is for ide-tape rw requests). Use rq->special
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Impact: rq->buffer usage cleanup
ide_raw_taskfile() directly uses rq->buffer to carry pointer to the
data buffer. This complicates both block interface and ide backend
request handling. Use blk_rq_map_kern() instead and drop special
handling for REQ_TYPE_ATA_TASKFILE from ide_map_sg().
Note that REQ_RW setting is moved upwards as blk_rq_map_kern() uses it
to initialize bio rw flag.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Impact: remove unnecessary code path
Block pc requests always use bio and rq->data is always NULL. No need
to worry about !rq->bio cases in idefloppy_block_pc_cmd(). Note that
ide-atapi uses ide_pio_bytes() for bio PIO transfer which handle sg
fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Impact: code simplification
ide_cd_request_sense_fixup() clears the tail of the sense buffer if
the device didn't completely fill it. This patch makes
cdrom_queue_request_sense() clear the sense buffer before issuing the
command instead of clearing it afterwards. This simplifies code and
eases future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
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ide doesn't have to worry about REQ_SOFTBARRIER. Don't set it.
Signed-off-by: Tejun Heo <tj@kernel.org>
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