We cannot reliably map more than one page at the time, or we risk
deadlocking. Just allocate the pages from low mem instead.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Splice is tied to pipes by design, it'll not change. And now that
the splice stuff is in splice.h (and note pipe.h), the rest of the comment
is out-of-date as well.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Commit c3a4d78c58 introduced
rq->data_len and converted residual count users to it. While
converting, it mistakenly converted scsi_end_request() to finish
requests with residual count when it wants to do is fully complete the
request. Fix it by using blk_end_request_all() instead.
This bug was spotted by Boaz Harrosh.
Signed-off-by: Tejun Heo <tj@kernel.org>
Spotted-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
If f_op->splice_write() is not implemented, fall back to a plain write.
Use vfs_writev() to write from the pipe buffers.
This will allow splice on all filesystems and file types. This
includes "direct_io" files in fuse which bypass the page cache.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
If f_op->splice_read() is not implemented, fall back to a plain read.
Use vfs_readv() to read into previously allocated pages.
This will allow splice and functions using splice, such as the loop
device, to work on all filesystems. This includes "direct_io" files
in fuse which bypass the page cache.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Allow splice(2) to work when both the input and the output is a pipe.
Based on the impementation of the tee(2) syscall, but instead of
duplicating the buffer references move the buffers from the input pipe
to the output pipe.
Moving the whole buffer only succeeds if the full length of the buffer
is spliced. Otherwise duplicate the buffer, just like tee(2), set the
length of the output buffer and advance the offset on the input
buffer.
Since splice is operating on two pipes, special care needs to be taken
with locking to prevent AN ABBA deadlock. Again this is done
similarly to the tee(2) syscall, first preparing the input and output
pipes so there's data to consume and space for that data, and then
doing the move operation while holding both locks.
If other processes are doing I/O on the same pipes parallel to the
splice, then by the time both inodes are locked there might be no
buffers left to move, or no space to move them to. In this case retry
the whole operation, including the preparation phase. This could lead
to starvation, but I'm not sure if that's serious enough to worry
about.
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Let's put the completion related functions back to block/blk-core.c
where they have lived. We can also unexport blk_end_bidi_request() and
__blk_end_bidi_request(), which nobody uses.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
blk_end_request_all() and __blk_end_request_all() should finish all
bytes including bidi, by definition. That's what all bidi users need ,
bidi requests must be complete as a whole (partial completion is
impossible).
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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>
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: Tejun Heo <tj@kernel.org>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: Tim Waugh <tim@cyberelk.net>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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: Tejun Heo <tj@kernel.org>
Cc: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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>
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>
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>
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>
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>
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>
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>
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: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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>
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>
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 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>
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>
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>
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>
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>
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>
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>
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 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 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 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 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 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>
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_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>
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>
