- 01 7月, 2008 1 次提交
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由 Divyesh Shah 提交于
AS scheduler alternates between issuing read and write batches. It does the batch switch only after all requests from the previous batch are completed. When switching to a write batch, if there is an on-going read request, it waits for its completion and indicates its intention of switching by setting ad->changed_batch and the new direction but does not update the batch_expire_time for the new write batch which it does in the case of no previous pending requests. On completion of the read request, it sees that we were waiting for the switch and schedules work for kblockd right away and resets the ad->changed_data flag. Now when kblockd enters dispatch_request where it is expected to pick up a write request, it in turn ends the write batch because the batch_expire_timer was not updated and shows the expire timestamp for the previous batch. This results in the write starvation for all the cases where there is the intention for switching to a write batch, but there is a previous in-flight read request and the batch gets reverted to a read_batch right away. This also holds true in the reverse case (switching from a write batch to a read batch with an in-flight write request). I've checked that this bug exists on 2.6.11, 2.6.18, 2.6.24 and linux-2.6-block git HEAD. I've tested the fix on x86 platforms with SCSI drives where the driver asks for the next request while a current request is in-flight. This patch is based off linux-2.6-block git HEAD. Bug reproduction: A simple scenario which reproduces this bug is: - dd if=/dev/hda3 of=/dev/null & - lilo The lilo takes forever to complete. This can also be reproduced fairly easily with the earlier dd and another test program doing msync(). The example test program below should print out a message after every iteration but it simply hangs forever. With this bugfix it makes forward progress. ==== Example test program using msync() (thanks to suleiman AT google DOT com) inline uint64_t rdtsc(void) { int64_t tsc; __asm __volatile("rdtsc" : "=A" (tsc)); return (tsc); } int main(int argc, char **argv) { struct stat st; uint64_t e, s, t; char *p, q; long i; int fd; if (argc < 2) { printf("Usage: %s <file>\n", argv[0]); return (1); } if ((fd = open(argv[1], O_RDWR | O_NOATIME)) < 0) err(1, "open"); if (fstat(fd, &st) < 0) err(1, "fstat"); p = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); t = 0; for (i = 0; i < 1000; i++) { *p = 0; msync(p, 4096, MS_SYNC); s = rdtsc(); *p = 0; __asm __volatile(""::: "memory"); e = rdtsc(); if (argc > 2) printf("%d: %lld cycles %jd %jd\n", i, e - s, (intmax_t)s, (intmax_t)e); t += e - s; } printf("average time: %lld cycles\n", t / 1000); return (0); } Cc: <stable@kernel.org> Acked-by: NNick Piggin <npiggin@suse.de> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 13 6月, 2008 1 次提交
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由 Carl Henrik Lunde 提交于
As we may run relay_reserve from interrupt context we must always disable IRQs. This is because a call to relay_reserve may expose previously written data to use space. Updated new message code and an old but related comment. Signed-off-by: NCarl Henrik Lunde <chlunde@ping.uio.no> Signed-off-by: NJens Axboe <jens.axboe@oracle.com> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 10 6月, 2008 1 次提交
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由 Linus Torvalds 提交于
Commit 30f2f0eb ("block: do_mounts - accept root=<non-existant partition>") extended blk_lookup_devt() to be able to look up partitions that had not yet been registered, but in the process made the assumption that the '&block_class.devices' list only contains disk devices and that you can do 'dev_to_disk(dev)' on them. That isn't actually true. The block_class device list also contains the partitions we've discovered so far, and you can't just do a 'dev_to_disk()' on those. So make sure to only work on devices that block/genhd.c has registered itself, something we can test by checking the 'dev->type' member. This makes the loop in blk_lookup_devt() match the other such loops in this file. [ We may want to do an alternate version that knows to handle _either_ whole-disk devices or partitions, but for now this is the minimal fix for a series of crashes reported by Mariusz Kozlowski in http://lkml.org/lkml/2008/5/25/25 and Ingo in http://lkml.org/lkml/2008/6/9/39 ] Reported-by: NMariusz Kozlowski <m.kozlowski@tuxland.pl> Reported-by: NIngo Molnar <mingo@elte.hu> Cc: Neil Brown <neilb@suse.de> Cc: Joao Luis Meloni Assirati <assirati@nonada.if.usp.br> Acked-by: NKay Sievers <kay.sievers@vrfy.org> Cc: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 28 5月, 2008 6 次提交
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由 Jens Axboe 提交于
cfq_cic_lookup() needs to properly protect ioc->ioc_data before dereferencing it and also exclude updaters of ioc->ioc_data as well. Also add a number of comments documenting why the existing RCU usage is OK. Thanks a lot to "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> for review and comments! Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Currently it uses a single static char array, but that risks being corrupted when multiple users issue message notes at the same time. Make the buffers dynamically allocated when the trace is setup and make them per-cpu instead. The default max message size of 1k is also very large, the interface is mainly for small text notes. So shrink it to 128 bytes. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Alan D. Brunelle 提交于
Signed-off-by: NAlan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Alan D. Brunelle 提交于
Allows messages to be inserted into blktrace streams. Signed-off-by: NAlan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Richard Kennedy 提交于
saves 8 bytes of padding & increases objects/slab from 30 to 32 on my AMD64 config Signed-off-by: NRichard Kennedy <richard@rsk.demon.co.uk> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Zhang, Yanmin 提交于
In function get_request_wait, the second call to get_request could be moved to the end of the while loop, because if the first call to get_request fails, the second call will fail without sleep. Signed-off-by: NZhang Yanmin <yanmin.zhang@intel.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 15 5月, 2008 2 次提交
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由 Neil Brown 提交于
As setting and clearing queue flags now requires that we hold a spinlock on the queue, and as blk_queue_stack_limits is called without that lock, get the lock inside blk_queue_stack_limits. For blk_queue_stack_limits to be able to find the right lock, each md personality needs to set q->queue_lock to point to the appropriate lock. Those personalities which didn't previously use a spin_lock, us q->__queue_lock. So always initialise that lock when allocated. With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no longer cause warnings as it will be clear that the proper lock is held. Thanks to Dan Williams for review and fixing the silly bugs. Signed-off-by: NNeilBrown <neilb@suse.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Alistair John Strachan <alistair@devzero.co.uk> Cc: Nick Piggin <npiggin@suse.de> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Jacek Luczak <difrost.kernel@gmail.com> Cc: Prakash Punnoor <prakash@punnoor.de> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Kay Sievers 提交于
Some devices, like md, may create partitions only at first access, so allow root= to be set to a valid non-existant partition of an existing disk. This applies only to non-initramfs root mounting. This fixes a regression from 2.6.24 which did allow this to happen and broke some users machines :( Acked-by: NNeil Brown <neilb@suse.de> Tested-by: NJoao Luis Meloni Assirati <assirati@nonada.if.usp.br> Cc: stable <stable@kernel.org> Signed-off-by: NKay Sievers <kay.sievers@vrfy.org> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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- 13 5月, 2008 1 次提交
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由 Jean Delvare 提交于
bdevname() fills the buffer that it is given as a parameter, so calling strcpy() or snprintf() on the returned value is redundant (and probably not guaranteed to work - I don't think strcpy and snprintf support overlapping buffers.) Signed-off-by: NJean Delvare <khali@linux-fr.org> Cc: Stephen Tweedie <sct@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 07 5月, 2008 7 次提交
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由 Jens Axboe 提交于
get_part() is fairly expensive, as it O(N) loops over partitions to find the right one. In lots of normal IO paths we end up looking up the partition twice, to make matters even worse. Change the stat add code to accept a passed in partition instead. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
We currently set all processes to the best-effort scheduling class, regardless of what CPU scheduling class they belong to. Improve that so that we correctly track idle and rt scheduling classes as well. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Original patch from Mikulas Patocka <mpatocka@redhat.com> Mike Anderson was doing an OLTP benchmark on a computer with 48 physical disks mapped to one logical device via device mapper. He found that there was a slowdown on request_queue->lock in function generic_unplug_device. The slowdown is caused by the fact that when some code calls unplug on the device mapper, device mapper calls unplug on all physical disks. These unplug calls take the lock, find that the queue is already unplugged, release the lock and exit. With the below patch, performance of the benchmark was increased by 18% (the whole OLTP application, not just block layer microbenchmarks). So I'm submitting this patch for upstream. I think the patch is correct, because when more threads call simultaneously plug and unplug, it is unspecified, if the queue is or isn't plugged (so the patch can't make this worse). And the caller that plugged the queue should unplug it anyway. (if it doesn't, there's 3ms timeout). Signed-off-by: NMikulas Patocka <mpatocka@redhat.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
They tend to depend a lot on the workload, so not a clear-cut likely or unlikely fit. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
put_io_context() drops the RCU read lock before calling into cfq_dtor(), however we need to hold off freeing there before grabbing and dereferencing the first object on the list. So extend the rcu_read_lock() scope to cover the calling of cfq_dtor(), and optimize cfq_free_io_context() to use a new variant for call_for_each_cic() that assumes the RCU read lock is already held. Hit in the wild by Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
For most initialization purposes, calling blk_queue_init_tags() without the queue lock held is OK. Only if called for resizing an existing map must the lock be held. Ditto for tag cleanup, the maps are reference counted. So switch the general queue flag setting to the unlocked variant, but retain the locked variant for resizing. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Jens Axboe 提交于
Concurrency isn't a big deal here since we have requests in flight at this point, but do the locked variant to set a better example. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 03 5月, 2008 1 次提交
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由 Boaz Harrosh 提交于
Add support for variable-length, extended, and vendor specific CDBs to scsi-ml. It is now possible for initiators and ULD's to issue these types of commands. LLDs need not change much. All they need is to raise the .max_cmd_len to the longest command they support (see iscsi patch). - clean-up some code paths that did not expect commands to be larger than 16, and change cmd_len members' type to short as char is not enough. Signed-off-by: NBoaz Harrosh <bharrosh@panasas.com> Signed-off-by: NBenny Halevy <bhalevy@panasas.com> Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
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- 02 5月, 2008 1 次提交
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由 FUJITA Tomonori 提交于
This enables bsg to handle the request length larger than BLK_MAX_CDB (mainly for the variable length CDB format). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Acked-by: NJens Axboe <jens.axboe@oracle.com> Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
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- 01 5月, 2008 1 次提交
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由 Harvey Harrison 提交于
__FUNCTION__ is gcc specific, use __func__ Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 30 4月, 2008 1 次提交
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由 Peter Zijlstra 提交于
Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block/<block>/queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: NGreg KH <greg@kroah.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 29 4月, 2008 11 次提交
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由 Alan D. Brunelle 提交于
The block I/O + elevator + I/O scheduler code spend a lot of time trying to merge I/Os -- rightfully so under "normal" circumstances. However, if one were to know that the incoming I/O stream was /very/ random in nature, the cycles are wasted. This patch adds a per-request_queue tunable that (when set) disables merge attempts (beyond the simple one-hit cache check), thus freeing up a non-trivial amount of CPU cycles. Signed-off-by: NAlan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
This patch changes rq->cmd from the static array to a pointer to support large commands. We rarely handle large commands. So for optimization, a struct request still has a static array for a command. rq_init sets rq->cmd pointer to the static array. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
This is a preparation for changing rq->cmd from the static array to a pointer. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Boaz Harrosh <bharrosh@panasas.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
This rename rq_init() blk_rq_init() and export it. Any path that hands the request to the block layer needs to call it to initialize the request. This is a preparation for large command support, which needs to initialize the request in a proper way (that is, just doing a memset() will not work). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
blk_get_request initializes rq->cmd (rq_init does) so the users don't need to do that. The purpose of this patch is to remove sizeof(rq->cmd) and &rq->cmd, as a preparation for large command support, which changes rq->cmd from the static array to a pointer. sizeof(rq->cmd) will not make sense and &rq->cmd won't work. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Alasdair G Kergon <agk@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Adrian Bunk 提交于
This patch fixes the following build error with UML and gcc 4.3: <-- snip --> ... CC block/blk-barrier.o /home/bunk/linux/kernel-2.6/git/linux-2.6/block/blk-barrier.c: In function ‘blk_do_ordered’: /home/bunk/linux/kernel-2.6/git/linux-2.6/block/blk-barrier.c:57: sorry, unimplemented: inlining failed in call to ‘blk_ordered_cur_seq’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/blk-barrier.c:252: sorry, unimplemented: called from here /home/bunk/linux/kernel-2.6/git/linux-2.6/block/blk-barrier.c:57: sorry, unimplemented: inlining failed in call to ‘blk_ordered_cur_seq’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/blk-barrier.c:253: sorry, unimplemented: called from here make[2]: *** [block/blk-barrier.o] Error 1 <-- snip --> Signed-off-by: NAdrian Bunk <bunk@kernel.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Adrian Bunk 提交于
This patch fixes the following build error with UML and gcc 4.3: <-- snip --> ... CC block/elevator.o /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c: In function ‘elv_merge’: /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:103: sorry, unimplemented: called from here /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:73: sorry, unimplemented: inlining failed in call to ‘elv_rq_merge_ok’: function body not available /home/bunk/linux/kernel-2.6/git/linux-2.6/block/elevator.c:495: sorry, unimplemented: called from here make[2]: *** [block/elevator.o] Error 1 make[1]: *** [block] Error 2 <-- snip --> Signed-off-by: NAdrian Bunk <bunk@kernel.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Nick Piggin 提交于
We can save some atomic ops in the IO path, if we clearly define the rules of how to modify the queue flags. Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
This patch adds bio_copy_kern similar to bio_copy_user. blk_rq_map_kern uses bio_copy_kern instead of bio_map_kern if necessary. bio_copy_kern uses temporary pages and the bi_end_io callback frees these pages. bio_copy_kern saves the original kernel buffer at bio->bi_private it doesn't use something like struct bio_map_data to store the information about the caller. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Adrian Bunk 提交于
blk_max_pfn can now be unexported. Signed-off-by: NAdrian Bunk <bunk@kernel.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
This requires moving rq_init() from get_request() to blk_alloc_request(). The upside is that we can now require an rq_init() from any path that wishes to hand the request to the block layer. rq_init() will be exported for the code that uses struct request without blk_get_request. This is a preparation for large command support, which needs to initialize struct request in a proper way (that is, just doing a memset() will not work). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 23 4月, 2008 1 次提交
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由 FUJITA Tomonori 提交于
This patch adds release callback support, which is called when a bsg device goes away. bsg_register_queue() takes a pointer to a callback function. This feature is useful for stuff like sas_host that can't use the release callback in struct device. If a caller doesn't need bsg's release callback, it can call bsg_register_queue() with NULL pointer (e.g. scsi devices can use release callback in struct device so they don't need bsg's callback). With this patch, bsg uses kref for refcounts on bsg devices instead of get/put_device in fops->open/release. bsg calls put_device and the caller's release callback (if it was registered) in kref_put's release. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>
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- 21 4月, 2008 4 次提交
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由 Akinobu Mita 提交于
blk_register_queue() returns -ENXIO when queue->request_fn is NULL. But there are some block drivers that call blk_register_queue() via add_disk() with queue->request_fn == NULL. (For example, brd, loop) Although no one checks return value of blk_register_queue(), this patch makes it return 0 instead of -ENXIO when queue->request_fn is NULL, Also this patch adds warning when blk_register_queue() and blk_unregister_queue() are called with queue == NULL rather than ignore invalid usage silently. Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 Nick Andrew 提交于
Modify the help descriptions of block/Kconfig for clarity, accuracy and consistency. Refactor the BLOCK description a bit. The wording "This permits ... to be removed" isn't quite right; the block layer is removed when the option is disabled, whereas most descriptions talk about what happens when the option is enabled. Reformat the list of what is affected by disabling the block layer. Add more examples of large block devices to LBD and strive for technical accuracy; block devices of size _exactly_ 2TB require CONFIG_LBD, not only "bigger than 2TB". Also try to say (perhaps not very clearly) that the config option is only needed when you want to have individual block devices of size >= 2TB, for example if you had 3 x 1TB disks in your computer you'd have a total storage size of 3TB but you wouldn't need the option unless you want to aggregate those disks into a RAID or LVM. Improve terminology and grammar on BLK_DEV_IO_TRACE. I also added the boilerplate "If unsure, say N" to most options. Precisely say "2TB and larger" for LSF. Indent the help text for BLK_DEV_BSG by 2 spaces in accordance with the standard. Signed-off-by: NNick Andrew <nick@nick-andrew.net> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
blk_rq_map_user adjusts bi_size of the last bio. It breaks the rule that req->data_len (the true data length) is equal to sum(bio). It broke the scsi command completion code. commit e97a294e was introduced to fix the above issue. However, the partial completion code doesn't work with it. The commit is also a layer violation (scsi mid-layer should not know about the block layer's padding). This patch moves the padding adjustment to blk_rq_map_sg (suggested by James). The padding works like the drain buffer. This patch breaks the rule that req->data_len is equal to sum(sg), however, the drain buffer already broke it. So this patch just restores the rule that req->data_len is equal to sub(bio) without breaking anything new. Now when a low level driver needs padding, blk_rq_map_user and blk_rq_map_user_iov guarantee there's enough room for padding. blk_rq_map_sg can safely extend the last entry of a scatter list. blk_rq_map_sg must extend the last entry of a scatter list only for a request that got through bio_copy_user_iov. This patches introduces new REQ_COPY_USER flag. Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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由 FUJITA Tomonori 提交于
With this patch, blk_rq_map_user_iov uses bio_copy_user_iov when a low level driver needs padding or a buffer in sg_iovec isn't aligned. That is, it uses temporary kernel buffers instead of mapping user pages directly. When a LLD needs padding, later blk_rq_map_sg needs to extend the last entry of a scatter list. bio_copy_user_iov guarantees that there is enough space for padding by using temporary kernel buffers instead of user pages. blk_rq_map_user_iov needs buffers in sg_iovec to be aligned. The comment in blk_rq_map_user_iov indicates that drivers/scsi/sg.c also needs buffers in sg_iovec to be aligned. Actually, drivers/scsi/sg.c works with unaligned buffers in sg_iovec (it always uses temporary kernel buffers). Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Tejun Heo <htejun@gmail.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: NJens Axboe <jens.axboe@oracle.com>
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- 20 4月, 2008 1 次提交
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由 Tony Jones 提交于
It's big, but there doesn't seem to be a way to split it up smaller... Signed-off-by: NTony Jones <tonyj@suse.de> Signed-off-by: NKay Sievers <kay.sievers@vrfy.org> Cc: Roland Dreier <rolandd@cisco.com> Cc: Sean Hefty <sean.hefty@intel.com> Cc: Hal Rosenstock <hal.rosenstock@gmail.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>
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