kernel/linux.git/block/blk-lib.c, branch v2.6.38

block: fix mis-synchronisation in blkdev_issue_zeroout()

2011-03-11T14:36:08+00:00

BZ29402 https://bugzilla.kernel.org/show_bug.cgi?id=29402 We can hit serious mis-synchronization in bio completion path of blkdev_issue_zeroout() leading to a panic. The problem is that when we are going to wait_for_completion() in blkdev_issue_zeroout() we check if the bb.done equals issued (number of submitted bios). If it does, we can skip the wait_for_completition() and just out of the function since there is nothing to wait for. However, there is a ordering problem because bio_batch_end_io() is calling atomic_inc(&bb->done) before complete(), hence it might seem to blkdev_issue_zeroout() that all bios has been completed and exit. At this point when bio_batch_end_io() is going to call complete(bb->wait), bb and wait does not longer exist since it was allocated on stack in blkdev_issue_zeroout() ==> panic! (thread 1) (thread 2) bio_batch_end_io() blkdev_issue_zeroout() if(bb) { ... if (bb->end_io) ... bb->end_io(bio, err); ... atomic_inc(&bb->done); ... ... while (issued != atomic_read(&bb.done)) ... (let issued == bb.done) ... (do the rest of the function) ... return ret; complete(bb->wait); ^^^^^^^^ panic We can fix this easily by simplifying bio_batch and completion counting. Also remove bio_end_io_t *end_io since it is not used. Signed-off-by: Lukas Czerner Reported-by: Eric Whitney Tested-by: Eric Whitney Reviewed-by: Jeff Moyer CC: Dmitry Monakhov Signed-off-by: Jens Axboe

block: fix kernel-doc format for blkdev_issue_zeroout

2011-03-01T18:45:24+00:00

Signed-off-by: Ben Hutchings Signed-off-by: Andrew Morton Signed-off-by: Jens Axboe

block: remove BLKDEV_IFL_WAIT

2010-09-16T18:52:58+00:00

All the blkdev_issue_* helpers can only sanely be used for synchronous caller. To issue cache flushes or barriers asynchronously the caller needs to set up a bio by itself with a completion callback to move the asynchronous state machine ahead. So drop the BLKDEV_IFL_WAIT flag that is always specified when calling blkdev_issue_* and also remove the now unused flags argument to blkdev_issue_flush and blkdev_issue_zeroout. For blkdev_issue_discard we need to keep it for the secure discard flag, which gains a more descriptive name and loses the bitops vs flag confusion. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

block: remove the BLKDEV_IFL_BARRIER flag

2010-09-10T10:35:40+00:00

Remove support for barriers on discards, which is unused now. Also remove the DISCARD_NOBARRIER I/O type in favour of just setting the rw flags up locally in blkdev_issue_discard. tj: Also remove DISCARD_SECURE and use REQ_SECURE directly. Signed-off-by: Christoph Hellwig Acked-by: Mike Snitzer Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe

block: add secure discard

2010-08-12T15:43:30+00:00

Secure discard is the same as discard except that all copies of the discarded sectors (perhaps created by garbage collection) must also be erased. Signed-off-by: Adrian Hunter Acked-by: Jens Axboe Cc: Kyungmin Park Cc: Madhusudhan Chikkature Cc: Christoph Hellwig Cc: Ben Gardiner Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

blkdev: fix blkdev_issue_zeroout return value

2010-08-08T16:31:08+00:00

- If function called without barrier option retvalue is incorrect Signed-off-by: Dmitry Monakhov Signed-off-by: Jens Axboe

block: fix problem with sending down discard that isn't of correct granularity

2010-08-07T16:26:33+00:00

If the queue doesn't have a limit set, or it just set UINT_MAX like we default to, we coud be sending down a discard request that isn't of the correct granularity if the block size is > 512b. Fix this by adjusting max_discard_sectors down to the proper alignment. Signed-off-by: Jens Axboe

block: don't allocate a payload for discard request

2010-08-07T16:23:08+00:00

Allocating a fixed payload for discard requests always was a horrible hack, and it's not coming to byte us when adding support for discard in DM/MD. So change the code to leave the allocation of a payload to the lowlevel driver. Unfortunately that means we'll need another hack, which allows us to update the various block layer length fields indicating that we have a payload. Instead of hiding this in sd.c, which we already partially do for UNMAP support add a documented helper in the core block layer for it. Signed-off-by: Christoph Hellwig Acked-by: Mike Snitzer Signed-off-by: Jens Axboe

block: fix bad use of min() on different types

2010-04-29T07:28:21+00:00

Just cast the page size to sector_t, that will always fit. Signed-off-by: Jens Axboe

blkdev: add blkdev_issue_zeroout helper function

2010-04-28T17:47:36+00:00

- Add bio_batch helper primitive. This is rather generic primitive for submitting/waiting a complex request which consists of several bios. - blkdev_issue_zeroout() generate number of zero filed write bios. Signed-off-by: Dmitry Monakhov Signed-off-by: Jens Axboe