diff options
| author | Christoph Hellwig <hch@infradead.org> | 2009-09-30 13:52:12 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2009-10-01 21:19:30 +0200 |
| commit | c15227de132f1295f3db6b7df9079956b1020fd8 (patch) | |
| tree | ad06f119f283cf8a6313681055e8132ba2851ddb /block/blk-settings.c | |
| parent | 3bd0f0c763e497c8674b28e3df2732f48683dabd (diff) | |
block: use normal I/O path for discard requests
prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible. This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set. Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.
It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not. blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.
The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.
Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-settings.c')
| -rw-r--r-- | block/blk-settings.c | 17 |
1 files changed, 0 insertions, 17 deletions
diff --git a/block/blk-settings.c b/block/blk-settings.c index eaf122ff5f16..d29498ef1eb5 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -34,23 +34,6 @@ void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) EXPORT_SYMBOL(blk_queue_prep_rq); /** - * blk_queue_set_discard - set a discard_sectors function for queue - * @q: queue - * @dfn: prepare_discard function - * - * It's possible for a queue to register a discard callback which is used - * to transform a discard request into the appropriate type for the - * hardware. If none is registered, then discard requests are failed - * with %EOPNOTSUPP. - * - */ -void blk_queue_set_discard(struct request_queue *q, prepare_discard_fn *dfn) -{ - q->prepare_discard_fn = dfn; -} -EXPORT_SYMBOL(blk_queue_set_discard); - -/** * blk_queue_merge_bvec - set a merge_bvec function for queue * @q: queue * @mbfn: merge_bvec_fn |