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| author | Boaz Harrosh <boaz@plexistor.com> | 2015-01-07 18:09:38 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-01-13 21:59:15 -0700 |
| commit | c8fa31730fc72a83bad762112a872675b3e76886 (patch) | |
| tree | 4ca498cb2c8e7899d13e29448fa105fcd6a23d45 /drivers | |
| parent | 937af5ecd0591e84ee54180fa97dcbe9bbe5fed6 (diff) | |
| download | linux-c8fa31730fc72a83bad762112a872675b3e76886.tar.gz linux-c8fa31730fc72a83bad762112a872675b3e76886.tar.xz | |
brd: Request from fdisk 4k alignment
Because of the direct_access() API which returns a PFN. partitions
better start on 4K boundary, else offset ZERO of a partition will
not be aligned and blk_direct_access() will fail the call.
By setting blk_queue_physical_block_size(PAGE_SIZE) we can communicate
this to fdisk and friends.
The call to blk_queue_physical_block_size() is harmless and will
not affect the Kernel behavior in any way. It is only for
communication to user-mode.
before this patch running fdisk on a default size brd of 4M
the first sector offered is 34 (BAD), but after this patch it
will be 40, ie 8 sectors aligned. Also when entering some random
partition sizes the next partition-start sector is offered 8 sectors
aligned after this patch. (Please note that with fdisk the user
can still enter bad values, only the offered default values will
be correct)
Note that with bdev-size > 4M fdisk will try to align on a 1M
boundary (above first-sector will be 2048), in any case.
CC: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Boaz Harrosh <boaz@plexistor.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/brd.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index a7463c9595e7..c01b921b1b4a 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -486,10 +486,19 @@ static struct brd_device *brd_alloc(int i) brd->brd_queue = blk_alloc_queue(GFP_KERNEL); if (!brd->brd_queue) goto out_free_dev; + blk_queue_make_request(brd->brd_queue, brd_make_request); blk_queue_max_hw_sectors(brd->brd_queue, 1024); blk_queue_bounce_limit(brd->brd_queue, BLK_BOUNCE_ANY); + /* This is so fdisk will align partitions on 4k, because of + * direct_access API needing 4k alignment, returning a PFN + * (This is only a problem on very small devices <= 4M, + * otherwise fdisk will align on 1M. Regardless this call + * is harmless) + */ + blk_queue_physical_block_size(brd->brd_queue, PAGE_SIZE); + brd->brd_queue->limits.discard_granularity = PAGE_SIZE; brd->brd_queue->limits.max_discard_sectors = UINT_MAX; brd->brd_queue->limits.discard_zeroes_data = 1; |