projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| a709ecc8 GKH |
1 | From neilb@suse.de Wed Apr 21 15:45:49 2010 |
| 2 | From: Neil Brown <neilb@suse.de> | |
| 3 | Date: Wed, 31 Mar 2010 12:07:16 +1100 | |
| 4 | Subject: md: deal with merge_bvec_fn in component devices better. | |
| 5 | To: stable@kernel.org | |
| 6 | Message-ID: <20100331120716.14054609@notabene.brown> | |
| 7 | ||
| 8 | From: NeilBrown <neilb@suse.de> | |
| 9 | ||
| 10 | commit 627a2d3c29427637f4c5d31ccc7fcbd8d312cd71 upstream. | |
| 11 | ||
| 12 | If a component device has a merge_bvec_fn then as we never call it | |
| 13 | we must ensure we never need to. Currently this is done by setting | |
| 14 | max_sector to 1 PAGE, however this does not stop a bio being created | |
| 15 | with several sub-page iovecs that would violate the merge_bvec_fn. | |
| 16 | ||
| 17 | So instead set max_phys_segments to 1 and set the segment boundary to the | |
| 18 | same as a page boundary to ensure there is only ever one single-page | |
| 19 | segment of IO requested at a time. | |
| 20 | ||
| 21 | This can particularly be an issue when 'xen' is used as it is | |
| 22 | known to submit multiple small buffers in a single bio. | |
| 23 | ||
| 24 | Signed-off-by: NeilBrown <neilb@suse.de> | |
| 25 | Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> | |
| 26 | ||
| 27 | --- | |
| 28 | drivers/md/linear.c | 12 +++++++----- | |
| 29 | drivers/md/multipath.c | 20 ++++++++++++-------- | |
| 30 | drivers/md/raid0.c | 13 +++++++------ | |
| 31 | drivers/md/raid10.c | 28 +++++++++++++++++----------- | |
| 32 | 4 files changed, 43 insertions(+), 30 deletions(-) | |
| 33 | ||
| 34 | --- a/drivers/md/linear.c | |
| 35 | +++ b/drivers/md/linear.c | |
| 36 | @@ -172,12 +172,14 @@ static linear_conf_t *linear_conf(mddev_ | |
| 37 | disk_stack_limits(mddev->gendisk, rdev->bdev, | |
| 38 | rdev->data_offset << 9); | |
| 39 | /* as we don't honour merge_bvec_fn, we must never risk | |
| 40 | - * violating it, so limit ->max_sector to one PAGE, as | |
| 41 | - * a one page request is never in violation. | |
| 42 | + * violating it, so limit max_phys_segments to 1 lying within | |
| 43 | + * a single page. | |
| 44 | */ | |
| 45 | - if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
| 46 | - queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) | |
| 47 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 48 | + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { | |
| 49 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 50 | + blk_queue_segment_boundary(mddev->queue, | |
| 51 | + PAGE_CACHE_SIZE - 1); | |
| 52 | + } | |
| 53 | ||
| 54 | conf->array_sectors += rdev->sectors; | |
| 55 | cnt++; | |
| 56 | --- a/drivers/md/multipath.c | |
| 57 | +++ b/drivers/md/multipath.c | |
| 58 | @@ -301,14 +301,16 @@ static int multipath_add_disk(mddev_t *m | |
| 59 | rdev->data_offset << 9); | |
| 60 | ||
| 61 | /* as we don't honour merge_bvec_fn, we must never risk | |
| 62 | - * violating it, so limit ->max_sector to one PAGE, as | |
| 63 | - * a one page request is never in violation. | |
| 64 | + * violating it, so limit ->max_phys_segments to one, lying | |
| 65 | + * within a single page. | |
| 66 | * (Note: it is very unlikely that a device with | |
| 67 | * merge_bvec_fn will be involved in multipath.) | |
| 68 | */ | |
| 69 | - if (q->merge_bvec_fn && | |
| 70 | - queue_max_sectors(q) > (PAGE_SIZE>>9)) | |
| 71 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 72 | + if (q->merge_bvec_fn) { | |
| 73 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 74 | + blk_queue_segment_boundary(mddev->queue, | |
| 75 | + PAGE_CACHE_SIZE - 1); | |
| 76 | + } | |
| 77 | ||
| 78 | conf->working_disks++; | |
| 79 | mddev->degraded--; | |
| 80 | @@ -476,9 +478,11 @@ static int multipath_run (mddev_t *mddev | |
| 81 | /* as we don't honour merge_bvec_fn, we must never risk | |
| 82 | * violating it, not that we ever expect a device with | |
| 83 | * a merge_bvec_fn to be involved in multipath */ | |
| 84 | - if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
| 85 | - queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) | |
| 86 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 87 | + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { | |
| 88 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 89 | + blk_queue_segment_boundary(mddev->queue, | |
| 90 | + PAGE_CACHE_SIZE - 1); | |
| 91 | + } | |
| 92 | ||
| 93 | if (!test_bit(Faulty, &rdev->flags)) | |
| 94 | conf->working_disks++; | |
| 95 | --- a/drivers/md/raid0.c | |
| 96 | +++ b/drivers/md/raid0.c | |
| 97 | @@ -176,14 +176,15 @@ static int create_strip_zones(mddev_t *m | |
| 98 | disk_stack_limits(mddev->gendisk, rdev1->bdev, | |
| 99 | rdev1->data_offset << 9); | |
| 100 | /* as we don't honour merge_bvec_fn, we must never risk | |
| 101 | - * violating it, so limit ->max_sector to one PAGE, as | |
| 102 | - * a one page request is never in violation. | |
| 103 | + * violating it, so limit ->max_phys_segments to 1, lying within | |
| 104 | + * a single page. | |
| 105 | */ | |
| 106 | ||
| 107 | - if (rdev1->bdev->bd_disk->queue->merge_bvec_fn && | |
| 108 | - queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) | |
| 109 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 110 | - | |
| 111 | + if (rdev1->bdev->bd_disk->queue->merge_bvec_fn) { | |
| 112 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 113 | + blk_queue_segment_boundary(mddev->queue, | |
| 114 | + PAGE_CACHE_SIZE - 1); | |
| 115 | + } | |
| 116 | if (!smallest || (rdev1->sectors < smallest->sectors)) | |
| 117 | smallest = rdev1; | |
| 118 | cnt++; | |
| 119 | --- a/drivers/md/raid10.c | |
| 120 | +++ b/drivers/md/raid10.c | |
| 121 | @@ -1155,13 +1155,17 @@ static int raid10_add_disk(mddev_t *mdde | |
| 122 | ||
| 123 | disk_stack_limits(mddev->gendisk, rdev->bdev, | |
| 124 | rdev->data_offset << 9); | |
| 125 | - /* as we don't honour merge_bvec_fn, we must never risk | |
| 126 | - * violating it, so limit ->max_sector to one PAGE, as | |
| 127 | - * a one page request is never in violation. | |
| 128 | + /* as we don't honour merge_bvec_fn, we must | |
| 129 | + * never risk violating it, so limit | |
| 130 | + * ->max_phys_segments to one lying with a single | |
| 131 | + * page, as a one page request is never in | |
| 132 | + * violation. | |
| 133 | */ | |
| 134 | - if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
| 135 | - queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) | |
| 136 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 137 | + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { | |
| 138 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 139 | + blk_queue_segment_boundary(mddev->queue, | |
| 140 | + PAGE_CACHE_SIZE - 1); | |
| 141 | + } | |
| 142 | ||
| 143 | p->head_position = 0; | |
| 144 | rdev->raid_disk = mirror; | |
| 145 | @@ -2155,12 +2159,14 @@ static int run(mddev_t *mddev) | |
| 146 | disk_stack_limits(mddev->gendisk, rdev->bdev, | |
| 147 | rdev->data_offset << 9); | |
| 148 | /* as we don't honour merge_bvec_fn, we must never risk | |
| 149 | - * violating it, so limit ->max_sector to one PAGE, as | |
| 150 | - * a one page request is never in violation. | |
| 151 | + * violating it, so limit max_phys_segments to 1 lying | |
| 152 | + * within a single page. | |
| 153 | */ | |
| 154 | - if (rdev->bdev->bd_disk->queue->merge_bvec_fn && | |
| 155 | - queue_max_sectors(mddev->queue) > (PAGE_SIZE>>9)) | |
| 156 | - blk_queue_max_sectors(mddev->queue, PAGE_SIZE>>9); | |
| 157 | + if (rdev->bdev->bd_disk->queue->merge_bvec_fn) { | |
| 158 | + blk_queue_max_phys_segments(mddev->queue, 1); | |
| 159 | + blk_queue_segment_boundary(mddev->queue, | |
| 160 | + PAGE_CACHE_SIZE - 1); | |
| 161 | + } | |
| 162 | ||
| 163 | disk->head_position = 0; | |
| 164 | } |