Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 03/17] blk-map: improve alignment checking for blk_rq_map_user_iov() | Date | Wed, 1 Apr 2009 22:44:18 +0900 |
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Impact: stricter more consistent alignment checking
Move all alignment checks in blk_rq_map_user_iov() to __bio_map_user_iov() which has to walk the iov at the beginning anyway. Improve alignment check such that it checks for both the start address and length of each segment.
Signed-off-by: Tejun Heo <tj@kernel.org> --- block/blk-map.c | 21 +++++---------------- fs/bio.c | 20 +++++++++++++------- 2 files changed, 18 insertions(+), 23 deletions(-)
diff --git a/block/blk-map.c b/block/blk-map.c index fdef591..b0b65ef 100644 --- a/block/blk-map.c +++ b/block/blk-map.c @@ -67,28 +67,17 @@ int blk_rq_map_user_iov(struct request_queue *q, struct request *rq, struct rq_map_data *map_data, struct sg_iovec *iov, int iov_count, unsigned int len, gfp_t gfp_mask) { - struct bio *bio; - int i, read = rq_data_dir(rq) == READ; - int unaligned = 0; + struct bio *bio = ERR_PTR(-EINVAL); + int read = rq_data_dir(rq) == READ; if (!iov || iov_count <= 0) return -EINVAL; - for (i = 0; i < iov_count; i++) { - unsigned long uaddr = (unsigned long)iov[i].iov_base; - - if (uaddr & queue_dma_alignment(q)) { - unaligned = 1; - break; - } - } - - if (unaligned || (q->dma_pad_mask & len) || map_data) + if (!map_data) + bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); + if (bio == ERR_PTR(-EINVAL)) bio = bio_copy_user_iov(q, map_data, iov, iov_count, read, gfp_mask); - else - bio = bio_map_user_iov(q, NULL, iov, iov_count, read, gfp_mask); - if (IS_ERR(bio)) return PTR_ERR(bio); diff --git a/fs/bio.c b/fs/bio.c index 728bef9..80f61ed 100644 --- a/fs/bio.c +++ b/fs/bio.c @@ -26,6 +26,7 @@ #include <linux/mempool.h> #include <linux/workqueue.h> #include <linux/blktrace_api.h> +#include <linux/pfn.h> #include <trace/block.h> #include <scsi/sg.h> /* for struct sg_iovec */ @@ -921,6 +922,7 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, int write_to_vm, gfp_t gfp_mask) { int i, j; + size_t tot_len = 0; int nr_pages = 0; struct page **pages; struct bio *bio; @@ -930,18 +932,22 @@ static struct bio *__bio_map_user_iov(struct request_queue *q, for (i = 0; i < iov_count; i++) { unsigned long uaddr = (unsigned long)iov[i].iov_base; unsigned long len = iov[i].iov_len; - unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; - unsigned long start = uaddr >> PAGE_SHIFT; - nr_pages += end - start; + nr_pages += PFN_UP(uaddr + len) - PFN_DOWN(uaddr); + tot_len += len; + /* - * buffer must be aligned to at least hardsector size for now + * Each segment must be aligned on DMA boundary. The + * last one may have unaligned length as long as the + * total length is aligned to DMA padding alignment. */ - if (uaddr & queue_dma_alignment(q)) + if (i == count - 1) + len = 0; + if ((uaddr | len) & queue_dma_alignment(q)) return ERR_PTR(-EINVAL); } - - if (!nr_pages) + /* and total length on DMA padding alignment */ + if (!nr_pages || tot_len & q->dma_pad_mask) return ERR_PTR(-EINVAL); bio = bio_kmalloc(gfp_mask, nr_pages); -- 1.6.0.2
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