From 886a39115005ced8b15ab067c9c2a8d546b40a5e Mon Sep 17 00:00:00 2001 From: Al Viro Date: Wed, 5 Mar 2014 13:50:45 -0500 Subject: [PATCH] new primitive: iov_iter_alignment() returns the value aligned as badly as the worst remaining segment in iov_iter is. Use instead of open-coded equivalents. Signed-off-by: Al Viro --- drivers/staging/lustre/lustre/llite/rw26.c | 7 ++---- fs/direct-io.c | 27 ++++------------------ include/linux/uio.h | 2 ++ mm/iov_iter.c | 25 ++++++++++++++++++++ 4 files changed, 34 insertions(+), 27 deletions(-) diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c index 38a5b580e7f0..f718585c9e08 100644 --- a/drivers/staging/lustre/lustre/llite/rw26.c +++ b/drivers/staging/lustre/lustre/llite/rw26.c @@ -391,11 +391,8 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb, MAX_DIO_SIZE >> PAGE_CACHE_SHIFT); /* Check that all user buffers are aligned as well */ - for (seg = 0; seg < iter->nr_segs; seg++) { - if (((unsigned long)iter->iov[seg].iov_base & ~CFS_PAGE_MASK) || - (iter->iov[seg].iov_len & ~CFS_PAGE_MASK)) - return -EINVAL; - } + if (iov_iter_alignment(iter) & ~CFS_PAGE_MASK) + return -EINVAL; env = cl_env_get(&refcheck); LASSERT(!IS_ERR(env)); diff --git a/fs/direct-io.c b/fs/direct-io.c index 1c677899b989..adfa1fb33456 100644 --- a/fs/direct-io.c +++ b/fs/direct-io.c @@ -1112,19 +1112,18 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, dio_submit_t submit_io, int flags) { int seg; - size_t size; - unsigned long addr; unsigned i_blkbits = ACCESS_ONCE(inode->i_blkbits); unsigned blkbits = i_blkbits; unsigned blocksize_mask = (1 << blkbits) - 1; ssize_t retval = -EINVAL; - loff_t end = offset; + loff_t end = offset + iov_iter_count(iter); struct dio *dio; struct dio_submit sdio = { 0, }; unsigned long user_addr; size_t bytes; struct buffer_head map_bh = { 0, }; struct blk_plug plug; + unsigned long align = offset | iov_iter_alignment(iter); if (rw & WRITE) rw = WRITE_ODIRECT; @@ -1134,32 +1133,16 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode, * the early prefetch in the caller enough time. */ - if (offset & blocksize_mask) { + if (align & blocksize_mask) { if (bdev) blkbits = blksize_bits(bdev_logical_block_size(bdev)); blocksize_mask = (1 << blkbits) - 1; - if (offset & blocksize_mask) + if (align & blocksize_mask) goto out; } - /* Check the memory alignment. Blocks cannot straddle pages */ - for (seg = 0; seg < iter->nr_segs; seg++) { - addr = (unsigned long)iter->iov[seg].iov_base; - size = iter->iov[seg].iov_len; - end += size; - if (unlikely((addr & blocksize_mask) || - (size & blocksize_mask))) { - if (bdev) - blkbits = blksize_bits( - bdev_logical_block_size(bdev)); - blocksize_mask = (1 << blkbits) - 1; - if ((addr & blocksize_mask) || (size & blocksize_mask)) - goto out; - } - } - /* watch out for a 0 len io from a tricksy fs */ - if (rw == READ && end == offset) + if (rw == READ && !iov_iter_count(iter)) return 0; dio = kmem_cache_alloc(dio_cache, GFP_KERNEL); diff --git a/include/linux/uio.h b/include/linux/uio.h index abbe83ded630..4ee17413fe1b 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -67,6 +67,7 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes); size_t iov_iter_single_seg_count(const struct iov_iter *i); size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i); +unsigned long iov_iter_alignment(const struct iov_iter *i); static inline void iov_iter_init(struct iov_iter *i, const struct iovec *iov, unsigned long nr_segs, @@ -88,4 +89,5 @@ static inline size_t iov_iter_count(struct iov_iter *i) int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len); int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len); + #endif diff --git a/mm/iov_iter.c b/mm/iov_iter.c index 22ec1ef068a8..2f762cc21080 100644 --- a/mm/iov_iter.c +++ b/mm/iov_iter.c @@ -195,3 +195,28 @@ size_t iov_iter_single_seg_count(const struct iov_iter *i) return min(i->count, iov->iov_len - i->iov_offset); } EXPORT_SYMBOL(iov_iter_single_seg_count); + +unsigned long iov_iter_alignment(const struct iov_iter *i) +{ + const struct iovec *iov = i->iov; + unsigned long res; + size_t size = i->count; + size_t n; + + if (!size) + return 0; + + res = (unsigned long)iov->iov_base + i->iov_offset; + n = iov->iov_len - i->iov_offset; + if (n >= size) + return res | size; + size -= n; + res |= n; + while (size > (++iov)->iov_len) { + res |= (unsigned long)iov->iov_base | iov->iov_len; + size -= iov->iov_len; + } + res |= (unsigned long)iov->iov_base | size; + return res; +} +EXPORT_SYMBOL(iov_iter_alignment); -- 2.39.2