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authorAl Viro <viro@zeniv.linux.org.uk>2014-03-05 13:50:45 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2014-05-06 17:32:47 -0400
commit886a39115005ced8b15ab067c9c2a8d546b40a5e (patch)
treecb72af0480369f31a449aa7a8451d407315c2bf3
parent26978b8b4d83c46f4310b253db70fa9e65149e7c (diff)
downloadlinux-886a39115005ced8b15ab067c9c2a8d546b40a5e.tar.gz
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 <viro@zeniv.linux.org.uk>
-rw-r--r--drivers/staging/lustre/lustre/llite/rw26.c7
-rw-r--r--fs/direct-io.c27
-rw-r--r--include/linux/uio.h2
-rw-r--r--mm/iov_iter.c25
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);