From: Zach Brown <zab@xxxxxxxxx>
This adds a helper function which allocates and initializes the dio
structure. We'll be calling this from another entry point like
__blockdev_direct_IO() in an upcoming patch.
Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx>
Cc: Zach Brown <zab@xxxxxxxxx>
---
fs/direct-io.c | 68 ++++++++++++++++++++++++++++++++++----------------------
1 file changed, 42 insertions(+), 26 deletions(-)
diff --git a/fs/direct-io.c b/fs/direct-io.c
index 21a1412..1fbb4ab 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1096,6 +1096,47 @@ static int dio_aligned(unsigned long offset, unsigned *blkbits,
return 1;
}
+static struct dio *dio_alloc_init(int flags, int rw, struct kiocb *iocb,
+ struct inode *inode, dio_iodone_t end_io,
+ loff_t end)
+{
+ struct dio *dio;
+
+ dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
+ if (!dio)
+ return NULL;
+
+ /*
+ * Believe it or not, zeroing out the page array caused a .5%
+ * performance regression in a database benchmark. So, we take
+ * care to only zero out what's needed.
+ */
+ memset(dio, 0, offsetof(struct dio, pages));
+
+ dio->flags = flags;
+ /*
+ * For file extending writes updating i_size before data
+ * writeouts complete can expose uninitialized blocks. So
+ * even for AIO, we need to wait for i/o to complete before
+ * returning in this case.
+ */
+ dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
+ (end > i_size_read(inode)));
+
+ dio->inode = inode;
+ dio->rw = rw;
+
+ dio->end_io = end_io;
+
+ dio->iocb = iocb;
+ dio->i_size = i_size_read(inode);
+
+ spin_lock_init(&dio->bio_lock);
+ dio->refcount = 1;
+
+ return dio;
+}
+
/*
* This is a library function for use by filesystem drivers.
*
@@ -1158,18 +1199,11 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
if (rw == READ && end == offset)
return 0;
- dio = kmem_cache_alloc(dio_cache, GFP_KERNEL);
+ dio = dio_alloc_init(flags, rw, iocb, inode, end_io, end);
retval = -ENOMEM;
if (!dio)
goto out;
- /*
- * Believe it or not, zeroing out the page array caused a .5%
- * performance regression in a database benchmark. So, we take
- * care to only zero out what's needed.
- */
- memset(dio, 0, offsetof(struct dio, pages));
- dio->flags = flags;
if (dio->flags & DIO_LOCKING) {
if (rw == READ) {
struct address_space *mapping =
@@ -1193,35 +1227,17 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
*/
atomic_inc(&inode->i_dio_count);
- /*
- * For file extending writes updating i_size before data
- * writeouts complete can expose uninitialized blocks. So
- * even for AIO, we need to wait for i/o to complete before
- * returning in this case.
- */
- dio->is_async = !is_sync_kiocb(iocb) && !((rw & WRITE) &&
- (end > i_size_read(inode)));
-
retval = 0;
- dio->inode = inode;
- dio->rw = rw;
sdio.blkbits = blkbits;
sdio.blkfactor = inode->i_blkbits - blkbits;
sdio.block_in_file = offset >> blkbits;
sdio.get_block = get_block;
- dio->end_io = end_io;
sdio.submit_io = submit_io;
sdio.final_block_in_bio = -1;
sdio.next_block_for_io = -1;
- dio->iocb = iocb;
- dio->i_size = i_size_read(inode);
-
- spin_lock_init(&dio->bio_lock);
- dio->refcount = 1;
-
/*
* In case of non-aligned buffers, we may need 2 more
* pages since we need to zero out first and last block.
--
1.7.9.2
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