提交 f9b5570d 编写于 作者: C Christoph Hellwig 提交者: Al Viro

fs: simplify handling of zero sized reads in __blockdev_direct_IO

Reject zero sized reads as soon as we know our I/O length, and don't
borther with locks or allocations that might have to be cleaned up
otherwise.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
上级 9ea7df53
......@@ -1200,6 +1200,10 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
}
}
/* watch out for a 0 len io from a tricksy fs */
if (rw == READ && end == offset)
return 0;
dio = kmalloc(sizeof(*dio), GFP_KERNEL);
retval = -ENOMEM;
if (!dio)
......@@ -1213,8 +1217,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
dio->flags = flags;
if (dio->flags & DIO_LOCKING) {
/* watch out for a 0 len io from a tricksy fs */
if (rw == READ && end > offset) {
if (rw == READ) {
struct address_space *mapping =
iocb->ki_filp->f_mapping;
......
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