Commit 53e0ee9f authored Jan 27, 2014 by Xiao Guangrong Committed by Linus Torvalds Jan 27, 2014

splice: fix unexpected size truncation



@splice_desc.total_len is 32 bit(unsigned int) which is used to store the
size passed from userspace which is 64 bit(size_t) so that the size is
unexpectedly truncated

That means vmsplice can not work if the size passed from userspace is >=
4G, for example, we noticed in vmsplice, splice-reader does not do
anything and splice-writer is waiting for available buffer forever if the
size is 4G

Fix it by extending @splice_desc.total_len to 64 bits as well

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e7ca2552

include/linux/splice.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -24,7 +24,8 @@
		* Passed to the actors
		*/
		struct splice_desc {
		unsigned int len, total_len; /* current and remaining length */
		size_t total_len; /* remaining length */
		unsigned int len; /* current length */
		unsigned int flags; /* splice flags */
		/*
		* actor() private data

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