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Commit 24da24de authored by Tom Zanussi's avatar Tom Zanussi Committed by Jens Axboe
Browse files

relay: fix bogus cast in subbuf_splice_actor() 



The current code that sets the read position in subbuf_splice_actor may
give erroneous results if the buffer size isn't a power of 2.  This
patch fixes the problem.

Signed-off-by: default avatarTom Zanussi <zanussi@us.ibm.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent 77320894

kernel/relay.c

+3 −1
Original line number Diff line number Diff line
@@ -1074,7 +1074,9 @@ static int subbuf_splice_actor(struct file *in, 
	unsigned int pidx, poff, total_len, subbuf_pages, ret;

	struct rchan_buf *rbuf = in->private_data;

	unsigned int subbuf_size = rbuf->chan->subbuf_size;

	size_t read_start = ((size_t)*ppos) % rbuf->chan->alloc_size;

	uint64_t pos = (uint64_t) *ppos;

	uint32_t alloc_size = (uint32_t) rbuf->chan->alloc_size;

	size_t read_start = (size_t) do_div(pos, alloc_size);

	size_t read_subbuf = read_start / subbuf_size;

	size_t padding = rbuf->padding[read_subbuf];

	size_t nonpad_end = read_subbuf * subbuf_size + subbuf_size - padding;