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authorAlex Elder <elder@inktank.com>2012-09-21 17:59:58 -0500
committerSage Weil <sage@inktank.com>2012-09-21 20:49:26 -0700
commit5ce765a540f34d1e2005e1210f49f67fdf11e997 (patch)
treecb442bbfd50da04f9d5b59be82b60c6880735da5
parent340c7a2b2c9a2da640af28a8c196356484ac8b50 (diff)
downloadop-kernel-dev-5ce765a540f34d1e2005e1210f49f67fdf11e997.zip
op-kernel-dev-5ce765a540f34d1e2005e1210f49f67fdf11e997.tar.gz
libceph: only kunmap kmapped pages
In write_partial_msg_pages(), pages need to be kmapped in order to perform a CRC-32c calculation on them. As an artifact of the way this code used to be structured, the kunmap() call was separated from the kmap() call and both were done conditionally. But the conditions under which the kmap() and kunmap() calls were made differed, so there was a chance a kunmap() call would be done on a page that had not been mapped. The symptom of this was tripping a BUG() in kunmap_high() when pkmap_count[nr] became 0. Reported-by: Bryan K. Wright <bryan@virginia.edu> Signed-off-by: Alex Elder <elder@inktank.com> Reviewed-by: Sage Weil <sage@inktank.com>
-rw-r--r--net/ceph/messenger.c5
1 files changed, 1 insertions, 4 deletions
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 24c5eea..159aa8b 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -1073,16 +1073,13 @@ static int write_partial_msg_pages(struct ceph_connection *con)
BUG_ON(kaddr == NULL);
base = kaddr + con->out_msg_pos.page_pos + bio_offset;
crc = crc32c(crc, base, len);
+ kunmap(page);
msg->footer.data_crc = cpu_to_le32(crc);
con->out_msg_pos.did_page_crc = true;
}
ret = ceph_tcp_sendpage(con->sock, page,
con->out_msg_pos.page_pos + bio_offset,
len, 1);
-
- if (do_datacrc)
- kunmap(page);
-
if (ret <= 0)
goto out;
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