This series was original by a bug fix in nvme-over-tcp driver which only
checked whether a page was allocated from slab allcoator, but forgot to
check its page_count: The page handled by sendpage should be neither a
Slab page nor 0 page_count page.
As Sagi Grimberg suggested, the original fix is refind to a more common
inline routine:
static inline bool sendpage_ok(struct page *page)
{
return (!PageSlab(page) && page_count(page) >= 1);
}
If sendpage_ok() returns true, the checking page can be handled by the
zero copy sendpage method in network layer.
The first patch in this series introduces sendpage_ok() in header file
include/linux/net.h, the second patch fixes the page checking issue in
nvme-over-tcp driver, the third patch adds page_count check by using
sendpage_ok() in do_tcp_sendpages() as Eric Dumazet suggested, and all
rested patches just replace existing open coded checks with the inline
sendpage_ok() routine.
Coly Li
Cc: Chaitanya Kulkarni <[email protected]>
Cc: Chris Leech <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Cong Wang <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Cc: Ilya Dryomov <[email protected]>
Cc: Jan Kara <[email protected]>
Cc: Jeff Layton <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Lee Duncan <[email protected]>
Cc: Mike Christie <[email protected]>
Cc: Mikhail Skorzhinskii <[email protected]>
Cc: Philipp Reisner <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Cc: Vasily Averin <[email protected]>
Cc: Vlastimil Babka <[email protected]>
---
Changelog:
v7: remove outer brackets from the return line of sendpage_ok() as
Eric Dumazet suggested.
v6: fix page check in do_tcp_sendpages(), as Eric Dumazet suggested.
replace other open coded checks with sendpage_ok() in libceph,
iscsi drivers.
v5, include linux/mm.h in include/linux/net.h
v4, change sendpage_ok() as an inline helper, and post it as
separate patch, as Christoph Hellwig suggested.
v3, introduce a more common sendpage_ok() as Sagi Grimberg suggested.
v2, fix typo in patch subject
v1, the initial version.
Coly Li (6):
net: introduce helper sendpage_ok() in include/linux/net.h
nvme-tcp: check page by sendpage_ok() before calling kernel_sendpage()
tcp: use sendpage_ok() to detect misused .sendpage
drbd: code cleanup by using sendpage_ok() to check page for
kernel_sendpage()
scsi: libiscsi: use sendpage_ok() in iscsi_tcp_segment_map()
libceph: use sendpage_ok() in ceph_tcp_sendpage()
drivers/block/drbd/drbd_main.c | 2 +-
drivers/nvme/host/tcp.c | 7 +++----
drivers/scsi/libiscsi_tcp.c | 2 +-
include/linux/net.h | 16 ++++++++++++++++
net/ceph/messenger.c | 2 +-
net/ipv4/tcp.c | 3 ++-
6 files changed, 24 insertions(+), 8 deletions(-)
--
2.26.2
