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| author | Tahsin Erdogan <trdgn@amazon.com> | 2023-08-09 09:47:52 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-08-10 19:33:35 -0700 |
| commit | 6231e47b6fadf42da2e7a45b8272e80aed53c444 (patch) | |
| tree | 88e72bf2193a5d6e53630b2fec8119940b7a6276 /drivers/net/tun.c | |
| parent | 5604ac35cb6ec34ad608008ba851568c385fd3f4 (diff) | |
| download | linux-6231e47b6fadf42da2e7a45b8272e80aed53c444.tar.gz linux-6231e47b6fadf42da2e7a45b8272e80aed53c444.tar.bz2 linux-6231e47b6fadf42da2e7a45b8272e80aed53c444.zip | |
tun: avoid high-order page allocation for packet header
When gso.hdr_len is zero and a packet is transmitted via write() or
writev(), all payload is treated as header which requires a contiguous
memory allocation. This allocation request is harder to satisfy, and may
even fail if there is enough fragmentation.
Note that sendmsg() code path limits the linear copy length, so this change
makes write()/writev() and sendmsg() paths more consistent.
Signed-off-by: Tahsin Erdogan <trdgn@amazon.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20230809164753.2247594-1-trdgn@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'drivers/net/tun.c')
| -rw-r--r-- | drivers/net/tun.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a05765448803..d4bd76297a2a 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1523,7 +1523,7 @@ static struct sk_buff *tun_alloc_skb(struct tun_file *tfile, int err; /* Under a page? Don't bother with paged skb. */ - if (prepad + len < PAGE_SIZE || !linear) + if (prepad + len < PAGE_SIZE) linear = len; if (len - linear > MAX_SKB_FRAGS * (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER)) @@ -1840,6 +1840,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, */ zerocopy = false; } else { + if (!linear) + linear = min_t(size_t, good_linear, copylen); + skb = tun_alloc_skb(tfile, align, copylen, linear, noblock); } |