Stefano Garzarella
2023-Jun-26 16:30 UTC
[RFC PATCH v1 0/4] virtio/vsock: some updates for MSG_PEEK flag
On Sun, Jun 18, 2023 at 09:24:47AM +0300, Arseniy Krasnov wrote:>Hello, > >This patchset does several things around MSG_PEEK flag support. In >general words it reworks MSG_PEEK test and adds support for this flag >in SOCK_SEQPACKET logic. Here is per-patch description: > >1) This is cosmetic change for SOCK_STREAM implementation of MSG_PEEK: > 1) I think there is no need of "safe" mode walk here as there is no > "unlink" of skbs inside loop (it is MSG_PEEK mode - we don't change > queue). > 2) Nested while loop is removed: in case of MSG_PEEK we just walk > over skbs and copy data from each one. I guess this nested loop > even didn't behave as loop - it always executed just for single > iteration. > >2) This adds MSG_PEEK support for SOCK_SEQPACKET. It could be implemented > be reworking MSG_PEEK callback for SOCK_STREAM to support SOCK_SEQPACKET > also, but I think it will be more simple and clear from potential > bugs to implemented it as separate function thus not mixing logics > for both types of socket. So I've added it as dedicated function. > >3) This is reworked MSG_PEEK test for SOCK_STREAM. Previous version just > sent single byte, then tried to read it with MSG_PEEK flag, then read > it in normal way. New version is more complex: now sender uses buffer > instead of single byte and this buffer is initialized with random > values. Receiver tests several things: > 1) Read empty socket with MSG_PEEK flag. > 2) Read part of buffer with MSG_PEEK flag. > 3) Read whole buffer with MSG_PEEK flag, then checks that it is same > as buffer from 2) (limited by size of buffer from 2) of course). > 4) Read whole buffer without any flags, then checks that is is same > as buffer from 3). > >4) This is MSG_PEEK test for SOCK_SEQPACKET. It works in the same way > as for SOCK_STREAM, except it also checks combination of MSG_TRUNC > and MSG_PEEK. > >Head is: >https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=d20dd0ea14072e8a90ff864b2c1603bd68920b4bNice cleanup, LGTM, but I'd like a comment from Bobby. Thanks, Stefano