Messages in this thread | | | From | "Michael Kelley (EOSG)" <> | Subject | RE: [Patch v2 1/6] cifs: smbd: Check for iov length on sending the last iov | Date | Sun, 22 Apr 2018 23:27:08 +0000 |
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> -----Original Message----- > From: linux-kernel-owner@vger.kernel.org <linux-kernel-owner@vger.kernel.org> On Behalf > Of Long Li > Sent: Tuesday, April 17, 2018 12:17 PM > To: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org; samba- > technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-rdma@vger.kernel.org > Cc: Long Li <longli@microsoft.com>; stable@vger.kernel.org > Subject: [Patch v2 1/6] cifs: smbd: Check for iov length on sending the last iov > > From: Long Li <longli@microsoft.com> > > When sending the last iov that breaks into smaller buffers to fit the > transfer size, it's necessary to check if this is the last iov. > > If this is the latest iov, stop and proceed to send pages. > > Signed-off-by: Long Li <longli@microsoft.com> > Cc: stable@vger.kernel.org
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
But a question unrelated to this change arose during my review: At the beginning and end of smbd_send(), the field smbd_send_pending is incremented and decremented, respectively. The increment/decrement are not done as atomic operations. Is this code guaranteed to be single threaded? If not, the count could become corrupted, and smbd_destroy_rdma_work(), which waits for the count to become zero, could hang. A similar question applies to smbd_recv_pending in smbd_recv().
> --- > fs/cifs/smbdirect.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c > index 90e673c..b5c6c0d 100644 > --- a/fs/cifs/smbdirect.c > +++ b/fs/cifs/smbdirect.c > @@ -2197,6 +2197,8 @@ int smbd_send(struct smbd_connection *info, struct smb_rqst *rqst) > goto done; > } > i++; > + if (i == rqst->rq_nvec) > + break; > } > start = i; > buflen = 0; > -- > 2.7.4
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