Re: code review request: simple usb stream interface (susi)
Edwin Olson <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Message-ID | <[email protected]> |
>> * Why does usb-serial set MAX_TRANFER to (PAGE_SIZE - 512)? What's the >> 512 for? >> > > A measure to make sure that a malicious user cannot use up unlimited > amounts of kernel memory. 512 is the maximum packet size of ehci. > Thus we make sure the number of packets on the page is an integer. > I definitely understand limiting the number of outstanding URBs to avoid a DoS, but I don't follow why MAX_TRANSFER is being set to this particular value. MAX_TRANSFER = PAGE_SIZE would seem like a better choice, as it wouldn't cause a PAGE_SIZE-sized write to fragment into two URBs (not that that's such a terrible thing anyway.) I'm not sure I see how the maximum packet size of the host enters into it. Can you clarify? -Ed ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier. Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel