Re: patch to shift memory allocations to usb_alloc_urb()
Matthew Dharm <[email protected]>
| Newsgroups | gmane.linux.usb.devel |
|---|---|
| Organization | One Eyed Alien Networks |
| Message-ID | <[email protected]> |
On Sun, Jul 01, 2007 at 11:00:43AM +0200, Oliver Neukum wrote: > My goals are: > > - guarantee the storage driver a fallback path without memory allocation What about avoiding allocation of memory during a usb-storage transfer completely? Does anyone know if the SCSI core actually follows the sg_tablesize parameter in the struct scsi_host_template ? Right now, it's set to SG_ALL, which means "unlimited number of sg elements", but any other non-zero value is supposed to be the maximum number of segments that the SCSI core sends to usb-storage. If it does, then we could advertise some maximum sg list size in that. We could then use that same limit to pre-allocate all the URBs that usb_sg_init would need. Thus, we wouldn't need a fallback path without memory allocation. Matt -- Matthew Dharm Home: [email protected] Maintainer, Linux USB Mass Storage Driver God, root, what is difference? -- Pitr User Friendly, 11/11/1999 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
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