On Tue, Mar 12 2002, Oliver Neukum wrote: > > > There's an additional question here. The new code will not > > > deadlock, but a USB error could occur, if kmalloc fails. > > > Is this acceptable ? > > > > Doesn't sound acceptable. USB needs a reserved pool to handle stuff like > > this, _NOIO allocations are not reliable in the same sense that > > GFP_KERNEL allocations are. pktcdvd goes to great lengths to assure > > deadlock free allocations during I/O. > > Are there other scsi drivers who need to allocate memory to process > a request ? How do they solve the problem ?
Not to my knowledge. The mid layer in 2.5 allocates scatter tables at init I/O time, they are protected by the mempool setup though. This is exactly the kind of precautions one needs to take to ensure deadlock free I/O. Just changing GFP_KERNEL to GFP_NOIO is not good enough. -- Jens Axboe _______________________________________________ [EMAIL PROTECTED] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
