On Thu, Nov 05, 2015 at 05:59:36PM +0530, Vignesh R wrote: > On 11/04/2015 08:09 PM, Mark Brown wrote: > > It's a bit worrying that this doesn't sync with the message queue except > > via the mutex: this means that we might be out of order with respect to > > any asynchronous transfers that are happening on the device. I'm not > > sure that this is a practical problem, though there is some risk of > > unfair scheduling that would have to be under extreme load and it might > > make sense to prioritise reads anyway. > Since mmap interface is used only by mtd flash drivers and since almost > all mtd flash devices use synchronous transfers (spi_sync()), IMO, there > wont be out of order problem wrt mtd flashes. > But mmap read might delay transfers queued for non mtd flash devices. It > is difficult to wait for all transfers already queued to be pumped out > by __spi_pump_messages() and then do the mmap transfer. Do you have any > thoughts on how to sync with message queue? Like I say I think it probably doesn't matter. The main issue would be with other devices sharing the bus with a flash chip.
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