Tejun Heo wrote:
For misc ATAPI commands which transfer variable length data to the host, overflow can occur due to application or hardware bug. Such overflows can be ignored safely as long as overflow data is properly drained. libata HSM implementation has this implemented in __atapi_pio_bytes() but it isn't enough. Improve drain logic such that... * Multiple PIO data phases are allowed. Not allowing this used to be okay when transfer chunk size was set to 8k unconditionally but with transfer hcunk size set to allocation size, treating extra PIO data phases as HSM violations cause a lot of trouble. * Limit the amount of draining to ATAPI_MAX_DRAIN (16k currently). * Don't whine if overflow is allowed and safe. When unexpected overflow occurs, trigger HSM violation and report the problem using ehi error description. * Properly calculate the number of bytes to be drained considering actual number of consumed bytes for partial draining. * Add and use ata_drain_page for draining. This change fixes the problem where LLDs which do 32bit IOs consumes 4 bytes on each 2 byte draining resulting in draining twice more data than requested. This patch fixes ATAPI regressions introduced by setting transfer chunk size to allocation size. Signed-off-by: Tejun Heo <htejun@xxxxxxxxx> Cc: Albert Lee <albertcc@xxxxxxxxxx>
I'm dropping this one, since a good portion of it is already upstream as140b5e59119a172a91b5fa13d54ca4f79bbefee1
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