On 13-06-23 02:37 PM, Akinobu Mita wrote:
do_device_access() is a function that abstracts copying SG list from/to
ramdisk storage (fake_storep).
It must deal with the ranges exceeding actual fake_storep size, because
such ranges are valid if virtual_gb is set greater than zero, and they
should be treated as fake_storep is repeatedly mirrored up to virtual size.
Unfortunately, it can't deal with the range which wraps around the end of
fake_storep. A wrap around range is copied by two sg_copy_{from,to}_buffer()
calls, but sg_copy_{from,to}_buffer() can't copy from/to in the middle of
SG list, therefore the second call can't copy correctly.
This fixes it by using sg_pcopy_{from,to}_buffer() that can copy from/to
the middle of SG list.
This also simplifies the assignment of sdb->resid in fill_from_dev_buffer().
Because fill_from_dev_buffer() is now only called once per command
execution cycle. So it is not necessary to take care to decrease
sdb->resid if fill_from_dev_buffer() is called more than once.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Cc: "James E.J. Bottomley" <JBottomley@xxxxxxxxxxxxx>
Cc: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
Cc: linux-scsi@xxxxxxxxxxxxxxx
---
* No change from v2
Acked-by: Douglas Gilbert <dgilbert@xxxxxxxxxxxx>
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