io: block: fix block_read/write may read/write overlap buffer
The block operations were trying to optimize the number of memory
copies, and it tried to use directly the buffer supplied by the user
to them. This was a mistake because it created too many corner cases:
1- It was possible to generate unaligned
operations to unaligned buffers. Drivers that were using
DMA transfer failed in that case.
2- It was possible to generate read operations
with sizes that weren't a multiple of the block size. Some
low level drivers assumed that condition and they calculated
the number of blocks dividing the number of bytes by the
size of the block, without considering the remaining bytes.
3- The block_* operations didn't control the
number of bytes actually copied to memory, because the
low level drivers were writing directly to the user buffer.
This patch rewrite block_read and block_write to use always the device
buffer, which the platform ensures that has the correct aligment and
the correct size.
Change-Id: I5e479bb7bc137e6ec205a8573eb250acd5f40420
Signed-off-by: Qixiang Xu <qixiang.xu@arm.com>
Signed-off-by: Roberto Vargas <roberto.vargas@arm.com>
1 file changed