Find and atomically map an sg-elemnt
void * scsi_kmap_atomic_sg(struct scatterlist * sgl, int sg_count, size_t * offset, size_t * len);
sgl
scatter-gather list
sg_count
number of segments in sg
offset
offset in bytes into sg, on return offset into the mapped area
len
bytes to map, on return number of bytes mapped
Returns virtual address of the start of the mapped page