Fix offset within page calculation #24
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In Linux kernel since commit torvalds/linux@e2b39df property "offset" is exported, but it was just `mem->addr & ~PAGE_MASK` until commit torvalds/linux@171058f when `addr` became "rounded to page size" and `offset` became a field of `struct uio_mem`. But in uio_pdrv_genirq until commit torvalds/linux@7aca462 `addr` wasn't rounded by page size and field `offset` wasn't even initialized. Memory to struct where uio_mem is allocated by kzalloc so offset was 0. In this commit `offset` calculated as `addr & (getpagesize () - 1)` if: 1) file "offset" doesn't exist 2) 0 was read from file "offset"
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In Linux kernel since commit torvalds/linux@e2b39df property "offset" is exported, but it was just
mem->addr & ~PAGE_MASKuntil commit torvalds/linux@171058f whenaddrbecame "rounded to page size" andoffsetbecame a field ofstruct uio_mem. But in uio_pdrv_genirq until commit torvalds/linux@7aca462addrwasn't rounded by page size and fieldoffsetwasn't even initialized. Memory to struct where uio_mem is allocated by kzalloc so offset was 0.In this commit
offsetcalculated asaddr & (getpagesize () - 1)if: