On (09/08/15 10:33), Sergey Senozhatsky wrote: > > I don't understand your concern. To me, this patch makes sense to me. > > Could you explain your point clearly, again? > > OK. suppose someone landed a typo in a 'zram device management' script > > echo llzo > /sys/block/zram0/comp_algorithm > -bash: echo: write error: Invalid argument > > > but the script ignores 'echo: write error'. > Because we added compression algorithm name check recently. > > then the script does > > echo 200M > /sys/block/zram0/disksize > -bash: echo: write error: Invalid argument > > > doing a simple dmesg reveals the problem > > [ 7076.657184] zram: Cannot initialise llzo compressing backend > > note that zram provides 'llzo' here, which is convenient.
ah, forgot to mention. there is another misleading thing. suppose the script checks the comp_algorithm() error code. and it attempts to do somthing like echo llzo > /sys/block/zram0/comp_algorithm -bash: echo: write error: Device or resource busy so user knows that comp_algorithm failed. so now he/she goes and checks zram cat /sys/block/zram0/comp_algorithm [lzo] lz4 and finds out... that [lzo] is supported and selected for usage. so what't the problem then? so user wrongly assumes now that the script has provided 'lzo' as input to zram... false! the existing scheme of things will provide additional hint. #current implementation cat /sys/block/zram0/comp_algorithm lzo lz4 so, none of the supported compression algorithms is selected. aha, that is obviously lead us to a conclusion that something wrong was with the input that script provided to zram. correct! -ss -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/