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On Sun, Apr 20, 2003, viro@parcelfarce.linux.theplanet.co.uk wrote: [lots of useful stuff]. Happy Easter! Concerning kdev_t vs dev_t, probably I said this before, but just to be sure: Long ago the purpose of kdev_t was to become a pointer. Roughly speaking we got that pointer, only it is called struct gendisk * today. Today the purpose of kdev_t is to be a form of dev_t: taking the minor of a kdev_t is just taking the lower 32 bits, no tests, no branches; taking the minor of a dev_t requires tests and branches - more code, slower code. So, the interface with filesystems and with userspace has dev_t. For kernel-internal numbers kdev_t is better than dev_t. Of course it may be possible to avoid kernel-internal numbers altogether. Sometimes that is an improvement, sometimes not. Pointers are more complicated than numbers - they point at something that must be allocated and freed and reference counted. A number is like a pointer without the reference counting. Andries - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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