On September 18, 2023 12:32:05 PM PDT, Jiri Kosina <jikos@xxxxxxxxxx> wrote: >On Mon, 18 Sep 2023, Linus Torvalds wrote: > >> But mmap() is *not* important for a filesystem that is used just for >> data transport. I bet that FAT is still widely used, for example, and >> while exFAT is probably making inroads, I suspect most of us have used a >> USB stick with a FAT filesystem on it in the not too distant past. Yet I >> doubt we'd have ever even noticed if 'mmap' didn't work on FAT. Because >> all you really want for data transport is basic read/write support. > >I am afraid this is not reflecting reality. > >I am pretty sure that "give me that document on a USB stick, and I'll take >a look" leads to using things like libreoffice (or any other editor liked >by general public) to open the file directly on the FAT USB stick. And >that's pretty much guaranteed to use mmap(). > I mean... fopen() on Linux optionally uses mmap()... and it used to do so unconditionally, even. mmap() is a good match for stdio (at least the input side), so it is a reasonable thing to do.
