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SubjectRe: question on SMP and read()/write()
On Saturday 28 October 2000 16:43, you wrote:
> > I've noticed that sys_read() and sys_write() don't grab the big kernel
> > lock. As file descriptors may be shared, must device drivers provide SMP
> > safe read() and write() methods ?
>
> no. FD's refer to files; block drivers don't, and the nontrivial
> code between sys_* and drivers deals with this sort of thing.

Sure block drivers need not do this, but how about drivers for character
devices ? It seems that sys_read() calls a function provided by the
f_op table without any locking. Isn't this the function a driver for a
character device must provide to the VFS ?

TIA
Oliver
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