Messages in this thread |  | | From | Oliver Neukum <> | Date | Sat, 28 Oct 2000 17:42:50 +0200 | Subject | Re: question on SMP and read()/write() |
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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 ?
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