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Commit 0e95c853 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Jonathan Corbet
Browse files

io_ordering.txt: standardize document format 



Each text file under Documentation follows a different
format. Some doesn't even have titles!

Change its representation to follow the adopted standard,
using ReST markups for it to be parseable by Sphinx:

- Add a title;
- mark literal-blocks as such.

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 9cf5116d

Documentation/io_ordering.txt

+33 −29
Original line number Diff line number Diff line 
==============================================

Ordering I/O writes to memory-mapped addresses

==============================================



On some platforms, so-called memory-mapped I/O is weakly ordered.  On such

platforms, driver writers are responsible for ensuring that I/O writes to

memory-mapped addresses on their device arrive in the order intended.  This is
@@ -8,7 +12,7 @@ critical section of code protected by spinlocks. This would ensure that 
subsequent writes to I/O space arrived only after all prior writes (much like a

memory barrier op, mb(), only with respect to I/O).



A more concrete example from a hypothetical device driver:

A more concrete example from a hypothetical device driver::



		...

	CPU A:  spin_lock_irqsave(&dev_lock, flags)
@@ -25,7 +29,7 @@ CPU B: spin_unlock_irqrestore(&dev_lock, flags) 
		...



In the case above, the device may receive newval2 before it receives newval,

which could cause problems.  Fixing it is easy enough though:

which could cause problems.  Fixing it is easy enough though::



		...

	CPU A:  spin_lock_irqsave(&dev_lock, flags)