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[PATCH] relayfs: Documentation cleanup, remove obsolete info
librelay and relay-app.h have been retired - update Documentation to reflect that. Signed-off-by: Tom Zanussi <zanussi@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -44,30 +44,41 @@ relayfs can operate in a mode where it will overwrite data not yet
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collected by userspace, and not wait for it to consume it.
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collected by userspace, and not wait for it to consume it.
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relayfs itself does not provide for communication of such data between
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relayfs itself does not provide for communication of such data between
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userspace and kernel, allowing the kernel side to remain simple and not
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userspace and kernel, allowing the kernel side to remain simple and
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impose a single interface on userspace. It does provide a separate
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not impose a single interface on userspace. It does provide a set of
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helper though, described below.
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examples and a separate helper though, described below.
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klog, relay-app & librelay
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klog and relay-apps example code
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==========================
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================================
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relayfs itself is ready to use, but to make things easier, two
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relayfs itself is ready to use, but to make things easier, a couple
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additional systems are provided. klog is a simple wrapper to make
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simple utility functions and a set of examples are provided.
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writing formatted text or raw data to a channel simpler, regardless of
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whether a channel to write into exists or not, or whether relayfs is
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compiled into the kernel or is configured as a module. relay-app is
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the kernel counterpart of userspace librelay.c, combined these two
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files provide glue to easily stream data to disk, without having to
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bother with housekeeping. klog and relay-app can be used together,
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with klog providing high-level logging functions to the kernel and
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relay-app taking care of kernel-user control and disk-logging chores.
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It is possible to use relayfs without relay-app & librelay, but you'll
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The relay-apps example tarball, available on the relayfs sourceforge
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have to implement communication between userspace and kernel, allowing
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site, contains a set of self-contained examples, each consisting of a
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both to convey the state of buffers (full, empty, amount of padding).
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pair of .c files containing boilerplate code for each of the user and
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kernel sides of a relayfs application; combined these two sets of
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boilerplate code provide glue to easily stream data to disk, without
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having to bother with mundane housekeeping chores.
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The 'klog debugging functions' patch (klog.patch in the relay-apps
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tarball) provides a couple of high-level logging functions to the
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kernel which allow writing formatted text or raw data to a channel,
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regardless of whether a channel to write into exists or not, or
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whether relayfs is compiled into the kernel or is configured as a
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module. These functions allow you to put unconditional 'trace'
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statements anywhere in the kernel or kernel modules; only when there
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is a 'klog handler' registered will data actually be logged (see the
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klog and kleak examples for details).
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It is of course possible to use relayfs from scratch i.e. without
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using any of the relay-apps example code or klog, but you'll have to
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implement communication between userspace and kernel, allowing both to
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convey the state of buffers (full, empty, amount of padding).
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klog and the relay-apps examples can be found in the relay-apps
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tarball on http://relayfs.sourceforge.net
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klog, relay-app and librelay can be found in the relay-apps tarball on
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http://relayfs.sourceforge.net
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The relayfs user space API
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The relayfs user space API
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==========================
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==========================
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