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authorDaniel Schaeffer <daniel@dschaeffer.localdomain>2008-01-30 15:42:41 -0500
committerDaniel Schaeffer <daniel@dschaeffer.localdomain>2008-01-30 15:42:41 -0500
commit648b932d8cf61f38d08a84e6388036b22766c2df (patch)
tree3c48859a194482b645b93c1bead3bcc323327fb7 /Documentation/DocBook/procfs-guide.tmpl
parent2506ae0663e660d8dc7624fcdae1814c8ee3d10a (diff)
parentbbf25010f1a6b761914430f5fca081ec8c7accd1 (diff)
Merge branch '2.6.23' into 2.6.22.6-imx27
Conflicts: Documentation/kernel-parameters.txt Makefile arch/arm/Kconfig arch/arm/Makefile arch/arm/mach-mx3/Kconfig arch/arm/mach-mx3/Makefile arch/arm/mach-mx3/mm.c arch/arm/mach-mx3/mx31ads.c arch/arm/mm/Kconfig arch/arm/plat-mxc/Kconfig arch/arm/plat-mxc/Makefile arch/arm/plat-mxc/irq.c block/cfq-iosched.c drivers/ata/ahci.c drivers/ata/libata-core.c drivers/char/watchdog/Kconfig drivers/firewire/fw-sbp2.c drivers/md/dm-crypt.c drivers/media/video/pwc/pwc-if.c drivers/mmc/card/Kconfig drivers/mmc/card/queue.c drivers/mmc/core/Makefile drivers/mmc/core/bus.c drivers/mmc/core/core.c drivers/mmc/core/host.c drivers/mmc/core/mmc.c drivers/mmc/core/sd.c drivers/mmc/core/sd_ops.c drivers/mmc/host/at91_mci.c drivers/mmc/host/sdhci.c drivers/net/bonding/bond_main.c drivers/net/fec.c drivers/net/forcedeth.c drivers/net/r8169.c drivers/net/sky2.c drivers/rtc/Kconfig drivers/rtc/Makefile drivers/spi/Kconfig drivers/spi/Makefile drivers/usb/gadget/Makefile drivers/usb/gadget/gadget_chips.h drivers/usb/host/ehci.h drivers/video/logo/logo.c drivers/w1/slaves/Makefile fs/9p/conv.c fs/direct-io.c fs/exec.c fs/ocfs2/file.c fs/signalfd.c fs/sysfs/file.c include/asm-arm/arch-mxc/dma.h include/asm-arm/arch-mxc/entry-macro.S include/asm-arm/arch-mxc/hardware.h include/asm-arm/arch-mxc/io.h include/asm-arm/arch-mxc/irqs.h include/asm-arm/arch-mxc/memory.h include/asm-arm/arch-mxc/mx31.h include/asm-arm/arch-mxc/mxc.h include/asm-arm/arch-mxc/system.h include/asm-arm/arch-mxc/timex.h include/asm-arm/arch-mxc/uncompress.h include/asm-arm/arch-mxc/vmalloc.h include/linux/fsl_devices.h include/linux/ioprio.h kernel/lockdep_proc.c kernel/signal.c mm/hugetlb.c mm/readahead.c net/bluetooth/rfcomm/tty.c net/bridge/br_device.c net/core/dev.c net/ieee80211/softmac/ieee80211softmac_assoc.c net/ieee80211/softmac/ieee80211softmac_wx.c net/ipv4/netfilter/nf_conntrack_proto_icmp.c net/ipv4/tcp_input.c net/netfilter/nf_conntrack_proto_sctp.c
Diffstat (limited to 'Documentation/DocBook/procfs-guide.tmpl')
-rw-r--r--Documentation/DocBook/procfs-guide.tmpl82
1 files changed, 63 insertions, 19 deletions
diff --git a/Documentation/DocBook/procfs-guide.tmpl b/Documentation/DocBook/procfs-guide.tmpl
index 45cad23efefa..2de84dc195a8 100644
--- a/Documentation/DocBook/procfs-guide.tmpl
+++ b/Documentation/DocBook/procfs-guide.tmpl
@@ -352,49 +352,93 @@ entry->write_proc = write_proc_foo;
<funcsynopsis>
<funcprototype>
<funcdef>int <function>read_func</function></funcdef>
- <paramdef>char* <parameter>page</parameter></paramdef>
+ <paramdef>char* <parameter>buffer</parameter></paramdef>
<paramdef>char** <parameter>start</parameter></paramdef>
<paramdef>off_t <parameter>off</parameter></paramdef>
<paramdef>int <parameter>count</parameter></paramdef>
- <paramdef>int* <parameter>eof</parameter></paramdef>
+ <paramdef>int* <parameter>peof</parameter></paramdef>
<paramdef>void* <parameter>data</parameter></paramdef>
</funcprototype>
</funcsynopsis>
<para>
The read function should write its information into the
- <parameter>page</parameter>. For proper use, the function
- should start writing at an offset of
- <parameter>off</parameter> in <parameter>page</parameter> and
- write at most <parameter>count</parameter> bytes, but because
- most read functions are quite simple and only return a small
- amount of information, these two parameters are usually
- ignored (it breaks pagers like <literal>more</literal> and
- <literal>less</literal>, but <literal>cat</literal> still
- works).
+ <parameter>buffer</parameter>, which will be exactly
+ <literal>PAGE_SIZE</literal> bytes long.
</para>
<para>
- If the <parameter>off</parameter> and
- <parameter>count</parameter> parameters are properly used,
- <parameter>eof</parameter> should be used to signal that the
+ The parameter
+ <parameter>peof</parameter> should be used to signal that the
end of the file has been reached by writing
<literal>1</literal> to the memory location
- <parameter>eof</parameter> points to.
+ <parameter>peof</parameter> points to.
</para>
<para>
- The parameter <parameter>start</parameter> doesn't seem to be
- used anywhere in the kernel. The <parameter>data</parameter>
+ The <parameter>data</parameter>
parameter can be used to create a single call back function for
several files, see <xref linkend="usingdata"/>.
</para>
<para>
- The <function>read_func</function> function must return the
- number of bytes written into the <parameter>page</parameter>.
+ The rest of the parameters and the return value are described
+ by a comment in <filename>fs/proc/generic.c</filename> as follows:
</para>
+ <blockquote>
+ <para>
+ You have three ways to return data:
+ </para>
+ <orderedlist>
+ <listitem>
+ <para>
+ Leave <literal>*start = NULL</literal>. (This is the default.)
+ Put the data of the requested offset at that
+ offset within the buffer. Return the number (<literal>n</literal>)
+ of bytes there are from the beginning of the
+ buffer up to the last byte of data. If the
+ number of supplied bytes (<literal>= n - offset</literal>) is
+ greater than zero and you didn't signal eof
+ and the reader is prepared to take more data
+ you will be called again with the requested
+ offset advanced by the number of bytes
+ absorbed. This interface is useful for files
+ no larger than the buffer.
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Set <literal>*start</literal> to an unsigned long value less than
+ the buffer address but greater than zero.
+ Put the data of the requested offset at the
+ beginning of the buffer. Return the number of
+ bytes of data placed there. If this number is
+ greater than zero and you didn't signal eof
+ and the reader is prepared to take more data
+ you will be called again with the requested
+ offset advanced by <literal>*start</literal>. This interface is
+ useful when you have a large file consisting
+ of a series of blocks which you want to count
+ and return as wholes.
+ (Hack by Paul.Russell@rustcorp.com.au)
+ </para>
+ </listitem>
+ <listitem>
+ <para>
+ Set <literal>*start</literal> to an address within the buffer.
+ Put the data of the requested offset at <literal>*start</literal>.
+ Return the number of bytes of data placed there.
+ If this number is greater than zero and you
+ didn't signal eof and the reader is prepared to
+ take more data you will be called again with the
+ requested offset advanced by the number of bytes
+ absorbed.
+ </para>
+ </listitem>
+ </orderedlist>
+ </blockquote>
+
<para>
<xref linkend="example"/> shows how to use a read call back
function.