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2010-10-15llseek: automatically add .llseek fopArnd Bergmann
All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Julia Lawall <julia@diku.dk> Cc: Christoph Hellwig <hch@infradead.org>
2010-05-19Add x64 support to debugfsHuang Ying
Add debugfs_create_x64. This is needed by ACPI APEI EINJ parameters support. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Len Brown <len.brown@intel.com>
2009-06-15debugfs: use specified mode to possibly mark files read/write onlyRobin Getz
In many SoC implementations there are hardware registers can be read or write only. This extends the debugfs to enforce the file permissions for these types of registers by providing a set of fops which are read or write only. This assumes that the kernel developer knows more about the hardware than the user (even root users) -- which is normally true. Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Bryan Wu <cooloney@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-06-15debugfs: fix docbook errorJonathan Corbet
Fix an error in debugfs_create_blob's docbook description It cannot actually be used to write a binary blob. Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2009-01-07debugfs: add helpers for exporting a size_t simple valueInaky Perez-Gonzalez
In the same spirit as debugfs_create_*(), introduce helpers for exporting size_t values over debugfs. The only trick done is that the format verifier is kept at %llu instead of %zu; otherwise type warnings would pop up: format ‘%zu’ expects type ‘size_t’, but argument 2 has type ‘long long unsigned int’ There is no real way to fix this one--however, we can consider %llu and %zu to be compatible if we consider that we are using the same for validating in debugfs_create_{x,u}{8,16,32}(). Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-04-30DEBUGFS: Correct location of debugfs API documentation.Robert P. J. Day
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-08libfs: allow error return from simple attributesChristoph Hellwig
Sometimes simple attributes might need to return an error, e.g. for acquiring a mutex interruptibly. In fact we have that situation in spufs already which is the original user of the simple attributes. This patch merged the temporarily forked attributes in spufs back into the main ones and allows to return errors. [akpm@linux-foundation.org: build fix] Signed-off-by: Christoph Hellwig <hch@lst.de> Cc: <stefano.brivio@polimi.it> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Greg KH <greg@kroah.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-15docbook: fix filesystems contentRandy Dunlap
Fix filesystems docbook warnings. Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'name' Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'mode' Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'parent' Warning(linux-2.6.23-git8//fs/debugfs/file.c:241): No description found for parameter 'value' Warning(linux-2.6.23-git8//include/linux/jbd.h:404): No description found for parameter 'h_lockdep_map' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-12debugfs: helper for decimal challengedRobin Getz
Allows debugfs helper functions to have a hex output, rather than just decimal Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-04-27debugfs: Add debugfs_create_u64()Michael Ellerman
I went to use this the other day, only to find it didn't exist. It's a straight copy of the debugfs u32 code, then s/u32/u64/. A quick test shows it seems to be working. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-16debugfs: implement symbolic linksPeter Oberparleiter
debugfs: implement symbolic links Implement a new function debugfs_create_symlink() which can be used to create symbolic links in debugfs. This function can be useful for people moving functionality from /proc to debugfs (e.g. the gcov-kernel patch). Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-02-12[PATCH] mark struct file_operations const 6Arjan van de Ven
Many struct file_operations in the kernel can be "const". Marking them const moves these to the .rodata section, which avoids false sharing with potential dirty data. In addition it'll catch accidental writes at compile time to these shared resources. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-09-27[PATCH] inode_diet: Replace inode.u.generic_ip with inode.i_privateTheodore Ts'o
The following patches reduce the size of the VFS inode structure by 28 bytes on a UP x86. (It would be more on an x86_64 system). This is a 10% reduction in the inode size on a UP kernel that is configured in a production mode (i.e., with no spinlock or other debugging functions enabled; if you want to save memory taken up by in-core inodes, the first thing you should do is disable the debugging options; they are responsible for a huge amount of bloat in the VFS inode structure). This patch: The filesystem or device-specific pointer in the inode is inside a union, which is pretty pointless given that all 30+ users of this field have been using the void pointer. Get rid of the union and rename it to i_private, with a comment to explain who is allowed to use the void pointer. This is just a cleanup, but it allows us to reuse the union 'u' for something something where the union will actually be used. [judith@osdl.org: powerpc build fix] Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Judith Lebzelter <judith@osdl.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-25Debugfs: kernel-doc fixes for debugfsRandy Dunlap
Fix kernel-doc and typos/spellos in fs/debugfs/. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-06-30Remove obsolete #include <linux/config.h>Jörn Engel
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
2006-03-28[PATCH] Make most file operations structs in fs/ constArjan van de Ven
This is a conversion to make the various file_operations structs in fs/ const. Basically a regexp job, with a few manual fixups The goal is both to increase correctness (harder to accidentally write to shared datastructures) and reducing the false sharing of cachelines with things that get dirty in .data (while .rodata is nicely read only and thus cache clean) Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-20[PATCH] debugfs: Add debugfs_create_blob() helper for exporting binary dataMichael Ellerman
I wanted to export a binary blob via debugfs, and although it was pretty easy it seems like it'd be easier if there was a helper for it. It's a pity we need the wrapper struct but I can't see a cleaner way to do it. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2006-02-06[PATCH] debugfs: trivial comment fixVincent Hanquez
Fix trivial type mixup in the debugfs function comments. Signed-off-by: Vincent Hanquez <vincent@snarc.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-06-20[PATCH] libfs: add simple attribute filesArnd Bergmann
Based on the discussion about spufs attributes, this is my suggestion for a more generic attribute file support that can be used by both debugfs and spufs. Simple attribute files behave similarly to sequential files from a kernel programmers perspective in that a standard set of file operations is provided and only an open operation needs to be written that registers file specific get() and set() functions. These operations are defined as void foo_set(void *data, u64 val); and u64 foo_get(void *data); where data is the inode->u.generic_ip pointer of the file and the operations just need to make send of that pointer. The infrastructure makes sure this works correctly with concurrent access and partial read calls. A macro named DEFINE_SIMPLE_ATTRIBUTE is provided to further simplify using the attributes. This patch already contains the changes for debugfs to use attributes for its internal file operations. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-04-16Linux-2.6.12-rc2Linus Torvalds
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!