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path: root/fs/pipe.c
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* Rationalize fasync return valuesJonathan Corbet2009-03-16
| | | | | | | | | | | | | | | | | | | | Most fasync implementations do something like: return fasync_helper(...); But fasync_helper() will return a positive value at times - a feature used in at least one place. Thus, a number of other drivers do: err = fasync_helper(...); if (err < 0) return err; return 0; In the interests of consistency and more concise code, it makes sense to map positive return values onto zero where ->fasync() is called. Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
* pipe_rdwr_fasync: fix the error handling to prevent the leak/crashOleg Nesterov2009-03-12
| | | | | | | | | | | | | | | | | | If the second fasync_helper() fails, pipe_rdwr_fasync() returns the error but leaves the file on ->fasync_readers. This was always wrong, but since 233e70f4228e78eb2f80dc6650f65d3ae3dbf17c "saner FASYNC handling on file close" we have the new problem. Because in this case setfl() doesn't set FASYNC bit, __fput() will not do ->fasync(0), and we leak fasync_struct with ->fa_file pointing to the freed file. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Andi Kleen <andi@firstfloor.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [CVE-2009-0029] System call wrappers part 33Heiko Carstens2009-01-14
| | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [CVE-2009-0029] System call wrappers part 32Heiko Carstens2009-01-14
| | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* [CVE-2009-0029] Remove __attribute__((weak)) from sys_pipe/sys_pipe2Heiko Carstens2009-01-14
| | | | | | | | | | | | | Remove __attribute__((weak)) from common code sys_pipe implemantation. IA64, ALPHA, SUPERH (32bit) and SPARC (32bit) have own implemantations with the same name. Just rename them. For sys_pipe2 there is no architecture specific implementation. Cc: Richard Henderson <rth@twiddle.net> Cc: David S. Miller <davem@davemloft.net> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* sanitize audit_fd_pair()Al Viro2009-01-04
| | | | | | | * no allocations * return void Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* CRED: Wrap task credential accesses in the filesystem subsystemDavid Howells2008-11-13
| | | | | | | | | | | | | | | | | Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Morris <jmorris@namei.org>
* saner FASYNC handling on file closeAl Viro2008-11-01
| | | | | | | | | | | | | | As it is, all instances of ->release() for files that have ->fasync() need to remember to evict file from fasync lists; forgetting that creates a hole and we actually have a bunch that *does* forget. So let's keep our lives simple - let __fput() check FASYNC in file->f_flags and call ->fasync() there if it's been set. And lose that crap in ->release() instances - leaving it there is still valid, but we don't have to bother anymore. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] reuse xxx_fifo_fops for xxx_pipe_fopsDenys Vlasenko2008-07-26
| | | | | | | Merge fifo and pipe file_operations. Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* flag parameters: NONBLOCK in pipeUlrich Drepper2008-07-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds O_NONBLOCK support to pipe2. It is minimally more involved than the patches for eventfd et.al but still trivial. The interfaces of the create_write_pipe and create_read_pipe helper functions were changed and the one other caller as well. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_pipe2 # ifdef __x86_64__ # define __NR_pipe2 293 # elif defined __i386__ # define __NR_pipe2 331 # else # error "need __NR_pipe2" # endif #endif int main (void) { int fds[2]; if (syscall (__NR_pipe2, fds, 0) == -1) { puts ("pipe2(0) failed"); return 1; } for (int i = 0; i < 2; ++i) { int fl = fcntl (fds[i], F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if (fl & O_NONBLOCK) { printf ("pipe2(0) set non-blocking mode for fds[%d]\n", i); return 1; } close (fds[i]); } if (syscall (__NR_pipe2, fds, O_NONBLOCK) == -1) { puts ("pipe2(O_NONBLOCK) failed"); return 1; } for (int i = 0; i < 2; ++i) { int fl = fcntl (fds[i], F_GETFL); if (fl == -1) { puts ("fcntl failed"); return 1; } if ((fl & O_NONBLOCK) == 0) { printf ("pipe2(O_NONBLOCK) does not set non-blocking mode for fds[%d]\n", i); return 1; } close (fds[i]); } puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* flag parameters: pipeUlrich Drepper2008-07-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch introduces the new syscall pipe2 which is like pipe but it also takes an additional parameter which takes a flag value. This patch implements the handling of O_CLOEXEC for the flag. I did not add support for the new syscall for the architectures which have a special sys_pipe implementation. I think the maintainers of those archs have the chance to go with the unified implementation but that's up to them. The implementation introduces do_pipe_flags. I did that instead of changing all callers of do_pipe because some of the callers are written in assembler. I would probably screw up changing the assembly code. To avoid breaking code do_pipe is now a small wrapper around do_pipe_flags. Once all callers are changed over to do_pipe_flags the old do_pipe function can be removed. The following test must be adjusted for architectures other than x86 and x86-64 and in case the syscall numbers changed. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ #include <fcntl.h> #include <stdio.h> #include <unistd.h> #include <sys/syscall.h> #ifndef __NR_pipe2 # ifdef __x86_64__ # define __NR_pipe2 293 # elif defined __i386__ # define __NR_pipe2 331 # else # error "need __NR_pipe2" # endif #endif int main (void) { int fd[2]; if (syscall (__NR_pipe2, fd, 0) != 0) { puts ("pipe2(0) failed"); return 1; } for (int i = 0; i < 2; ++i) { int coe = fcntl (fd[i], F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if (coe & FD_CLOEXEC) { printf ("pipe2(0) set close-on-exit for fd[%d]\n", i); return 1; } } close (fd[0]); close (fd[1]); if (syscall (__NR_pipe2, fd, O_CLOEXEC) != 0) { puts ("pipe2(O_CLOEXEC) failed"); return 1; } for (int i = 0; i < 2; ++i) { int coe = fcntl (fd[i], F_GETFD); if (coe == -1) { puts ("fcntl failed"); return 1; } if ((coe & FD_CLOEXEC) == 0) { printf ("pipe2(O_CLOEXEC) does not set close-on-exit for fd[%d]\n", i); return 1; } } close (fd[0]); close (fd[1]); puts ("OK"); return 0; } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Signed-off-by: Ulrich Drepper <drepper@redhat.com> Acked-by: Davide Libenzi <davidel@xmailserver.org> Cc: Michael Kerrisk <mtk.manpages@googlemail.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [patch 1/4] vfs: path_{get,put}() cleanupsJan Blunck2008-06-23
| | | | | | | | | | | Here are some more places where path_{get,put}() can be used instead of dput()/mntput() pair. Signed-off-by: Jan Blunck <jblunck@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* sys_pipe(): fix file descriptor leaksUlrich Drepper2008-05-08
| | | | | | | | | | | | Remember to close the files if copy_to_user() failed. Spotted by dm.n9107@gmail.com. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Cc: DM <dm.n9107@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* unified (weak) sys_pipe implementationUlrich Drepper2008-05-03
| | | | | | | | | | | | | | | | | | | This replaces the duplicated arch-specific versions of "sys_pipe()" with one unified implementation. This removes almost 250 lines of duplicated code. It's marked __weak, so that *if* an architecture wants to override the default implementation it can do so by simply having its own replacement version, since many architectures use alternate calling conventions for the 'pipe()' system call for legacy reasons (ie traditional UNIX implementations often return the two file descriptors in registers) I still haven't changed the cris version even though Linus says the BKL isn't needed. The arch maintainer can easily do it if there are really no obstacles. Signed-off-by: Ulrich Drepper <drepper@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] double-free of inode on alloc_file() failure exit in create_write_pipe()Al Viro2008-04-22
| | | | | | | Duh... Fortunately, the bug is quite recent (post-2.6.25) and, embarrassingly, mine ;-/ Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] fix up new filp allocatorsDave Hansen2008-03-19
| | | | | | | | | | | | | | | | | | | Some new uses of get_empty_filp() have crept in; switched to alloc_file() to make sure that pieces of initialization won't be missing. We really need to kill get_empty_filp(). [AV] fixed dentry leak on failure exit in anon_inode_getfd() Cc: Erez Zadok <ezk@cs.sunysb.edu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J Bruce Fields" <bfields@fieldses.org> Acked-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* kernel-doc: fix fs/pipe.c notationRandy Dunlap2008-02-13
| | | | | | | | | Fix several kernel-doc notation errors in fs/pipe.c. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* BKL-Removal: convert pipe to use unlocked_ioctl tooAndi Kleen2008-02-08
| | | | | | | | | No BKL needed in pipe_ioctl Signed-off-by: Andi Kleen <ak@suse.de> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched: affine sync wakeupsIngo Molnar2007-10-15
| | | | | | | | make sync wakeups affine for cache-cold tasks: if a cache-cold task is woken up by a sync wakeup then use the opportunity to migrate it straight away. (the two tasks are 'related' because they communicate) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cleanup, remove the TASK_NONINTERACTIVE flagMike Galbraith2007-10-15
| | | | | | | | | Here's another piece of low hanging obsolete fruit. Remove obsolete TASK_NONINTERACTIVE. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* docbook: add pipes, other fixesRandy Dunlap2007-07-27
| | | | | | | | Fix some typos in pipe.c and splice.c. Add pipes API to kernel-api.tmpl. Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* pipe: add documentation and commentsJens Axboe2007-07-10
| | | | | | | | As per Andrew Mortons request, here's a set of documentation for the generic pipe_buf_operations hooks, the pipe, and pipe_buffer structures. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* pipe: change the ->pin() operation to ->confirm()Jens Axboe2007-07-10
| | | | | | | | | | | | The name 'pin' was badly chosen, it doesn't pin a pipe buffer in the most commonly used sense in the kernel. So change the name to 'confirm', after debating this issue with Hugh Dickins a bit. A good return from ->confirm() means that the buffer is really there, and that the contents are good. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* VFS: delay the dentry name generation on sockets and pipesEric Dumazet2007-05-08
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1) Introduces a new method in 'struct dentry_operations'. This method called d_dname() might be called from d_path() to build a pathname for special filesystems. It is called without locks. Future patches (if we succeed in having one common dentry for all pipes/sockets) may need to change prototype of this method, but we now use : char *d_dname(struct dentry *dentry, char *buffer, int buflen); 2) Adds a dynamic_dname() helper function that eases d_dname() implementations 3) Defines d_dname method for sockets : No more sprintf() at socket creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... 4) Defines d_dname method for pipes : No more sprintf() at pipe creation. This is delayed up to the moment someone does an access to /proc/pid/fd/... A benchmark consisting of 1.000.000 calls to pipe()/close()/close() gives a *nice* speedup on my Pentium(M) 1.6 Ghz : 3.090 s instead of 3.450 s Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Christoph Hellwig <hch@infradead.org> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] AUDIT_FD_PAIRAl Viro2007-02-17
| | | | | | | | Provide an audit record of the descriptor pair returned by pipe() and socketpair(). Rewritten from the original posted to linux-audit by John D. Ramsdell <ramsdell@mitre.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* [PATCH] fix leaks on pipe(2) failure exitsAl Viro2006-12-21
| | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] constify pipe_buf_operationsEric Dumazet2006-12-13
| | | | | | | | | | | - pipe/splice should use const pipe_buf_operations and file_operations - struct pipe_inode_info has an unused field "start" : get rid of it. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: change struct file to use struct pathJosef "Jeff" Sipek2006-12-08
| | | | | | | | | | | | | This patch changes struct file to use struct path instead of having independent pointers to struct dentry and struct vfsmount, and converts all users of f_{dentry,vfsmnt} in fs/ to use f_path.{dentry,mnt}. Additionally, it adds two #define's to make the transition easier for users of the f_dentry and f_vfsmnt. Signed-off-by: Josef "Jeff" Sipek <jsipek@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] don't insert pipe dentries into dentry_hashtable.Eric Dumazet2006-12-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We currently insert pipe dentries into the global dentry hashtable. This is suboptimal because there is currently no way these entries can be used for a lookup(). (/proc/xxx/fd/xxx uses a different mechanism). Inserting them in dentry hashtable slows dcache lookups. To let __dpath() still work correctly (ie not adding a " (deleted)") after dentry name, we do : - Right after d_alloc(), pretend they are hashed by clearing the DCACHE_UNHASHED bit. - Call d_instantiate() instead of d_add() : dentry is not inserted in hash table. __dpath() & friends work as intended during dentry lifetime. - At dismantle time, once dput() must clear the dentry, setting again DCACHE_UNHASHED bit inside the custom d_delete() function provided by pipe code, so that dput() can just kill_it. This patch, combined with (avoid RCU for never hashed dentries) reduced time of { pipe(p); close(p[0]); close(p[1]);} on my UP machine (1.6GHz Pentium-M) from 3.23 us to 2.86 us (But this patch does not depend on other patches, only bench results) Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: David Miller <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Some cleanup in the pipe codeAndi Kleen2006-10-01
| | | | | | | | | | | | | | | | Split the big and hard to read do_pipe function into smaller pieces. This creates new create_write_pipe/free_write_pipe/create_read_pipe functions. These functions are made global so that they can be used by other parts of the kernel. The resulting code is more generic and easier to read and has cleaner error handling and less gotos. [akpm@osdl.org: cleanup] Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Remove readv/writev methods and use aio_read/aio_write insteadBadari Pulavarty2006-10-01
| | | | | | | | | | This patch removes readv() and writev() methods and replaces them with aio_read()/aio_write() methods. Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] inode-diet: Eliminate i_blksize from the inode structureTheodore Ts'o2006-09-27
| | | | | | | | | | | | | | | | This eliminates the i_blksize field from struct inode. Filesystems that want to provide a per-inode st_blksize can do so by providing their own getattr routine instead of using the generic_fillattr() function. Note that some filesystems were providing pretty much random (and incorrect) values for i_blksize. [bunk@stusta.de: cleanup] [akpm@osdl.org: generic_fillattr() fix] Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] VFS: Permit filesystem to override root dentry on mountDavid Howells2006-06-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Extend the get_sb() filesystem operation to take an extra argument that permits the VFS to pass in the target vfsmount that defines the mountpoint. The filesystem is then required to manually set the superblock and root dentry pointers. For most filesystems, this should be done with simple_set_mnt() which will set the superblock pointer and then set the root dentry to the superblock's s_root (as per the old default behaviour). The get_sb() op now returns an integer as there's now no need to return the superblock pointer. This patch permits a superblock to be implicitly shared amongst several mount points, such as can be done with NFS to avoid potential inode aliasing. In such a case, simple_set_mnt() would not be called, and instead the mnt_root and mnt_sb would be set directly. The patch also makes the following changes: (*) the get_sb_*() convenience functions in the core kernel now take a vfsmount pointer argument and return an integer, so most filesystems have to change very little. (*) If one of the convenience function is not used, then get_sb() should normally call simple_set_mnt() to instantiate the vfsmount. This will always return 0, and so can be tail-called from get_sb(). (*) generic_shutdown_super() now calls shrink_dcache_sb() to clean up the dcache upon superblock destruction rather than shrink_dcache_anon(). This is required because the superblock may now have multiple trees that aren't actually bound to s_root, but that still need to be cleaned up. The currently called functions assume that the whole tree is rooted at s_root, and that anonymous dentries are not the roots of trees which results in dentries being left unculled. However, with the way NFS superblock sharing are currently set to be implemented, these assumptions are violated: the root of the filesystem is simply a dummy dentry and inode (the real inode for '/' may well be inaccessible), and all the vfsmounts are rooted on anonymous[*] dentries with child trees. [*] Anonymous until discovered from another tree. (*) The documentation has been adjusted, including the additional bit of changing ext2_* into foo_* in the documentation. [akpm@osdl.org: convert ipath_fs, do other stuff] Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Cc: Nathan Scott <nathans@sgi.com> Cc: Roland Dreier <rolandd@cisco.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] vmsplice: restrict stealing a little moreJens Axboe2006-05-02
| | | | | | | Apply the same rules as the anon pipe pages, only allow stealing if no one else is using the page. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] pipe: enable atomic copying of pipe data to/from user spaceJens Axboe2006-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pipe ->map() method uses kmap() to virtually map the pages, which is both slow and has known scalability issues on SMP. This patch enables atomic copying of pipe pages, by pre-faulting data and using kmap_atomic() instead. lmbench bw_pipe and lat_pipe measurements agree this is a Good Thing. Here are results from that on a UP machine with highmem (1.5GiB of RAM), running first a UP kernel, SMP kernel, and SMP kernel patched. Vanilla-UP: Pipe bandwidth: 1622.28 MB/sec Pipe bandwidth: 1610.59 MB/sec Pipe bandwidth: 1608.30 MB/sec Pipe latency: 7.3275 microseconds Pipe latency: 7.2995 microseconds Pipe latency: 7.3097 microseconds Vanilla-SMP: Pipe bandwidth: 1382.19 MB/sec Pipe bandwidth: 1317.27 MB/sec Pipe bandwidth: 1355.61 MB/sec Pipe latency: 9.6402 microseconds Pipe latency: 9.6696 microseconds Pipe latency: 9.6153 microseconds Patched-SMP: Pipe bandwidth: 1578.70 MB/sec Pipe bandwidth: 1579.95 MB/sec Pipe bandwidth: 1578.63 MB/sec Pipe latency: 9.1654 microseconds Pipe latency: 9.2266 microseconds Pipe latency: 9.1527 microseconds Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] pipe: introduce ->pin() buffer operationJens Axboe2006-05-01
| | | | | | | | | | | | | The ->map() function is really expensive on highmem machines right now, since it has to use the slower kmap() instead of kmap_atomic(). Splice rarely needs to access the virtual address of a page, so it's a waste of time doing it. Introduce ->pin() to take over the responsibility of making sure the page data is valid. ->map() is then reduced to just kmap(). That way we can also share a most of the pipe buffer ops between pipe.c and splice.c Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: fix bugs in pipe_to_file()Jens Axboe2006-05-01
| | | | | | | | | | | | | | | | Found by Oleg Nesterov <oleg@tv-sign.ru>, fixed by me. - Only allow full pages to go to the page cache. - Check page != buf->page instead of using PIPE_BUF_FLAG_STOLEN. - Remember to clear 'stolen' if add_to_page_cache() fails. And as a cleanup on that: - Make the bottom fall-through logic a little less convoluted. Also make the steal path hold an extra reference to the page, so we don't have to differentiate between stolen and non-stolen at the end. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: fix bugs with stealing regular pipe pagesJens Axboe2006-04-30
| | | | | | | | | - Check that page has suitable count for stealing in the regular pipes. - pipe_to_file() assumes that the page is locked on succesful steal, so do that in the pipe steal hook - Missing unlock_page() in add_to_page_cache() failure. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: add support for sys_tee()Jens Axboe2006-04-11
| | | | | | | | | | | | Basically an in-kernel implementation of tee, which uses splice and the pipe buffers as an intelligent way to pass data around by reference. Where the user space tee consumes the input and produces a stdout and file output, this syscall merely duplicates the data inside a pipe to another pipe. No data is copied, the output just grabs a reference to the input pipe data. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] another round of fs/pipe.c cleanupsIngo Molnar2006-04-11
| | | | | | | make pipe.c a bit more readable and hackable. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] pipe.c/fifo.c code cleanupsIngo Molnar2006-04-11
| | | | | | | | | | more code cleanups after the macro conversion: - standardize on 'struct pipe_inode_info *pipe' variable names - introduce 'pipe' temporaries to reduce mass inode->i_pipe dereferencing Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] get rid of the PIPE_*() macrosIngo Molnar2006-04-11
| | | | | | | get rid of the PIPE_*() macros. Scripted transformation. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: add direct fd <-> fd splicing supportJens Axboe2006-04-11
| | | | | | | | | | | | It's more efficient for sendfile() emulation. Basically we cache an internal private pipe and just use that as the intermediate area for pages. Direct splicing is not available from sys_splice(), it is only meant to be used for sendfile() emulation. Additional patch from Ingo Molnar to avoid the PIPE_BUFFERS loop at exit for the normal fast path. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] introduce a "kernel-internal pipe object" abstractionIngo Molnar2006-04-10
| | | | | | | | | | | | | | | | | | separate out the 'internal pipe object' abstraction, and make it usable to splice. This cleans up and fixes several aspects of the internal splice APIs and the pipe code: - pipes: the allocation and freeing of pipe_inode_info is now more symmetric and more streamlined with existing kernel practices. - splice: small micro-optimization: less pointer dereferencing in splice methods Signed-off-by: Ingo Molnar <mingo@elte.hu> Update XFS for the ->splice_read/->splice_write changes. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: fix page stealing LRU handling.Jens Axboe2006-04-02
| | | | | | | | | | | | Originally from Nick Piggin, just adapted to the newer branch. You can't check PageLRU without holding zone->lru_lock. The page release code can get away with it only because the page refcount is 0 at that point. Also, you can't reliably remove pages from the LRU unless the refcount is 0. Ever. Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: improve writeback and clean up page stealingJens Axboe2006-04-02
| | | | | | | | | | By cleaning up the writeback logic (killing write_one_page() and the manual set_page_dirty()), we can get rid of ->stolen inside the pipe_buffer and just keep it local in pipe_to_file(). This also adds dirty page balancing logic and O_SYNC handling. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] splice: add support for SPLICE_F_MOVE flagJens Axboe2006-03-30
| | | | | | | | | This enables the caller to migrate pages from one address space page cache to another. In buzz word marketing, you can do zero-copy file copies! Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Introduce sys_splice() system callJens Axboe2006-03-30
| | | | | | | | | | | | | | | | | | | | | | | This adds support for the sys_splice system call. Using a pipe as a transport, it can connect to files or sockets (latter as output only). From the splice.c comments: "splice": joining two ropes together by interweaving their strands. This is the "extended pipe" functionality, where a pipe is used as an arbitrary in-memory buffer. Think of a pipe as a small kernel buffer that you can use to transfer data from one end to the other. The traditional unix read/write is extended with a "splice()" operation that transfers data buffers to or from a pipe buffer. Named by Larry McVoy, original implementation from Linus, extended by Jens to support splicing to files and fixing the initial implementation bugs. Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Make most file operations structs in fs/ constArjan van de Ven2006-03-28
| | | | | | | | | | | | | | 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>
* [PATCH] Use __read_mostly on some hot fs variablesEric Dumazet2006-03-26
| | | | | | | | | | | | | | I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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