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![Alexey Dobriyan](/assets/img/avatar_default.png)
First thing mm.h does is including sched.h solely for can_do_mlock() inline function which has "current" dereference inside. By dealing with can_do_mlock() mm.h can be detached from sched.h which is good. See below, why. This patch a) removes unconditional inclusion of sched.h from mm.h b) makes can_do_mlock() normal function in mm/mlock.c c) exports can_do_mlock() to not break compilation d) adds sched.h inclusions back to files that were getting it indirectly. e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were getting them indirectly Net result is: a) mm.h users would get less code to open, read, preprocess, parse, ... if they don't need sched.h b) sched.h stops being dependency for significant number of files: on x86_64 allmodconfig touching sched.h results in recompile of 4083 files, after patch it's only 3744 (-8.3%). Cross-compile tested on all arm defconfigs, all mips defconfigs, all powerpc defconfigs, alpha alpha-up arm i386 i386-up i386-defconfig i386-allnoconfig ia64 ia64-up m68k mips parisc parisc-up powerpc powerpc-up s390 s390-up sparc sparc-up sparc64 sparc64-up um-x86_64 x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig as well as my two usual configs. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
155 lines
3.1 KiB
C
155 lines
3.1 KiB
C
/*
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* linux/fs/fifo.c
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*
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* written by Paul H. Hargrove
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*
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* Fixes:
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* 10-06-1999, AV: fixed OOM handling in fifo_open(), moved
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* initialization there, switched to external
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* allocation of pipe_inode_info.
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*/
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/pipe_fs_i.h>
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static void wait_for_partner(struct inode* inode, unsigned int *cnt)
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{
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int cur = *cnt;
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while (cur == *cnt) {
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pipe_wait(inode->i_pipe);
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if (signal_pending(current))
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break;
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}
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}
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static void wake_up_partner(struct inode* inode)
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{
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wake_up_interruptible(&inode->i_pipe->wait);
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}
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static int fifo_open(struct inode *inode, struct file *filp)
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{
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struct pipe_inode_info *pipe;
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int ret;
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mutex_lock(&inode->i_mutex);
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pipe = inode->i_pipe;
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if (!pipe) {
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ret = -ENOMEM;
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pipe = alloc_pipe_info(inode);
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if (!pipe)
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goto err_nocleanup;
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inode->i_pipe = pipe;
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}
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filp->f_version = 0;
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/* We can only do regular read/write on fifos */
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filp->f_mode &= (FMODE_READ | FMODE_WRITE);
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switch (filp->f_mode) {
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case 1:
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/*
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* O_RDONLY
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* POSIX.1 says that O_NONBLOCK means return with the FIFO
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* opened, even when there is no process writing the FIFO.
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*/
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filp->f_op = &read_fifo_fops;
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pipe->r_counter++;
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if (pipe->readers++ == 0)
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wake_up_partner(inode);
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if (!pipe->writers) {
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if ((filp->f_flags & O_NONBLOCK)) {
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/* suppress POLLHUP until we have
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* seen a writer */
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filp->f_version = pipe->w_counter;
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} else
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{
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wait_for_partner(inode, &pipe->w_counter);
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if(signal_pending(current))
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goto err_rd;
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}
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}
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break;
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case 2:
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/*
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* O_WRONLY
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* POSIX.1 says that O_NONBLOCK means return -1 with
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* errno=ENXIO when there is no process reading the FIFO.
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*/
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ret = -ENXIO;
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if ((filp->f_flags & O_NONBLOCK) && !pipe->readers)
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goto err;
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filp->f_op = &write_fifo_fops;
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pipe->w_counter++;
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if (!pipe->writers++)
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wake_up_partner(inode);
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if (!pipe->readers) {
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wait_for_partner(inode, &pipe->r_counter);
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if (signal_pending(current))
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goto err_wr;
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}
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break;
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case 3:
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/*
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* O_RDWR
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* POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
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* This implementation will NEVER block on a O_RDWR open, since
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* the process can at least talk to itself.
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*/
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filp->f_op = &rdwr_fifo_fops;
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pipe->readers++;
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pipe->writers++;
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pipe->r_counter++;
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pipe->w_counter++;
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if (pipe->readers == 1 || pipe->writers == 1)
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wake_up_partner(inode);
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break;
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default:
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ret = -EINVAL;
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goto err;
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}
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/* Ok! */
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mutex_unlock(&inode->i_mutex);
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return 0;
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err_rd:
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if (!--pipe->readers)
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wake_up_interruptible(&pipe->wait);
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ret = -ERESTARTSYS;
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goto err;
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err_wr:
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if (!--pipe->writers)
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wake_up_interruptible(&pipe->wait);
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ret = -ERESTARTSYS;
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goto err;
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err:
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if (!pipe->readers && !pipe->writers)
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free_pipe_info(inode);
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err_nocleanup:
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mutex_unlock(&inode->i_mutex);
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return ret;
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}
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/*
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* Dummy default file-operations: the only thing this does
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* is contain the open that then fills in the correct operations
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* depending on the access mode of the file...
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*/
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const struct file_operations def_fifo_fops = {
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.open = fifo_open, /* will set read or write pipe_fops */
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};
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