Linux-2.6.12-rc2v2.6.12-rc2

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!

1 files changed, 155 insertions, 0 deletions

diff --git a/fs/fifo.c b/fs/fifo.c
new file mode 100644
index 000000000000..5455916241f0
--- /dev/null
+++ b/fs/fifo.c
@@ -0,0 +1,155 @@
+/*
+ *  linux/fs/fifo.c
+ *
+ *  written by Paul H. Hargrove
+ *
+ *  Fixes:
+ *      10-06-1999, AV: fixed OOM handling in fifo_open(), moved
+ *                      initialization there, switched to external
+ *                      allocation of pipe_inode_info.
+ */
+
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/fs.h>
+#include <linux/pipe_fs_i.h>
+
+static void wait_for_partner(struct inode* inode, unsigned int* cnt)
+{
+        int cur = *cnt; 
+        while(cur == *cnt) {
+                pipe_wait(inode);
+                if(signal_pending(current))
+                        break;
+        }
+}
+
+static void wake_up_partner(struct inode* inode)
+{
+        wake_up_interruptible(PIPE_WAIT(*inode));
+}
+
+static int fifo_open(struct inode *inode, struct file *filp)
+{
+        int ret;
+
+        ret = -ERESTARTSYS;
+        if (down_interruptible(PIPE_SEM(*inode)))
+                goto err_nolock_nocleanup;
+
+        if (!inode->i_pipe) {
+                ret = -ENOMEM;
+                if(!pipe_new(inode))
+                        goto err_nocleanup;
+        }
+        filp->f_version = 0;
+
+        /* We can only do regular read/write on fifos */
+        filp->f_mode &= (FMODE_READ | FMODE_WRITE);
+
+        switch (filp->f_mode) {
+        case 1:
+        /*
+         *  O_RDONLY
+         *  POSIX.1 says that O_NONBLOCK means return with the FIFO
+         *  opened, even when there is no process writing the FIFO.
+         */
+                filp->f_op = &read_fifo_fops;
+                PIPE_RCOUNTER(*inode)++;
+                if (PIPE_READERS(*inode)++ == 0)
+                        wake_up_partner(inode);
+
+                if (!PIPE_WRITERS(*inode)) {
+                        if ((filp->f_flags & O_NONBLOCK)) {
+                                /* suppress POLLHUP until we have
+                                 * seen a writer */
+                                filp->f_version = PIPE_WCOUNTER(*inode);
+                        } else 
+                        {
+                                wait_for_partner(inode, &PIPE_WCOUNTER(*inode));
+                                if(signal_pending(current))
+                                        goto err_rd;
+                        }
+                }
+                break;
+        
+        case 2:
+        /*
+         *  O_WRONLY
+         *  POSIX.1 says that O_NONBLOCK means return -1 with
+         *  errno=ENXIO when there is no process reading the FIFO.
+         */
+                ret = -ENXIO;
+                if ((filp->f_flags & O_NONBLOCK) && !PIPE_READERS(*inode))
+                        goto err;
+
+                filp->f_op = &write_fifo_fops;
+                PIPE_WCOUNTER(*inode)++;
+                if (!PIPE_WRITERS(*inode)++)
+                        wake_up_partner(inode);
+
+                if (!PIPE_READERS(*inode)) {
+                        wait_for_partner(inode, &PIPE_RCOUNTER(*inode));
+                        if (signal_pending(current))
+                                goto err_wr;
+                }
+                break;
+        
+        case 3:
+        /*
+         *  O_RDWR
+         *  POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
+         *  This implementation will NEVER block on a O_RDWR open, since
+         *  the process can at least talk to itself.
+         */
+                filp->f_op = &rdwr_fifo_fops;
+
+                PIPE_READERS(*inode)++;
+                PIPE_WRITERS(*inode)++;
+                PIPE_RCOUNTER(*inode)++;
+                PIPE_WCOUNTER(*inode)++;
+                if (PIPE_READERS(*inode) == 1 || PIPE_WRITERS(*inode) == 1)
+                        wake_up_partner(inode);
+                break;
+
+        default:
+                ret = -EINVAL;
+                goto err;
+        }
+
+        /* Ok! */
+        up(PIPE_SEM(*inode));
+        return 0;
+
+err_rd:
+        if (!--PIPE_READERS(*inode))
+                wake_up_interruptible(PIPE_WAIT(*inode));
+        ret = -ERESTARTSYS;
+        goto err;
+
+err_wr:
+        if (!--PIPE_WRITERS(*inode))
+                wake_up_interruptible(PIPE_WAIT(*inode));
+        ret = -ERESTARTSYS;
+        goto err;
+
+err:
+        if (!PIPE_READERS(*inode) && !PIPE_WRITERS(*inode))
+                free_pipe_info(inode);
+
+err_nocleanup:
+        up(PIPE_SEM(*inode));
+
+err_nolock_nocleanup:
+        return ret;
+}
+
+/*
+ * Dummy default file-operations: the only thing this does
+ * is contain the open that then fills in the correct operations
+ * depending on the access mode of the file...
+ */
+struct file_operations def_fifo_fops = {
+        .open           = fifo_open,    /* will set read or write pipe_fops */
+};