nfsd4: ignore WANT bits in open downgrade
[linux-2.6.git] / fs / pipe.c
index 5a36927..0e0be1d 100644 (file)
--- a/fs/pipe.c
+++ b/fs/pipe.c
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/fs.h>
+#include <linux/log2.h>
 #include <linux/mount.h>
 #include <linux/pipe_fs_i.h>
 #include <linux/uio.h>
 #include <linux/highmem.h>
 #include <linux/pagemap.h>
+#include <linux/audit.h>
+#include <linux/syscalls.h>
+#include <linux/fcntl.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
 
 /*
+ * The max size that a non-root user is allowed to grow the pipe. Can
+ * be set by root in /proc/sys/fs/pipe-max-size
+ */
+unsigned int pipe_max_size = 1048576;
+
+/*
+ * Minimum pipe size, as required by POSIX
+ */
+unsigned int pipe_min_size = PAGE_SIZE;
+
+/*
  * We use a start+len construction, which provides full use of the 
  * allocated memory.
  * -- Florian Coosmann (FGC)
  * -- Manfred Spraul <manfred@colorfullife.com> 2002-05-09
  */
 
+static void pipe_lock_nested(struct pipe_inode_info *pipe, int subclass)
+{
+       if (pipe->inode)
+               mutex_lock_nested(&pipe->inode->i_mutex, subclass);
+}
+
+void pipe_lock(struct pipe_inode_info *pipe)
+{
+       /*
+        * pipe_lock() nests non-pipe inode locks (for writing to a file)
+        */
+       pipe_lock_nested(pipe, I_MUTEX_PARENT);
+}
+EXPORT_SYMBOL(pipe_lock);
+
+void pipe_unlock(struct pipe_inode_info *pipe)
+{
+       if (pipe->inode)
+               mutex_unlock(&pipe->inode->i_mutex);
+}
+EXPORT_SYMBOL(pipe_unlock);
+
+void pipe_double_lock(struct pipe_inode_info *pipe1,
+                     struct pipe_inode_info *pipe2)
+{
+       BUG_ON(pipe1 == pipe2);
+
+       if (pipe1 < pipe2) {
+               pipe_lock_nested(pipe1, I_MUTEX_PARENT);
+               pipe_lock_nested(pipe2, I_MUTEX_CHILD);
+       } else {
+               pipe_lock_nested(pipe2, I_MUTEX_PARENT);
+               pipe_lock_nested(pipe1, I_MUTEX_CHILD);
+       }
+}
+
 /* Drop the inode semaphore and wait for a pipe event, atomically */
 void pipe_wait(struct pipe_inode_info *pipe)
 {
@@ -44,18 +95,16 @@ void pipe_wait(struct pipe_inode_info *pipe)
         * Pipes are system-local resources, so sleeping on them
         * is considered a noninteractive wait:
         */
-       prepare_to_wait(&pipe->wait, &wait,
-                       TASK_INTERRUPTIBLE | TASK_NONINTERACTIVE);
-       if (pipe->inode)
-               mutex_unlock(&pipe->inode->i_mutex);
+       prepare_to_wait(&pipe->wait, &wait, TASK_INTERRUPTIBLE);
+       pipe_unlock(pipe);
        schedule();
        finish_wait(&pipe->wait, &wait);
-       if (pipe->inode)
-               mutex_lock(&pipe->inode->i_mutex);
+       pipe_lock(pipe);
 }
 
 static int
-pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
+pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len,
+                       int atomic)
 {
        unsigned long copy;
 
@@ -64,8 +113,13 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
                        iov++;
                copy = min_t(unsigned long, len, iov->iov_len);
 
-               if (copy_from_user(to, iov->iov_base, copy))
-                       return -EFAULT;
+               if (atomic) {
+                       if (__copy_from_user_inatomic(to, iov->iov_base, copy))
+                               return -EFAULT;
+               } else {
+                       if (copy_from_user(to, iov->iov_base, copy))
+                               return -EFAULT;
+               }
                to += copy;
                len -= copy;
                iov->iov_base += copy;
@@ -75,7 +129,8 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len)
 }
 
 static int
-pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
+pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len,
+                     int atomic)
 {
        unsigned long copy;
 
@@ -84,8 +139,13 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
                        iov++;
                copy = min_t(unsigned long, len, iov->iov_len);
 
-               if (copy_to_user(iov->iov_base, from, copy))
-                       return -EFAULT;
+               if (atomic) {
+                       if (__copy_to_user_inatomic(iov->iov_base, from, copy))
+                               return -EFAULT;
+               } else {
+                       if (copy_to_user(iov->iov_base, from, copy))
+                               return -EFAULT;
+               }
                from += copy;
                len -= copy;
                iov->iov_base += copy;
@@ -94,13 +154,52 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len)
        return 0;
 }
 
+/*
+ * Attempt to pre-fault in the user memory, so we can use atomic copies.
+ * Returns the number of bytes not faulted in.
+ */
+static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len)
+{
+       while (!iov->iov_len)
+               iov++;
+
+       while (len > 0) {
+               unsigned long this_len;
+
+               this_len = min_t(unsigned long, len, iov->iov_len);
+               if (fault_in_pages_writeable(iov->iov_base, this_len))
+                       break;
+
+               len -= this_len;
+               iov++;
+       }
+
+       return len;
+}
+
+/*
+ * Pre-fault in the user memory, so we can use atomic copies.
+ */
+static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len)
+{
+       while (!iov->iov_len)
+               iov++;
+
+       while (len > 0) {
+               unsigned long this_len;
+
+               this_len = min_t(unsigned long, len, iov->iov_len);
+               fault_in_pages_readable(iov->iov_base, this_len);
+               len -= this_len;
+               iov++;
+       }
+}
+
 static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
                                  struct pipe_buffer *buf)
 {
        struct page *page = buf->page;
 
-       buf->flags &= ~PIPE_BUF_FLAG_STOLEN;
-
        /*
         * If nobody else uses this page, and we don't already have a
         * temporary page, let's keep track of it as a one-deep
@@ -112,52 +211,146 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe,
                page_cache_release(page);
 }
 
-static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe,
-                               struct pipe_buffer *buf)
+/**
+ * generic_pipe_buf_map - virtually map a pipe buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer that should be mapped
+ * @atomic:    whether to use an atomic map
+ *
+ * Description:
+ *     This function returns a kernel virtual address mapping for the
+ *     pipe_buffer passed in @buf. If @atomic is set, an atomic map is provided
+ *     and the caller has to be careful not to fault before calling
+ *     the unmap function.
+ *
+ *     Note that this function occupies KM_USER0 if @atomic != 0.
+ */
+void *generic_pipe_buf_map(struct pipe_inode_info *pipe,
+                          struct pipe_buffer *buf, int atomic)
 {
+       if (atomic) {
+               buf->flags |= PIPE_BUF_FLAG_ATOMIC;
+               return kmap_atomic(buf->page, KM_USER0);
+       }
+
        return kmap(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_map);
 
-static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe,
-                               struct pipe_buffer *buf)
+/**
+ * generic_pipe_buf_unmap - unmap a previously mapped pipe buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer that should be unmapped
+ * @map_data:  the data that the mapping function returned
+ *
+ * Description:
+ *     This function undoes the mapping that ->map() provided.
+ */
+void generic_pipe_buf_unmap(struct pipe_inode_info *pipe,
+                           struct pipe_buffer *buf, void *map_data)
 {
-       kunmap(buf->page);
+       if (buf->flags & PIPE_BUF_FLAG_ATOMIC) {
+               buf->flags &= ~PIPE_BUF_FLAG_ATOMIC;
+               kunmap_atomic(map_data, KM_USER0);
+       } else
+               kunmap(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_unmap);
 
-static int anon_pipe_buf_steal(struct pipe_inode_info *pipe,
-                              struct pipe_buffer *buf)
+/**
+ * generic_pipe_buf_steal - attempt to take ownership of a &pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to attempt to steal
+ *
+ * Description:
+ *     This function attempts to steal the &struct page attached to
+ *     @buf. If successful, this function returns 0 and returns with
+ *     the page locked. The caller may then reuse the page for whatever
+ *     he wishes; the typical use is insertion into a different file
+ *     page cache.
+ */
+int generic_pipe_buf_steal(struct pipe_inode_info *pipe,
+                          struct pipe_buffer *buf)
 {
        struct page *page = buf->page;
 
+       /*
+        * A reference of one is golden, that means that the owner of this
+        * page is the only one holding a reference to it. lock the page
+        * and return OK.
+        */
        if (page_count(page) == 1) {
-               buf->flags |= PIPE_BUF_FLAG_STOLEN;
                lock_page(page);
                return 0;
        }
 
        return 1;
 }
+EXPORT_SYMBOL(generic_pipe_buf_steal);
 
-static void anon_pipe_buf_get(struct pipe_inode_info *info,
-                             struct pipe_buffer *buf)
+/**
+ * generic_pipe_buf_get - get a reference to a &struct pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to get a reference to
+ *
+ * Description:
+ *     This function grabs an extra reference to @buf. It's used in
+ *     in the tee() system call, when we duplicate the buffers in one
+ *     pipe into another.
+ */
+void generic_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
 {
        page_cache_get(buf->page);
 }
+EXPORT_SYMBOL(generic_pipe_buf_get);
 
-static struct pipe_buf_operations anon_pipe_buf_ops = {
+/**
+ * generic_pipe_buf_confirm - verify contents of the pipe buffer
+ * @info:      the pipe that the buffer belongs to
+ * @buf:       the buffer to confirm
+ *
+ * Description:
+ *     This function does nothing, because the generic pipe code uses
+ *     pages that are always good when inserted into the pipe.
+ */
+int generic_pipe_buf_confirm(struct pipe_inode_info *info,
+                            struct pipe_buffer *buf)
+{
+       return 0;
+}
+EXPORT_SYMBOL(generic_pipe_buf_confirm);
+
+/**
+ * generic_pipe_buf_release - put a reference to a &struct pipe_buffer
+ * @pipe:      the pipe that the buffer belongs to
+ * @buf:       the buffer to put a reference to
+ *
+ * Description:
+ *     This function releases a reference to @buf.
+ */
+void generic_pipe_buf_release(struct pipe_inode_info *pipe,
+                             struct pipe_buffer *buf)
+{
+       page_cache_release(buf->page);
+}
+EXPORT_SYMBOL(generic_pipe_buf_release);
+
+static const struct pipe_buf_operations anon_pipe_buf_ops = {
        .can_merge = 1,
-       .map = anon_pipe_buf_map,
-       .unmap = anon_pipe_buf_unmap,
+       .map = generic_pipe_buf_map,
+       .unmap = generic_pipe_buf_unmap,
+       .confirm = generic_pipe_buf_confirm,
        .release = anon_pipe_buf_release,
-       .steal = anon_pipe_buf_steal,
-       .get = anon_pipe_buf_get,
+       .steal = generic_pipe_buf_steal,
+       .get = generic_pipe_buf_get,
 };
 
 static ssize_t
-pipe_readv(struct file *filp, const struct iovec *_iov,
-          unsigned long nr_segs, loff_t *ppos)
+pipe_read(struct kiocb *iocb, const struct iovec *_iov,
+          unsigned long nr_segs, loff_t pos)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct file *filp = iocb->ki_filp;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        struct pipe_inode_info *pipe;
        int do_wakeup;
        ssize_t ret;
@@ -178,25 +371,36 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
                if (bufs) {
                        int curbuf = pipe->curbuf;
                        struct pipe_buffer *buf = pipe->bufs + curbuf;
-                       struct pipe_buf_operations *ops = buf->ops;
+                       const struct pipe_buf_operations *ops = buf->ops;
                        void *addr;
                        size_t chars = buf->len;
-                       int error;
+                       int error, atomic;
 
                        if (chars > total_len)
                                chars = total_len;
 
-                       addr = ops->map(filp, pipe, buf);
-                       if (IS_ERR(addr)) {
+                       error = ops->confirm(pipe, buf);
+                       if (error) {
                                if (!ret)
-                                       ret = PTR_ERR(addr);
+                                       ret = error;
                                break;
                        }
-                       error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars);
-                       ops->unmap(pipe, buf);
+
+                       atomic = !iov_fault_in_pages_write(iov, chars);
+redo:
+                       addr = ops->map(pipe, buf, atomic);
+                       error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic);
+                       ops->unmap(pipe, buf, addr);
                        if (unlikely(error)) {
+                               /*
+                                * Just retry with the slow path if we failed.
+                                */
+                               if (atomic) {
+                                       atomic = 0;
+                                       goto redo;
+                               }
                                if (!ret)
-                                       ret = -EFAULT;
+                                       ret = error;
                                break;
                        }
                        ret += chars;
@@ -205,7 +409,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
                        if (!buf->len) {
                                buf->ops = NULL;
                                ops->release(pipe, buf);
-                               curbuf = (curbuf + 1) & (PIPE_BUFFERS-1);
+                               curbuf = (curbuf + 1) & (pipe->buffers - 1);
                                pipe->curbuf = curbuf;
                                pipe->nrbufs = --bufs;
                                do_wakeup = 1;
@@ -237,7 +441,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
                        break;
                }
                if (do_wakeup) {
-                       wake_up_interruptible_sync(&pipe->wait);
+                       wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM);
                        kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
                }
                pipe_wait(pipe);
@@ -246,7 +450,7 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
 
        /* Signal writers asynchronously that there is more room. */
        if (do_wakeup) {
-               wake_up_interruptible(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLOUT | POLLWRNORM);
                kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
        }
        if (ret > 0)
@@ -255,18 +459,11 @@ pipe_readv(struct file *filp, const struct iovec *_iov,
 }
 
 static ssize_t
-pipe_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
+pipe_write(struct kiocb *iocb, const struct iovec *_iov,
+           unsigned long nr_segs, loff_t ppos)
 {
-       struct iovec iov = { .iov_base = buf, .iov_len = count };
-
-       return pipe_readv(filp, &iov, 1, ppos);
-}
-
-static ssize_t
-pipe_writev(struct file *filp, const struct iovec *_iov,
-           unsigned long nr_segs, loff_t *ppos)
-{
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct file *filp = iocb->ki_filp;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        struct pipe_inode_info *pipe;
        ssize_t ret;
        int do_wakeup;
@@ -294,27 +491,34 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
        chars = total_len & (PAGE_SIZE-1); /* size of the last buffer */
        if (pipe->nrbufs && chars != 0) {
                int lastbuf = (pipe->curbuf + pipe->nrbufs - 1) &
-                                                       (PIPE_BUFFERS-1);
+                                                       (pipe->buffers - 1);
                struct pipe_buffer *buf = pipe->bufs + lastbuf;
-               struct pipe_buf_operations *ops = buf->ops;
+               const struct pipe_buf_operations *ops = buf->ops;
                int offset = buf->offset + buf->len;
 
                if (ops->can_merge && offset + chars <= PAGE_SIZE) {
+                       int error, atomic = 1;
                        void *addr;
-                       int error;
 
-                       addr = ops->map(filp, pipe, buf);
-                       if (IS_ERR(addr)) {
-                               error = PTR_ERR(addr);
+                       error = ops->confirm(pipe, buf);
+                       if (error)
                                goto out;
-                       }
+
+                       iov_fault_in_pages_read(iov, chars);
+redo1:
+                       addr = ops->map(pipe, buf, atomic);
                        error = pipe_iov_copy_from_user(offset + addr, iov,
-                                                       chars);
-                       ops->unmap(pipe, buf);
+                                                       chars, atomic);
+                       ops->unmap(pipe, buf, addr);
                        ret = error;
                        do_wakeup = 1;
-                       if (error)
+                       if (error) {
+                               if (atomic) {
+                                       atomic = 0;
+                                       goto redo1;
+                               }
                                goto out;
+                       }
                        buf->len += chars;
                        total_len -= chars;
                        ret = chars;
@@ -333,11 +537,12 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                        break;
                }
                bufs = pipe->nrbufs;
-               if (bufs < PIPE_BUFFERS) {
-                       int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1);
+               if (bufs < pipe->buffers) {
+                       int newbuf = (pipe->curbuf + bufs) & (pipe->buffers-1);
                        struct pipe_buffer *buf = pipe->bufs + newbuf;
                        struct page *page = pipe->tmp_page;
-                       int error;
+                       char *src;
+                       int error, atomic = 1;
 
                        if (!page) {
                                page = alloc_page(GFP_HIGHUSER);
@@ -357,11 +562,27 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                        if (chars > total_len)
                                chars = total_len;
 
-                       error = pipe_iov_copy_from_user(kmap(page), iov, chars);
-                       kunmap(page);
+                       iov_fault_in_pages_read(iov, chars);
+redo2:
+                       if (atomic)
+                               src = kmap_atomic(page, KM_USER0);
+                       else
+                               src = kmap(page);
+
+                       error = pipe_iov_copy_from_user(src, iov, chars,
+                                                       atomic);
+                       if (atomic)
+                               kunmap_atomic(src, KM_USER0);
+                       else
+                               kunmap(page);
+
                        if (unlikely(error)) {
+                               if (atomic) {
+                                       atomic = 0;
+                                       goto redo2;
+                               }
                                if (!ret)
-                                       ret = -EFAULT;
+                                       ret = error;
                                break;
                        }
                        ret += chars;
@@ -378,7 +599,7 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                        if (!total_len)
                                break;
                }
-               if (bufs < PIPE_BUFFERS)
+               if (bufs < pipe->buffers)
                        continue;
                if (filp->f_flags & O_NONBLOCK) {
                        if (!ret)
@@ -391,7 +612,7 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
                        break;
                }
                if (do_wakeup) {
-                       wake_up_interruptible_sync(&pipe->wait);
+                       wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
                        kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                        do_wakeup = 0;
                }
@@ -402,7 +623,7 @@ pipe_writev(struct file *filp, const struct iovec *_iov,
 out:
        mutex_unlock(&inode->i_mutex);
        if (do_wakeup) {
-               wake_up_interruptible(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLRDNORM);
                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
        }
        if (ret > 0)
@@ -411,15 +632,6 @@ out:
 }
 
 static ssize_t
-pipe_write(struct file *filp, const char __user *buf,
-          size_t count, loff_t *ppos)
-{
-       struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
-
-       return pipe_writev(filp, &iov, 1, ppos);
-}
-
-static ssize_t
 bad_pipe_r(struct file *filp, char __user *buf, size_t count, loff_t *ppos)
 {
        return -EBADF;
@@ -432,11 +644,9 @@ bad_pipe_w(struct file *filp, const char __user *buf, size_t count,
        return -EBADF;
 }
 
-static int
-pipe_ioctl(struct inode *pino, struct file *filp,
-          unsigned int cmd, unsigned long arg)
+static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        struct pipe_inode_info *pipe;
        int count, buf, nrbufs;
 
@@ -449,7 +659,7 @@ pipe_ioctl(struct inode *pino, struct file *filp,
                        nrbufs = pipe->nrbufs;
                        while (--nrbufs >= 0) {
                                count += pipe->bufs[buf].len;
-                               buf = (buf+1) & (PIPE_BUFFERS-1);
+                               buf = (buf+1) & (pipe->buffers - 1);
                        }
                        mutex_unlock(&inode->i_mutex);
 
@@ -464,7 +674,7 @@ static unsigned int
 pipe_poll(struct file *filp, poll_table *wait)
 {
        unsigned int mask;
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        struct pipe_inode_info *pipe = inode->i_pipe;
        int nrbufs;
 
@@ -480,7 +690,7 @@ pipe_poll(struct file *filp, poll_table *wait)
        }
 
        if (filp->f_mode & FMODE_WRITE) {
-               mask |= (nrbufs < PIPE_BUFFERS) ? POLLOUT | POLLWRNORM : 0;
+               mask |= (nrbufs < pipe->buffers) ? POLLOUT | POLLWRNORM : 0;
                /*
                 * Most Unices do not set POLLERR for FIFOs but on Linux they
                 * behave exactly like pipes for poll().
@@ -505,7 +715,7 @@ pipe_release(struct inode *inode, int decr, int decw)
        if (!pipe->readers && !pipe->writers) {
                free_pipe_info(inode);
        } else {
-               wake_up_interruptible(&pipe->wait);
+               wake_up_interruptible_sync_poll(&pipe->wait, POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM | POLLERR | POLLHUP);
                kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
                kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
        }
@@ -517,71 +727,59 @@ pipe_release(struct inode *inode, int decr, int decw)
 static int
 pipe_read_fasync(int fd, struct file *filp, int on)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        int retval;
 
        mutex_lock(&inode->i_mutex);
        retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_readers);
        mutex_unlock(&inode->i_mutex);
 
-       if (retval < 0)
-               return retval;
-
-       return 0;
+       return retval;
 }
 
 
 static int
 pipe_write_fasync(int fd, struct file *filp, int on)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        int retval;
 
        mutex_lock(&inode->i_mutex);
        retval = fasync_helper(fd, filp, on, &inode->i_pipe->fasync_writers);
        mutex_unlock(&inode->i_mutex);
 
-       if (retval < 0)
-               return retval;
-
-       return 0;
+       return retval;
 }
 
 
 static int
 pipe_rdwr_fasync(int fd, struct file *filp, int on)
 {
-       struct inode *inode = filp->f_dentry->d_inode;
+       struct inode *inode = filp->f_path.dentry->d_inode;
        struct pipe_inode_info *pipe = inode->i_pipe;
        int retval;
 
        mutex_lock(&inode->i_mutex);
-
        retval = fasync_helper(fd, filp, on, &pipe->fasync_readers);
-
-       if (retval >= 0)
+       if (retval >= 0) {
                retval = fasync_helper(fd, filp, on, &pipe->fasync_writers);
-
+               if (retval < 0) /* this can happen only if on == T */
+                       fasync_helper(-1, filp, 0, &pipe->fasync_readers);
+       }
        mutex_unlock(&inode->i_mutex);
-
-       if (retval < 0)
-               return retval;
-
-       return 0;
+       return retval;
 }
 
 
 static int
 pipe_read_release(struct inode *inode, struct file *filp)
 {
-       pipe_read_fasync(-1, filp, 0);
        return pipe_release(inode, 1, 0);
 }
 
 static int
 pipe_write_release(struct inode *inode, struct file *filp)
 {
-       pipe_write_fasync(-1, filp, 0);
        return pipe_release(inode, 0, 1);
 }
 
@@ -590,7 +788,6 @@ pipe_rdwr_release(struct inode *inode, struct file *filp)
 {
        int decr, decw;
 
-       pipe_rdwr_fasync(-1, filp, 0);
        decr = (filp->f_mode & FMODE_READ) != 0;
        decw = (filp->f_mode & FMODE_WRITE) != 0;
        return pipe_release(inode, decr, decw);
@@ -599,111 +796,95 @@ pipe_rdwr_release(struct inode *inode, struct file *filp)
 static int
 pipe_read_open(struct inode *inode, struct file *filp)
 {
-       /* We could have perhaps used atomic_t, but this and friends
-          below are the only places.  So it doesn't seem worthwhile.  */
+       int ret = -ENOENT;
+
        mutex_lock(&inode->i_mutex);
-       inode->i_pipe->readers++;
+
+       if (inode->i_pipe) {
+               ret = 0;
+               inode->i_pipe->readers++;
+       }
+
        mutex_unlock(&inode->i_mutex);
 
-       return 0;
+       return ret;
 }
 
 static int
 pipe_write_open(struct inode *inode, struct file *filp)
 {
+       int ret = -ENOENT;
+
        mutex_lock(&inode->i_mutex);
-       inode->i_pipe->writers++;
+
+       if (inode->i_pipe) {
+               ret = 0;
+               inode->i_pipe->writers++;
+       }
+
        mutex_unlock(&inode->i_mutex);
 
-       return 0;
+       return ret;
 }
 
 static int
 pipe_rdwr_open(struct inode *inode, struct file *filp)
 {
+       int ret = -ENOENT;
+
        mutex_lock(&inode->i_mutex);
-       if (filp->f_mode & FMODE_READ)
-               inode->i_pipe->readers++;
-       if (filp->f_mode & FMODE_WRITE)
-               inode->i_pipe->writers++;
+
+       if (inode->i_pipe) {
+               ret = 0;
+               if (filp->f_mode & FMODE_READ)
+                       inode->i_pipe->readers++;
+               if (filp->f_mode & FMODE_WRITE)
+                       inode->i_pipe->writers++;
+       }
+
        mutex_unlock(&inode->i_mutex);
 
-       return 0;
+       return ret;
 }
 
 /*
  * The file_operations structs are not static because they
  * are also used in linux/fs/fifo.c to do operations on FIFOs.
+ *
+ * Pipes reuse fifos' file_operations structs.
  */
-const struct file_operations read_fifo_fops = {
+const struct file_operations read_pipefifo_fops = {
        .llseek         = no_llseek,
-       .read           = pipe_read,
-       .readv          = pipe_readv,
+       .read           = do_sync_read,
+       .aio_read       = pipe_read,
        .write          = bad_pipe_w,
        .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
+       .unlocked_ioctl = pipe_ioctl,
        .open           = pipe_read_open,
        .release        = pipe_read_release,
        .fasync         = pipe_read_fasync,
 };
 
-const struct file_operations write_fifo_fops = {
+const struct file_operations write_pipefifo_fops = {
        .llseek         = no_llseek,
        .read           = bad_pipe_r,
-       .write          = pipe_write,
-       .writev         = pipe_writev,
+       .write          = do_sync_write,
+       .aio_write      = pipe_write,
        .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
+       .unlocked_ioctl = pipe_ioctl,
        .open           = pipe_write_open,
        .release        = pipe_write_release,
        .fasync         = pipe_write_fasync,
 };
 
-const struct file_operations rdwr_fifo_fops = {
+const struct file_operations rdwr_pipefifo_fops = {
        .llseek         = no_llseek,
-       .read           = pipe_read,
-       .readv          = pipe_readv,
-       .write          = pipe_write,
-       .writev         = pipe_writev,
+       .read           = do_sync_read,
+       .aio_read       = pipe_read,
+       .write          = do_sync_write,
+       .aio_write      = pipe_write,
        .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
-       .open           = pipe_rdwr_open,
-       .release        = pipe_rdwr_release,
-       .fasync         = pipe_rdwr_fasync,
-};
-
-static struct file_operations read_pipe_fops = {
-       .llseek         = no_llseek,
-       .read           = pipe_read,
-       .readv          = pipe_readv,
-       .write          = bad_pipe_w,
-       .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
-       .open           = pipe_read_open,
-       .release        = pipe_read_release,
-       .fasync         = pipe_read_fasync,
-};
-
-static struct file_operations write_pipe_fops = {
-       .llseek         = no_llseek,
-       .read           = bad_pipe_r,
-       .write          = pipe_write,
-       .writev         = pipe_writev,
-       .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
-       .open           = pipe_write_open,
-       .release        = pipe_write_release,
-       .fasync         = pipe_write_fasync,
-};
-
-static struct file_operations rdwr_pipe_fops = {
-       .llseek         = no_llseek,
-       .read           = pipe_read,
-       .readv          = pipe_readv,
-       .write          = pipe_write,
-       .writev         = pipe_writev,
-       .poll           = pipe_poll,
-       .ioctl          = pipe_ioctl,
+       .unlocked_ioctl = pipe_ioctl,
        .open           = pipe_rdwr_open,
        .release        = pipe_rdwr_release,
        .fasync         = pipe_rdwr_fasync,
@@ -715,25 +896,32 @@ struct pipe_inode_info * alloc_pipe_info(struct inode *inode)
 
        pipe = kzalloc(sizeof(struct pipe_inode_info), GFP_KERNEL);
        if (pipe) {
-               init_waitqueue_head(&pipe->wait);
-               pipe->r_counter = pipe->w_counter = 1;
-               pipe->inode = inode;
+               pipe->bufs = kzalloc(sizeof(struct pipe_buffer) * PIPE_DEF_BUFFERS, GFP_KERNEL);
+               if (pipe->bufs) {
+                       init_waitqueue_head(&pipe->wait);
+                       pipe->r_counter = pipe->w_counter = 1;
+                       pipe->inode = inode;
+                       pipe->buffers = PIPE_DEF_BUFFERS;
+                       return pipe;
+               }
+               kfree(pipe);
        }
 
-       return pipe;
+       return NULL;
 }
 
 void __free_pipe_info(struct pipe_inode_info *pipe)
 {
        int i;
 
-       for (i = 0; i < PIPE_BUFFERS; i++) {
+       for (i = 0; i < pipe->buffers; i++) {
                struct pipe_buffer *buf = pipe->bufs + i;
                if (buf->ops)
                        buf->ops->release(pipe, buf);
        }
        if (pipe->tmp_page)
                __free_page(pipe->tmp_page);
+       kfree(pipe->bufs);
        kfree(pipe);
 }
 
@@ -744,30 +932,37 @@ void free_pipe_info(struct inode *inode)
 }
 
 static struct vfsmount *pipe_mnt __read_mostly;
-static int pipefs_delete_dentry(struct dentry *dentry)
+
+/*
+ * pipefs_dname() is called from d_path().
+ */
+static char *pipefs_dname(struct dentry *dentry, char *buffer, int buflen)
 {
-       return 1;
+       return dynamic_dname(dentry, buffer, buflen, "pipe:[%lu]",
+                               dentry->d_inode->i_ino);
 }
 
-static struct dentry_operations pipefs_dentry_operations = {
-       .d_delete       = pipefs_delete_dentry,
+static const struct dentry_operations pipefs_dentry_operations = {
+       .d_dname        = pipefs_dname,
 };
 
 static struct inode * get_pipe_inode(void)
 {
-       struct inode *inode = new_inode(pipe_mnt->mnt_sb);
+       struct inode *inode = new_inode_pseudo(pipe_mnt->mnt_sb);
        struct pipe_inode_info *pipe;
 
        if (!inode)
                goto fail_inode;
 
+       inode->i_ino = get_next_ino();
+
        pipe = alloc_pipe_info(inode);
        if (!pipe)
                goto fail_iput;
        inode->i_pipe = pipe;
 
        pipe->readers = pipe->writers = 1;
-       inode->i_fop = &rdwr_pipe_fops;
+       inode->i_fop = &rdwr_pipefifo_fops;
 
        /*
         * Mark the inode dirty from the very beginning,
@@ -777,10 +972,9 @@ static struct inode * get_pipe_inode(void)
         */
        inode->i_state = I_DIRTY;
        inode->i_mode = S_IFIFO | S_IRUSR | S_IWUSR;
-       inode->i_uid = current->fsuid;
-       inode->i_gid = current->fsgid;
+       inode->i_uid = current_fsuid();
+       inode->i_gid = current_fsgid();
        inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
-       inode->i_blksize = PAGE_SIZE;
 
        return inode;
 
@@ -791,106 +985,293 @@ fail_inode:
        return NULL;
 }
 
-int do_pipe(int *fd)
+struct file *create_write_pipe(int flags)
 {
-       struct qstr this;
-       char name[32];
-       struct dentry *dentry;
-       struct inode * inode;
-       struct file *f1, *f2;
-       int error;
-       int i, j;
-
-       error = -ENFILE;
-       f1 = get_empty_filp();
-       if (!f1)
-               goto no_files;
-
-       f2 = get_empty_filp();
-       if (!f2)
-               goto close_f1;
+       int err;
+       struct inode *inode;
+       struct file *f;
+       struct path path;
+       struct qstr name = { .name = "" };
 
+       err = -ENFILE;
        inode = get_pipe_inode();
        if (!inode)
-               goto close_f12;
+               goto err;
+
+       err = -ENOMEM;
+       path.dentry = d_alloc_pseudo(pipe_mnt->mnt_sb, &name);
+       if (!path.dentry)
+               goto err_inode;
+       path.mnt = mntget(pipe_mnt);
+
+       d_instantiate(path.dentry, inode);
+
+       err = -ENFILE;
+       f = alloc_file(&path, FMODE_WRITE, &write_pipefifo_fops);
+       if (!f)
+               goto err_dentry;
+       f->f_mapping = inode->i_mapping;
+
+       f->f_flags = O_WRONLY | (flags & O_NONBLOCK);
+       f->f_version = 0;
+
+       return f;
 
-       error = get_unused_fd();
+ err_dentry:
+       free_pipe_info(inode);
+       path_put(&path);
+       return ERR_PTR(err);
+
+ err_inode:
+       free_pipe_info(inode);
+       iput(inode);
+ err:
+       return ERR_PTR(err);
+}
+
+void free_write_pipe(struct file *f)
+{
+       free_pipe_info(f->f_dentry->d_inode);
+       path_put(&f->f_path);
+       put_filp(f);
+}
+
+struct file *create_read_pipe(struct file *wrf, int flags)
+{
+       /* Grab pipe from the writer */
+       struct file *f = alloc_file(&wrf->f_path, FMODE_READ,
+                                   &read_pipefifo_fops);
+       if (!f)
+               return ERR_PTR(-ENFILE);
+
+       path_get(&wrf->f_path);
+       f->f_flags = O_RDONLY | (flags & O_NONBLOCK);
+
+       return f;
+}
+
+int do_pipe_flags(int *fd, int flags)
+{
+       struct file *fw, *fr;
+       int error;
+       int fdw, fdr;
+
+       if (flags & ~(O_CLOEXEC | O_NONBLOCK))
+               return -EINVAL;
+
+       fw = create_write_pipe(flags);
+       if (IS_ERR(fw))
+               return PTR_ERR(fw);
+       fr = create_read_pipe(fw, flags);
+       error = PTR_ERR(fr);
+       if (IS_ERR(fr))
+               goto err_write_pipe;
+
+       error = get_unused_fd_flags(flags);
        if (error < 0)
-               goto close_f12_inode;
-       i = error;
+               goto err_read_pipe;
+       fdr = error;
 
-       error = get_unused_fd();
+       error = get_unused_fd_flags(flags);
        if (error < 0)
-               goto close_f12_inode_i;
-       j = error;
-
-       error = -ENOMEM;
-       sprintf(name, "[%lu]", inode->i_ino);
-       this.name = name;
-       this.len = strlen(name);
-       this.hash = inode->i_ino; /* will go */
-       dentry = d_alloc(pipe_mnt->mnt_sb->s_root, &this);
-       if (!dentry)
-               goto close_f12_inode_i_j;
-
-       dentry->d_op = &pipefs_dentry_operations;
-       d_add(dentry, inode);
-       f1->f_vfsmnt = f2->f_vfsmnt = mntget(mntget(pipe_mnt));
-       f1->f_dentry = f2->f_dentry = dget(dentry);
-       f1->f_mapping = f2->f_mapping = inode->i_mapping;
-
-       /* read file */
-       f1->f_pos = f2->f_pos = 0;
-       f1->f_flags = O_RDONLY;
-       f1->f_op = &read_pipe_fops;
-       f1->f_mode = FMODE_READ;
-       f1->f_version = 0;
-
-       /* write file */
-       f2->f_flags = O_WRONLY;
-       f2->f_op = &write_pipe_fops;
-       f2->f_mode = FMODE_WRITE;
-       f2->f_version = 0;
-
-       fd_install(i, f1);
-       fd_install(j, f2);
-       fd[0] = i;
-       fd[1] = j;
+               goto err_fdr;
+       fdw = error;
+
+       audit_fd_pair(fdr, fdw);
+       fd_install(fdr, fr);
+       fd_install(fdw, fw);
+       fd[0] = fdr;
+       fd[1] = fdw;
 
        return 0;
 
-close_f12_inode_i_j:
-       put_unused_fd(j);
-close_f12_inode_i:
-       put_unused_fd(i);
-close_f12_inode:
-       free_pipe_info(inode);
-       iput(inode);
-close_f12:
-       put_filp(f2);
-close_f1:
-       put_filp(f1);
-no_files:
-       return error;   
+ err_fdr:
+       put_unused_fd(fdr);
+ err_read_pipe:
+       path_put(&fr->f_path);
+       put_filp(fr);
+ err_write_pipe:
+       free_write_pipe(fw);
+       return error;
 }
 
 /*
+ * sys_pipe() is the normal C calling standard for creating
+ * a pipe. It's not the way Unix traditionally does this, though.
+ */
+SYSCALL_DEFINE2(pipe2, int __user *, fildes, int, flags)
+{
+       int fd[2];
+       int error;
+
+       error = do_pipe_flags(fd, flags);
+       if (!error) {
+               if (copy_to_user(fildes, fd, sizeof(fd))) {
+                       sys_close(fd[0]);
+                       sys_close(fd[1]);
+                       error = -EFAULT;
+               }
+       }
+       return error;
+}
+
+SYSCALL_DEFINE1(pipe, int __user *, fildes)
+{
+       return sys_pipe2(fildes, 0);
+}
+
+/*
+ * Allocate a new array of pipe buffers and copy the info over. Returns the
+ * pipe size if successful, or return -ERROR on error.
+ */
+static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long nr_pages)
+{
+       struct pipe_buffer *bufs;
+
+       /*
+        * We can shrink the pipe, if arg >= pipe->nrbufs. Since we don't
+        * expect a lot of shrink+grow operations, just free and allocate
+        * again like we would do for growing. If the pipe currently
+        * contains more buffers than arg, then return busy.
+        */
+       if (nr_pages < pipe->nrbufs)
+               return -EBUSY;
+
+       bufs = kcalloc(nr_pages, sizeof(struct pipe_buffer), GFP_KERNEL);
+       if (unlikely(!bufs))
+               return -ENOMEM;
+
+       /*
+        * The pipe array wraps around, so just start the new one at zero
+        * and adjust the indexes.
+        */
+       if (pipe->nrbufs) {
+               unsigned int tail;
+               unsigned int head;
+
+               tail = pipe->curbuf + pipe->nrbufs;
+               if (tail < pipe->buffers)
+                       tail = 0;
+               else
+                       tail &= (pipe->buffers - 1);
+
+               head = pipe->nrbufs - tail;
+               if (head)
+                       memcpy(bufs, pipe->bufs + pipe->curbuf, head * sizeof(struct pipe_buffer));
+               if (tail)
+                       memcpy(bufs + head, pipe->bufs, tail * sizeof(struct pipe_buffer));
+       }
+
+       pipe->curbuf = 0;
+       kfree(pipe->bufs);
+       pipe->bufs = bufs;
+       pipe->buffers = nr_pages;
+       return nr_pages * PAGE_SIZE;
+}
+
+/*
+ * Currently we rely on the pipe array holding a power-of-2 number
+ * of pages.
+ */
+static inline unsigned int round_pipe_size(unsigned int size)
+{
+       unsigned long nr_pages;
+
+       nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
+       return roundup_pow_of_two(nr_pages) << PAGE_SHIFT;
+}
+
+/*
+ * This should work even if CONFIG_PROC_FS isn't set, as proc_dointvec_minmax
+ * will return an error.
+ */
+int pipe_proc_fn(struct ctl_table *table, int write, void __user *buf,
+                size_t *lenp, loff_t *ppos)
+{
+       int ret;
+
+       ret = proc_dointvec_minmax(table, write, buf, lenp, ppos);
+       if (ret < 0 || !write)
+               return ret;
+
+       pipe_max_size = round_pipe_size(pipe_max_size);
+       return ret;
+}
+
+/*
+ * After the inode slimming patch, i_pipe/i_bdev/i_cdev share the same
+ * location, so checking ->i_pipe is not enough to verify that this is a
+ * pipe.
+ */
+struct pipe_inode_info *get_pipe_info(struct file *file)
+{
+       struct inode *i = file->f_path.dentry->d_inode;
+
+       return S_ISFIFO(i->i_mode) ? i->i_pipe : NULL;
+}
+
+long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+       struct pipe_inode_info *pipe;
+       long ret;
+
+       pipe = get_pipe_info(file);
+       if (!pipe)
+               return -EBADF;
+
+       mutex_lock(&pipe->inode->i_mutex);
+
+       switch (cmd) {
+       case F_SETPIPE_SZ: {
+               unsigned int size, nr_pages;
+
+               size = round_pipe_size(arg);
+               nr_pages = size >> PAGE_SHIFT;
+
+               ret = -EINVAL;
+               if (!nr_pages)
+                       goto out;
+
+               if (!capable(CAP_SYS_RESOURCE) && size > pipe_max_size) {
+                       ret = -EPERM;
+                       goto out;
+               }
+               ret = pipe_set_size(pipe, nr_pages);
+               break;
+               }
+       case F_GETPIPE_SZ:
+               ret = pipe->buffers * PAGE_SIZE;
+               break;
+       default:
+               ret = -EINVAL;
+               break;
+       }
+
+out:
+       mutex_unlock(&pipe->inode->i_mutex);
+       return ret;
+}
+
+static const struct super_operations pipefs_ops = {
+       .destroy_inode = free_inode_nonrcu,
+};
+
+/*
  * pipefs should _never_ be mounted by userland - too much of security hassle,
  * no real gain from having the whole whorehouse mounted. So we don't need
  * any operations on the root directory. However, we need a non-trivial
  * d_name - pipe: will go nicely and kill the special-casing in procfs.
  */
-
-static struct super_block *
-pipefs_get_sb(struct file_system_type *fs_type, int flags,
-             const char *dev_name, void *data)
+static struct dentry *pipefs_mount(struct file_system_type *fs_type,
+                        int flags, const char *dev_name, void *data)
 {
-       return get_sb_pseudo(fs_type, "pipe:", NULL, PIPEFS_MAGIC);
+       return mount_pseudo(fs_type, "pipe:", &pipefs_ops,
+                       &pipefs_dentry_operations, PIPEFS_MAGIC);
 }
 
 static struct file_system_type pipe_fs_type = {
        .name           = "pipefs",
-       .get_sb         = pipefs_get_sb,
+       .mount          = pipefs_mount,
        .kill_sb        = kill_anon_super,
 };
 
@@ -910,8 +1291,8 @@ static int __init init_pipe_fs(void)
 
 static void __exit exit_pipe_fs(void)
 {
+       kern_unmount(pipe_mnt);
        unregister_filesystem(&pipe_fs_type);
-       mntput(pipe_mnt);
 }
 
 fs_initcall(init_pipe_fs);