[PATCH]: Fill the size of pipes Instead of reporting 0 in size when stating() a pipe, we give the number of queued bytes. This might avoid using ioctl(FIONREAD) to get this information. References and derived from: http://lkml.org/lkml/2007/4/2/138 Cc: Eric Dumazet <dada1@xxxxxxxxxxxxx> Signed-off-by: Jan Engelhardt <jengelh@xxxxxx> --- fs/pipe.c | 49 ++++++++++++++++++++++++++++++++++++------------- 1 file changed, 36 insertions(+), 13 deletions(-) Index: linux-2.6.23/fs/pipe.c =================================================================== --- linux-2.6.23.orig/fs/pipe.c +++ linux-2.6.23/fs/pipe.c @@ -577,27 +577,35 @@ bad_pipe_w(struct file *filp, const char return -EBADF; } +static unsigned int pipe_size(struct inode *inode) +{ + struct pipe_inode_info *pipe; + unsigned int count, buf; + int nrbufs; + + mutex_lock(&inode->i_mutex); + pipe = inode->i_pipe; + count = 0; + buf = pipe->curbuf; + nrbufs = pipe->nrbufs; + while (--nrbufs >= 0) { + count += pipe->bufs[buf].len; + buf = (buf + 1) & (PIPE_BUFFERS - 1); + } + mutex_unlock(&inode->i_mutex); + return count; +} + static int pipe_ioctl(struct inode *pino, struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = filp->f_path.dentry->d_inode; - struct pipe_inode_info *pipe; - int count, buf, nrbufs; + unsigned int count; switch (cmd) { case FIONREAD: - mutex_lock(&inode->i_mutex); - pipe = inode->i_pipe; - count = 0; - buf = pipe->curbuf; - nrbufs = pipe->nrbufs; - while (--nrbufs >= 0) { - count += pipe->bufs[buf].len; - buf = (buf+1) & (PIPE_BUFFERS-1); - } - mutex_unlock(&inode->i_mutex); - + count = pipe_size(inode); return put_user(count, (int __user *)arg); default: return -EINVAL; @@ -915,6 +923,20 @@ static struct dentry_operations pipefs_d .d_dname = pipefs_dname, }; +int pipe_getattr(struct vfsmount *mnt, struct dentry *dentry, + struct kstat *stat) +{ + struct inode *inode = dentry->d_inode; + + generic_fillattr(inode, stat); + stat->size = pipe_size(inode); + return 0; +} + +const struct inode_operations pipe_inode_operations = { + .getattr = pipe_getattr, +}; + static struct inode * get_pipe_inode(void) { struct inode *inode = new_inode(pipe_mnt->mnt_sb); @@ -928,6 +950,7 @@ static struct inode * get_pipe_inode(voi goto fail_iput; inode->i_pipe = pipe; + inode->i_op = &pipe_inode_operations; pipe->readers = pipe->writers = 1; inode->i_fop = &rdwr_pipe_fops; - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
