[RFC cr-pipe-v13][PATCH 2/3] Checkpoint open pipes

[Nathan Lynch]

On Thu, 05 Feb 2009 10:45:55 +0100
Cedric Le Goater <clg at fr.ibm.com> wrote:

> >  
> > +/* cr_write_pipebuf - dump contents of a pipe/fifo (assume i_mutex taken) */
> > +static int cr_write_pipebuf(struct cr_ctx *ctx, struct pipe_inode_info *pipe)
> > +{
> > +	struct cr_hdr h;
> > +	void *kbuf, *addr;
> > +	int i, ret = 0;
> > +
> > +	kbuf = (void *) __get_free_page(GFP_KERNEL);
> 
> this can sleep and inode->i_mutex is locked.

Generally, it is okay to perform operations that may sleep while
holding a mutex (not so with spinlocks, though).  Unless the page
allocator could try to acquire the same inode->i_mutex, this code
should be fine, no?