Messages in this thread | | | Date | Tue, 13 Mar 2007 11:08:29 +1100 | From | Timothy Shimmin <> | Subject | Re: [PATCH 2/2] xfs: stop using kmalloc in xfs_buf_get_noaddr |
| |
Hi,
--On 9 March 2007 12:55:11 PM +0100 Christoph Hellwig <hch@lst.de> wrote:
> Ed Cashin found a bug in the error handling code for the case where > a page allocation fails. Here's the updated version: > > Index: linux-2.6/fs/xfs/linux-2.6/xfs_buf.c > =================================================================== > --- linux-2.6.orig/fs/xfs/linux-2.6/xfs_buf.c 2007-03-08 19:08:38.000000000 +0100 > +++ linux-2.6/fs/xfs/linux-2.6/xfs_buf.c 2007-03-09 08:59:15.000000000 +0100 .... > + for (i = 0; i < page_count; i++) { > + bp->b_pages[i] = alloc_page(GFP_KERNEL); > + if (!bp->b_pages[i]) > + goto fail_free_mem; > + } > + bp->b_flags |= _XBF_PAGES; > + > + error = _xfs_buf_map_pages(bp, XBF_MAPPED); > + if (unlikely(error)) { > + printk(KERN_WARNING "%s: failed to map pages\n", > + __FUNCTION__); > goto fail_free_mem; > - bp->b_flags |= _XBF_KMEM_ALLOC; > + } > > xfs_buf_unlock(bp); > > XB_TRACE(bp, "no_daddr", data); > return bp; > + > fail_free_mem: > - kmem_free(data, malloc_len); > + for ( ; i >= 0; i--) > + __free_page(bp->b_pages[i]); > fail_free_buf: > xfs_buf_free(bp); > fail:
It looks like you might need: for (i--; i >= 0; i--) (or: for (j = 0; j < i; j++) etc.)
Because if the initial alloc_page loop goes to completion then: i == pagecount and if alloc_page loop terminates early then bp->b_pages[i] == NULL So we have gone 1 too far in both cases and need to start free'ing back one. Unless I missed something.
--Tim
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |