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NOMMU: Fix cleanup handling in ramfs_nommu_get_umapped_area() 

Fix cleanup handling in ramfs_nommu_get_umapped_area() by only freeing the
number of pages that find_get_pages() said it had returned (nr) rather than
attempting to free the number of pages we asked for (lpages) - thus avoiding
the situation whereby put_page() may be handed NULL pointers if
find_get_pages() returned fewer pages that were requested.

Also avoid a warning about nr being uninitialised and the need for an
if-statement in the cleanup path by using appropriate gotos.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2009-01-08 12:04:46 +00:00
parent 9e42d0cf50
commit 0e8f989a25
1 changed files with 10 additions and 11 deletions
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21
fs/ramfs/file-nommu.c
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@ -262,11 +262,11 @@ unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
ret = -ENOMEM;
pages = kzalloc(lpages * sizeof(struct page *), GFP_KERNEL);
if (!pages)
goto out;
goto out_free;
nr = find_get_pages(inode->i_mapping, pgoff, lpages, pages);
if (nr != lpages)
goto out; /* leave if some pages were missing */
goto out_free_pages; /* leave if some pages were missing */
/* check the pages for physical adjacency */
ptr = pages;
@ -274,19 +274,18 @@ unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
page++;
for (loop = lpages; loop > 1; loop--)
if (*ptr++ != page++)
goto out;
goto out_free_pages;
/* okay - all conditions fulfilled */
ret = (unsigned long) page_address(pages[0]);
out:
if (pages) {
ptr = pages;
for (loop = lpages; loop > 0; loop--)
put_page(*ptr++);
kfree(pages);
}
out_free_pages:
ptr = pages;
for (loop = nr; loop > 0; loop--)
put_page(*ptr++);
out_free:
kfree(pages);
out:
return ret;
}