[lc-checkins] CVS: linux/mm memory.c,1.34,1.35

[Rodrigo S. de C. <rc...@us...>]

Update of /cvsroot/linuxcompressed/linux/mm
In directory usw-pr-cvs1:/tmp/cvs-serv19795/mm

Modified Files:
	memory.c 
Log Message:
Bug fixes
o Fixed race between comp_cache_use_address() and do_swap_page(). A pte
could be unsafely changed during a page fault service.



Index: memory.c
===================================================================
RCS file: /cvsroot/linuxcompressed/linux/mm/memory.c,v
retrieving revision 1.34
retrieving revision 1.35
diff -C2 -r1.34 -r1.35
*** memory.c	16 Jul 2002 18:41:55 -0000	1.34
--- memory.c	18 Jul 2002 13:32:50 -0000	1.35
***************
*** 1130,1133 ****
--- 1130,1134 ----
  	int ret = 1;
  
+ 	get_vswap(entry);
  	spin_unlock(&mm->page_table_lock);
  	page = lookup_swap_cache(entry);
***************
*** 1135,1145 ****
  		/* perform readahead only if the page is on disk */
  		if (!in_comp_cache(&swapper_space, entry.val)) {
  			swapin_readahead(entry);
  			/* major fault */
  			ret = 2;
  		}
- 		get_vswap(entry);
  		page = read_swap_cache_async(entry);
- 		put_vswap(entry);
  		if (!page) {
  			/*
--- 1136,1146 ----
  		/* perform readahead only if the page is on disk */
  		if (!in_comp_cache(&swapper_space, entry.val)) {
+ 			if (vswap_address(entry))
+ 				BUG();
  			swapin_readahead(entry);
  			/* major fault */
  			ret = 2;
  		}
  		page = read_swap_cache_async(entry);
  		if (!page) {
  			/*
***************
*** 1151,1154 ****
--- 1152,1156 ----
  			retval = pte_same(*page_table, orig_pte) ? -1 : 1;
  			spin_unlock(&mm->page_table_lock);
+ 			put_vswap(entry);
  			return retval;
  		}
***************
*** 1168,1171 ****
--- 1170,1174 ----
  		unlock_page(page);
  		page_cache_release(page);
+ 		put_vswap(entry);
  		return 1;
  	}
***************
*** 1194,1197 ****
--- 1197,1201 ----
  	update_mmu_cache(vma, address, pte);
  	spin_unlock(&mm->page_table_lock);
+ 	put_vswap(entry);
  	return ret;
  }