From: Dan Carpenter [mailto:error27@gmail.com]
Sent: Tuesday, August 30, 2011 3:47 PM
To: Dan Magenheimer
Cc: linux-mm@kvack.org
Subject: re: mm: frontswap: core code

Hello Dan Magenheimer,

This is a semi-automatic email to let you know that df0aade19b6a:
"mm: frontswap: core code" leads to the following Smatch complaint.

mm/frontswap.c +250 frontswap_curr_pages(7)
	 error: we previously assumed 'si' could be null (see line 252)

mm/frontswap.c
   249		spin_lock(&swap_lock);
   250		for (type = swap_list.head; type >= 0; type = si->next) {
                                                              ^^^^^^^^
Dereference.

   251			si = swap_info[type];
   252			if (si != NULL)
                            ^^^^^^^^^^
Check for NULL.

   253				totalpages += atomic_read(&si->frontswap_pages);
   254		}

These semi-automatic emails are in testing.  Let me know how they can
be improved.

regards,
dan carpenter

Thanks Dan!  On second look, the check for si against NULL is
unnecessary.  The "type >=0" guarantees that (and this idiom
for walking the list of swap devices is used elsewhere in the
swap subsystem).

Will fix it.

Dan

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