CHIPS: Fix potential starvation in cfi_cmdset_0001

The patch below fixes a potential starvation issue that can arise when
there is contention on a chip during a period when a process is
currently writing to it.  The starvation is avoided by conditionally
rescheduling when the chip is left in a state usable by other processes.

Signed-off-by: Josh Boyer <jdub@us.ibm.com>
Signed-off-by: Tom Gall <tom_gall@vnet.ibm.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

diff --git a/drivers/mtd/chips/cfi_cmdset_0001.c b/drivers/mtd/chips/cfi_cmdset_0001.c
index 898c321ab86de2d6a3044c4af105b40d2aebb878..e797752f7c0b7640852c0799aa8ac5824f1fed4d 100644 (file)
--- a/drivers/mtd/chips/cfi_cmdset_0001.c
+++ b/drivers/mtd/chips/cfi_cmdset_0001.c
@@ -1691,6 +1691,11 @@ static int cfi_intelext_writev (struct mtd_info *mtd, const struct kvec *vecs,
                        if (chipnum == cfi->numchips)
                                return 0;
                }
+
+               /* Be nice and reschedule with the chip in a usable state for other
+                  processes. */
+               cond_resched();
+
        } while (len);
 
        return 0;