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dmaengine: edma: avoid uninitialized variable use

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If edma_read_slot() gets an invalid argument, it does not set a result,
as found by "gcc -Wmaybe-uninitialized"

drivers/dma/edma.c: In function 'dma_ccerr_handler':
drivers/dma/edma.c:1499:21: error: 'p.a_b_cnt' may be used uninitialized in this function [-Werror=maybe-uninitialized]
drivers/dma/edma.c:1499:21: error: 'p.ccnt' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  if (p.a_b_cnt == 0 && p.ccnt == 0) {

If we change the function to return an error in this case, we can handle
the failure more gracefully and treat this the same way as a null slot
that we already catch.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
This commit is contained in:
Arnd Bergmann 2016-09-30 18:19:01 +02:00 committed by Vinod Koul
parent 3a03ea763a
commit 2cc40ee7ae
1 changed files with 8 additions and 4 deletions
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12
drivers/dma/edma.c
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@ -464,13 +464,15 @@ static void edma_write_slot(struct edma_cc *ecc, unsigned slot,
memcpy_toio(ecc->base + PARM_OFFSET(slot), param, PARM_SIZE); memcpy_toio(ecc->base + PARM_OFFSET(slot), param, PARM_SIZE);
} }
static void edma_read_slot(struct edma_cc *ecc, unsigned slot, static int edma_read_slot(struct edma_cc *ecc, unsigned slot,
struct edmacc_param *param) struct edmacc_param *param)
{ {
slot = EDMA_CHAN_SLOT(slot); slot = EDMA_CHAN_SLOT(slot);
if (slot >= ecc->num_slots) if (slot >= ecc->num_slots)
return; return -EINVAL;
memcpy_fromio(param, ecc->base + PARM_OFFSET(slot), PARM_SIZE); memcpy_fromio(param, ecc->base + PARM_OFFSET(slot), PARM_SIZE);
return 0;
} }
/** /**
@ -1476,13 +1478,15 @@ static void edma_error_handler(struct edma_chan *echan)
struct edma_cc *ecc = echan->ecc; struct edma_cc *ecc = echan->ecc;
struct device *dev = echan->vchan.chan.device->dev; struct device *dev = echan->vchan.chan.device->dev;
struct edmacc_param p; struct edmacc_param p;
int err;
if (!echan->edesc) if (!echan->edesc)
return; return;
spin_lock(&echan->vchan.lock); spin_lock(&echan->vchan.lock);
edma_read_slot(ecc, echan->slot[0], &p); err = edma_read_slot(ecc, echan->slot[0], &p);
/* /*
* Issue later based on missed flag which will be sure * Issue later based on missed flag which will be sure
* to happen as: * to happen as:
@ -1495,7 +1499,7 @@ static void edma_error_handler(struct edma_chan *echan)
* lead to some nasty recursion when we are in a NULL * lead to some nasty recursion when we are in a NULL
* slot. So we avoid doing so and set the missed flag. * slot. So we avoid doing so and set the missed flag.
*/ */
if (p.a_b_cnt == 0 && p.ccnt == 0) { if (err || (p.a_b_cnt == 0 && p.ccnt == 0)) {
dev_dbg(dev, "Error on null slot, setting miss\n"); dev_dbg(dev, "Error on null slot, setting miss\n");
echan->missed = 1; echan->missed = 1;
} else { } else {