dmaengine: edma: avoid uninitialized variable use (2cc40ee7) · Commits · 戴 / test

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>

drivers/dma/edma.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -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);
		}

		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)
		{
		slot = EDMA_CHAN_SLOT(slot);
		if (slot >= ecc->num_slots)
		return;
		return -EINVAL;
		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 device *dev = echan->vchan.chan.device->dev;
		struct edmacc_param p;
		int err;

		if (!echan->edesc)
		return;

		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
		* 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
		* 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");
		echan->missed = 1;
		} else {

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