[PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2) (33480a0e) · Commits · 戴 / test

Calling sg_init_one() with NULL buf causes oops on certain configurations. Don't initialize sg in ata_exec_internal() if DMA_NONE and make the function complain if @buf is NULL when dma_dir isn't DMA_NONE. While at it, fix comment. The problem is discovered and initial patch was submitted by Arnd Bergmann. Signed-off-by:

Tejun Heo <htejun@gmail.com> Cc: Arnd Bergmann <arnd.bergmann@de.ibm.com> Signed-off-by:

Jeff Garzik <jeff@garzik.org>

drivers/ata/libata-core.c

+10 −4

Original line number	Diff line number	Diff line
		@@ -1332,7 +1332,7 @@ unsigned ata_exec_internal_sg(struct ata_device *dev,
		}

		/**
		* ata_exec_internal_sg - execute libata internal command
		* ata_exec_internal - execute libata internal command
		* @dev: Device to which the command is sent
		* @tf: Taskfile registers for the command and the result
		* @cdb: CDB for packet command
		@@ -1353,11 +1353,17 @@ unsigned ata_exec_internal(struct ata_device *dev,
		struct ata_taskfile tf, const u8 cdb,
		int dma_dir, void *buf, unsigned int buflen)
		{
		struct scatterlist sg;
		struct scatterlist *psg = NULL, sg;
		unsigned int n_elem = 0;

		if (dma_dir != DMA_NONE) {
		WARN_ON(!buf);
		sg_init_one(&sg, buf, buflen);
		psg = &sg;
		n_elem++;
		}

		return ata_exec_internal_sg(dev, tf, cdb, dma_dir, &sg, 1);
		return ata_exec_internal_sg(dev, tf, cdb, dma_dir, psg, n_elem);
		}

		/**

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