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authorTejun Heo <htejun@gmail.com>2006-12-12 02:15:31 +0900
committerJeff Garzik <jeff@garzik.org>2006-12-16 10:13:22 -0500
commit33480a0ede8dcc7e6483054279008f972bd56fd3 (patch)
treedb0f1ad9f3e7ba78a7f12d3a2ed3dc0e7534ac67 /drivers/ata
parentc10340aca270abb141154cd93dcf1be0b92143fc (diff)
[PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2)
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>
Diffstat (limited to 'drivers/ata')
-rw-r--r--drivers/ata/libata-core.c14
1 files changed, 10 insertions, 4 deletions
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 011c0a8a2dc..0d51d13b16b 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -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;
- sg_init_one(&sg, buf, buflen);
+ 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);
}
/**